Showing papers in "International Journal of Food Science and Technology in 2011"

The development of fruit‐based functional foods targeting the health and wellness market: a review

Abstract: Summary Functional foods and their health benefits beyond individual nutrients present challenges to the traditional ‘nutrition’ approach to foods. Epidemiological studies suggest that regular or increased consumption of fruits may promote general health and well-being as well as reduce the risk of chronic diseases. Therefore, a broad range of research amongst academic, industry and government institutes has been stimulated in attempts to add the goodness of fruits into popular consumer foods. This article provides a brief overview of the research opportunities in the emerging functional foods area, with an emphasis on fruit-derived products. Based on recent research in the fruit-based functional food area, a structured approach for designing and developing functional finished products is presented. Included are the technical challenges and their associated solutions during food design, formulation, processing and storage. A consumer-oriented food product development process is highlighted. Controlling the interactions among the targeted bioactives and other food components during food processing, handling and storage is the key to ensure that a stable and appealing functional food is produced. Manipulating the beneficial synergies among food ingredients, and among food formulation and processing methods, has the potential to lead to substantial food innovations.

Possibilities for the utilisation of marine by‐products

Abstract: Summary Fish industry by-products can account for up to 75% of the catch depending on postharvest or industrial preparation processes. Different terms such as ‘fish waste’, ‘by-product’ and ‘rest raw materials’ have been used. The review gives an overview of value-added processes that provide an alternative to low-profit uses such as silage, fish meal and mince. The preparation of different by-product fractions such as fish blood, marine lipids, omega-3 fatty acids, fish protein fractions and bioactive components with nutraceutical potential, i.e. antioxidants and bioactive peptides, is considered. There are several future opportunities for the preparation of high-value by-products such as enzymes, minerals and other bioactive substances including hydroxyapatite, phosphorus, taurine and creatine. Both regulatory status and future market potential need to be considered. In addition, there is a need for technologies that maintain good quality by-products and ‘simple’ processes to produce bulk products for further refining.

Salt in food processing; usage and reduction: a review

Abstract: Summary Salt is one of the most widely used additives in food industries because of its low cost and varied properties. It has a preservative and antimicrobial effect as a direct consequence of the capacity of sodium chloride to reduce water activity values. In addition, sodium chloride is a flavour enhancer as a consequence of its effect on different biochemical mechanisms. It also has flavour enhancing effects from reducing or enhancing the enzymatic activity of some enzymes responsible for the development of different organoleptic parameters. Trends in sodium chloride use in food industries point to salt replacement or reduction by means of the use of sodium chloride substitutes such as KCl or phosphates; flavour enhancers and the optimisation of the physical form of salt. This trend has arisen as a result of the greater awareness of the negative effects of excess dietary intake of sodium, which has been linked to hypertension and consequently an increased risk of cardiovascular disease. The average total daily sodium intake per individual in developed countries is 4–5 g of Na, which is up to 25 times greater than the minimum adult requirement.

Effect of extraction parameters on the carotenoid recovery from tomato waste

Abstract: Tomato waste is an important source of natural carotenoids This study was carried out to assess the extractability of tomato waste carotenoids in different organic solvents and to optimise the extraction parameters (type of solvent, extraction time, temperature and extraction steps) for maximum yield Among other solvents, we tested a new environmentally friendly one, ethyl lactate, which gave the highest carotenoid yield (24300 mg kg -1 dry tomato waste) at 70 °C, compared to acetone (5190 mg kg -1 ), ethyl acetate (4621 mg kg -1 ), hexane (3445 mg kg -1 ) and ethanol (1757 mg kg -1 ) The carotenoid recovery was significantly (P < 005) affected by the number of extraction steps and temperature in all solvents Mathematic equations predicted rather satisfactorily (R 2 = 089-093) the rate of carotenoid extraction in the above-mentioned solvents Carotenoid concentration increased with time, approaching a quasi-saturated condition at approximately 30 min of extraction

