Showing papers in "Lwt - Food Science and Technology in 2011"

Acrylamide and 5-hydroxymethylfurfural (HMF): A review on metabolism, toxicity, occurrence in food and mitigation strategies

Abstract: Neo-formed contaminants (NFCs) are compounds forming during heating or preservation processes and exhibiting possible harmful effects to humans. Among the several NFCs described in literature, Acrylamide and 5-hydroxymethylfurfural (HMF) have attracted the attention of the scientific community in recent years. Both acrylamide and HMF are considered as probably or potentially carcinogenic to humans or might be metabolized by humans to potentially carcinogenic compounds. Acrylamide and HMF are mainly formed through Maillard Reaction and can be regarded as the most important heat-induced contaminants occurring in bread and bakery products. Acrylamide is carcinogen in rodent and some recent epidemiological studies have highlighted the association between dietary acrylamide and an increased risk of some types of cancer. HMF has been recently shown to be converted in vivo to 5-sulfoxymethylfurfural (SMF) which is a genotoxic compound. Dietary intake of HMF is in the order of mg/kg far above that of other food toxicants. In this paper, the latest available data on acrylamide and HMF have been reviewed focusing on available mitigation strategies, metabolism, dietary exposure, and toxicity. The results from the epidemiological studies about acrylamide and cancer risk and their relevance have been discussed, the major gaps of knowledge have been identified and the perspective of ongoing and future research was established.

Microbiological food safety assessment of high hydrostatic pressure processing: A review

Abstract: High hydrostatic pressure (HHP) processing as a novel non-thermal method has shown great potential in producing microbiologically safer products while maintaining the natural characteristics of the food items. Scientific research of the process and its industrial applications has been widespread in the past two decades with many scientific publications describing its uses, advantages and limitations. The review describes the effect of HHP on foodborne pathogenic microorganisms, their structures and adaptive mechanisms, the intrinsic and extrinsic factors that affect its application with a focus on microbiological safety, and research needs. In a risk assessment context, tools and mechanisms in place to monitorize, optimize and validate the process, and procedures for assessing and modelling the lethal effect of the treatment are reviewed.

Beta casein-micelle as a nano vehicle for solubility enhancement of curcumin; food industry application

Abstract: Curcumin is a potent anticancer and antioxidant natural polyphenol poorly soluble in aqueous solutions. Beta-casein (B-CN), an amphiphilic self-assembling protein that can form micellar nanostructures, could be used as a carrier system for hydrophobic therapeutic agents such as curcumin. In this study, camel B-CN was used for curcumin encapsulation. Critical micelle concentration of camel B-CN was determined at 25, 30 and 37 °C using pyrene fluorescence and the solubility of curcumin was evaluated according to the solvent-evaporation technique. Presence of camel B-CN increased the solubility of curcumin at least 2500 fold. Analysis of fluorescence emission of curcumin showed that hydrophobic interactions are predominant in its formulation with B-CN. Additionally, the cytotoxicity of curcumin to human leukemia cell line K-562 was enhanced in the presence of B-CN micelles giving inhibitory concentration (IC50) values of 26.5 and 17.7 μmol/L for free and encapsulated curcumin, respectively. Antioxidant activity of curcumin encapsulated in B-CN was higher than that of both free B-CN and curcumin.

Microencapsulation of flax oil with zein using spray and freeze drying

Abstract: Microencapsulation of flax oil was investigated using zein as the coating material. Central Composite Design – Face Centered was used to optimize the microencapsulation with respect to zein concentration ( x 1 ) and flax oil concentration ( x 2 ) using spray drying. Also, freeze drying was carried out at two zein:oil ratios. The quality of microcapsules was evaluated by determining encapsulation efficiency, flowing properties (Hausner ratio), and evaluating the morphology with scanning electron microscopy. The response surface model for microencapsulation efficiency showed a high coefficient of determination ( R 2 = 0.992) and a non-significant lack of fit ( p = 0.256). The maximum microencapsulation efficiencies were 93.26 ± 0.95 and 59.63 ± 0.36% for spray drying and freeze drying, respectively. However, microcapsules prepared by spray and freeze drying had very poor handling properties based on the Hausner ratio. The bulk density decreased with an increase in zein concentration at the same flax oil concentration. The morphology of the flax oil microcapsules depended on the zein:flax oil ratio and the process used for microencapsulation. Flax oil microcapsules prepared by spray drying appeared to be composed of heterogeneous spheres of various sizes at high zein:flax oil ratios. Microcapsules prepared by freeze drying resulted in agglomerated small spheres. These microcapsules might find a niche as functional food ingredients.

