Showing papers in "European Journal of Lipid Science and Technology in 2016"

Manipulation of milk fatty acid composition in lactating cows: Opportunities and challenges

Abstract: Public health policies recommend a population wide decrease in the consumption of saturated fatty acids (SFA) to lower the incidence of cardiovascular and metabolic diseases. In most developed countries, milk and dairy products are the major source of SFA in the human diet. Altering milk fat composition offers the opportunity to lower the consumption of SFA without requiring a change in eating habits. Supplementing the diet of lactating cows with oilseeds, plant oils and marine lipids can be used to replace the SFA in milk fat with monounsaturated fatty acids (MUFA), and to a lesser extent, polyunsaturated fatty acids (PUFA). Due to ruminal metabolism, the decreases in milk SFA are also accompanied by increases in trans fatty acids (TFA), including conjugated isomers. The potential to lower SFA, enrich cis MUFA and PUFA, and alter the abundance and distribution of individual TFA in milk differs according to oil source, form of lipid supplement and degree of oilseed processing, and the influence of other components in the diet. The present review summarises recent evidence on changes in milk fat composition that can be achieved using dietary lipid supplements and highlights the challenges to commercial production of modified milk and dairy products. A meta-analysis on the effects of oilseeds on milk fatty acid composition is also presented.

Extraction, benefits and valorization of olive polyphenols

Abstract: Already used as antioxidants and antimicrobials in functional foods and beverages, as well as in several cosmetic products, olive polyphenols will also play an important role in the treatment and prevention of inflammation, and thus of numerous free-radical mediated chronic diseases. By integrating chemical, health, extraction technology, and market aspects into a unified picture, this study provides arguments supporting the viewpoint that current investments into extraction plants based on green chemistry technologies will shortly translate into widespread utilization of these powerful antioxidants, well beyond the Mediterranean basin countries where the olive tree has been cultivated for >5000 years. Olive polyphenols will play a central role in the treatment and prevention of inflammation, and thus of numerous free-radical mediated chronic diseases. By integrating chemical, health, extraction technology and market aspects into a unified picture, this study provides arguments supporting the viewpoint that current investments into extraction plants based on green chemistry technologies will shortly translate into widespread utilization of these powerful antioxidants.

The feasibility of wax-based oleogel as a potential co-structurant with palm oil in low-saturated fat confectionery fillings

Abstract: In this research, food-grade oleogels (differing in concentration of bees wax in rice bran oil) were combined with palm oil at three replacement levels (17, 33, and 50%wt) to form a continuous fat phase reduced in saturated fatty acids. We explored the crystallization and gelling behavior of the wax-based palm-blend mixtures, and those of the fillings containing sugar and hazelnut particles dispersed in these wax-based palm-blend fat phases. The wax-based palm-blends were different in chemical nature (unique triacyglycerols in hazelnut oil, rice bran oil, and palm oil; fatty esters, n-alkanes, free fatty acids, and free fatty alcohols in bees wax), resulting in the formation of different crystalline morphologies when oleogels and palm oil were crystallized together. The crystallization of BW-oleogel has proven its contribution to the gelation of the hybrid mixtures during the instant cooling step. The maximum amount of palm oil being replaced by wax-based oleogels was 17%, resulting in a system having similar gel strength with the reference (100% of palm oil). The gel strength obtained from rheological measurements was explained based on the information obtained from oil binding capacity, microstructure (polarized light microscopy), and thermal studies. The dilution effect was observed and the melting enthalpy decreased with the increasing oleogel fraction. The solid fat content of the final filling products at body temperature was lower than 2.0%wt, suggesting a non-waxy mouthfeel. This research provides imperative information involved in the use of oleogels for the engineering of low saturated-fat confectionery products. Practical applications: Food grade beeswax-oleogel was used in search of a novel alternative for palm oil to limit the consumption of saturated fat content in confectionery products, especially hazelnut filling. A fundamental understanding in the rheological behavior and thermal properties of wax-based palm-blend mixtures, and of the wax-based fillings is very important to evaluate the influence of BW-oleogel on the crystallization of the continuous fat phase. The obtained data are imperative for the achievement of low-saturated fat products with a well-defined structure. These findings will be interest to the readers who are working in the area of food lipid science and technology, especially the use of food-grade fat-based alternatives in chocolate and confectionary industry. In this research, food-grade oleogels (differing in concentration of bees wax in rice bran oil) were combined with palm oil at three replacement levels (17, 33, and 50%wt) to form a continuous fat phase reduced in saturated fatty acids. We explored the crystallization and gelling behavior of the wax-based palm-blend mixtures, and those of the fillings containing sugar and hazelnut particles dispersed in these wax-based palm-blend fat phases. This research provides imperative information involved in the use of oleogels for the engineering of low saturated-fat confectionery products.

Preparation and stability of astaxanthin solid lipid nanoparticles based on stearic acid

Abstract: Astaxanthin (ASTA), a natural pigment carotenoid, is endowed with remarkable antioxidant activity in food and cosmetic products. However, the utilization of ASTA is limited due to its poor water-solubility, low bioavailability, and the decomposition under light, heat, and oxygen. In order to overcome these drawbacks, ASTA was encapsulated within solid lipid nanoparticles (SLNs). ASTA-SLNs, composed of lipid nucleation (ASTA, soybean oil, solid lipid matrix) and external water phase (Tween 20, deionized water), were prepared by high pressure homogenization (HPH). The contents of three different solid matrixes (stearic acid, glycerin monostearate, and glycerol distearates) and the preparation conditions (pressure and number of cycles) were optimized. Stearic acid (1 wt%) was selected on the basis of physico-chemical properties of ASTA-SLNs, such as mean particle size, zeta potential, and polydispersivity index (PDI). Moreover, ASTA-SLNs exhibited good long-term stability at 4 and 25°C, with no significant modification in the particle size. Comparative with the free ASTA, the chemical stability of ASTA in SLNs was significantly enhanced. Finally, the release experiments of ASTA-SLNs showed that SLNs could provide prolonged release of ASTA in simulated gastric and intestinal juices. Practical application: SLNs, a promising submicron drug delivery system, could be widely applied in food, cosmetics, drugs, and health products. In the fields of targeted delivery and controlled release of drugs, SLNs have attracted increasing attention. ASTA-SLNs can be prepared into various pharmaceutical dosage forms, such as oral tablet, intravenous infusion, and percutaneous absorption, thus achieving a long-time and stable therapeutic effect in small dosage. More importantly, based on the high pressure homogenization technology, ASTA-SLNs can be produced in large-scale. Astaxanthin solid lipid nanoparticles (ASTA-SLNs) were produced using high pressure homogenization. Internal lipid phase was prepared by adding the solid lipid matrix and ASTA into soybean oil with heating and stirring under a nitrogen atmosphere. External aqueous phase was prepared by dispersing Tween 20 (10% w/w) in deionized water. ASTA-SLNs were obtained through dispersion, high pressure homogenization, and refrigeration. The physical characteristics, stability, release behavior of ASTA-SLNs were measured.