Assessment of convection, hot-air combined with microwave-vacuum and freeze-drying methods for mushrooms with regard to product quality

Abstract: Summary Combined drying of hot air and microwave-vacuum has been proposed as an alternative method to improve the quality of dried mushrooms, especially the structural and textural properties. In the present study, the effect of different drying methods namely, convective hot-air drying, hot air combined with microwave-vacuum drying and freeze-drying on qualitative attributes of pretreated mushrooms was investigated. The quality assessment was based on colour, texture, density, porosity and rehydration characteristics of the dried mushrooms. Combined drying of hot air and microwave-vacuum resulted in a dried product of superior quality when compared to the slices dried completely by conventional hot air, exhibiting lower overall colour variation, higher porosity, greater rehydration ratio and softer texture. In a dry state, mushrooms with a puffy structure and unique crispy texture were created by the combined drying method, which might be considered as important characteristics for developing nonfat snack-type food products.

Nutritional quality, sensory quality and consumer acceptability of sorghum and bread wheat biscuits fortified with defatted soy flour

Abstract: Summary Biscuits were produced by compositing sorghum or bread wheat flours with defatted soy flour Compared to the 100% cereal biscuits, sorghum-soy and bread wheat-soy 1:1 ratio composite biscuits had at least double the protein content and the lysine content increased by 500–700% For the sorghum-soy biscuits, in vitro protein digestibility increased by 170% Two such biscuits of 28 g each could provide 50% of the recommended daily protein intake for 3- to 10- year-olds Descriptive sensory evaluation revealed that sorghum-soy composite biscuits had crispy and dry texture characteristics associated with biscuits Sensory evaluation by school children showed that the composite biscuits were rated as acceptable as the cereal only biscuits, and this was maintained over 4 days of evaluation Hence, sorghum- and bread wheat-soy biscuits have considerable potential as protein-rich supplementary foods to prevent Protein Energy Malnutrition in children

Effects of drying temperature on the flavonoid, phenolic acid and antioxidative capacities of the methanol extract of citrus fruit (Citrus sinensis (L.) Osbeck) peels

Abstract: Summary There are many active functional compounds in citrus peels, such as flavonoid and phenolic acid. Scientists tried to obtain more bioactive components from citrus peels by various methods. This research investigated the effects of different drying temperatures (50, 60, 70, 80, 90 and 100 °C) on changes in the flavonoid, phenolic acid and antioxidative activities of citrus fruit (Citrus sinensis (L.) Osbeck) peels. The total phenolic and flavonoid contents of drying treated orange peels were decreased by lower drying temperature (50 and 60 °C) and increased by higher drying temperature (70, 80, 90 and 100 °C). Amounts of phenolic compounds in the 100 °C treated sample extract were significantly higher than the amounts in the samples heated at other temperatures (P < 0.05). EC50 values of orange peel extracts by DPPH radical scavenging effects and ABTS·+ scavenging effects were increased with lower drying temperature and decreased with higher drying temperature, and the values of 100 °C treated sample extract were significantly lower than the samples heated at other temperatures (P < 0.05). However, the chelating Fe2 + activities of samples showed the opposite trend.

Comparison of catechins and volatile compounds among different types of tea using high performance liquid chromatograph and gas chromatograph mass spectrometer

Abstract: Summary As tea is one of the most popular beverages consumed worldwide, it is important for customers and business investigators to develop an easy and reliable method to discriminate between different types of teas from each other. A total of eighty-seven types of various white, green, oolong, black and Puer teas were collected from the major tea estates in China, and their catechin contents and volatile compounds were compared by high performance liquid chromatograph and gas chromatograph mass spectrometer. It was found green tea contained the highest concentrations of total catechins, (−)-epicatechin gallate (ECG) and (−)-epigallocatechin gallate (EGCG), while oolong teas contained the highest concentrations of (−)-epigallocatechin (EGC) among these five types of teas. The aroma composition and their quantities in different types of teas varied quite widely. The concentration of ECG, EGCG, pentanal, hexanal, methyl jasmonate, indole, (E,E)-2,4-hexadienal and 1,2,3-trimethoxybenzene was shown to be different and could be used to discriminate white, green, oolong, black and Puer teas. The result showed that different types of teas could be partially classified by cluster analysis using index of individual catechins and volatile components.