Preparation of active antimicrobial methyl cellulose/carvacrol/montmorillonite nanocomposite films and investigation of carvacrol release

Abstract: Methyl cellulose (MC)/carvacrol (CRV)/montmorillonite (MMT) nanocomposite films were prepared to obtain active antimicrobial packaging materials. The characterization of film samples by X-ray diffraction and transmission electron microscopy showed that composite films were of nano structures. CRV addition to the MC film and MC/MMT nanocomposite films led to a decrease in the thickness and opacity values of them, whereas MMT addition to the film matrix caused an increase in these values. Thermal stability of films slightly increased with increasing MMT concentration in film matrix. CRV release from films was investigated at different temperatures for 30 days. An increase in the MMT concentration matrix caused a decrease in CRV release at 25.0 ± 0.5 °C and in 60 ± 4% relative humidity (RH). CRV release increased with temperature at a constant RH. The antimicrobial activities of films were tested against Escherichia coli ( E. coli ) and Staphylococcus aureus ( S. aureus ) by the microatmosphere method and these organisms were completely inhibited on the nutrient broth/bacteriological agar medium when film samples containing 11.1 ± 0.2 mg CRV were present. MC/CRV film and MC/CRV/MMT-60% nanocomposite films on sausage reduced E. coli and S. aureus counts by 0.9 and 0.7 log cfu/mL, respectively, compared to the control film. The amount of CRV release from developed antimicrobial films can be controlled by MMT concentration within the film matrix and by the storage temperature of film.

Microencapsulation of propolis extract by complex coacervation

Abstract: The propolis has potential to be a natural food additive. However, its application is limited, because it is alcohol-soluble and has strong flavour. Microencapsulation may be an alternative for reducing these problems. The aim of this study was to encapsulate propolis extract by complex coacervation using isolated soy protein and pectin as encapsulant agents. The coacervation was studied as a function of pH (5.0, 4.5, 4.0 and 3.5) and the concentration of encapsulants and core (2.5 and 5.0 g/100 mL). Samples obtained at pH 4.0 in both concentrations were lyophilized and analyzed for hygroscopicity, encapsulation efficiency, particle size, morphology, thermal behavior, stability of phenolic and flavonoids during storage, as well as antioxidant and antimicrobial activities. It was possible to encapsulate propolis extract by complex coacervation and to obtain it in the form of powder, alcohol-free, stable, with antioxidant property, antimicrobial activity against Staphylococcus aureus and with the possibility of controlled release in foods.

Chitosan/whey protein film as active coating to extend Ricotta cheese shelf-life

Abstract: Shelf-life extension of Ricotta cheese coated with a chitosan/whey protein edible film and stored under modified atmosphere at 4 °C was evaluated. The chitosan/whey protein film had 35% and 21% lower oxygen and carbon dioxide permeability, respectively, and about three times higher water vapor permeability than film prepared with chitosan alone. Over a 30-day storage period, no differences in the pH of control and coated Ricotta cheeses were observed. While the titratable acidity of the control increased linearly during the first two weeks and remained constant for the rest of the storage period, the corresponding values for coated Ricotta cheese did not change significantly during the first 21 days and reached the acidity level (0.34 ± 0.02 milliequivalent/100 g of analyzed sample) of the control only on day 30. The viable numbers of lactic acid bacteria and mesophilic and psychrotrophic microorganisms were significantly lower ( p

Production of antioxidant hydrolyzates from a whey protein concentrate with thermolysin: Optimization by response surface methodology

Abstract: Whey protein concentrate (WPC) enriched in β-lactoglobulin (β-Lg) was hydrolyzed using Corolase PP® and thermolysin to produce hydrolyzates with antioxidant activity. The optimization of the main experimental variables involved in the process, such as type of enzyme, and hydrolysis conditions, concretely enzyme to substrate ratio, time and temperature, were evaluated using response surface methodology. A central composite circumscribed (CCC) design was employed to study the effect of the experimental variables on the antioxidant activity determined by radical scavenging potency. The parameters of the model were estimated by multiple linear regression, and the highest radical scavenging activity (2.57 μmol Trolox/mg protein) was found in WPC hydrolyzed with thermolysin after 8 h at 80 °C and an enzyme/substrate ratio of 0.10 (w/w). Nineteen β-Lg derived peptides were identified by RP-HPLC-MS/MS in this hydrolyzate. Of special interest are peptides LQKW f(58–61) and LDTDYKK f(95–101), which amino acid composition makes them potential contributors on the radical scavenging activity detected.