Rapid and innovative instrumental approaches for quality and authenticity of olive oils

Abstract: The quality of virgin olive oils is assessed through the determination of several analytical parameters, whose values must be within the ranges established by the different institutions involved. In addition to official methods, there is a strong need for simple, rapid, and environmentally friendly techniques for the quality control of virgin olive oils and for addressing the challenging task of determining geographical origin and detecting adulterants. Toward this purpose, some of the most interesting applications based on optical spectroscopic techniques, on the measurement of electrical characteristics and on the use of instruments equipped with electronic chemical sensors, including also other promising techniques are herein discussed. These techniques, adequately coupled with an appropriate statistical approach, appear to be promising for assessment of several quality-related parameters. The prediction of sensory attributes and of the oxidative status of virgin olive oils have also been reviewed by adopting these selected techniques, which are also considered to be potentially appropriate solutions for identification of the geographical origin of virgin olive oils and to assess their adulteration with cheaper oils. Overall, the techniques discussed are promising and cutting-edge approaches for the establishment of useful portable instruments for in situ monitoring of the quality of virgin olive oils. Practical applications: The simple, rapid, and environmentally friendly analytical approaches discussed herein represent promising analytical tools for assuring the authenticity and monitoring the quality of virgin olive oils. Such innovative techniques and tools need to be ring-tested and validated. Some innovative reviewed approaches will permit to develop useful portable instruments able to perform in situ appropriate controls also by small laboratories or olive oil mills with limited technical facilities. These equipments will be potentially usable also by trained “non-professional analytical skilled” people. Some other approaches, rapid but more expensive, will be applicable mainly by quality control labs and will increase the number of samples analyzed per day, thus fostering laboratory proficiency and an effective fighting against olive oil fraud. Quality analysis of virgin olive oil can be achieved by a set of chemical and sensory determinations. Reference chemical analyses are usually carried out in a laboratory by trained personnel and requires high costs and lengthy times to obtain results. Innovative techniques characterized by high accuracy, short response time, and possibility of in situ analysis to evaluate olive oil quality are reviewed herein. Such techniques can be divided in different groups depending on the principle of the methodology: 1) optical techniques, such as UV-Vis, NIR, MIR, Raman, and fluorescence spectroscopy; 2) electrical techniques, such as electrical impedance spectroscopy, amperometry, and time domain reflectometry; and 3) electronic noses, electronic tongues and other promising approaches, where an array of electrodes or other technical solutions (PTR-MS, FGC E-nose, NMR) are used in conjunction with multivariate data analysis to obtain a chemical fingerprint of the product.

Physicochemical properties, volatile compounds, and oxidative stability of cold pressed kernel oils from raw and roasted pistachio (Pistacia vera L. Var Kerman)

Abstract: Pistachio kernel oil (PKO) was prepared by cold‐pressing from raw (RPKO), conventional (CRPKO), and microwave (MRPKO) roasted kernels for Kerman pistachio. Physicochemical properties, bioactive compounds, antioxidant activities, and thermal behaviors of extracted oils were determined in this study. Volatile compounds were tentatively identified and semi‐quantified by headspace solid‐phase micro‐extraction combined with gas chromatography‐mass spectrometry technique. The results showed that there was no significant difference between oil samples for some physicochemical parameters and fatty acid profiles. Roasting treatments caused an increase in total phenolics and antioxidant capacity and a decrease in levels of total tocopherols and chlorophylls. The thermal transition temperatures of the RPKO were −47.15 and −19.85°C for crystallization, and −13.11 and 3.11°C for melting. Among the 43 volatile compounds identified, the major compounds were limonene, α‐pinene, β‐myrcene, hexanoic acid, and nonanal in RPKO. The levels of these compounds decreased after roasting. However, concentrations of pyrazines, furans, and pyrroles increased significantly as a result of roasting, especially for CRPKO. Using a PV of 15 meq/kg oil as a quality criterion, PKO stored in transparent glass bottles after exposed to fluorescent light (720 Lux) and room temperature conditions had an acceptable quality for only 30 days of storage. Practical applications: Pistachios are normally consumed as salted and roasted snacks or as an ingredient in bakery and confectionery products, desserts, and ice‐creams. With the increasing consumption and demand for novel edible oils, the market is expanding and creating space for the production of the pistachio kernel oil. After analyzing the physicochemical characteristics and volatile compounds, roasting treatments may provide additional volatile compounds in the pistachio kernel oil. The research results suggest that cold‐pressed pistachio kernel oil is highly susceptible to photo‐oxidative degradation, and must be stored in containers with light‐barrier properties together with the addition of some appropriate natural antioxidants. Physicochemical properties, volatile compounds, and oxidative stability of pistachio kernel oils obtained from different treated pistachio kernels (raw, conventional, and microwave roasting) by cold pressing method were analyzed. Results indicate that pistachio kernel oil can be produced by the cold pressing technique giving edible quality, which does not require chemical refining, and only a simple filtering or centrifugation to remove suspended plant materials may be needed. Conventional or microwave roasting treatments before pressing did not change the oil specifications significantly.

Micronutrients in vegetable oils: The impact of crushing and refining processes on vitamins and antioxidants in sunflower, rapeseed, and soybean oils

