Showing papers in "Food and Bioprocess Technology in 2013"

Colour Measurement and Analysis in Fresh and Processed Foods: A Review

Abstract: Colour is an important quality attribute in the food and bioprocess industries, and it influences consumer’s choice and preferences. Food colour is governed by the chemical, biochemical, microbial and physical changes which occur during growth, maturation, postharvest handling and processing. Colour measurement of food products has been used as an indirect measure of other quality attributes such as flavour and contents of pigments because it is simpler, faster and correlates well with other physicochemical properties. This review discusses the techniques and procedures for the measurement and analysis of colour in food and other biomaterial materials. It focuses on the instrumental (objective) and visual (subjective) measurements for quantifying colour attributes and highlights the range of primary and derived objective colour indices used to characterise the maturity and quality of a wide range of food products and beverages. Different approaches applied to model food colour are described, including reaction mechanisms, response surface methodology and others based on probabilistic and non-isothermal kinetics. Colour is one of the most widely measured product quality attributes in postharvest handling and in the food processing research and industry. Apart from differences in instrumentation, colour measurements are often reported based on different colour indices even for the same product, making it difficult to compare results in the literature. There is a need for standardisation to improve the traceability and transferability of measurements. The correlation between colour and other sensory quality attributes is well established, but future prospects exist in the application of objective non-destructive colour measurement in predictive modelling of the nutritional quality of fresh and processed food products.

Nanoencapsulation Techniques for Food Bioactive Components: A Review

Abstract: The protection and controlled release of bioactive compounds at the right time and the right place can be implemented by encapsulation. Nanoencapsulation remains to be the one of the most promising technologies having the feasibility to entrap bioactive compounds. Nanoencapsulation of bioactive compounds has versatile advantages for targeted site-specific delivery and efficient absorption through cells. However, researches in the application of nanotechnology in the food industry have been very limited and there are only a few review articles that explored the nanoencapsulation technology. This review focuses on the various nanoencapsulation techniques such as emulsification, coacervation, inclusion, complexation nanoprecipitation, emulsification–solvent evaporation, and supercritical fluid for food ingredients. Drying techniques such as spray drying and freeze drying for stabilization of nanoparticles are also discussed. Current state of knowledge, limitations of these techniques, and recent trends are also discussed. Finally, safety and regulatory issues in the nanoencapsulation of bioactive compounds are also highlighted.

A Review on Agri-food Supply Chain Traceability by Means of RFID Technology

Abstract: Radio Frequency Identification (RFID) is a technology which provides appealing opportunities to improve the management of information flow within the supply chain and security in the agri-food sector. Nowadays, food safety is considered a major requirement in several countries, in particular, the traceability of food products which is mandatory by law. Thus, technological implementation leading to traceability strengthening in the agri-food sector is crucial. The first aim of this review is to analyze the current developments in RFID technology in the agri-food sector, through an operative framework which organizes the literature and facilitate a quick content analysis identifying future research direction. RFID technology seems to be able to bring great opportunities to this sector; nevertheless, several constraints are slowing its adoption. This survey may provide readers with an exhaustive overview of opportunities and constraints for the wide adoption of RFID. The second aim of this review is to provide an updated analysis on the current developments of RFID technology for different product typologies within the agri-food industry, discussing at the same time its potential in technological and logistical development regarding different sectors of the production/distribution chain. As referenced here, RFID implementations in the agri-food sector are increasing at a fast rate, and technological advancement follows the applicability opportunities. However, real applications of RFID technologies are still limited because of various technical and economical obstacles which are also discussed.

Modified Atmosphere Packaging Technology of Fresh and Fresh-cut Produce and the Microbial Consequences—A Review

Abstract: Modified atmosphere packaging (MAP) technology offers the possibility to retard the respiration rate and extend the shelf life of fresh produce, and is increasingly used globally as value adding in the fresh and fresh-cut food industry. However, the outbreaks of foodborne diseases and emergence of resistant foodborne pathogens in MAP have heightened public interest on the effects of MAP technology on the survival and growth of pathogenic organisms. This paper critically reviews the effects of MAP on the microbiological safety of fresh or fresh-cut produce, including the role of innovative tools such as the use of pressurised inert/noble gases, predictive microbiology and intelligent packaging in the advancement of MAP safety. The integration of Hazard Analysis and Critical Control Points-based programs to ensure fresh food quality and microbial safety in packaging technology is highlighted.