Physical and nutritional evaluation of wheat cookies supplemented with pulse flours of different particle sizes

Abstract: With the aim to develop functionally and nutritionally improved cookies, the influence of the total or partial replacement of wheat flour by pulses flours on the quality characteristics of cookies was analysed. Blends containing 25, 50, 75 and 100 g/100 g of navy bean, pinto bean, green lentil and commercial yellow pea flours were prepared. Green lentil, navy and pinto bean flours were used at two degrees of milling (fine and coarse). The incorporation of pulse flours significantly affected the physical and chemical parameters of the cookies. Incorporation of fine flours remarkably increased cookies’ hardness and decreased spread while coarse flours marginally reduced both parameters. The greatest impact on the physical characteristics was observed with the incorporation of green lentil flour, where cookies made with coarse flour were of unacceptable structure and were sticky to handle. Cookies baked with pulse flours were higher in protein level and showed increased antioxidant activity compared to the control. Overall analysis indicated that cookies with acceptable physical characteristics and improved nutritional profile could be produced with partial or complete replacement of the wheat flour.

Carotenoid retention and storage stability of spray-dried encapsulated paprika oleoresin using gum Arabic and Soy protein isolate as wall materials

Abstract: The performance of gum arabic (GA) and soy protein isolate (SPI) on paprika oleoresin microcapsules preparation and their storage were evaluated. Paprika oleoresin emulsions with a ratio of paprika oleoresin/wall material of 1:4 (w/w) were prepared using high-pressure homogenization, and then spray dried. Both treatments showed that carotenoid retention in the microcapsules increased as inlet air temperature was increased from 160 to 200 °C, and the yellow fraction was more stable than the red fraction at all temperatures tested. Microcapsules with the highest carotenoid retention were stored at different aw’s at 35 °C. Maximal stability for carotenoid oxidation was found at aw’s of 0.274 and 0.710 for microcapsules prepared with GA and SPI respectively. In both treatments the lowest carotenoid degradation was associated to the minimum integral entropy zone and affected in the same way to the red and yellow pigments, during storage at 35 °C. Additionally, in contrast to microcapsules prepared with SPI, GA microcapsules were unable to retain their structural integrity at water activities above 0.743.

Effect of different drying temperatures on the moisture and phytochemical constituents of edible Irish brown seaweed

Abstract: The effect of different temperatures on the drying kinetics and the phytochemical constituents of edible Irish brown seaweed, Himanthalia elongata were studied. This kinetic study involved the modelling of the terms of Fick’s diffusion equation, for estimation of the diffusion coefficients. The diffusivity coefficient increased from 5.6 × 10−07 to 12.2 × 10−07 m2/s as the drying temperatures increased with an estimated activation energy of 37.2 kJ/mol. The experimental data was also fitted to different empirical kinetic models, Newton, Logarithmic and Henderson–Pabis, and the goodness of fit for the different models was evaluated. The effect of drying temperatures on the phytochemical constituents in seaweed was also evaluated. Drying at 25 °C resulted in 49% and 51% reduction in the total phenol and total flavonoid content, respectively, as compared to fresh seaweed. However, the reduction declined as the drying temperatures were increased. The scavenging effect on DPPH radical was also greater for the fresh seaweed as compared to the dried form. An increase in the phytochemical content was seen for higher temperatures (35 °C and 40 °C) when the moisture content reduced by 50% indicating that this semi-dry state is even more nutritious than the fresh form and could be an interesting starting point for seaweed processing.

Evolution of sensory aroma attributes from coffee beans to brewed coffee.

