Showing papers in "Lwt - Food Science and Technology in 2009"

Tensile, water vapor barrier and antimicrobial properties of PLA/nanoclay composite films

Abstract: PLA-based composite films with different types of nanoclays, such as Cloisite Na + , Cloisite 30B and Cloisite 20A, were prepared using a solvent casting method and their tensile, water vapor barrier and antimicrobial properties were tested Tensile strength (TS), elongation at break ( E ), and water vapor permeability (WVP) of control PLA film were 5045 ± 075 MPa, 30 ± 01%, and 18 × 10 −11 g m/m 2 s Pa, respectively TS and E of nanocomposite films prepared with 5 g of clay/100 g of PLA decreased 10–20% and 11–17%, respectively, depending on the clays used On the contrary, WVP of the nanocomposite films decreased 6–33% through nanoclay compounding Among the clay types used, Cloisite 20A was the most effective in improving the water vapor barrier property while sacrificing tensile properties the least The effect of clay concentration tested using Cloisite 20A showed a significant decrease in TS and WVP, with increases in clay content Among the PLA/clay composite films tested, only PLA/Cloisite 30B composite film showed a bacteriostatic function against Listeria monocytogenes

Potential alternative disinfection methods for organic fresh-cut industry for minimizing water consumption and environmental impact

Abstract: Disinfection is one of the most important processing steps affecting the quality and safety and the shelf-life of the end product in fresh-cut processing. Chlorine is the most widely used disinfectant in fresh-cut industry. However, recent outbreaks associated with pathogen contamination in fresh-cut vegetables raised the concerns about the efficacy of chlorine treatment in assuring the safety of the products. Moreover, due to the environmental and health risks posed by the use of chlorine, there is a trend in eliminating chlorine from the disinfection process. Thus, there is a need for alternative sanitizers to be used for the disinfection of fresh-cut vegetables, not only for the organic food sector but also for the conventional food processors. Another challenge for the food industry is the minimization of water consumption and wastewater discharge rates. The United Nations Environment Programme stated that Europe is one of the two global regions where more water is used for industry than for agriculture. Among the different industries, the food industry ranks third in water consumption and wastewater discharge rates coming after the chemical and refinery industries. The adoption of less water consuming systems is required for improved water management in the industry. Therefore the food industry is now seeking alternatives to chlorine which assure the safety of the products, maintain the quality and shelf-life, while also reducing the water consumption rates in processing. Chlorine dioxide, ozone, organic acids, peroxyacetic acid, electrolyzed oxidizing water and hydrogen peroxide are the main alternative sanitizing agents that gained interest in recent years. The effects of these disinfecting agents on the microbiological, nutritional and sensory quality of fresh-cut produce, and also the possible environmental impact and the potential on minimizing water consumption rates in the food industry are reviewed in this manuscript.

Physicochemical properties and bioactive compounds of selected seed oils

Abstract: The physicochemical properties and chemical composition of oil extracted from five varieties of plant seeds (bittermelon, Kalahari melon, kenaf, pumpkin and roselle seeds) were examined by established methods. The thermal properties of extracted oils by differential scanning calorimetry were also evaluated. Sensorial profiles of these seed oils were defined through the CieLab ( L *, a *, b *) colour. Most of the quality indices and fatty acid compositions showed significant ( P 2 /100 g oil; saponification value, 171.0–190.7 mg of KOH/g of oil; acid value, 1.1–12.9 mg of KOH/g of oil, free fatty acid, 0.6–6.5 g/100 g of oil, and peroxide value 1.5–6.5 meq of O 2 /kg of oil. Palmitic, oleic and linoleic acids were the major fatty acids in all of the extracted seed oils except for bittermelon, where eleostearic acid was the major fatty acid. Gallic, protocatechuic, p -hydroxybenzoic, vanillic, caffeic, syringic, p -coumaric and ferulic acids were identified in the extracted plant oils. Among these, vanillic acid was predominant in all extracted oils. The oils were rich in tocopherols with γ-tocopherol as the major components in all oil samples. Among the phytosterols, sitosterol was the major phytosterol extracted from the five plant seed oils. The seeds of these plants contain a great number of valuable minor compounds, which have a potential high value as food and for production of non-food products.