Detection of Pesticides in Fruits by Surface-Enhanced Raman Spectroscopy Coupled with Gold Nanostructures

Abstract: There is growing concern in recent years for consumers about contamination of pesticides in fruits due to increasing use of pesticides in fruits. The objective of this study was to use surface-enhanced Raman spectroscopy (SERS) to detect and characterize pesticides extracted from fruit surfaces. Gold-coated SERS-active nanosubstrates were used for SERS measurement. Three types of pesticides (carbaryl, phosmet, and azinphos-methyl) widely used in apples and tomatoes were selected. Significantly enhanced Raman signals of pesticides were acquired by SERS from the extract of fruit samples and exhibited characteristic patterns of the analytes. Multivariate statistical methods such as partial least squares and principal component analysis were used to develop quantitative and qualitative models. SERS was able to detect all three types of pesticides extracted from fruit samples at the parts per million level. The study of detection limit demonstrated that at 99.86% confidence interval, SERS can detect carbaryl at 4.51 ppm, phosmet at 6.51 ppm, and azinphos-methyl at 6.66 ppm spiked on apples; and carbaryl at 5.35 ppm, phosmet at 2.91 ppm, and azinphos-methyl at 2.94 ppm on tomatoes. Most of these detection limits meet the maximum residue limits established by Food and Agriculture Organization of the United Nations and World Health Organization. Satisfactory recoveries (78–124%) were achieved for samples with concentrations at and larger than the detection limit. These results demonstrate that SERS coupled with novel SERS-active nanosubstrates is a rapid, sensitive, and reliable method for detection and characterization of chemical contaminants in foods.

Total Phenolics, Flavonoids, and Antioxidant Activity of Sage ( Salvia officinalis L.) Plants as Affected by Different Drying Methods

Abstract: In the current study, we determined the effects of seven drying methods on total phenolics, flavonoids, individual phenolics, and antioxidant activity of the methanol extract of Salvia officinalis L. As compared with total phenolic content (TPC) of fresh plants, results showed that the highest TPC was recorded in plants dried by microwave (MW) at a power of 800 W/30 g of fresh plant and was 4.2 times higher than that of fresh plants whereas the lowest content was found in the case of plants dried by far-infrared (FIR) at 45 °C. The analysis of the different extracts by RP-HPLC showed a predominance of phenolic acids particularly in fresh plants and those dried by MW (600 W/30 g of fresh plant) whereas flavonoids predominate in the case of plants dried by FIR (65 °C). The assessment of the radical scavenging activity (RSA) against the stable radical 1,1-diphenyl-1-picrylhydrazyl (DPPH) showed an increase in the scavenging effect particularly in MW (800 W/30 g of fresh plant) dried plants with an IC50 = 13.49 μg ml−1 (IC50 is the concentration required to cause 50 % DPPH inhibition). The complementary assessment of the RSA using the β-carotene/linoleic acid system showed an increase of this activity for all extracts and particularly for the extract derived from MW (600 W/30 g of fresh plant) dried plants as compared to fresh ones. Finally, all the plant extracts showed moderate reducing power as assessed by the ferric-reducing antioxidant potential. These results suggested that MW drying could be applied to retain phenolic contents and to enhance antioxidant activity of sage plant materials.

Effect of Oxidation on the Emulsifying Properties of Myofibrillar Proteins

Abstract: The aim of this work was to investigate the effect of chemical oxidation on the emulsifying properties of myofibrillar proteins. Myofibrillar proteins were oxidized by a hydroxyl radical generating system (Fenton reaction). Structural changes of oxidized or non-oxidized myofibrillar proteins were determined using surface hydrophobicity (H0) and Fourier transform infrared (FTIR) spectroscopy. The results suggested that H0 increased (p < 0.05) after treatment with oxidizing agent. Result from FTIR suggested that protein aggregation occurred and there was an increase in β-sheet structure accompanied by a decrease in turns, alpha helix, and random structures with the increase of oxidizing agent. Changes in zeta potential of the test emulsions suggested that protein oxidation could alter the electric charge of myofibrillar proteins. The analysis of the emulsions showed that protein oxidation had a negative effect on the emulsifying properties of myofibrillar proteins due to changes in electric charge, surface active properties, and protein molecular flexibility.

Influence of Wall Material and Inlet Drying Air Temperature on the Microencapsulation of Fish Oil by Spray Drying

Abstract: Several single and composite milk-originated wall materials were used to microencapsulate fish oil via spray drying at various inlet drying air temperatures. Skim milk powder (SMP), whey protein concentrate, whey protein isolate (WPI), 80% WPI + 20% milk protein concentrate, and 80% WPI + 20% sodium caseinate (NaCas) were applied as the wall for capsules generated at drying air temperatures of 140, 160, and 180 °C. The higher the drying air temperature, the higher was the particle size, encapsulation efficiency, and peroxide value and the lower was the moisture content and bulk density. The microcapsules prepared with SMP showed the highest encapsulation efficiency and lowest peroxide value for the oil due to the presence of lactose in its chemical composition. Differential scanning calorimetry and Fourier transform infrared analyses indicated the absence of any significant interaction between SMP and fish oil.