Flaxseed proteins: food uses and health benefits

Abstract: Summary Flaxseed proteins are potent multi-functional ingredients for food formulation owing to their techno-functionalities, food preservation capacity, and health benefits. A possible synergistic effect with mucilage on their functionalities could be valuable even though this co-product in flaxseed may limit the protein yield during their production processes. Their techno-functional properties could also be considered in mixture with other flax bioactive components such as lignans and fibre to enhance the value of the flaxseed meal. The present paper reviews flaxseed protein uses in food and their health benefits. New perspectives according to consumers’ demand for products with health promoting bioactive components are also suggested.

Effect of nano‐ZnO‐coated active packaging on quality of fresh‐cut ‘Fuji’ apple

Abstract: Summary A novel nanopackaging was synthesised by coating polyvinyl chloride (PVC) film with nano-ZnO powder, and its effects on the preservation quality of fresh-cut ‘Fuji’ apple were investigated at 4 °C for 12 days. Compared with the control (PVC film), nanopackaging significantly reduced the fruit decay rate (P < 0.05), as well as decreased the accumulation of malondialdehyde (MDA) from 74.9 nmol g−1 in the control to 53.9 nmol g−1 in the nanopackaging. Cutting caused an increase in ethylene level, suggesting wound-induced ethylene production, which was suppressed in nanopackaging. Both the polyphenoloxidase and pyrogallol peroxidase activities were decreased in nanopackaging fruit. The initial appearance of apple slices was retained, and the browning index was prevented in nanopackaging samples, which was only 23.9, much lower than the control of 31.7 on day 12. These results indicated that nano-ZnO active packaging could be a viable alternative to common technologies for improving the shelf-life properties of ‘Fuji’ apples as a fresh-cut product.

Effects of roasting degree on radical scavenging activity, phenolics and volatile compounds of Arabica coffee beans (Coffea arabica L. cv. Catimor)

Abstract: Summary We investigated the effect of roasting degree on volatile and phenolic compounds of coffee beans (Coffea Arabica L. cv. Catimor). The colour, 1,1-diphenyl-2-picrylhydrazyl radical-scavenging activity and phenolic acids of the aqueous extracts were studied. For the colour, L and b values were increased with an increase in roasting degree. Increasing roasting degrees led to a decrease in radical-scavenging activity. Maximum radical-scavenging activity was observed for the light-roasted coffee. Chlorogenic acid was the most predominant amongst the ten phenolic acids identified, in green and all roasted beans. Syringic acid, p-coumaric acid, gallic acid and sinapic acid increased with an increase in roasting degree. The volatile compounds were analysed using gas chromatography and mass spectroscopy. Aldehyde was the major volatile compound in green coffee. Our study has demonstrated that light-roasted coffee gave the most desirable quality of roasted coffee with respect to phenolic content and radical-scavenging activities.