Antioxidant activity, phenolic compounds and anthocyanins content of eighteen strains of Mexican maize

Abstract: Free-radical scavenging, reducing activity and some phytochemical content (total phenolic, anthocyanin and ferulic acid) of eighteen Mexican maize phenotypes were determined. Total phenolic contents ranged from 215.8 to 3400.1 mg gallic acid/100 g of whole grain flour and total anthocyanins ranged from 1.54 to 850.9 mg cyanidin-glucoside equivalents/100 g of whole grain flour. Most of the phenolics in grain were in the bound form (ca. 85%), while anthocyanins were the major free phenolic compounds. Among the different samples, bound phenolic extracts of corn appeared to have greater anti-radical and reducing activities than free phenolic extracts from the same grain samples when tested at a normalized phenolic concentration. The phenotypes Veracruz 42 and AREQ516540TL exhibited the greatest activities and these purple-colored strains were most enriched in anthocyanins. Extracts from a red-colored phenotype Pinto were also among the most effective at exhibiting anti-radical activities. Differences in free-radical scavenging and reducing activities appeared to be dependent on the unique profile of anthocyanins and other phenolics in each phenotype.

Physicochemical properties of a fibrous fraction from chia (Salvia hispanica L.).

Abstract: An evaluation was done of some physicochemical properties of a fiber-rich fraction (FRF) obtained by dry processing of defatted chia (Salvia hispanica) flour. The fiber-rich fraction (FRF) had 29.56 g/100 g crude fiber content and 56.46 g/100 g total dietary fiber (TDF) content, of which 53.45 g/100 g was insoluble dietary fiber (IDF) and 3.01 g/100 g was soluble dietary fiber (SDF). The FRF water-holding capacity was 15.41 g/g, its water absorption capacity 11.73 g/g, and its organic molecule absorption capacity 1.09 g/g. The FRF also had low oil-holding (2.02 g/g) and water adsorption (0.3 g/g) capacities. Emulsifying activity in this fraction was 53.26% and emulsion stability was 94.84%. Its evaluated antioxidant activity was 488.8 μmol/L Trolox equivalents/g FRF, which is higher than for many cereals and similar to drinks such as wine, tea, coffee and orange juice. The chia FRF values for the evaluated properties, particularly for water-holding, oil-holding and organic molecule absorption capacity, suggest it could be a useful ingredient in dietetic products such as baked and fried foods, among others.

Antioxidant and antiproliferative activities of common edible nut seeds

Abstract: Frequent consumption of nuts has been linked to a lowered risk of cardiovascular disease. Phytochemicals, especially phenolics, in nuts may be considered to be the major bioactive compounds for health benefits. Nine types of tree nuts and peanuts commonly available in the United States were evaluated for total phenolic and flavonoid contents, antioxidant, and antiproliferative activities. The profiles of total phenolics and flavonoids, including both soluble free and bound forms, were investigated by utilizing solvent extraction, base digestion, and solid-phase extraction methods. Walnuts had the highest total phenolic and flavonoid contents (1580.5 ± 58.0 mg/100 g, 744.8 ± 93.3 mg/100 g, respectively). Walnuts also possessed the highest total antioxidant activity (458.1 ± 14.0 μmol of vitamin C equiv/g of nut). Both soluble phenolic and flavonoid contents were positively correlated with total antioxidant activity (R2 = 0.9901, p

Nutritional quality of legume seeds as affected by some physical treatments 2. Antinutritional factors

Abstract: Raw and treated cowpea, pea and kidney bean seeds were investigated for their content of antinutritional factors including tannins, phytic acid, trypsin inhibitors and oligosaccharides. Treatments applied included water soaking, boiling, roasting, microwave cooking, autoclaving, fermentation and micronization. Kidney bean contained the highest antinutrient content among all investigated seeds. The least tannins and phytic acid contents were recorded in Canadian cowpea while Canadian pea showed the lowest TIA. All treatments conducted caused significant decreases in tannins, phytic acid, TIA and oligosaccharides as compared to the raw seeds. Boiling caused the highest reduction in tannins followed by autoclaving and microwave cooking. Autoclaving and fermentation were the most effective in reducing phytic acid content. Heat treatments (boiling, roasting, microwave cooking and autoclaving) brought a total removal of trypsin inhibitors of all samples. Furthermore, autoclaving caused the highest reduction in oligosaccharides followed by fermentation while the least reductions were caused by either roasting or micronization with no significant difference between these two treatments.