Hesperetin-Loaded Solid Lipid Nanoparticles and Nanostructure Lipid Carriers for Food Fortification: Preparation, Characterization, and Modeling

Abstract: Solid lipid nanoparticles and nanostructure lipid carriers were used to entrap hesperetin and broaden confined knowledge of application of nanocarriers as the functional ingredients in food sectors. The produced nanocarriers using a high mechanical shear method were subjected to size and zeta potential analysis. The developed nanosize carriers had the encapsulation efficiency ranging from 39.90 to 63.08 %. Differential scanning calorimetry, X-ray diffraction, and Fourier transform infrared spectroscopy were also employed to study thermal behavior, crystalline state, and chemical structure. The release behavior of hesperetin in simulated gastrointestinal conditions was investigated and kinetically modeled. The modeling results indicated that the release phenomenon is mostly governed by combination of Fickian and dissolution mechanisms. Stability of the nanocarriers, as analyzed for up to 30 days, at 6 and 25 °C in aqueous suspension, showed no detectable hesperetin leakage. Cryoprotectant effect of different compounds (i.e., glucose, sorbitol, glycerin, lactose, and sucrose) was also examined. Finally, the potential capability of nanocarriers for food fortification was studied using milk as a model food. The fortified milk samples were subjected to sensory analysis and results betokened that the developed nanocarriers did not show any significant difference with blank milk sample and could well mask the bitter taste, after taste, and obviate poor solubility of hesperetin.

Application of Visible and Near Infrared Hyperspectral Imaging to Differentiate Between Fresh and Frozen–Thawed Fish Fillets

Abstract: The potential of visible and near infrared (VIS/NIR) hyperspectral imaging was investigated as a rapid and nondestructive technique to determine whether fish has been frozen–thawed. A total of 108 halibut (Psetta maxima) fillets were studied, including 48 fresh and 60 frozen–thawed (F-T) samples. Regarding the F-T samples, two speeds of freezing (fast and slow) were tested. The hyperspectral images of fillets were captured using a pushbroom hyperspectral imaging system in the spectral region of 380 to 1,030 nm. All images were calibrated for reflectance, followed by the minimum noise fraction rotation to reduce the noise. A region-of-interest (ROI) at the image center was selected, and the average spectral data were generated from the ROI image. Dimension reduction was carried out on the ROI image by principal component analysis. The first three principal components (PCs) explained over 98 % of variances of all spectral bands. Gray-level co-occurrence matrix analysis was implemented on the three PC images to extract 36 textural feature variables in total. Least squares-support vector machine classification models were developed to differentiate between fresh and F-T fish based on (1) spectral variables; (2) textural variables; (3) combined spectral and textural variables, respectively. Satisfactory average correct classification rate of 97.22 % for the prediction samples based on (3) was achieved, which was superior to the results based on (1) or (2). The results turned worse when different freezing rates were taken into consideration to classify three groups of fish. The overall results indicate that VIS/NIR hyperspectral imaging technique is promising for the reliable differentiation between fresh and F-T fish.

Mechanical Continuous Oil Expression from Oilseeds: A Review

Abstract: The oil extraction by mechanical pressing is the most common method for continuous treatment of oleaginous seeds without solvent. Different types of presses can be used depending on the purpose (expeller, expander, and twin-screw extruder) and on the capacity range (3 kg h−1 to 150 t day−1). At the laboratory scale, many authors have highlighted the effect of operating parameters (screw rotation speed, temperature, and back pressure) and raw material (seed species, variety, water content, and pre-treatment) on process performance (oil yield and press capacity). For a given species, the main factors influencing the process are the pressure, temperature, and moisture content. The design of models mathematically describing the operation of continuous press allows to predict the behavior and performance of various presses.

High-Intensity Ultrasound Processing of Pineapple Juice

Abstract: The influence of ultrasound processing on the physicochemical characteristics of pineapple juice was investigated through an experimental design changing ultrasound time and intensity. After processing, the polyphenoloxidase (PPO) activity in the pineapple juice was reduced by 20% as result of the treatment with longer exposure and higher intensity (376 W/cm2 and 10 min). The effect on phenolic compounds compared to the fresh pineapple juice (non-sonicated) was not statistically significant. Ultrasound processing reduced juice viscosity by 75% of the initial value (non-sonicated juice). The higher the ultrasound intensity and the juice exposure (processing time), the higher the final temperature of the juice, reaching a maximum of 54 °C. Ultrasound processing enhanced the juice color and its stabilization along 42 days of storage compared to the non-sonicated juice. Thermal treatment at the highest temperature reached due to juice sonication (54 °C) showed no effect on PPO inactivation.