Enzymatic hydrolysis of soy proteins and the hydrolysates utilisation

Abstract: Summary Soy proteins are very important protein source for human being and livestock. Enzymatic hydrolysis of soy protein can enhance or reduce its functional properties and improve its nutritious value. Soy protein hydrolysates were primarily used as functional food ingredients, flavour and nutritious enhancers, protein substitute, and clinical products. Conditions for hydrolysis were usually mild, whereas recently high pressure treatment attracted more interest. Degree of hydrolysis (DH) was usually between 1% and 39.5%. The main problem associated with proteolytic hydrolysis of soy protein was production of bitter taste, hydrolysates coagulation and high cost of enzymes. Bitterness reduction can be achieved by control of DH, selective separation of bitter peptides from hydrolysates, treatment of hydrolysates with exo-peptidases, addition of various components [adenosine monophosphate (AMP), some amino acids, monosodium glutamate (MSG), etc.] to block or mask the bitter taste, and modification of taste signalling. Hydrolysates coagulation can be resolved by selecting appropriate enzymes and by applying immobilisation technology the production cost can be reduced. Enzymatic hydrolysis also enhances bioactivity of soy proteins through conversion of glycosides to aglycones, increasing antioxidant and immunoregulatory properties. Finally, future works have been discussed.

Essential oil composition and antibacterial activity of the grapefruit (Citrus Paradisi. L) peel essential oils obtained by solvent-free microwave extraction: comparison with hydrodistillation

Abstract: Summary The chemical composition of the essential oil (EO) obtained by solvent-free microwave extraction (SFME) and hydrodistillation (HD) from the peel of grapefruit (Citrus Paradisi. L) was analysed by gas chromatography/mass spectrometry (GC/MS). Totally, twenty-five components were identified in the EO. Limonene was observed as dominant (91.5–88.6%) for two extraction methods, SFME and HD, respectively. β-Pinene (0.8–1.2%), linalool (1.1–0.7%), α-terpinene (0.7–1.0%) and the other minor components were also detected. Disc diffusion method was applied to determine the antibacterial properties of the EO. The results showed that the EO of grapefruit peel had a wide spectrum of antimicrobial activities against Staphylococcus aureus, Enterococcus faecalis, Staphylococcus epidermidis, Escherichia coli, Salmonella typhimurium, Serratia marcescens and Proteus vulgaris, with their inhibition zones ranging from 11 to 53 mm.

The effects of rosemary extract combination with vacuum packing on the quality changes of Atlantic mackerel fish burgers

Abstract: Summary The effects of the use of antioxidant technology on the quality of mackerel burgers stored at 4 °C were investigated in terms of sensory, biochemical [thiobarbituric acid (TBA), total volatile basic nitrogen (TVB-N), peroxide value (PV) and free fatty acids (FFA)] and microbiological analyses [total viable count (TVC)]. Fish meat was divided into three groups; the control (C) without rosemary extract, the second group with 0.4% rosemary extracts (Group A) and the third with 0.8% rosemary extracts (Group B). Results showed that the TVB-N level did not exceed acceptability limit (30–35 mg 100 g−1) for all groups. TBA value for the control significantly increased from 1.47 to 4.80 MA kg−1 whereas it slightly increased in treatment groups as the storage time increased. Significantly higher PV and FFA (P < 0.05) were obtained from the control group. Rosemary extract, in combination with vacuum pack was effective in controlling the growth of bacteria and biochemical indices.

Review on the main differences between organic and conventional plant‐based foods

Abstract: Summary The present review reports on the main characteristics and properties of plants cultivated following organic and conventional procedures, in the attempt to clarify give a deeper insight into some possible differences and to compare the two cultivation procedures. Here, we summarise research results regarding nutritional and safety properties of vegetable foods, evidencing qualitative differences observed between the two cultivation methods. It appears that the intake of organic foods leads to some advantages, such as the ingestion of a higher content of phenolic compounds and some vitamins, such as vitamin C, and a lower content of nitrates and pesticides. From literature, it appears that a special care should be taken about the ingestion of foods in relation to the content of some substances, e.g. polyamines, substances stimulating cellular division, because some foods coming from organic origin present a higher content of these compounds, which could explain some of the effect of the diet on patients affected by certain syndromes.