Abstract: This study investigated the impact of degree of roasting, grinding, and brewing on the evolution of coffee aroma in green coffee beans from Ethiopia, Hawaii, and El Salvador. Using a highly-trained descriptive panel, 15 aromatic sensory attributes were identified and quantified in green beans, roasted beans (light, medium, and dark), ground coffee, and brewed coffee. Analysis of variance (ANOVA) and principal components analysis (PCA) were done separately for each preparation stage/step. The ANOVA showed that green beans had low coffee-related characteristics and were high in beany, green, musty/earthy, and sour aromatics, all of which carried through to the final brews. In general, the light roast was perceived to be sweeter in all stages and the darker roasts attained higher intensity of the typical ‘coffee’ attributes with which coffee consumers might like (coffee, roasted, burnt/acrid, and ashy/sooty). The aroma profiles generated were more influenced by the preparation stages and degrees of roasting than the coffee varieties.

Phenolic fortification of yogurt using grape and callus extracts

Abstract: In this study, acidified ethanol extracts of four different grape varieties (Cabernet sauvignon, Chardonnay, Shyrah, and Merlot) and grape callus were supplemented into yogurt as functional ingredients. The total phenolic substances, total anthocyanin content, and antioxidant activity of the yogurts were measured using chemical analyses. Yogurts inoculated with red grape and callus extracts displayed high phenolic – anthocyanin content and thus exhibited higher antioxidant power compared to yogurts containing chardonnay extracts and control samples. The storage time significantly affected the free radical scavenging capacity of the yogurts. The yogurts supplied with grape callus extract displayed the greatest antioxidant power on the first day of storage compared to all the assayed samples. The Gas Chromatography (GC) analysis revealed the presence of at least 10 individual bioactive phenolic compounds in the callus yogurt. The results obtained from this investigation shows that grape callus culture has a potential to be used as a food supplement to play a role in reducing the risk of developing chronic diseases such as cancer and cardiovascular disease.

Cocoa fibre and its application as a fat replacer in chocolate muffins

Abstract: A study was made of the texture, composition, appearance, colour and descriptive sensory analysis of low-fat chocolate muffins in which part of the oil ingredient (25%, 50% and 75%) had been replaced by soluble cocoa fibre and full-fat (no fat replacement) control sample to which cocoa powder had been added for comparison purposes. The rheology of the batter was studied with a rheometer. The height of the baked product fell as the fat replacement percentage rose, but no weight loss differences were observed after 1-h cooling. The texture of the fat replacement muffins showed lower values for hardness, chewiness and resilience than those of the control sample and retained greater moisture. The chocolate colour of samples with the highest level of fat replacement was scored similar to the full-fat control formulation indicating a good colour development without adding cocoa powder. The sponginess and springiness of the samples with the lowest fat replacement were scored similar to the full-fat control formulation. In general, muffins containing cocoa fibre were increasingly more cohesive and more difficult to chew and swallow when higher level of cocoa fibre was added. A certain degree of stickiness and a bitter taste different from that of cocoa were found.

Chemical composition and antioxidant activity of the husk and endosperm of fenugreek seeds

Abstract: Fenugreek ( Trigonella foenum-graecum) is used as a spice, vegetable and a medicinal plant. In the present study, fenugreek seeds were separated into husk and endosperm. The proximate composition of fenugreek seeds, husk and cotyledons showed that endosperm had the highest saponin (4.63 g/100 g) and protein (43.8 g/100 g) content. In contrast, husk had higher total polyphenols (103.8 mg of gallic acid equivalent/g, and TDF (77.1 g/100 g), comprising IDF (31.9 g/100 g) and SDF (45.2 g/100 g). At 200 μg concentration, extracts of husk, fenugreek seed, and endosperm exhibited 72%, 64%, and 56% antioxidant activity respectively by free-radical scavenging method. The study indicated that separation of fenugreek seeds into husk and endosperm could have advantage of process viability with respect to prior selective fractionation of bioactive components for their effective isolation.

The antioxidant activity and the bioactive compound content of Stevia rebaudiana water extracts

Abstract: Stevia rebaudiana (SR), a chrysanthemum herb, has been used as a vegetable-based sweetening additive in health drinks and in other foods. This study was conducted to investigate the antioxidant activity and the bioactive compounds found in water extracts taken from SR leaves and calli. Analysis of vitamins in the leaves showed that folic acid (52.18 mg/100 g) was a major component, followed by vitamin C. The total phenolic and flavonoid contents were found to be 130.76 μg catechin and 15.64 μg quercetin for leaves and 43.99 μg catechin and 1.57 μg quercetin for cellus at mg of water extracts, respectively. Pyrogallol was the major material among the phenolic compounds in both leaf and callus extracts. Furthermore, our results showed that the leaf extracts contained higher amounts of free radicals, hydroxyl radicals and superoxide anion radical scavenging activities than those of the callus extracts.