Abstract: Tocopherols, phytosterols, polyphenols, and coenzymes Q are naturally present in oilseeds such as sunflower, rape, and soybean. Besides contributing to taste and color, micronutrients help protect against health disorders such as cardiovascular diseases and cancer. However, during the conventional oil manufacturing process, many minor components are lost. Given that diet is a major cause of cardiovascular diseases and cancer, it makes sense to optimize the content of micronutrients in food, and specifically in vegetable oils. These micronutrients have antioxidant properties that inhibit the oxidation of low-density lipoprotein cholesterol. This review summarizes important recent research emphasizing the impact of crushing and refining processes on the micronutrient content of different vegetable oils. After the crushing step, the total sterol content was high in crude rape, sunflower, and soybean oils, at 4358–10 569, 2212–4146, and 1735–4328 mg/kg, respectively. The tocopherol content was lower, at 464–1458, 725–1892, and 1094–2484 mg/kg, respectively, and the level of phenolics was 113–629, 10–120, and 23–148 mg/kg, respectively. The refining process destroyed micronutrients: 10–36% loss of total tocopherols, 6–52% loss of total sterols, and 93–98% loss of polyphenols. Studies have focused on improving the extraction of tocopherols by alternative heating (microwave treatment, roasting, or steaming processes). These treatments improved tocopherol content, and extraction was faster and consumed less energy. Practical applications: Some researchers later tested the ability of different alternative solvents (supercritical CO2 and pressurized solvents) to raise the concentration of micronutrients. Enzymatic extraction also offered an innovative technique to conserve micronutrients in oils. Researchers and the oil extraction industry have also tested some alternative refining processes, such as alternative neutralization, based on the use of different alkaline agents, and soft refining, which offered the possibility of micronutrient preservation and recovery. Upstream, genetic factors, cultivation conditions, and seed storage strongly influence micronutrient concentration in vegetable oils. Upstream steps in the industrial oil process were important for the nutritional quality of edible oils. This review of micronutrient evolution during oil processing highlights the impact of industrial processes, and points to methods for improved extraction of oil constituents. The micronutrient content in vegetable oils is strongly influenced by crushing and refining processes. A focus on sunflower, rapeseed and soybean oils is performed in this review.

Protein and lipid oxidation affect the viscoelasticity of whey protein layers at the oil‐water interface

Abstract: Protein and lipid oxidation are prevailing issues that negatively affect the nutritional and sensory quality of food emulsions. It is probable that such oxidative modifications affect the functional properties of proteins, and in particular their ability to form densely packed, interconnected viscoelastic films at the oil–water interface. However, these aspects have hardly been investigated. We induced controlled levels of protein and lipid oxidation using whey protein solution and sunflower oil as substrates, respectively. The adsorption kinetics, surface activity, and dilatational interfacial rheology of whey proteins at the sunflower oil–water interface were investigated using a drop tensiometer. Both protein and lipid oxidation led to a decrease in interfacial elasticity compared to the non-oxidized samples, though through different pathways: protein oxidation led to a broad range of proteinaceous species, including peptides and aggregates, which did not form an interconnected network. Lipid oxidation induced the formation of surface active compounds, which presumably formed segregated domains at the interface. Practical applications: Oxidative reactions prevent whey proteins to form strong, viscoelastic layers at the oil–water interface. This could, in turn, drastically affect their ability to stabilize food emulsions. These findings suggest that considering the initial oxidative state of ingredients should be an integral part of food emulsion formulation. Protein oxidation leads to the formation of a broad range of proteinasceous material, including peptides and aggregates. Lipid oxidation leads to the formation of surface-active compounds. Both oxidative reactions decrease the ability of whey proteins to form interconnected, elastic interfacial layers at the oil–water interface.

Antioxidant capacity is a surrogate measure of the quality and stability of vegetable oils

Abstract: Total antioxidant capacity (TAC) may be a comprehensive oil quality index because of its potential association with chemical composition, oxidative stability, and fresh oil quality. We aimed to investigate the chemical determinants of the oxidative stability and TAC of oils using multivariate statistical analyses and the use of the TAC assay as a predictor of oil stability. Fatty acids, tocols, phenolic compounds, peroxide value, acid value, induction period (by the Rancimat test) and TAC (by the TEAC assay) were determined in refined canola, corn, soybean, and sunflower oils as well as cold-pressed nut oils. Principal component analysis was used for data reduction and variable extraction. Generalized linear models successfully estimated the TAC (R2 = 90.3%, p < 0.005) and oxidative stability (R2 = 91.6%, p < 0.001) of the oils, and γ-tocopherol was the most important predictor in both of the models. The peroxide value and induction period were linearly associated with antioxidant capacity (R2 = 0.65, p < 0.01 and R2 = 0.70, p < 0.01, respectively), allowing the prediction of the initial quality and oxidative stability of the oils by the TEAC assay. Additionally, the proposed minimum TAC value for good quality refined oils was 2.2 mmol TE/kg. Practical Applications: Lipid oxidation is one of the major causes of vegetable oil degradation, affecting its global quality and limiting its shelf life. Therefore, a quality index applicable for estimating oxidative stability and initial quality of refined and cold-pressed vegetable oils might be an important tool for quality control of oils in the food industry. We show that the TEAC assay, a simple and rapid spectrophotometric assay of antioxidant capacity, may be a useful tool for the determination of the global quality of oils due to its significant associations with the induction period and peroxide value. A minimum TAC value is advisable for good quality refined plant oils, especially when the initial quality and the shelf life are of concern. Antioxidant capacity is a surrogate measure of the quality and stability of vegetable oils. 2.2 mmol trolox equivalents/kg was proposed as a minimum total antioxidant capacity value for good quality refined oils.

A widely used spectrophotometric assay to quantify olive oil biophenols according to the health claim (EU Reg. 432/2012)

Abstract: The purpose of this work was to find a simple, cheap, and suitable method, among the most widely employed, able to guarantee a proper determination and quantification of the phenolic content of extra virgin olive oils (EVOOs), in order to satisfy the requirements of the specific health claim (EU Reg. 432/2012). Total phenolic content by Folin–Ciocalteu (FC) was used and compared versus phenolic profile by HPLC-UV, considering this latter as the most sensitive and specific method for evaluating the phenolic content. Both protocols were performed before and after an acid hydrolysis of the polar phenolic fraction that involves a break of the bound forms of hydroxytyrosol (HTyr) and tyrosol (Tyr), with a simplification of the phenolic profile, and quantification of their total free forms. Results of the phenolic compounds of twelve EVOOs, determined by the different analytical approaches, were statistically compared by means of two-tailed paired t-tests: data obtained by the FC assay (expressed as HTyr) before and/or after acid hydrolysis were statistically comparable with results obtained by acid hydrolysis-HPLC (as sum of HTyr and Tyr). Practical applications: The promising results obtained in this study show that the simple and cheap colorimetric assay based on the use of the FC reagent, commonly used for the evaluation of phenolic compounds in hydro-alcoholic extracts of EVOO, can be also efficiently applied, without acid hydrolysis of extracts and HPLC analysis, to verify the compliance to the polyphenols health claim introduced by EU Reg. 432/2012. In fact, in order to preserve the positive image of EVOO due to its healthy properties, it is necessary i) to share an analytical protocol to determine the amount of hydroxytyrosol and its derivatives having a demonstrated effect of protection of blood lipids from oxidative stress ii) to check by this protocol if EVOOs satisfy the EU requirement for including the specific health claim on the oil label. The simple and cheap Folin–Ciocalteu colorimetric assay, commonly used for the evaluation of phenolic compounds in hydro-alcoholic extracts of EVOO, can also be efficiently applied to verify the compliance to the health claim introduced by EU Reg. 432/2012.