Optimization of Microwave-Assisted Extraction of Phenolic Antioxidants from Grape Seeds (Vitis vinifera)

Abstract: Grape seeds (Vitis vinifera) are rich in phytochemicals that have antioxidant properties. The influence of independent variables such as microwave power (100, 150, and 200 W), extraction time (2, 4, and 6 min), and solvent concentration (30%, 45%, and 60% ethanol) and their interactions on total phenols and the antioxidant activity (1,1-diphenyl-2-picrylhydrazyl (DPPH) and ferric ion reducing antioxidant power (FRAP)) were determined; and the microwave-assisted extraction (MAE) process was optimized using a central composite design. The total phenols that were expressed as gallic acid equivalents (GAE), catechin equivalents (CAT), and tannic acid equivalents (TAE) were significantly influenced by the solvent concentration and the time of extraction. A numerical optimization was carried out to obtain the overall conditions for MAE of phenolic antioxidants from grape seed. The response variables were maximized for 6 min of MAE of grape seed (GS) with 32.6% ethanol at 121 W with a desirability function of 0.947. The predicted extraction yields were 13 ± 0.89, 21.6 ± 1.59, and 15.9 ± 1.32 mg GAE, CAT, and TAE, respectively per gram of GS. The predicted antioxidant activity per gram of dry weight GS was 80.9% for the inhibition of DPPH and 135 μM ascorbic acid equivalents for FRAP test. The predicted response values were significantly correlated with the observed ones as follows: GAE r = 0.995, CAT r = 0.990, TAE r = 0.996, DPPH r = 0.996, and FRAP r = 0.996.

Fractionation of α-Lactalbumin and β-Lactoglobulin from Whey Protein Isolate Using Selective Thermal Aggregation, an Optimized Membrane Separation Procedure and Resolubilization Techniques at Pilot Plant Scale

Abstract: An optimized fractionation method in the pilot scale for production of isolated α-lactalbumin (α-La) and β-lactoglobulin (β-Lg) was developed. The method comprises following steps: (1) selective thermal precipitation of α-La, (2) aging of the formed particles, (3) separation of native β-Lg from the precipitate via microfiltration and ultrafiltration, (4) purification of β-Lg, (5) resolubilization of the precipitate, and (6) purification of α-La. The native status of the isolated fractions was confirmed by reversed-phase high-performance liquid chromatography (RP-HPLC), sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS-PAGE), and differential scanning calorimetry (DSC). Protein fractions with a purity of 91.3% for α-La and 97.2% for β-Lg were produced. These values were based on the native protein detectable in RP-HPLC. High overall yields for α-La between 60.7% and 80.4% and for β-Lg between 80.2% and 97.3%, depending on membrane operation parameters, were achieved. The method offers potential for pilot plant scale and possibly industrial application to produce pure native fractions of α-La and/or β-Lg.

Advances in the Design and Production of Reduced-Fat and Reduced-Cholesterol Salad Dressing and Mayonnaise: A Review

Abstract: Reducing fat and cholesterol content is currently one of the primary trends in food product innovation. Fat plays an important role in maintaining food quality, particularly the texture, flavor, and stability of food emulsion products. The food industry faces major challenges in seeking to produce reduced-fat and low-cholesterol mayonnaise and dressings that have attributes similar to full-fat products. Efficient monitoring of products to ensure desirable quality requires knowledge of their physicochemical characteristics, including appearance, rheology, emulsion stability, microstructure, and flavor, as well as particle size and charge distribution. The purpose of this paper is to provide a comprehensive overview of trends in the development of reduced-fat and low-cholesterol dressings. The effects of reducing fat content or using various fat replacers on the physicochemical properties of dressing and mayonnaise products are detailed with supporting experimental results. The possibility of using plant-based ingredients or reduced-cholesterol egg yolk in the formulation of such products is also examined.

Extraction of Polyphenols from Red Grape Pomace Assisted by Pulsed Ohmic Heating

Abstract: The present work is devoted to the investigation of the effect of pulsed ohmic heating (POH) on cells membrane damage and intensification of polyphenols extraction from red grape pomace. Untreated, POH-treated and freeze-thawed samples were compared. The effects of electric field strength (E = 100–800 V/cm) and the percentage of ethanol in water (E/W = 0–50 %) on polyphenols extraction were discussed. Measurements of electrical conductivity and electric energy consumption were performed for POH pretreatment optimization. Results show that POH treatment results in cells membrane denaturation. This permeabilization increases with the elevation of electric field strength and temperature. POH pretreatment accelerates the extraction kinetics of total polyphenols from grape pomace. Freeze-thawed samples are always accompanied with a high degree of cell damage and high concentration of polyphenols in the extract. The highest extraction yields were obtained with a POH pretreatment at 400 V/cm followed by a diffusion step for 60 min at 50 °C and with a solvent composed of 30 % of ethanol in water. In these conditions, the polyphenol content was 36 % more than untreated samples. The proposed technique (POH pretreatment) appears to be promising for future industrial applications of polyphenols extraction from pomace.