Changes in Yogurt Fermentation Characteristics, And Antioxidant Potential And In Vitro Inhibition Of Angiotensin-1 Converting Enzyme Upon The Inclusion Of Peppermint, Dill And Basil

Abstract: The present study investigated the effects of peppermint (Mentha piperita), dill (Anethum graveolens) and basil (Ocimum basilicum) on yogurt formation, proteolysis and inhibition of angiotensin-1 converting enzyme (ACE). Herbal-yogurts had faster rates of pH reduction than plain-yogurt. All herbal-yogurts had higher (p < 0.05) antioxidant activities than plain-yogurt, both at the end of fermentation and throughout the storage period. The o-phthalaldehyde (OPA) peptides in herbal-yogurts increased by 28 e36% after 7 days of storage. All herbal-yogurts showed higher anti-ACE activity than plain-yogurt at corresponding storage periods. M. piperita yogurt had highest inhibitory effect on ACE activity throughout the storage period. Peppermint, dill and basil may be used to modify microbial fermentation of milk with the intention of producing dairy products with higher antioxidant and enhanced anti-ACE activities.

Determination of effective moisture diffusivity and assessment of quality attributes of banana slices during drying

Abstract: The influence of drying temperatures on the moisture diffusivity and quality attributes of the dried banana slices in terms of volatile compound, shrinkage, color, texture and microstructure were studied. Bananas with peel color index of 5 corresponding to yellow color with green tip were sliced into 3 mm thickness, dipped into ascorbic acid solution and dried at four temperatures of 70, 80, 90 and 100 � C. Drying rate of banana slices can be divided into two sub-drying periods, first and second falling rate periods. The effective diffusivity estimated by the optimization technique was found to decrease sharply with moisture content in the first falling rate period and changed slightly in the second falling rate period. High-temperature drying seems to provide lower loss of volatile compounds in the dried sample. Moreover, the dried banana was very porous, resulting in remarkably lower hardness value than that obtained from the low-temperature drying whilst the crispiness was not significantly different amongst the samples obtained at various drying temperatures. Although the textural property could be improved at high temperature, the product color was brown as manifested by the low L- and hue values in particular at the drying temperature of 100 � C.

Colloidal delivery systems in foods: A general comparison with oral drug delivery

Abstract: The modern food industry is facing a stiff challenge of devising novel techniques for delivering functional ingredients without compromising the product functionalities. In recent times the focus on multidisciplinary research has led to the translation of expertise and knowledge from one field to another. Likewise, the field of colloidal delivery systems which has a strong existence in the pharmaceutical arena can find a great deal of application in foods especially with the growing demand of functional foods. This article is an introductory mini-review about the colloidal delivery systems which can be used in foods. And a general comparison with oral drug delivery systems with respect to the ways in which the knowledge from drug delivery can be extended to foods and the factors which need to be considered for development of colloidal delivery systems for food ingredients.

Antioxidant activity of several marine skin gelatins

Abstract: Gelatins obtained from the skins of tuna and halibut, and from the tunics of jumbo flying squid were hydrolysed by Alcalase to produce antioxidant peptides. Hydrolysis yielded an increase in the antioxidant capacity of gelatins of around two-fold when measured by the Fe reducing capacity (FRAP) method and even more when measured by the ABTS radical scavenging method. When both squid and tuna gelatins were hydrolysed with different enzymes (collagenase, trypsin, pepsin), Alcalase and pepsin gave the hydrolysates with the highest and lowest ABTS radical scavenging ability, respectively. FRAP assay showed that the squid hydrolysates prepared using Alcalase were the most effective in reducing ferric ions, whereas trypsin gave rise to the tuna hydrolysates with the highest iron reducing ability. When the amino acid composition of the gelatins was related to the antioxidant properties, ABTS radical scavenging was observed to be negatively correlated to the total content of hydrophobic amino acids and imino acids in all the samples, while Fe reducing power (FRAP) was strongly correlated with Hyl and degree of hydroxylation.