Relationship between chocolate microstructure, oil migration, and fat bloom in filled chocolates

Abstract: Fat bloom is one of the main quality problems in the chocolate industry. A bloomed chocolate product is characterized by the loss of its initial gloss and the formation of a grey-whitish haze, which makes the product unappealing from a consumer point of view. In the industry, most of the fat bloom related problems arise in filled chocolate products, like pralines and chocolate-coated biscuits. In these products oil migration is considered the main cause of fat bloom development. It leads to the dissolution of solid cocoa butter crystals in the chocolate shell which may recrystallize with the formation of undesired crystals. These give rise, upon growth, to visual fat bloom. When looking at the available literature, most of the studies elucidate the possible mechanisms of oil migration and the subsequent fat bloom formation using model systems. These model systems are sometimes too distant from the real industrial applications and the important role of the microstructure of the products is often neglected, although it plays a crucial role in migration-induced fat bloom development. The main objective of this review is to describe the relationships between chocolate microstructure, oil migration and fat bloom. Practical applications: This review can be used as a base for the development of microstructural strategies to retard oil migration and fat bloom development in filled chocolates. An important strategy to retard oil migration and migration-induced fat bloom is the creation of more dense structures. By creating denser structures, the overall mobility is reduced leading to a decrease in the rate and extent of oil migration. Also, more dense structures hinder recrystallization and Ostwald ripening, thereby delaying the migration-induced fat bloom development. As fillings are less standardized and not bound by legislation, modification of the filling composition and microstructure offers more opportunities in delaying fat bloom.

Differentiation of Greek extra virgin olive oils according to cultivar based on volatile compound analysis and fatty acid composition

Abstract: Volatile compound (VC) analysis and fatty acids (FA) composition in combination with statistical analysis [Multivariate Analysis of Variance/Linear Discriminant Analysis (MANOVA/LDA)] were used for the differentiation of extra virgin olive oils (EVOO) according to cultivar. A total of 104 olive oil samples from six Greek cultivars were collected during the harvesting period 2012–2013. Fifty-six VC were identified and semi-quantified by Head Space-Solid Phase Microextraction-Gas Chromatography/Mass Spectrometry (HS-SPME-GC/MS). FA composition was determined by Gas Chromatography-Flame Ionization Detector (GC-FID). The application of MANOVA/LDA to total VC and FA showed that 34 VC and 9 FA were significant for the differentiation of olive oil cultivar. Based on volatiles’ analysis a classification rate of 83.0% was achieved. The respective classification rate for FA analysis was 92.1% while that of the combination of VC and FA was 93%. Practical applications: This research documents that VC and FA composition could play an important role in the differentiation of cultivar origin of EVOO. Furthermore, researchers had the opportunity to study the characteristics of some less-known olive oil varieties such as Galano from Chalkidiki and Samothraki from Samothraki island. The results obtained may aid toward the labelling as “Protected Designation of Origin” (PDO) or “Protected Geographical Indication” (PGI) for EVOO from these olive cultivars. Differentiation of Greek olive oil samples according to cultivar based on instrumental analysis and chemometrics.

Aqueous enzymatic extraction and demulsification of camellia seed oil (Camellia oleifera Abel.) and the oil's physicochemical properties

Abstract: An aqueous enzymatic extraction method was developed to extract oil from camellia seed (Camellia oleifera Abel.). Individual enzymes and combinations of enzymes, pH, the ratio of material to water, reaction time and methods of demulsification were studied. The effects of hexane and aqueous enzymatic extraction on the oil's physicochemical properties (acid value, peroxide value, fatty acid profile, phenolics, and phospholipids content) were compared. The combination of protease/cellulase yielded significantly more oil than did other combinations. Under the optimal reaction conditions, a free oil yield of 82.37% was obtained. Four types of demulsification methods were compared. After demulsification with 20% ethanol (v/v), the highest total free oil yield of 91.38% was achieved. Compared with hexane-extracted oil, aqueous enzymatic-extracted oil was more acidic; had a higher percentage of monounsaturated fatty acid and contents of vitamin E and squalene; and had lower peroxide values, percentage of total saturated fatty acid, polyunsaturated acid, and content of both total phenolics and total phospholipids. Practical applications: The current work will contribute to an efficient enzymatic extraction method for camellia seed oil and help with the develop a method to demulsify the emulsion. An aqueous enzymatic extraction method was developed to extract oil from camellia seed (Camellia oleifera Abel.). Individual enzymes and combinations of enzymes, pH, the ratio of material to water, reaction time and methods of demulsification were studied. The effects of hexane and aqueous enzymatic extraction on the oil's physicochemical properties (acid value, peroxide value, fatty acid profile, phenolics, and phospholipids content) were compared. The combination of protease/cellulase yielded significantly more oil than did other combinations. Under the optimal reaction conditions, a free oil yield of 82.37% was obtained. Four types of demulsification methods were compared. After demulsification with 20% ethanol (v/v), the highest total free oil yield of 91.38% was achieved. Compared with hexane-extracted oil, aqueous enzymatic-extracted oil was more acidic; had a higher percentage of monounsaturated fatty acid and contents of vitamin E and squalene; and had lower peroxide values, percentage of total saturated fatty acid, polyunsaturated acid, and content of both total phenolics and total phospholipids.

Phytosterol oxidation products (POP) in foods with added phytosterols and estimation of their daily intake: A literature review