Selection of Optimal Wavelength Features for Decay Detection in Citrus Fruit Using the ROC Curve and Neural Networks

Abstract: Early automatic detection of fungal infections in post-harvest citrus fruits is especially important for the citrus industry because only a few infected fruits can spread the infection to a whole batch during operations such as storage or exportation, thus causing great economic losses. Nowadays, this detection is carried out manually by trained workers illuminating the fruit with dangerous ultraviolet lighting. The use of hyperspectral imaging systems makes it possible to advance in the development of systems capable of carrying out this detection process automatically. However, these systems present the disadvantage of generating a huge amount of data, which must be selected in order to achieve a result that is useful to the sector. This work proposes a methodology to select features in multi-class classification problems using the receiver operating characteristic curve, in order to detect rottenness in citrus fruits by means of hyperspectral images. The classifier used is a multilayer perceptron, trained with a new learning algorithm called extreme learning machine. The results are obtained using images of mandarins with the pixels labelled in five different classes: two kinds of sound skin, two kinds of decay and scars. This method yields a reduced set of features and a classification success rate of around 89%.

Effects of Pulsed Electric Field on Yield Extraction and Quality of Olive Oil

Abstract: The effect of the application of pulsed electric field (PEF) treatments of different intensities (0–2 kV/cm) on Arbequina olive paste in reference to olive oil extraction at different malaxation times (0, 15, and 30 min) and temperatures (15 and 26 °C) was investigated. The extraction yield improved by 54 % when the olive paste was treated with PEF (2 kV/cm) without malaxation. When the olive paste was malaxated at 26 °C, the application of a PEF treatment did not increase the extraction yield as compared with the control. However, at 15 °C, a PEF treatment of 2 kV/cm improved the extraction yield by 14.1 %, which corresponded with an enhancement of 1.7 kg of oil per 100 kg of olive fruits. The application of a PEF treatment could permit reduction of the malaxation temperature from 26 to 15 °C without impairing the extraction yield. Parameters legally established (acidity, peroxide value, K232, and K270) to measure the level of quality of the virgin olive oil were not affected by the PEF treatments. A sensory analysis revealed that the application of a PEF treatment did not generate any bad flavor or taste in the oil.

Using Multispectral Imaging for Spoilage Detection of Pork Meat

Abstract: The quality of stored minced pork meat was monitored using a rapid multispectral imaging device to quantify the degree of spoilage. Bacterial counts of a total of 155 meat samples stored for up to 580 h have been measured using conventional laboratory methods. Meat samples were maintained under two different storage conditions: aerobic and modified atmosphere packages as well as under different temperatures. Besides bacterial counts, a sensory panel has judged the spoilage degree of all meat samples into one of three classes. Results showed that the multispectral imaging device was able to classify 76.13 % of the meat samples correctly according to the defined sensory scale. Furthermore, the multispectral camera device was able to predict total viable counts with a standard error of prediction of 7.47 %. It is concluded that there is a good possibility that a setup like the one investigated will be successful for the detection of spoilage degree in minced pork meat.

Industry-Relevant Approaches for Minimising the Bitterness of Bioactive Compounds in Functional Foods: A Review

Abstract: Functional foods, with their synergistic health benefits that go beyond just being a source of individual nutrients, present challenges to the traditional ‘nutrition’ view of foods. Consumers demand proven health benefits without compromising flavour, taste and colour. A successful functional food must offer nutrients, specific health-promoting functionality and desirable sensory attributes. Attempts to increase the intake of desirable bioactive compounds are driven by the need to deliver optimal bioactivity to consumers for disease prevention and health enhancement. Increasing the bioactive concentration in foods often leads to bitterness, particularly when incorporating bioactive phytochemicals. This article provides an overview of the strategies which can be used for food bitterness reduction, with an emphasis on those approaches which are industrially relevant and economically feasible, i.e. tailored food formulation, processing and delivery technology approaches. Solutions for reducing bitterness from phytochemicals in food are proposed, including blocking, inhibiting, suppressing, minimising and masking mechanisms. The potential of encapsulation and non-encapsulation approaches for functional food applications is highlighted, and their effect in improving stability, bioactivity, bioaccessibility and bioavailability is addressed.

The Production, Benefits, and Applications of Monoacylglycerols and Diacylglycerols of Nutritional Interest

Abstract: In light of the increasing interest in the development of functional food, several researches have focused on the production of food grade emulsifiers of nutritional interest, especially enriched in the eicosapentaenoic (EPA) and docosahexaenoic acids (DHA). The aim of this paper is to make a review of the production of monoacylglycerols (MAG) and diacylglycerols (DAG) obtained from different feedstock, mainly fish oil. A section of this paper is dedicated to the raw materials used as feedstock for these emulsifiers production. The health benefits of these partial acylglycerols are outlined. The chemical and enzymatic methods for producing these esters of glycerol are discussed, focusing on glycerolysis reactions. Recent advances on the lipase-catalyzed production of these partial acylglycerols in alternative reaction media and systems are also reviewed.