Bio-protective effects of glucosinolates - a review.

Abstract: Glucosinolates are an important and unique class of secondary plant products containing β-D-thioglucose and sulphonated oxime moieties. These include thioglucosides, characterized by side chain with varying aliphatic, aromatic and heteroaromatic carbon skeletons. Glucosinolates get converted into various degradation products (isothiocyanates, thiocyanates, indoles etc.), when vegetables containing them are cut or chewed because during this process they come in contact with the enzyme myrosinase which hydrolyses them. Though the available literature emphasizes the drawbacks of this class of compounds, but the potential benefits that might emerge from their biological activities have been ignored. These compounds possess diverse biological activities including protection against various pathogens and weeds in case of plants and as potent anticarcinogens. The enormous importance of this group of compounds cannot be overlooked and detailed insight into their role in diverse fields and the mechanisms operating behind them is required. The present review focuses on the beneficial bioactivities of glucosinolates such as antifungal, antibacterial, bioherbicidal, antioxidant, antimutagenic and anticarcinogenic etc. along with their experimental evidence and mode of action. These phytochemicals deserve proper position in therapeutic armamentarium. Clinical studies with these biomolecules are required to be accelerated to validate their affect in vivo .

Effect of dietary fibre enrichment on selected properties of gluten-free bread.

Abstract: The enrichment of gluten-free baked products with dietary fibre seems to be necessary since it has been reported that coeliac patients have generally a low intake of fibre due to their gluten-free diet. In the present study different cereal fibres (wheat, maize, oat and barley) were added at 3, 6 and 9 g/100 g level into a gluten-free bread formulation based on corn starch, rice flour and hydroxypropyl methyl cellulose (HPMC). Doughs were evaluated based on consistency, viscosity and thermal properties. Results showed that maize and oat fibre can be added to gluten-free bread with positive impact on bread nutritional and sensory properties. All breads with 9 g/100 g fibre increased the fibre content of control by 218%, but they were rated lower than those with 3 and 6 g/100 g fibre due to their powdery taste. The formulation containing barley fibre produced loaves that had more intense color and volume comparable to the control. During storage of breads a reduction in crumb moisture content and an increase in firmness were observed. The micrographs of the crumb showed the continuous matrix between starch and maize and/or oat fibre obtaining a more aerated structure.

Antifungal activity and chemical composition of Citrus reticulata Blanco essential oil against phytopathogens from North East India

Abstract: The essential oil (EO) isolated by hydro-distillation from the peel of fully matured ripen fruits of Citrus reticulata Blanco were analyzed by GC and GC–MS. Thirty seven different components were identified constituting approximately ≥99% of the oil. The major components were limonene (46.7%), geranial (19.0%), neral (14.5%), geranyl acetate (3.9%), geraniol (3.5%), β-caryophyllene (2.6%), nerol (2.3%), neryl acetate (1.1%) etc. The antifungal activity of the oil was tested by poisoned food (PF) technique and the volatile activity (VA) assay against five plant pathogenic fungi viz Alternaria alternata (Aa), Rhizoctonia solani (Rs), Curvularia lunata (Cl), Fusarium oxysporum (Fo) and Helminthosporium oryzae (Ho). The oil showed better activity in VA assay. The Minimum inhibitory concentration (MIC) for Aa, Rs and Cl was 0.2 ml/100 ml whereas >0.2 ml/100 ml for Fo and Ho in PF technique. Fungal sporulation was also completely inhibited at 2 ml/100 ml of the oil except for Cl and Ho, which was only 0.5% (±0.5) and 0.25% (±0.25) respectively as compared to control.