Abstract: To evaluate the content of phytosterol oxidation products (POP) of foods with added phytosterols, in total 14 studies measuring POP contents of foods with added phytosterols were systematically reviewed. In non-heated or stored foods, POP contents were low, ranging from (medians) 0.03–3.6 mg/100 g with corresponding oxidation rates of phytosterols (ORP) of 0.03–0.06%. In fat-based foods with 8% of added free plant sterols (FPS), plant sterol esters (PSE) or plant stanol esters (PAE) pan-fried at 160–200°C for 5–10 min, median POP contents were 72.0, 38.1, and 4.9 mg/100 g, respectively, with a median ORP of 0.90, 0.48, and 0.06%. Hence resistance to thermal oxidation was in the order of PAE > PSE > FPS. POP formation was highest in enriched butter followed by margarine and rapeseed oil. In margarines with 7.5–10.5% added PSE oven-heated at 140–200°C for 5–30 min, median POP content was 0.3 mg/100 g. Further heating under same temperature conditions but for 60–120 min markedly increased POP formation to 384.3 mg/100 g. Estimated daily upper POP intake was 47.7 mg/d (equivalent to 0.69 mg/kg BW/d) for foods with added PSE and 78.3 mg/d (equivalent to 1.12 mg/kg BW/d) for foods with added FPS as calculated by multiplying the advised upper daily phytosterol intake of 3 g/d with the 90% quantile values of ORP. In conclusion, heating temperature and time, chemical form of phytosterols added and the food matrix are determinants of POP formation in foods with added phytosterols, leading to an increase in POP contents. Practical applications: Phytosterol oxidation products (POP) are formed in foods containing phytosterols especially when exposed to heat treatment. This review summarising POP contents in foods with added phytosterols in their free and esterified forms reveals that heating temperature and time, the chemical form of phytosterols added and the food matrix itself are determinants of POP formation with heating temperature and time having the biggest impact. The estimated upper daily intakes of POP is 78.3 mg/d for fat-based products with added free plant sterols and 47.7 mg/d for fat-based products with added plant sterol esters. Phytosterols in foods are susceptible to oxidation to form phytosterol oxidation products (POP). This review summarizes literature data regarding POP contents of foods with added phytosterols that were exposed to storage and heat treatments.

Antioxidant ability of potato (Solanum tuberosum) peel extracts to inhibit soybean oil oxidation

Abstract: Potato peels are an agro industrial waste of one of the major crops worldwide. However, the potential of potato peels as source of antioxidants in the food industry is not yet sufficiently known. In this work, the antioxidant effect of potato peel extract (PPE) on oxidative stability of soybean oil was evaluated. We found that the addition of low PPE concentrations to soybean oil at four different levels, expressed as chlorogenic acid concentrations (14.01, 20.37, and 31.94 ppm), affected lipid oxidation indices (peroxide, anisidine, and conjugated dienes values), fatty acid composition, and volatile compounds. Antioxidant effect increased with increasing dose extract. Inhibition percentages of hexanal production increased with the PPE concentration. In addition, low concentrations of PPE showed higher oxidation stability than control untreated samples. Overall, our study shows that low concentrations of PPE exhibited promising antioxidant activity to be applied over a wider range of products in the food industry. Practical applications: The prevention of lipid oxidation during processing and storage of food products is of great concern in order to obtain products of high quality and health. Together with the fact that synthetic antioxidants may constitute a potential health hazard for consumers, interest in natural antioxidants and search on naturally occurring compounds with antioxidant activity has increased dramatically. The study of the antioxidant capacity of potato peel extracts to inhibit soybean oil oxidation provides information about an alternative antioxidant further are by-products of agro-industries and their use could represent a significant step toward maintaining an environmental balance. The prevention of lipid oxidation during processing and storage of food products is of great concern in order to obtain products of high quality and health. Together with the fact that synthetic antioxidants may constitute a potential health hazard for consumers, interest in natural antioxidants and search on naturally occurring compounds with antioxidant activity has increased dramatically. The study of the antioxidant capacity of potato peel extracts to inhibit soybean oil oxidation provides information about an alternative antioxidant further are by-products of agro-industries and their use could represent a significant step toward maintaining an environmental balance.

Castor oil‐based waterborne polyurethanes with tunable properties and excellent biocompatibility

Abstract: Biopolymers materials with tunable properties are the spotlight in the polymer molecules design and synthesis. Here, we synthesize a series of castor oil based‐waterborne polyurethanes (CWPUs) with highly tunable properties by adjusting the content of 2,2‐dimethylolbutanoic acid (DMBA), a hydrophilic chain extender. The size of the polyurethane dispersions (PUDs) decreases from 120 nm to 20 nm, when DMBA content increases from 5 to 9 wt%. Infrared spectrum of the corresponding CWPUs films shows that the hydrogen bonds between hard segments have an enhancement as DMBA content increases. The thermal and mechanical properties of the CWPUs films have an obvious change due to this enhanced hydrogen bond interactions and behave like soft elastomer or rigid plastic. For example, the glass transition temperature (Tg) of the CWPUs films increases from 47.8 to 92.9 °C and meanwhile the tensile strength increases from 9.6 to 20.0 MPa. In addition, the CWPUs films are enzymatically hydrolysable due to the surface hydrophilicity. Importantly, those films exhibit excellent biocompatibility to mouse fibroblast (L‐929) cells and a relative cell viability of 76% compared to tissue culture polystyrene (TCPS) plates is obtained. Practical applications: The synthesized CWPUs are versatile by change of the content of DMBA. The CWPUs can potentially replace wide range of part of petroleum‐based polymeric materials. In view of their good biodegradability and biocompatibility, the CWPUs are promising in biomedical applications. Castor oil‐based waterborne polyurethanes show highly tunable properties and excellent biocompatibility, which are promising in on‐demand biomedical applications.

Contribution of tocopherols and squalene to the oxidative stability of cold-pressed pumkin seed oil (Cucurbita pepo L.)

Abstract: Consumption of cold-pressed pumpkin seed oil (CPSO) is gaining ground due to increasing interest in natural products. The present study aimed at the examination of the contribution of two important classes of antioxidant compounds, tocopherols and squalene, in the course of autoxidation and photo-oxidation of this oil. Roasted pumpkin seed oil (RPSO) was used for comparison. During autoxidation studies, CPSOs were more vulnerable to oxidation than the RPSOs. The respective losses in α- (24–69% and 21–59%) and γ- (13–21% and 18–20%) tocopherols, and squalene (12–27% and 22–28%) contents, indicated their strong participation to oil resistance. Squalene exhibited a weak antioxidant activity at the early stages of autoxidation whereas tocopherols showed their antioxidant effect after 3 weeks of storage. After that period, the content of squalene remained stable whereas loss in tocopherol content continued. The contribution of tocopherols and squalene to the stability of CPSOs oils under light exposure was also important, higher than that reported for virgin olive oil under the same conditions. Overall, CPSO is more prone to oxidation than RPSO, a finding that is important in its packing and distribution line. Practical applications: Pumpkin seed oil comes to the market in two types. Little is known for the stability of the cold-pressed one, which does not contain the strong antioxidants formed during seed roasting. The examination of the evolution of α- and γ-tocopherols as well as squalene in the course of autoxidation and photo-oxidation of cold-pressed and roasted pumpkin seed oils is of scientific interest regarding their contribution to oil oxidation and of practical application in view of reducing loss in nutrients and other bioactive ingredients upon packing and distribution line. The present study examines the contribution of tocopherols and squalene in the course of autoxidation and photo-oxidation of cold-pressed pumpkin seed oil. The respective losses in both tocopherols and squalene contents, indicate their strong participation to oil resistance. The findings are of practical application in view of reducing loss in nutrients and other bioactive ingredients upon packing and distribution line.