Evaluation of chemical constituents and antioxidant activity of sweet cherry (Prunus avium L.) cultivars

Abstract: Summary This research was undertaken to evaluate the sugars, organic acids, phenolic compositions and antioxidant capacities of sweet cherry cultivars (Van, Noir de Guben, Larian and 0-900 Ziraat) grown in Turkey. High-performance liquid chromatographic methods were used to identify and quantify four sugars (sucrose, glucose, fructose and sorbitol) and four organic acids (malic, citric, shikimic, and fumaric acid). The major organic acid was found as malic acid (8.54–10.02 g kg−1 of FW). With regard to sugars, glucose was present in the largest amounts (44.71–48.31 g kg−1 of FW) for sweet cherry cultivars. The sum of sugars ranged from 103.87 (Larian) to 113.13 g kg−1 of FW (0-900 Ziraat) and that of organic acids from 12.01 (0-900 Ziraat) to 14.17 g kg−1 of FW (Noir de Guben). A total of eleven phenolic compounds were identified and quantified in sweet cherry cultivars, including hydroxycinnamic acids (3), anthocyanins (5), flavan-3-ols (2) and flavonol (1) compounds. Total phenolic contents ranged from 88.72 (Van) to 239.54 (Noir de Guben) mg/100 g of FW, while antioxidant activities ranged from 2.02 to 7.75 μm Trolox equivalents g−1 of FW.

Effect of food processing on the resistant starch content of cereals and cereal products – a review

Abstract: Depending on the conditions, processing of cereal grains may cause an increase or a decrease in the resistant starch (RS) content. This review discusses the impact of some of the processing techniques (cooking, tempering and extrusion) on the RS contents of cereals and cereal products. In addition to processing, the review briefly summarises the effects of lipids, dietary fibre and sugars, which may be present within the food matrix, on starch digestibility. The review also provides definitions for the four types of RS (RS type 1, 2, 3 and 4) and brief information about the beneficial effects of RS on human health.

Phenolic profile and antioxidant properties of Polish honeys

Abstract: Summary The phenolic components of honeys have great participation in their nutritional value and antioxidant activity. Moreover, phenolic components are promising markers for the determination of botanical and geographical origin of honey. The purpose of the present work was to study the antioxidant activity and profiles of phenolic acids and flavonoids of honeys of various origins. The total phenolic content of honeys varied from 4.46 to 15.04 mg of gallic acid equivalents per 100 g of product and the total phenolic acid content determined chromatographically varied from 201.05 to 2089.08 μg per 100 g of product. Buckwheat honey exhibited the highest antioxidant activity and contained the highest total phenolic amount, whereas rape honey exhibited the lowest values in this respect. Moreover, the buckwheat honey contained the highest amount of phenolic acids. There were significant linear correlations between total phenolic content and antioxidant activity of honey extracts in the reaction with DPPH• (1,1-diphenyl-2-picrylhydrazyl) and ABTS• + (2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid)) free radicals. In most samples, p-coumaric acid was the dominant phenolic acid (39.1–677.2 μg per 100 g). The honeys also contained considerable amount of gallic acid (6.0–913.8 μg per 100 g). Among flavonoids naringenin was predominant in the most studied honey samples.

Proximate composition and fatty acid profile of three different fresh and dried commercial sea cucumbers from Turkey

Abstract: Proximate composition and fatty acid (FA) profile of three commercial sea cucumbers; Holothuria tubulosa, Holothuria polii and Holothuria mammata caught from Aegean Sea of Turkey were analysed. The effects of regional variation and drying process on FA composition were also investigated. Moisture, protein, fat and ash contents of the species ranged between 81.24% and 85.24%, 7.88% and 8.82%, 0.09% and 0.18%, and 5.13% and 7.85%, respectively, with a significant changes among species (P < 0.05) with some exceptions. Although FA values varied significantly (P < 0.05) among species and regions, the changes for most FA types representing the same region for different species were not significantly different. Total polyunsaturated fatty acids (PUFA) were found to be higher than total saturated (SFA) and monosaturated FAs (MUFA) accounting for 53.0-62.12% for ∑PUFA, 13.28-16.41% for ∑MUFA and 13.99-19.21% for ∑SFA. While some individual SFAs and PUFAs decreased after drying process, various individual FAs of MUFA increased in their amounts (P < 0.05). Among PUFAs, the highest mean value of eicosapentaenoic acid and docosahexaenoic acid for all regions were determined for H. polii as 7.25% and H. tubulosa as 12.37% in fresh samples, respectively. This study represents new information relating to FA contents and drying effect on FA profile for these species.