Influence of cooking and dehulling on nutritional composition of several varieties of lentils (Lens culinaris)

Abstract: The effect of cooking and dehulling on nutrients and anti-nutritional factors of several varieties of lentils (Lens culinaris) was investigated. Significant (p < 0.05) variations existed among the lentil varieties with respect to their crude protein, starch, ash, soluble dietary fiber (SDF), insoluble dietary fiber (IDF), total dietary fiber (TDF), resistant starch (RS), trypsin inhibitor activity (TIA), minerals, phytic acid, tannins, sucrose and oligosaccharides (raffinose, stachyose and verbascose) content. Cooking lentils in boiling water significantly increased protein, starch, IDF, TDF, resistant starch, Ca, Cu and Mn content, whereas reduced ash, Fe, K, Mg, P, Zn, TIA, phytic acid, tannins, sucrose and oligosaccharides were observed. Dehulling (removal of seed coat) resulted in a significant increase in protein, starch, resistant starch, K, P, phytic acid, stachyose and verbascose content, however, a significant decrease in SDF, IDF, TDF, Ca, Cu, Fe, Mg, Mn and tannin content was observed.

Nutritional quality of legume seeds as affected by some physical treatments, Part 1: Protein quality evaluation

Abstract: The effect of water soaking, boiling, roasting, microwave cooking, autoclaving, fermentation and micronization on the nutritional quality of cowpea, pea and kidney bean was investigated. Pea seeds showed the highest crude fat, crude fiber and the lowest moisture contents while kidney bean had the lowest crude fat and the highest crude protein and ash contents. Glu and Asp were the main amino acids in all legumes while Cys and Met contents were the lowest. The protein efficiency ratio (PER), protein chemical score (CS) and the essential amino acid index (EAAI) of raw seeds ranged from 2.15 to 2.95, 39.07 to 68.30, and 55.49 to 62.84, respectively. Soaking, boiling, microwave cooking and autoclaving increased the total essential amino acids in all samples. Furthermore, raw and treated samples showed higher Lys content than the reference protein. Autoclaving was the most effective in improving protein quality followed by micronization, microwave cooking and fermentation. In addition, in vitro protein digestibility was improved after soaking, boiling, microwave cooking, autoclaving and fermentation but was reduced after roasting and micronization.

Brazil nuts and associated health benefits: A review

Abstract: Epidemiological studies have shown an inverse relationship between nut intakes and chronic diseases such as cardiovascular diseases and cancers. The composition of lipids, minerals, and phytochemicals, and their associated health functions in Brazil nuts are critically reviewed. The nuts have high nutritive food value containing 60–70% oil and 17% protein. Brazil nuts contain abundant dietary antioxidants, especially selenium (Se). One single Brazil nut provides 160% of the US Recommended Daily Allowance (RDA) of selenium - perhaps the best source of Se from plant-based foods. Brazil nuts possess phenolics and flavonoids in both free and bound forms and are rich in tocopherol, phytosterols, and squalene. These compounds' possible beneficial effects are due to their antioxidant and antiproliferative activities, which are linked to a reduced risk for developing atherosclerosis and cancer.

Effect of grape antioxidant dietary fiber on the lipid oxidation of raw and cooked chicken hamburgers.

Abstract: Efficiency of four concentrations (0.5, 1, 1.5 and 2%) of grape antioxidant dietary fiber (GADF) on susceptibility of raw and cooked chicken breast hamburger to lipid oxidation was investigated after 0, 3, 5 and 13 days of refrigerated storage at 4 °C. Color changes, sensorial qualities and acceptability by panellist were evaluated. Lipid oxidation was assessed by monitoring malondialdehyde formation with 2-thiobarbituric acid (TBARS) assay and radical scavenging capacity by ABTS method. A significant reduction in lightness and yellowness and a significant increase in redness as a result of GADF addition were observed in raw and chicken hamburgers. Addition of GADF significantly improved the oxidative stability and the radical scavenging activity in raw and cooked chicken hamburgers. The ability of GADF to prevent lipid oxidation was concentration-dependent. Acceptability of chicken meat was not affected by the addition of GADF. These results show that GADF is a very effective inhibitor of lipid oxidation and has potential as a natural antioxidant in raw and chicken cooked meats.