High pressure homogenization of Nannochloropsis oculata for the extraction of intracellular components: Effect of process conditions and culture age

Abstract: Nannochloropsis is a genus of unicellular eukaryotes known primarily from the marine environment whose members are potential sources of lipids and long-chain polyunsaturated fatty acids; for the extraction of these and other valuable cell components, cell disruption is needed. High pressure homogenization (HPH) would be particularly suitable for microalgae with a recalcitrant cell wall such as Nannochloropsis. HPH conditions should be determined based on both the target cell component and properties of the cell suspension that in some cases are dependent on the age of the culture. The yields of soluble protein and total sugars from N. oculata ranged from 22.7 to 50.4 mg/g and from 55.0 to 62.5 mg/g, respectively, depending on HPH conditions (loading pressure and number of passes). The yield of the lipids extracted with the method of Bligh and Dyer was not affected by HPH conditions whereas lipids extracted with Soxhlet method ranged between 8.2 and 16.2%. Main fatty acids in the lipids extracted with the method of Bligh and Dyer and total lipids were palmitic acid (17.2 ± 0.1–23.0 ± 0.2%), palmitoleic acid (22.9 ± 0.3–19.1 ± 0.9%), and eicosapentaenoic acid (20.6 ± 0.3–29.2 ± 0.3%). HPH of N. oculata cells promoted a different effect on particle size distribution (PSD) depending on the age of the culture. HPH reduced cell aggregation observed in the 10 day cell suspension, whereas it promoted aggregation of the 30 day cell suspension. Practical applications: The feasibility of producing a wide range of products from microalgae is determined by the culture conditions and the conditions of the stages in the downstream processing. Because main microalgae components are intracellular, a scalable cell disruption operation such as HPH is required. Cell disruption degree is determined not only by the equipment design and its operational conditions but also by the cell suspension properties. The results allowed us to conclude that a different combination loading pressure/number of passes in HPH maximizes the recovery of hydrosoluble compounds (proteins and sugars) and lipids in N. oculata. Besides, since the PSD of the microalgae suspension is a function of culture age, this variable could affect process productivity. The effects of HPH conditions on the subsequent recovery of hydrosoluble intracellular components (protein and sugars) and the extraction of lipids accumulated by N. oculata were determined. The best combination of the operation conditions for HPH was used for the recovery of the studied components from the microalgae harvested at different periods (culture age). Particle size distribution (PSD) of the cell suspension before and after homogenization was determined to test the effect of culture age on cell disruption. Our results suggest that the conditions of HPH of N. oculata should be defined considering the component of interest.

Physicochemical quality and oxidative stability of linseed (Linum usitatissimum) and camelina (Camelina sativa) cold-pressed oils from retail outlets.

Abstract: Cold-pressed linseed and camelina oils have been available on the global market for many years. They are known for their high contents of polyunsaturated fatty acids (PUFAs), mainly α-linolenic (ALA). This study aimed to evaluate the quality and oxidative stability of linseed and camelina cold-pressed oils purchased in retail outlets in Poland. The fatty acid composition, peroxide value, acid value, anisidine value, chlorophyll pigments, carotenoid pigments, and oxidative stability of these oils were analyzed. It was found that all analyzed oils meet the standards of requirements of the Codex Alimentarius (2009) for cold-pressed oils. The content of chlorophyll and carotenoid pigments of linseed and camelina oils was significantly different. The percentage composition of PUFAs was high in both types of oils, but it was significantly higher in linseed than in camelina oils. The results of Rancimat and PDSC tests show low oxidative stability of all tested oils, although camelina oils were more stable than linseed oils. 1 Practical applications Based on the study, it can be concluded that linseed and camelina oils should be included in the human diet to provide an optimal ratio of omega-6 to omega-3 fatty acids. The differences between tested oils of the same seed species were significant. This study shows that quick methods of testing an oils oxidative stability (Rancimat and PDSC) may be successfully applied in oil studies. The study evaluates the quality of cold-pressed linseed and camelina oils purchased in retail outlets in Poland. The research shows a correlation (r = −0.673) between content of polyunsaturated fatty acids and oxidative stability of tested oils. Oxidative stability was determined by Rancimat test and fatty acid composition by GC-FID.

Continuous high power ultrasound treatment before malaxation, a laboratory scale approach: Effect on virgin olive oil quality criteria and yield

Abstract: Continuous application of high power ultrasound (HPU) on olive paste previous to malaxation at laboratory scale for virgin olive oil (VOO) extraction and its effect on process yield and the VOO quality have been studied. For the VOO samples, we determined the quality indices (free acidity value, peroxide value, K232, K270), bitterness, volatile composition, phenolic content (total and biophenols), tocopherol content, and pigments. The application of ultrasound induced a quick heating of the paste from 20 to 28°C. The sonication treatment improved the industrial oil yield by 1% and the oil extractability by 5.74%. Moreover the HPU treatment did not cause changes in the quality indices, fatty acid composition and volatile aromatic compounds of the VOO. Furthermore the fat autoxidation process was not accelerated by this treatment. Meanwhile oil obtained from olive pastes treated with HPU showed higher content of tocopherol, chlorophylls and carotenoids whereas a reduction in phenolic content and bitterness index was observed. Practical applications: The high power ultrasound (HPU) treatment of olive paste, before malaxation during the virgin olive oil (VOO) elaboration process, can improve the oil extraction yield without alteration of its quality parameters. The olive paste instantaneous heating observed with the HPU can allow the reduction of the malaxation step duration. The results obtained nowadays at laboratory scale are promising for the possibility of the continuous HPU treatment introduction in the olive oil elaboration process as aid or alternative to the malaxation. For this purpose further experiment at pilot and industrial scale are needed. Continuous application of high power ultrasound before malaxation and its effect on the oil extractability and virgin olive oil characteristics.