Physicochemical aspects of hydrocolloid extract from the seeds of Lepidium sativum

Abstract: Summary Acid equivalent weight, intrinsic viscosity and FT-IR measurements have demonstrated a polyelectrolyte nature to Lepidium sativum seed extract. The polyelectrolyte nature relates to the carboxyl groups carried by galacturonic acid and glucuronic acid unit. The seed extract exhibited pronounced shear thinning in steady shear rheology and a weak gel type behaviour in dynamic rheology when the concentration is high i.e. > 1%. Such behaviour suggests the ability of L. sativum seed extract to structure a liquid, thus showing the possibility of applying it as a novel thickener and stabiliser in aqueous systems. The characteristic could be due to a strong tendency of molecular association of L. sativum seed extract as found for high M/G ratio galactomannans, and possibly also the enhanced macromolecular entanglement due to relatively rigid chain conformation. Temperature dependence study showed that the rheological properties of L. sativum structured solution is stable against temperature variation.

Are consumer profiling techniques equivalent for some product categories? The case of orange-flavoured powdered drinks

Abstract: Taking into account consumers' perception in new product development has been regarded as a key strategy to developing more successful food products. In this context, consumer profiling techniques have increased their popularity in the last decade. The aim of the present work was to compare four consumer profiling techniques (sorting, projective mapping, intensity scales and check-all-that-apply questions) in orange-flavoured powdered juice drinks. A consumer study was carried out with 200 regular consumers of the category, which were divided into four groups. Each group used a different methodology to evaluate seven commercial powdered drinks. After completing the task consumers were asked to rate its difficulty on a nine-point hedonic scale. Results showed that the four evaluated methodologies were able to identify differences in consumers' perception of the sensory characteristics of the drinks, providing similar information. However, the application of CATA questions and intensity scales was regarded as easier for consumers. Advantages and disadvantages of the evaluated methodologies are discussed.

Kinetics of colour change of bamboo shoot slices during microwave drying

Abstract: Summary The effect of microwave power on colour change kinetics of bamboo shoot slices was investigated during microwave drying. Colour changes were quantified by tri-stimulus Hunter L (whiteness/darkness), a (redness/greenness), and b (yellowness/blueness) system. These values were also used for calculation of total colour change (ΔE), chroma, hue angle, and browning index (BI). Microwave drying as expected changed colour parameters because of browning. The values of L and b decreased, while values of a and ΔE increased during drying. Mathematical modelling of colour change kinetics indicated that L, b, chroma and BI could be defined using a first-order kinetic model, while a, ΔE and hue angle could be defined using a zero-order kinetic model. Considering together colour deterioration and quality of dried bamboo shoot slices at higher power reveals the need of process standardisation for getting good quality product.

Effect of rapeseed protein–gelatin film containing grapefruit seed extract on ‘Maehyang’ strawberry quality

Abstract: Summary To develop a packaging film for ‘Maehyang’ strawberries, an edible film containing antimicrobial grapefruit seed extract (GSE) was manufactured. Addition of GSE to the rapeseed protein–gelatin (RG) film inhibited the growth of pathogenic bacteria such as Escherichia coli O157:H7 and Listeria monocytogenes. Packaging of ‘Maehyang’ strawberries with the RG film containing 1.0% GSE decreased the populations of total aerobic bacteria and of yeast and moulds in the strawberries by 1.03 and 1.34 log CFU g−1, respectively, after 14 days of storage, compared to that of the control. Sensory evaluation of the GSE-RG film-packaged strawberries produced better sensory scores than did the control. These results suggest that RG film containing GSE can be used to package strawberries and to extend shelf life.