Chemical cross-linking and molecular aggregation of soybean protein during extrusion cooking at low and high moisture content

Abstract: Soybean protein isolate (SPI) was extruded using a co-rotating twin-screw extruder at low (28%) and high (60%) moisture content. Dead-stop operation was employed to obtain samples from different zones of the extruder. The protein solubility of extrudate was analyzed based on 8 different combinations of chemical bond-breaking solutions, which contained only phosphate buffer (P); two reagents, i.e. sodium dodecyl sulfate (SDS) in P (P + S), urea in P (P + U) and 2-mercaptoethanol (2-ME) in P (P + M); three reagents, i.e. (P + S + U), (P + U + M) and (P + M + S); four reagents, i.e. (P + S + U + M). Based on the protein solubility in the combined extraction solutions, each specific chemical bond and their interactions responsible for supporting the extrudate structure were further analyzed. The aggregation of protein subunits in extruded sample was investigated by using SDS-PAGE electrophoresis. The results showed that hydrophobic interactions, hydrogen bonds, disulfide bonds and their interactions collectively hold the structure of extrudate; and the importance of non-covalent bonds outweighs covalent bonds. Increasing feed moisture content could increase the interactions between disulfide bonds and hydrogen bonds and between disulfide bonds and hydrophobic interactions (p

Effect of extruded wheat bran on dough rheology and bread quality

Abstract: Bran extrusion is mainly under study and works should be performed to know the effect on dough and bread. This study was designed to investigate the effect of bran extrusion (addition of 2.5 g/100 g to 20 g/100g bran) on the rheological characteristics of bread dough, behaviour during fermentation, and bread quality. Extruded bran increased dough development time and tenacity to a greater extent than non-extruded bran, and minimized the loss of stability if over-mixing occurred. Extruded bran, due to its greater gas production, also reduced loss of dough height during fermentation to a greater extent than untreated bran. However, breads with extruded bran showed a higher volume and lower initial firmness than breads with normal bran if improver was added. However, no differences were found in the organoleptic evaluation. Bran extrusion therefore modified dough rheology but did not negatively affect bread quality. It could even improve the quality of breads with bran when improvers are added.

Clarification of fruit juices by fungal pectinases

Abstract: This study analyses the efficiency of fungal pectinolytic preparations produced in laboratory and commercial products used in the clarification process of apple, butia palm fruit, blueberry, and grape juices. Two crude enzymatic extracts, produced by Aspergillus niger T0005007-2 (TE1) and Aspergillus oryzae IPT 301 (TE2), were tested in solid-state and submerse cultures, respectively, in comparison to the commercial preparations Pectinex ® Clear and Pectinex ® BE Colour, used for the clarification of clear (apple, butia palm fruit) and dark (blueberry and grape) juices, respectively. With pectinases total activity at 1 U/mL of fruit juice, reactions were conducted at 30 and 50 °C, for 30 and 60 min. Time increase resulted in an improved clarification, whereas temperature increase could not be clearly linked to a greater clarification. When compared to the commercial products, the use of the crude preparation TE1 resulted in similar clarification of apple and blueberry juices. For butia palm and grape juice, however, TE1 presented the highest clarification results, revealing the potential of A. niger T0005007-2 enzymes for commercial application.

A simple UV-Vis spectrophotometric method for determination of β-carotene content in raw carrot, sweet potato and supplemented chicken meat nuggets

Abstract: A simple, rapid and low cost analytical method for the determination of β-carotene content in four different food categories is developed and validated. This method is based on solvent extraction followed by UV-Vis spectrometric detection. Target compound was extracted with four different solvents, in which acetone appears to be an excellent extractant as recovery of the analyte at 1 μg/g concentration in spiked samples was in the range of 67.8–98.8%, with relative standard deviation (RSD) ranging between 4.8 and 6.6%. Intra- and inter-day assay precisions of the method at 0.1, 1.0 and 5.0 μg/g concentrations ranged in between 3.4 and 8.9%. The linearities for β- carotene in the pure acetone, raw carrot, sweet potato, and fortified raw and cooked chicken meat nuggets were 0.994, 0.995, 0.990, 0.984 and 0.984, respectively. For robustness, the analytical method was applied to 24 samples of four different food categories namely carrot, sweet potato and carrot and sweet potato supplemented chicken meat nuggets.