3‐MCPD‐ and glycidyl esters can be mitigated in vegetable oils by use of short path distillation

Abstract: Short path distillation was applied to produce edible oils low in 3-MCPD-FE and G-FE, but with comparable quality to conventionally deodorized oils. By use of the Response Surface Methology the effect of different process parameters (condenser temperature (X1), evaporator temperature (X2), stirrer speed (X3) and pump frequency (X4)) on quality parameters of the oil (content of 3-MCPD-FE/G-FE (minimal), acid value (minimal), content of vitamin-E-active compounds (sum of tocopherols and tocotrienols, maximal) and oxidation stability (maximal)) was investigated. A model was calculated for the production of refined palm oil with lowest amounts of 3-MCPD-FE/G-FE and a chemical and sensory quality comparable to oil produced by standard deodorization. For the different variables of short path distillation no 3-MCPD-FE was detected in any of the samples, while the level for G-FE ranged between the limit of detection and 0.7 mg/kg. A target conflict between the content of vitamin-E-active compounds (maximal) and acid value (minimal) was found, but in a (global) optimum of all target quality parameters (condenser temperature = 60°C, evaporator temperature = 170°C, stirrer speed = 100 rpm and pump frequency = 20 Hz) the quality of the short path distilled palm oil was comparable to conventionally refined palm oil. Slightly poorer sensory quality regarding taste and smell can be improved by a mild deodorization after short path distillation. Only the colour of the resulting oil differs from that of a conventionally refined oil, one being orange red due to the carotinoids which were not thermally decomposed. Practical Application: Mitigation of 3-MCPD-FE and G-FE is a big issue in oil processing. Especially for sensible products such as baby food the content of the esters should be as low as possible without changing the quality of the edible oil. Short path distillation is known as a gentle method used for the enrichment and purification of heat-sensitive compounds. Thus the application of short path distillation on the purification of edible oils within the refining process could be an interesting option for the production of oils low in 3-MCPD and glycidyl esters while maintaining high oil quality. Use of Response Surface Methology short path distillation followed by mild deodorization (180°C, 120 min) has been optimized to obtain edible oils low in 3-MCPD-FE and G-FE but with comparable oil quality to conventionally deodorization. Only the red colour of palm oil was not reduced by this procedure.

Preparation of 1, 3‐dioleoyl‐2‐palmitoylglycerol‐rich structured lipids from basa catfish oil: Combination of fractionation and enzymatic acidolysis

Abstract: 1,3-dioleoyl-2-palmitoylglycerol (OPO)-rich structured lipids were successfully prepared from basa catfish oil by a two-step process, namely, fractionation to enrich triacylglycerol (TAG) fractions with high content of sn-2 palmitic acid and Lipozyme RM IM-catalyzed acidolysis of the fractionated products with free fatty acids from high oleic acid sunflower oil to increase the content of OPO. In the first step, the content of sn-2 palmitic acid of solid fraction was increased from 49.34 to 60.42% after programmed temperature treatment of basa catfish oil at 60°C for 30 min followed by 30°C for 12 h. In the second step, the solid fraction was used for transesterification with the fatty acids from high oleic acid sunflower oil and the conditions selected for acidolysis reactions were as follows: substrate molar ratio, 1:6 (fatty acids/solid fat); enzyme load, 12 wt%; reaction temperature, 50°C; and reaction time, 2 h. Under these conditions, the contents of sn-2 plamitic acid and sn-1, 3 oleic acid were 57.80 and 79.21%, respectively, and the content of POO was increased from 20.13% in the basa catfish oil to 43.80% in the enzymatic product, which indicated high content of OPO. Practical applications: Basa catfish oil is a type of newly discovered oil occurring in nature with similar fatty acid composition and distribution to human milk fat. Preparation of OPO-rich structured lipids from basa catfish oil is a new method which is important for development of human milk fat substitutes. This process for OPO-rich structured lipid preparation practically developed by combination of dry fractionation and enzymatic acidolysis has great potential for use in infant formula industry. Basa catfish oil was found to have similar triacylglycerol (TAG) structure to that of human milk fat. The oil was used to produce OPO-rich structured lipids via a two-step approach. The first step is to enrich TAG fractions with palmitic acid (PA) at sn-2 position by low-temperature fractionation, and the second step is to incorporate more oleic acid (OA) in sn-1, 3 positions of triacylglycerols by Lipozyme RM IM-catalyzed acidolysis. The final product had 22.29% total PA, 58.43% PA at sn-2 position, 80.16% OA at sn-1, 3 positions, and the content of POO was 43.80%, which indicated high content of OPO.

Acyl migration in enzymatic interesterification of triacylglycerols : Effects of lipases from Thermomyces lanuginosus and Rhizopus oryzae, support material, and water activity

Abstract: The enzymatic interesterification of a solvent-free, equimolar mixture of trilaurin and 1,3-palmitin-2-olein was studied using three immobilized lipase preparations as catalysts. Analysis of triacylglycerol (TAG) content and fatty acid (FA) distribution monitored the lipase-catalyzed interesterification in sn-1,3 positions and FA exchange in the sn-2 position caused by acyl migration. Lipase from Rhizopus oryzae immobilized on polypropylene showed high sn-1,3 regioselectivity, and minimal exchange in the sn-2 position. With lipase from Thermomyces lanuginosus on silica (Lipozyme® TL IM), completely randomized FA distribution was obtained in 24 h. T. lanuginosus lipase on polypropylene caused a moderate rate of FA exchange in the sn-2 position. Thus, the T. lanuginosus lipase and silica promoted randomization of FA distribution, whereas the R. oryzae lipase and polypropylene did not. Higher water activity promoted hydrolysis and thereby increased concentrations of partial acylglycerols, but at the same time a decrease in the acyl migration rate of these intermediates was also observed. The net result was that at a certain degree of interesterification, there was no significant effect of water activity on the degree of exchange in the sn-2 position. On the other hand, a low water activity had the major advantage of giving a high yield of TAG. Practical applications: Both the type and the position of FA affect the properties of TAG. In TAG interesterification, there are thus different requirements for regiospecificity in FA exchange, depending on which product is desired. According to our results, lipase-based catalysts can be used for TAG interesterification either to achieve unchanged FA composition in sn-2 position or fast FA randomization in all positions. This helps to broaden the application of lipases in interesterification. The production of TAG can be tailor-made for lipid mixtures with particular TAG composition and FA distribution using proper lipases, support materials, water activity, and reaction time. The enzymatic LLL–POP model reaction was used to investigate effects of lipase, support material, and water activity on acyl migration. (Fig. A): effect of Lipozyme® TL IM, TLPP and ROPP at aw 0.26, (Fig. B): effect of aw between 0.15 and 0.80 using Lipozyme® TL IM as the example. (Less)

Oxidative stability, thermal decomposition, and oxidation onset prediction of carrot, flax, hemp, and canola seed oils in relation to oil composition and positional distribution of fatty acids