Chemical Composition, Antioxidant Capacity, and Sensory Quality of Pomegranate ( Punica granatum L.) Arils and Rind as Affected by Drying Method

Abstract: The objective of this study was to evaluate the application of: (1) freeze drying, (2) convective drying (50, 60, or 70 °C), (3) vacuum–microwave drying (240, 360, or 480 W), and (4) a combined method of convective pre-drying and vacuum–microwave finish drying in the processing of pomegranate arils and rind. The quality parameters under study included sugars and organic acids, punicalagins and ellagic acid, total polyphenols, total antioxidant activity, and sensory quality. In general, drying led to a reduction in all studied parameters; however, the behavior of arils and rind was different. Vacuum–microwave drying at 240 or 360 W was the best drying treatment for arils, while rind required freeze drying or soft conditions of convective drying (50 °C). Further research is needed to obtain proper results with convective pre-drying and vacuum–microwave finish drying of arils and rind. With proper selection of the drying protocol, high-quality dried arils will be available for consumers; these arils will be characterized by high contents of fructose (25 g 100 g−1), phytic acid (2.2 g 100 g−1), punicalagins (0.57 mg g−1), total polyphenols (1.6 mg eq gallic acid g−1), high antioxidant capacity (0.6 mg eq Trolox g−1), and high intensities of garnet color, sweetness, sourness, and fresh pomegranate aroma. Besides, dried rind with very high contents of active compounds (123 mg g−1 of punicalagins and 108 mg eq gallic acid g−1) and high antioxidant capacity (26 mg eq Trolox g−1) will be also available as functional material.

Quality Indicators of Rice-Based Gluten-Free Bread-Like Products: Relationships Between Dough Rheology and Quality Characteristics

Abstract: The design of gluten-free bread-like products involves the study of gluten-free dough rheology and the resulting baked product characteristics, but little information has been obtained connecting dough and baked product properties. The aim of this study was to determine quality predictors of gluten-free bread-like products at dough level by defining possible correlations between dough rheological properties and both instrumental parameters and sensory characteristics of those products. Diverse rice-based gluten-free doughs were defined and rheologically characterised at dough level, and the technological and sensorial quality of the resulting baked products was investigated. Dough Mixolab® parameters, bread-like quality parameters (moisture content, specific volume, water activity, colour and crumb texture) and chemical composition significantly (P 0.70) were found when quality instrumental parameters of the baked products were correlated with the dough Mixolab® parameters, and lower correlation coefficients (r < 0.70) were found when sensory characteristics were correlated with dough rheology or instrumental parameters. Dough consistency during mixing (C1), amplitude and dough consistency after cooling (C5) would be useful predictors of crumb hardness; and C5 would be also a predictor of perceived hardness of gluten-free bread-like products.

Efficiency of Lactic Acid Bacteria Strains for Decontamination of Aflatoxin M1 in Phosphate Buffer Saline Solution and in Skimmed Milk

Abstract: The aim of this study was to evaluate the ability of seven lactic acid bacteria (LAB) strains to remove aflatoxin M1 (AFM1) in phosphate buffer saline (PBS) and in skimmed milk samples. The mean AFM1 removal by LAB in PBS ranged from 5.60 ± 0.45% to 45.67 ± 1.65% (n = 3). Heat-killed cells showed AFM1 removal percentages significantly higher than viable cells in contact times of 15 min or 24 h, although there were no significant differences between those times. AFM1/LAB complex resulted from tests with PBS was unstable, as 40.57 ± 4.66% to 87.37 ± 1.82% of AFM1 retained by bacteria were recovered in solution after washing with PBS. Heat-killed cells of Lactobacillus rhamnosus, Lactobacillus delbrueckii spp. bulgaricus, and Bifidobacterium lactis had the highest percentage (>33%) of AFM1 removal in PBS tests. In ultrahigh temperature (UHT) skimmed milk spiked with AFM1, the three selected LAB strains showed no significant differences in removing AFM1 at 37 °C, and only B. lactis had greater ability to remove AFM1 at 4 °C. Results demonstrated that AFM1 removal by LAB has a potential application to reduce toxin concentrations until safe levels in milk.