Vacuum drying kinetics of Asian white radish (Raphanus sativus L.) slices

Abstract: In this study, radish slices were dried as single layers with thickness of 4 and 6 mm in the ranges of 40–60 °C of drying air temperature in a laboratory scale vacuum dryer. The effect of drying air temperature and slice thickness on the drying characteristics was determined. Moisture transfer from radish slices was described by applying the Fick's diffusion model, and the effective diffusivity changes between 6.92 × 10−9 and 14.59 × 10−9 m2/s within the given temperature range. Effective diffusivity increased with increasing temperature. An Arrhenius relation with activation energy values of 16.49 and 20.26 kJ/mol for the thickness of 4 and 6 mm expressed the effect of temperature and sample thickness on the diffusivity. A non-linear regression procedure was used to fit nine thin-layer drying models available in the literature to the experimental moisture loss data. The models were compared based on the coefficient of determination, mean relative percent deviation, root mean square error, and the reduced chi-square between the observed and predicted moisture ratios. The logarithmic model has shown a better fit to the experimental drying data as compared to other models.

Thermal properties and resistant starch content of green banana flour (Musa cavendishii) produced at different drying conditions

Abstract: The objective of this research was to verify the effect of drying conditions on thermal properties and resistant starch content of green banana flour (Musa cavendishii). The green banana flour is a complex-carbohydrates source, mainly of resistant starch, and quantifying its gelatinization is important to understand how it affects food processing and the functional properties of the flour. The green banana flour was obtained by drying unripe peeled bananas (first stage of ripening) in a dryer tunnel at 52 °C, 55 °C and 58 °C and air velocity at 0.6 m s−1, 1.0 m s−1 and 1.4 m s−1. The results obtained from differential scanning calorimetry (DSC) curves show a single endothermic transition and a flow of maximum heating at peak temperatures from (67.95 ± 0.31) °C to (68.63 ± 0.28) °C. ANOVA shows that only drying temperature influenced significantly (P

Safety and quality assessment of packaged spinach treated with a novel ozone-generation system

Abstract: The quality and safety of packaged salad are major concerns to consumers. Ozone gas is a non-thermal processing technology capable of treating food to reduce pathogens. The ozone generation system (PK-1) used in this study consisted of a pair of electrodes with an adjustable gap inside a package. Individual, fresh, prepackaged, whole spinach leaves inoculated with Escherichia coli O157:H7 6460 were treated in packaging with ozone generated in air and oxygen. Samples were treated for 5 min and stored at room temperature (22 °C) or refrigeration (5 °C) for 0.5, 2, and 24 h. Gas composition and relative humidity were measured. All treated samples showed reductions in E. coli O157:H7 populations with the largest reductions (3–5 log10 CFU/leaf) after 24 h of storage. After 5 min of treatment, ozone concentrations were 1.6 and 4.3 mg/L for air and oxygen gas, respectively. The concentrations of ozone decreased with time and were not detectable after 24 h. A 5-point Spinach Color Quality (SCQ) scale was established (5-best, 1-worst). Treated spinach showed discoloration with SCQ-values of 3.83 and 1.00 for air and oxygen gas exposed leaves after 24 h. These results indicate that the PK-1 system is capable of reducing E. coli O157:H7 in packaged spinach; however, minimizing quality changes after treatment requires further research.

Shelf life modelling of frozen shrimp at variable temperature conditions.

Abstract: The objective of this study was to investigate the effect of variable storage conditions on shelf life and quality characteristics of frozen shrimp. Colour change measured both instrumentally and visually was modelled by apparent zero order equations and showed high dependence on temperature. TVB-N and TMA values increased with storage time and were modelled with apparent first order equations. Taste and overall acceptability scores of frozen shrimp had high correlation with TVB-N and TMA values. The temperature dependence of quality deterioration was adequately modelled by the Arrhenius equation and activation energy ranged from 118 to 156 kJ/mol for the different indices measured. The developed models were validated in fluctuating time–temperature conditions in order to establish their applicability in the real cold chain.

Influence of chemical refining process and oil type on bound 3-chloro-1,2-propanediol contents in palm oil and rapeseed oil.