Abstract: Triacylglyceride positional distribution of fatty acids in flax, hemp, and canola seed oils were determined using Novozyme 435 and high performance liquid chromatography (HPLC) compared with the less convenient standard method using pancreatic lipase and thin layer chromatography (TLC). SFA were exclusively incorporated into the sn-1,3 position and PUFA were higher at the sn-2 position as expected. Thermogravimetic analysis (TGA) was used to predict onset of oxidation of carrot, flax, hemp, and canola seed oils and could replace conventional oxidation prediction methods due to its simplicity and time-saving nature. Carrot seed oil exhibited higher oxidative stability and longer oxidation onset time compared with the other three oils in the isothermal heating trials due to having the lowest polyunsaturated fatty acids (PUFA) content. Thermal decomposition was influenced by the fatty acids in the oils. Flax, hemp, and canola seed oils contained higher levels of natural antioxidants due to their extraction methods although the effect of natural antioxidants on the maximum temperature of thermal decomposition was masked because of the significant differences in their unsaturated fatty acid compositions, as temperature increased. The decomposition for carrot seed oil commenced earlier compared with the seed oils containing more antioxidants, despite having low PUFA content, once natural antioxidants had been exhausted. Practical applications: This research illustrates the advantage of using novozyme 435, HPLC, and ESI-MS for positional distribution analysis compared to the traditional method employing pancreatic lipase and thin layer chromatography followed by gas chromatographic analysis. Further, the use of thermogravimetry for determination of oxidative stability, shelf life determination and thermal decompositional analysis is illustrated. Results demonstrate influence of fatty acid type and antioxidant content on stability and positional distribution of fatty acids in the oil triglycerides. Triglyceride structure and fatty acid contents of seed oils are analyzed by HPLC, positional location and fatty acid type. These are shown to affect onset of oxidation and thermal stability profiles. Instrumental methods of thermal analysis allow for rapid analysis of shelf-life prediction.

Using a tubular heat exchanger to improve the conditioning process of the olive paste: Evaluation of yield and olive oil quality

Abstract: In this research, the evaluation of the pre-heating effect on olive paste before malaxation was performed. The olive paste was treated by means of a tubular heat exchanger. The heat exchanger performances on yield and olive oil quality were evaluated considering two different types of olive paste obtained, respectively, by means of a disc crusher and a de-pitter machine. The experimental tests were conducted on an industrial olive oil extraction plant. The results of the experimental test showed that it is possible to reduce the malaxation time by about 10 min, maintaining constant the extraction yield, when a disc crusher was used. On the other hand, using the heat exchanger to condition the de-stoned paste, a reduction of the malaxation time compared to the control test was observed, but with significant loss in extraction yield. Concerning the olive oil quality, the flash thermal treatment of the olive paste after the crushing operation improves the phenolic and volatile compound content significantly with respect to the traditional process, in which the malaxation time has a duration of at least 30 min. By employing a tubular heat exchanger we observed some advantages, like the reduction of malaxation time and the improving of phenolic and volatile compounds. Practical applications: The practical application of this research concerns the possibility of evaluating the effects inherent in the insertion of a tubular heat exchanger before the malaxer, in an industrial olive oil extraction plant. The effects were evaluated on an industrial scale olive oil extraction plant considering these quantitative parameters: extraction efficiency of the decanter and the amount of oil lost in the husk. The olive oil quality was also evaluated. The research provides useful information to the operators of the olive oil sector and to researchers in understanding the changes manifested in the extraction plant in traditional configuration and innovative configuration with the tubular heat exchanger. A tubular heat exchanger to pre-heat the olive paste in an industrial olive oil extraction plant.

Shea butter solid nanoparticles for curcumin encapsulation: Influence of nanoparticles size on drug loading

Abstract: In the present work, shea butter solid lipid nanoparticles (SLN) were prepared by sonication using nonionic surfactants as stabilizers without organic solvent. The mixture design methodology enabled to control particles size from 50 nm to more than 1 μm according to the mixture composition. Then, curcumin, a natural polyphenol, has been encapsulated in nanoparticles with a wide range of diameters (50–230 nm) and the encapsulation efficiency has been related to the particles sizes. The bigger the nanoparticles, the lower the encapsulation efficiency. The lipid structure at non dispersed state and under SLN form has been studied by differential scanning calorimetry and X‐ray diffraction. From the obtained results, encapsulated curcumin did not affect the lipid properties at the SLN state unlike at non dispersed state. The localization of the curcumin in the outer shell of the lipid nanoparticles explained the evolution of the encapsulation efficiency according to the nanoparticles size. Practical applications: Solid lipid nanoparticles (SLN) can be used for the delivery of both hydrophobic and hydrophilic drugs. Preparing such nanovectors with natural, non‐expensive materials and easily available (i.e., shea butter) will promote their potential use in several applications like oral, parenteral, dermal or ocular delivery. Controlling the particles size from the formulation composition and also the drug loading from SLN properties is of main importance to optimize the use of SLN as colloidal carrier. Mixture design of experiments methodology allowed the control of shea butter solid lipid nanoparticles size upon system composition. The influence of SLN size on the encapsulation efficiency of curcumin was studied.

An overview of recent developments in volatile compounds analysis from edible oils: Technique-oriented perspectives

Abstract: The analysis of the volatile compounds from edible oils is a tool used for the evaluation of aroma compounds, the quantitative determination of contaminants or the study of oil degradation and represents a major analytical challenge. This review deals with the recent evolution of methods for vapor phase sampling of the headspace of edible oils combined with gas chromatography. Non-selective sampling methods, such as static headspace (SHS), sampling techniques with adsorbents, including direct thermal desorption (DTD) and dynamic headspace (DHS), and high concentration capacity headspace techniques (HCC-HS), as headspace solid phase microextraction (HS-SPME) and headspace sorptive extraction (HSSE), are presented. Advantages, drawbacks, and applications to edible oils are critically discussed. HS-SPME is shown to be the most popular technique for the volatile fraction sampling of edible oils. Finally, other promising in-tube sorptive extraction techniques that are not yet applied to edible oils are also described. Practical applications: The analysis of the volatile compounds from edible oils is a major analytical challenge and is applied in many fields. An overview of different sampling techniques with a critical point of view can be useful to determine the best technique to apply in a specific context. The composition of the headspace of edible oils can provide different information related to the evaluation of aroma compounds, the quantitative determination of contaminants, or the study of oil degradation. Several techniques can be considered to respond to this challenge with different advantages and drawbacks, such as static headspace, solid phase microextraction, dynamic headspace, or headspace sorptive extraction.