Use of grape by‐product as a source of dietary fibre and phenolic compounds in sourdough mixed rye bread

Abstract: Summary The study evaluated the effect of grape by-products (GP) on the chemical composition, soluble (SDF) and insoluble (IDF) dietary fibre, phenolic compounds and antioxidant activity (AA) and organoleptic characteristics of sourdough mixed rye bread. The following samples of sourdough mixed rye bread were prepared: control bread (BC) and breads with GP at four different levels: 4%, 6%, 8% and 10%. Addition of GP significantly improves dietary fraction contents, as bread with a 10% addition of GP accounts for 39% and 37% higher contents of IDF and SDF than BC. The assay of radical-scavenging activity and reducing ability showed that GP addition greatly enhanced antioxidant properties of mixed rye breads. Profiles of phenolic compounds of supplemented breads were dominated by procyanidin B1 and B2, catechin, epicatechin, caffeic acid and myricetin. With an increase in the level of GP, the hardness and gumminess of the bread significantly increase. Although both BC and supplemented breads showed common volatile compound profiles, there were slight differences in the concentrations of those components. Sensory evaluation of GP-enhanced breads revealed that a maximum of 6% GP could be incorporated to prepare acceptable products.

Comparative analyses of total phenols, flavonoids, saponins and antioxidant activity in yellow soy beans and mung beans

Abstract: Summary Total phenol, flavonoid and saponin content of soy bean and mung bean were systemically compared in order to evaluate their contribution to overall antioxidant activity. Mung bean extract possessed significantly higher total phenol (2.03 GAE g−1 vs. 1.13 GAE g−1) and flavonoid contents (1.49 GAE g−1 vs. 0.41 CAE g−1) than soy bean extract, while the saponin content of the soy beans was 4.5 times greater than that of the mung beans. In several antioxidant assays including DPPH and ABTS radical scavenging, FRAP, SOD-like activity, and a β-carotene bleaching assay, mung bean extract consistently showed significantly greater antioxidant activity than soy bean extract. The specific antioxidant activity, which was evaluated at the same phenolic content suggested that the phenolic compounds present in the mung bean extract were not only of greater quantity but also had better quality to eliminate radicals. The radical scavenging activities of saponins were only marginal.

Effect of gelatin coating incorporated with cinnamon oil on the quality of fresh rainbow trout in cold storage

Abstract: Summary Cinnamon essential oil was used in gelatin coatings to maintain the quality of refrigerated rainbow trout fillets over a period of 20 days. Fish fillets were coated with a solution of 4% gelatin incorporated with cinnamon essential oil and then stored in refrigerator (4 ± 1 °C). Coating’s preservative effect was assessed periodically (every 5 days) by microbial analyses (aerobic plate count and psychrotrophic count), chemical determinations (total volatile basic nitrogen, thiobarbituric acid, free fatty acid) and sensory characteristics. When gelatin coating with cinnamon applied to the preservation of trout fillets, a reduction in the growth of total bacteria was observe after 15 days of storage. Fish fillets with gelatin coating containing 1%, 1.5% and 2% v/v cinnamon oil produced significantly lower (P < 0.05) total volatile basic nitrogen then gelatin-coated fillets and control until 15 days of storage period (35, 22.86, 30.33, 57.76 and 53.26 mg per 100 g of fillet, respectively). The obtained results indicate that gelatin in the form of coating enriched with cinnamon oil is suitable for the preservation of rainbow trout fresh fillets and to efficiently maintain the quality attributes to an acceptable level during storage.