Abstract: The formation of bound 3-chloro-1,2-propanediol (3-MCPD-ester) in oils during chemical refining process was investigated for two palm oils and one rapeseed oil. Additionally, contents of mono- and diglycerides as well as total chlorine and chloride were determined. For all oils the deodorisation step representing one part of the refining process had the main impact on formation of 3-MCPD-esters whereas a direct effect of the other process steps could be neglected. 3-MCPD values in the range of 4–5 ppm for palm oil and 1 ppm for rapeseed oil were found. The chloride content was below detection limit. However, measurable amounts of total chlorine were found in palm oil with the highest 3-MCPD-ester contents. A considerable part of this total chlorine in the refined palm oil was embedded in the 3-MCPD-esters. On the other hand, content of diglycerides as the other potential pre-cursor was between 1% and 10% exceeding the 3-MCPD-ester contents by up to five magnitudes.

Effect of high pressure treatment on aggregation and structural properties of soy protein isolate

Abstract: The aggregation and structural properties of soy protein isolate (SPI), induced by high pressure (HP) treatment at 200–600 MPa were investigated by size-exclusion chromatography combined with multi-angle laser scattering (SEC-MALLS) and fourier transform infrared (FTIR) spectroscopy. HP treatment at lower pressure level (e.g., 200 MPa) resulted in formation of marked insoluble aggregate of SPI, while the treatment at higher pressure level (e.g., 600 MPa) led to transformation of insoluble aggregate to soluble one. The soluble aggregate formed at 400 or 600 MPa had much less mean molecular weight (MW) (about 5.2 × 10 6 g/mol) than that at 200 MPa (about 1.6 × 10 7 g/mol), and was also much more homogenous in MW distribution. FTIR analyses confirmed changes in secondary and tertiary structures, induced by HP treatment. These results can provide direct evidence or explanation for HP-induced modification of soy proteins.

Production and evaluation of some physicochemical parameters of peanut milk yoghurt

Abstract: The peanut milk for yoghurt production was prepared by fortifying peanut milk (∼12 g/100 g total solids) with 4 g/100 g skimmed milk powder. The final product was subjected to physicochemical analysis using cow milk yoghurt (CMY) as a control throughout the study. Peanut milk yoghurt (PMY) had higher protein content, fat, water holding capacity and lower susceptibility to Syneresis than CMY. PMY had lower lactose level (1.73 g/100 ml) compared to CMY (4.93 g/100 ml). Generally both PMY and CMY had high mineral composition and contained high amounts of essential amino acids. PMY also contained a higher proportion of unsaturated fatty acids than saturated fatty acids as compared to CMY. Therefore, in terms of fatty acid composition, PMY could be considered to be more health promoting than CMY. Sensory evaluation revealed that though PMY had better sensory texture scores than CMY, its sensory appearance, flavor and overall acceptability scores were lower than those of CMY.

Understanding potato chips crispy texture by simultaneous fracture and acoustic measurements, and sensory analysis

Abstract: The fracture and acoustic properties of six commercial potato chips that differ in sensory hardness and sensory crispness were analysed and related in this work. Principal component analysis showed a correlation among the sensory attributes and the instrumental parameters (both mechanical and acoustic). Two components mainly explained the behaviour of the different potato chips. The first component was positively related to the number of force and sound events, to sound pressure level maximum, to the area under the force curve, and to sensory crispness, and negatively related to fat content; and the second component was positively related to the gradient (slope of the first part of the curve), the potato chip thickness, and to sensory hardness and sensory crispness. The behaviour of the different potato chips was explained by either one of the two components or by both components. Results indicate that certain degree of sensory hardness is necessary for higher crispness perception.