Antioxidant Bioactive Compounds in Selected Industrial Processing and Fresh Consumption Tomato Cultivars

Abstract: Four selected fresh consumption tomato varieties, harvested at different ripening stages (green, breaker, pink, red) and five industrial processing tomato varieties, harvested at red ripe stage, were analysed for lycopene and its isomers, β-carotene, total and individual phenolics, vitamin C and hydrophilic antioxidant activity. Tomato variety and ripening stage significantly affected carotenoids, total phenolic compounds and hydrophilic antioxidant activity when fresh consumption tomatoes were compared. The average of total lycopene content at the different ripening stages was 0.63, 12.20, 26.76 and 116.66 mg/kg of fresh weight (FW). Vitamin C ranged from 2.79 (breaker Cherry Pera) to 297.62 (red Cherry Pera) mg/kg FW. In green and breaker tomatoes, a positive correlation of hydrophilic antioxidant activity with vitamin C and chlorogenic acid was observed. However, in industrial tomato varieties (red ripe stage) and fresh consumption varieties harvested at pink and red stages, hydrophilic antioxidant activity was correlated with total phenolics and rutin. Tomato varieties for industrial processing did not show significant differences in total phenolic compounds and lycopene content. Lycopene ranged from 83.17 to 97.60 mg/kg FW, while total phenolic compounds varied between 257.91 and 284.13 mg/kg FW. Chlorogenic acid and rutin were the most abundant individual phenolics found in all the samples studied. Moreover, the content of total phenolics was always significantly correlated with the content of rutin. The amounts of all individual phenolics were affected by variety, with the exception of ferulic acid. Generally, these individual phenolics were more abundant in green and intermediate ripening stages, decreasing in full red tomatoes.

Application of Time Series Hyperspectral Imaging (TS-HSI) for Determining Water Distribution Within Beef and Spectral Kinetic Analysis During Dehydration

Abstract: This study was carried out for rapid and noninvasive determination of water distribution within beef during dehydration using time series hyperspectral imaging (TS-HSI). Hyperspectral images (380–1,700 nm) of beef slices were acquired at different periods of dehydration process. The spectra of beef were extracted from the TS-HSI images using image segmentation process. Principal component analysis was conducted to obtain an overview of the systematic spectral variations during dehydration. Instead of the traditional data mining strategies to cope with the large multivariate data structures in the TS-HSI images, the selection of effective wavelengths was conducted for the first time to reduce the computational burden of the TS-HSI data and predigest calibration modeling. On the basis of the effective wavelengths identified by using successive projections algorithm (SPA), three spectral calibration algorithms of partial least squares regression, least squares support vector machines, and multiple linear regression (MLR) were compared. The SPA-MLR model with Spectral Set I was considered to be the best for determining water content of beef slice. The model led to a coefficient of determination ( $$ r_V^2 $$ ) of 0.953 and root mean square error estimated by cross-validation of 1.280 %. The visualization of water distribution within beef slice during dehydration was finally generated by transferring the quantitative model to each pixel in the image to determine water content in all spots of the beef sample. Kinetic analysis of the TS-HSI images was also conducted for the first time to analyze spectral changes of beef during dehydration. The results demonstrate that TS-HSI has the potential of quantitatively visualizing water content of beef rapidly and noninvasively during dehydration in a reasonable accuracy.

Detecting Fertility and Early Embryo Development of Chicken Eggs Using Near-Infrared Hyperspectral Imaging

Abstract: Early detection of infertile and non-hatchable eggs would benefit hatcheries and poultry breeding farms by saving space, handling costs, and preventing contamination from exploder eggs. Therefore, it would be advantageous to the hatchery industry of developing a non-destructive, rapid, and accurate method to detect the fertility and embryo development of eggs. For this purpose, a near-infrared hyperspectral imaging system was developed to detect fertility and early embryo development. A total of 174 white-shell chicken eggs including 156 fertile eggs and 18 infertile eggs were used in this study and all eggs were incubated in a commercial incubator for 4 days. Hyperspectral images were captured for all eggs on each day of incubation. After imaging on each day, developing embryos in randomly selected eggs were stopped by injecting sodium azide (NaN3). All the eggs were divided into two classes, fertile eggs and non-fertile eggs (including infertile eggs and dead embryos), and the data set of each class varied with day of incubation. The region of interest (ROI) of each hyperspectral image was segmented and the image texture information was extracted from the ROI of spectral images using Gabor filters. Two types of spectral transmission characteristics termed MS and MG, were obtained by averaging the spectral information of ROI and Gabor-filtered ROI, respectively. The dimensionality of the spectral transmission characteristics were reduced by PCA. The first three PCs were used for K-means clustering, as well as the first three bands with maximum responses of each spectral transmission characteristic. The best classification results were 100 % at day 0, 78.8 % at day 1, 74.1 % at day 2, 81.8 % at day 3, and 84.1 % at day 4. A perfect detection of fertility prior to incubation was obtained using only the first three bands of maximum responses of MS. The classification results suggested the usefulness of the image texture information for detection of early embryo development. Promising results were also obtained when only the first three bands with maximum response of spectral transmission characteristics were used, which indicated the potential in applying hyperspectral imaging techniques to develop a real-time system for detecting fertility and early embryo development of chicken eggs.