Anthocyanins: optimisation of extraction from Cabernet Sauvignon grapes, microcapsulation and stability in soft drink

Abstract: Summary The aim of this study was to establish the optimum conditions for the extraction of anthocyanins from Cabernet Sauvignon (Vitis vinifera L.) grapes using the response surface methodology and to evaluate the stability of these anthocyanins encapsulated with different carrier agents in an isotonic soft drink system under different light and temperature conditions. The extraction process was optimised with the response surface methodology to obtain the highest anthocyanin concentration (40 mL of ethanol:1.5 N HCL (85:15) as solvent, extraction time 29.4 h at pH 2.4). The degradation of the anthocyanins followed first-order kinetics in the situations evaluated. Maltodextrin, maltodextrin/γ-cyclodextrin and maltodextrin/arabic gum were tested as carrier agents and the combination of maltodextrin/arabic gum presented the longest half-life time and lowest degradation constant for all the conditions evaluated. The formation of microcapsules was observed through scanning electron microscopy.

Assessment of production efficiency, physicochemical properties and storage stability of spray-dried chlorophyllide, a natural food colourant, using gum Arabic, maltodextrin and soy protein isolate-based carrier systems

Abstract: Summary The aim of this research was to study spray drying as potential action to protect chlorophyllide from environmental conditions for shelf-life extension and characterisation of the powders. Six formulations were prepared with 7.5 and 10 g of carrier agents [gum Arabic (GA), maltodextrin (MA) and soybean protein isolate (SPI)] ⁄ 100 mL of chlorophyllide solutions. The powders were evaluated for morphological characteristics (SEM), particle size, water activity, moisture, density, hygroscopicity, cold water solubility, sorption isotherms, colour and stability, during 90 days. All the powders were highly soluble, with solubility values around 97%. A significant lower hygroscopicity was observed for GA powders, whilst the lower Xm values obtained by GAB equation fitting of the sorption isotherms was observed for the 7.5 g MA ⁄ 100 mL samples. All formulations, but the 1 (7.5 g SPI ⁄ 100 mL of chlorophyllide), provided excellent stability to the chlorophyllide during 90 days of storage even at room temperature.

Effect of temperature on the drying characteristics, colour, antioxidant and beta‐carotene contents of two apricot varieties

Abstract: Summary In this study, the drying characteristics, colour, oxygen reactive antioxidant capacity (ORAC) and beta-carotene contents of two apricot varieties dried at different temperatures were compared. The hot air drying of apricot slices for both varieties consisted of a constant rate period (CRP) and two of falling rate periods (FRP). The CRP drying rate and the first and second FRP drying coefficients increased with drying temperature for both apricot varieties. The first and second FRP of both apricot varieties gave activation energies of 23.5–28.7 and 25.6–29.3 kJ mole−1, respectively. The colour values (L*, a* and b*) of both dried apricot varieties decreased with increasing temperature, while the total colour change of both dried apricot varieties increased with temperature. The chroma, hue angle and browning index values of both dried apricot varieties decreased with increasing temperature, and the hydrophilic ORAC and beta-carotene contents increased with drying temperature.

Microalgal and cyanobacterial cell extracts for use as natural antibacterial additives against food pathogens

Abstract: Summary Intra- and extracellular extracts of thirteen cyanobacteria and twelve microalgae were screened for their activity against a few of the most relevant food-borne pathogens – viz. Salmonella sp., Pseudomonas aeruginosa, Escherichia coli and Staphylococcus aureus. Strain M2-1 of Scenedesmus obliquus was the microalga that exhibited the highest antibacterial activity, except against Salmonella sp. Although cyanobacteria possessed in general wider antibacterial spectra than microalgae, the former have also been associated with toxin production – and may thus be less useful in food formulation. Nostoc sp. was particularly effective against E. coli and P. aeruginosa, whereas Gloeothece sp. stood out because of its capacity to inhibit all food pathogens tested. Typically, the intracellular extracts were more powerful than their extracellular counterparts; and those with antibacterial features were found to possess high contents of long chain fatty acids – some of which are well-known for their antibacterial activities.