Processing optimization and characterization of gelatin from lizardfish (Saurida spp.) scales

Abstract: Response surface methodology (RSM) with a 4-factor, 5-level central composite design (CCD) was conducted to ascertain the optimum gelatin extraction conditions from lizardfish scales. The effects of concentration of NaOH (%, X 1 ), treatment time (h, X 2 ), extraction temperature (°C, X 3 ) and extraction time (h, X 4 ) were determined. The responses included extraction yield (%), gel strength (g) at 9–10 °C and viscosity (cP) at 25 °C. The results showed the optimum conditions for the highest values of the three responses when a concentration of NaOH at 0.51%, a treatment time at 3.10 h, an extraction temperature at 78.5 °C and an extraction time at 3.02 h. The predicted responses were 10.7% extraction yield, 240 g gel strength and 5.61 cP viscosity. The experimental values were 10.6 ± 0.82% extraction yield, 252 ± 1.21 g gel strength and 7.50 ± 0.28 cP viscosity. The physicochemical properties of the lizardfish scales gelatin were characterized and the results indicated high protein and low ash content. Texture profile analysis (TPA) with compression was carried out at 30% deformation. The lizardfish scales gelatin was found to contain 20.4% imino acids (proline and hydroxyproline). Furthermore, slightly loose strands of the gel microstructure were observed using scanning electron microscopy (SEM).

The effect of drying method and storage on color characteristics of paprika

Abstract: Discoloration and microbial proliferation are two major problems associated with production of paprika (Capsicum annuum L.) with traditional drying methods. In the present study, the Refractance Window™ drying (RWD) method was employed to dry paprika in comparison with freeze drying, hot-air oven drying, and natural convective drying methods. In order to evaluate the color quality of paprika, the reflected color parameters, extractable color, red/yellow pigment ratio, and browning index were measured immediately after drying and during three-month storage. The freeze-dried and RWD-dried paprika showed better reflected color characteristics. The highest extractable color and browning index values were recorded in naturally convective dried paprika. There was no significant difference in browning index between freeze-died and RWD-died samples. The reflected color degradation of the paprika was highly associated with brown reaction. A gradual discoloration was observed in all paprika samples during storage.

Effect of edible coatings on the quality of frozen fish fillets

Abstract: The objective of this study was to determine the changes in the quality of coated trout fillets after coating with edible materials. Fillets were coated and stored at −18 °C for a period lasting up to 7 months. Coating materials were applied in three different stages (first, second, and last coatings). The coated fillets were fried and analyzed for oil absorption and moisture content throughout the storage period. Sensorial attributes and the physical–biochemical changes were also measured before the frying process in each month. It was observed that it is more advantageous to use gluten as the first coating, xanthan gum as the second coating, and wheat (W) and corn (C) flours in the ratio of 1:1 or 2:1 as the last coating. In terms of the fillet quality, the following results were obtained in the analyses conducted before frying. The lowest pH found was 6.25 in zein-containing samples and 6.30 in guar-containing samples. The effects of the last coatings on pH were unimportant (P > 0.05). The lowest thiobarbituric acid levels found were 2.07 mg kg in the fillets coated with casein mixture, 2.44 mg kg in the fillets coated with xanthan gum, and 2.25 mg kg in the fillets coated with W:C flour mixture in the ratio of 2:1. The lowest total volatile basic nitrogen levels found were18.06 mg 100 g in the fillets coated with casein mixture, 18.62 mg 100 g in the fillets coated with xanthan gum, and 18.47 mg 100 g in the fillets coated with W:C flour mixture at 1:1 ratio. In the sensorial analysis, the coated samples were much more preferred than those not coated. As a result of the effects of all the materials, the coating layers on the meat surface provided more resistance against mass transfer during storage.

The effect of simulated digestion in vitro on bioactivity of wheat bread with Tartary buckwheat flavones addition

Abstract: The antioxidant activity of bread enriched in an extract from the green parts of buckwheat plant (TBF – Tartary buckwheat flavones) was determined. The bread's quality was slightly decreased when 2.5% TBF was added; however, with an addition of 5% TBF caused a high decrease in the bread's quality. Despite the digestion stage, the content of total phenolic compounds were the lowest in the case of the samples from the control bread (without buckwheat addition). Despite the kinds of bread, the lowest content of total phenolics and flavonoids and the highest phenolic acids content were detected in the fluids after simulated saliva digestion. Despite the digestion stage, the highest antiradical activity, reducing power and ability to inhibition of lipid peroxidation was observed in the samples with a 5% TBF addition. The free radical scavenging activity grew along with the increase of buckwheat preparate addition and in the progress of the in vitro digestion. The maximum of reducing and chelating power in the control sample were observed after simulated saliva digestion, whereas in the case of bread with the TBF addition the highest reducing power was observed after simulated gastric digestion, and maximum of chelating power – after simulated intestinal digestion.