Comparison of Chemical Composition, Antioxidant and Antimicrobial Activity of Lavender (Lavandula angustifolia L.) Essential Oils Extracted by Supercritical CO2, Hexane and Hydrodistillation

Abstract: The effects of three different extraction methods, namely hydrodistillation, supercritical CO2 extraction (SCE) and hexane extraction on the yield, chemical composition and antimicrobial and antioxidant activities of lavender essential oil were investigated in this study. SCE produced a yield of 6.7 % (dry weight), which was comparable to that of solvent extraction (7.6 %), but significantly higher than that of hydrodistillation (4.6 %). The chemical composition of the oils showed considerable variations among the extraction methods, with linalool, linalyl acetate, camphor and borneol making up approximately 80 % of identified components in all extracts. Hexane extraction produced oils with the presence of waxes, colour pigments and albuminious materials with semi-solid consistency, while hydrodistillation extracts showed signs of thermal degradation. The SCE extracts had an aroma with the closest resemblance to the starting material, showing negligible thermal degradation, and exhibited significantly higher antioxidant activity than the hydrodistillation and hexane extracts. Oils produced by SCE and hydrodistillation had antimicrobial activities higher than hexane extracts. The results of this study demonstrate that SCE is a promising process for the extraction of lavender essential oil.

Microencapsulation of Lactobacillus reuteri DSM 17938 Cells Coated in Alginate Beads with Chitosan by Spray Drying to Use as a Probiotic Cell in a Chocolate Soufflé

Abstract: The main objective of this work was to obtain microencapsulated probiotic cells in order to improve their resistance to heat stress and gastrointestinal conditions. A further aim was to obtain a potentially probiotic chocolate souffle. Lactobacillus reuteri DSM 17938 cells were microencapsulated by spray drying in alginate matrix and further coated with chitosan. Bacterial survival after exposure to different heat treatments and simulated gastrointestinal conditions were measured to test the microcapsules. They were also dyed by using a LIVE/DEAD®BacLight™ Bacterial Viability Kit and characterized by epifluorescence microscope observation. Furthermore, a potentially chocolate souffle was prepared using microencapsulated cells. The results indicated that alginate microcapsules did not improve acid tolerance or heat resistance in “in vitro” experiments, while they were able to protect 7% of the Lactobacillus reuteri population during the baking of a chocolate souffle, compared to a survival rate of 1% of free cells. By contrast, the cells microencapsulated with alginate coated with chitosan showed, compared to free cells, improved acid tolerance, allowing the cell population to remain constant after 3 h in simulated gastric conditions. Moreover, the heat resistance of cells in co-cross-linked microcapsules significantly improved compared to free cells, both in “in vitro” and “in food” experiments. Microencapsulation led to a survival rate of 10% after baking a chocolate souffle. However, the final level of bacterial cells in the product was too low to consider the chocolate souffle as a probiotic product.

Spray-Drying Microencapsulation of Polyphenol Bioactives: A Comparative Study Using Different Natural Fibre Polymers as Encapsulants

Abstract: This research explores the spray-drying microencapsulation of polyphenols (PPs), quercetin and vanillin, using four different fibre polymers as encapsulants (sodium alginate, methyl β-cyclodextrin (MβCD), hydroxypropylmethyl cellulose (HPMC) and inulin). The microstructure, physico-chemical properties, PP content and reconstitution properties in water of the spray-dried powders were systematically evaluated and compared. Techniques used for powder characterisation were scanning electron microscopy, N2 physisorption, Fourier transform infrared (FT-IR) spectroscopy and water activity measurements. High-performance liquid chromatography and viscosity measurements were used to characterise the solutions obtained by reconstitution of the spray-dried powders in methanol or water, respectively. Results show that the type of encapsulant strongly influenced powder morphology, powder surface area and encapsulation efficiency of PPs. Powders prepared using sodium alginate and MβCD possessed more spherical particle shape, smaller average particle size and higher specific surface area than those using HPMC or inulin as encapsulants. For each encapsulant, higher encapsulation efficiencies were achieved for vanillin (37–53 %) than quercetin (9–19 %). Encapsulation efficiencies were inulin > MβCD > HPMC > sodium alginate for vanillin-containing powders. Inulin, MβCD and sodium alginate all gave similar encapsulation efficiencies for quercetin-containing powders. All powders possessed low water activity and excellent dissolution properties in water. Therefore, spray-drying microencapsulation using natural fibre encapsulants is a feasible approach for delivering the dual health benefits of PPs and dietary fibre to consumers. Spray-drying yields a product in a convenient powder form, which can be reconstituted in water or other beverages for direct consumption or used as a functional additive in solid food systems.