Supercritical CO2 extraction optimization of pomegranate (Punica granatum L.) seed oil using response surface methodology

Abstract: This study examined extraction of pomegranate seed oil by using supercritical carbon dioxide. Response surface methodology was used to evaluate the effects of the process parameters, namely extraction pressure, temperature and CO2 flow rate on the yield of pomegranate seed oil. The extraction parameters were optimized with a central composite design experiment. The linear term of pressure, followed by the linear term of CO2 flow rate, the quadratic terms of pressure, temperature and CO2 flow rate and the interactions between pressure and temperature, as well as CO2 flow rate and temperature, had significant effects on the oil yield (p

Effects of milk supplementation with skim milk powder, whey protein concentrate and sodium caseinate on acidification kinetics, rheological properties and structure of nonfat stirred yogurt

Abstract: Milk supplementation with milk proteins in four different levels was used to investigate the effect on acidification and textural properties of yogurt. Commercial skim milk powder was diluted in distilled water, and the supplements were added to give different enriched-milk bases; these were heat treated at 90 °C for 5 min. These mixtures were incubated with the bacterial cultures for fermentation in a water bath, at 42 °C, until pH 4.50 was reached. Chemical changes during fermentation were followed by measuring the pH. Protein concentration measurements, microbial counts of Lactobacillus bulgaricus and Streptococcus thermophilus, and textural properties (G′, G″, yield stress and firmness) were determined after 24 h of storage at 4 °C. Yogurt made with milk supplemented with sodium caseinate resulted in significant properties changes, which were decrease in fermentation time, and increase in yield stress, storage modulus, and firmness, with increases in supplement level. Microstructure also differed from that of yogurt produced with milk supplemented with skim milk powder or sodium caseinate.

Ascorbic acid degradation kinetics of sonicated orange juice during storage and comparison with thermally pasteurised juice

Abstract: Ascorbic acid degradation kinetics of sonicated orange juice during storage were determined and compared to thermally pasteurised samples. Acoustic energy densities (AED) ranging from 0.30 to 0.81 W/mL and treatment times of 2–10 min were investigated. The degradation kinetics of sonicated samples followed first-order kinetics ( R 2 ≥ 0.91) during processing. During storage ascorbic acid degradation of sonicated samples followed the Weibull model ( R 2 ≥ 0.97) with β values ranging from 0.662 to 0.697. Comparatively, first-order degradation kinetics were observed during storage for thermally pasteurised ( R 2 = 0.98) and control samples ( R 2 = 0.96). Increased shelf life based on ascorbic acid retention was found for sonicated samples compared to thermally pasteurised samples. Predicted shelf life for sonicated orange juice ranged from 27 to 33 days compared to 19 days for thermally pasteurised juice during storage at 10 °C. These results indicate that sonication results in enhanced retention of ascorbic acid in orange juice during storage compared to thermal processing.

Antioxidant properties and bioactive components of Norton (Vitis aestivalis) and Cabernet Franc (Vitis vinifera) wine grapes

Abstract: Three wine grapes, Norton ( Vitis aestivalis ), Cabernet Franc clone1, and Cabernet Franc clone313 ( Vitis vinifera ), collected from a Virginia vineyard were evaluated and compared for their antioxidant properties and phenolic profile. All grape extracts exerted remarkable antioxidant activities. Their oxygen radical absorbance capacity (ORAC) values were not significantly different from one another, ranging from 22.9 to 26.7 μmol TE/g of fresh weight. The Cabernet Franc clone1 had the strongest 1,1-diphenyl-2-picrylhydrazyl (DPPH ) radicals scavenging activity (8.8 μmol TE/g) compared to the Norton or Cabernet Franc clone313 grape extracts (7.9 μmol TE/g and 5.4 μmol TE/g, respectively). The Norton grape contained significantly higher total phenolic, anthocyanin, and flavonoid content than the Cabernet Franc grapes ( p