Determination of antioxidant activity and antioxidant content in tomato varieties and evaluation of mutual interactions between antioxidants

Abstract: Major antioxidants and antioxidant activity in eight varieties of tomatoes were determined. Hydrophilic and lipophilic antioxidant activity (HAA and LAA) was determined by the ABTS assay and ascorbic acid and carotenoid contents were determined by HPLC-DAD. The HAA has far more significant impact on total antioxidant activity (83%) as compared with LAA. HAA was increasing during all ripening stages and was strongly correlated with ascorbic acid content ( r = 0.83). During the ripening the LAA was increasing till the III. stage of maturity and then decreased. The main carotenoids determined in the red-fruit tomatoes were lycopene, β-carotene and lutein. The content of lycopene has been increasing equally during the ripening. β-Carotene and lutein were intensively synthesized between the I. and II. stage of maturity. Among ascorbic acid, α-tocopherol, lycopene, β-carotene and lutein standards ascorbic acid was determined as the most efficient antioxidant followed by α-tocopherol and β-carotene. Antioxidant activity of ascorbic acid, α-tocopherol, β-carotene and lutein grew equally with increasing concentration, however lycopene was the most effective in its lowest concentration. The analysis of two-component mixtures showed significant synergism between lycopene-lutein, lycopene-β-carotene and α-tocopherol-β-carotene.

Effect of UV irradiation on enzymatic activities and physicochemical properties of apple juices from different varieties

Abstract: The influence of ultraviolet irradiation (UV) on some quality attributes (colour, pH, soluble solids content, formol index, total phenolics, sugars and vitamin C) and enzymatic activities (polyphenol oxidase, peroxidase and pectinolytic enzymes) of fresh apple juice was investigated. Apple juices made from four different varieties (Golden, Starking, Fuji and King David) were irradiated during 120 min with a high-pressure mercury lamp of 400 W that emits in a range between 250 and 740 nm with a resulting incident energy of 3.88·10−7 E·min−1. The treatment was effective in the inactivation of the assayed enzymes. Polyphenol oxidase was inactivated in 100 min, while peroxidase was completely destroyed in only 15 min in all the four varieties. No variations were observed in pH, soluble solids content, formol index, total phenolics and sugars. The colour of the juice made from King David was unvariable during all the experiment. In the ones made from Golden, Starking and Fuji, UV radiation impaired some of the pigments present in the juice, either initially present or the ones formed later. This fact can be especially observed in the increase of the CIELab parameter L*, which increased from 23.2 to 24.6 in Fuji juice. The content of vitamin C in juices from Golden, Starking and Fuji slightly changed during the experiment, decreasing a 4.0% in Fuji juice, 5.7% in Golden one and 5.6% in Starking one. Meanwhile, in the juice from King David the loss was 70.0%. This significant difference can be attributed to the lack of pigmentation of this juice.

Study on chemical composition and biological activities of essential oil and extracts from Stevia rebaudiana Bertoni leaves

Abstract: Essential oil (EO), water extract (WE), and methanol–water (MWE) (50/50 v:v) were prepared from Stevia rebaudiana Bertoni leaves Their chemicals compounds, antioxidant, anti-inflammation and antimicrobial activities were evaluated The EO was analyzed by gas chromatography/mass spectrometry The WE, and MWE compounds were identified by RP-HPLC In EO, carvacrol, caryophyllene, caryophyllene oxide, spathulenol, cardinol, α-pinene, limonene, isopinocarveol and ibuprofen were identified as major compounds Furthermore, in the WE and MWE, the major compounds were, quercetin dihydrate, protocatechuic acid and quercetin glucosyl These results show that S rebaudiana EO and extracts possess high antioxidant, anti-inflammation and antimicrobial properties The antimicrobial and antifungal activities of the extracts (EO, WE, MWE) were tested on Staphylococcus aureus ; Bacillus subtillis ; Escherichia coli ; Pseudomonas aeruginosa ; Aspergillus niger and Candida albicans , the lowest activity was founded on the EO extract

Influence of alcoholic fermentation process on antioxidant activity and phenolic levels from mulberries (Morus nigra L.)

Abstract: The aim of the present study was to evaluate the profile of the phenolic constituents of Morus nigra fruits and their antioxidant activity (DPPH) and to compare their contents before and after fermentation. Antioxidant phenolics of black mulberry ( M. nigra L.) samples grown in Galicia (NW Spain) were extracted with methanol/formic acid/water (MFW) and determined by high performance liquid chromatography (HPLC). Two major anthocyanins (cyanidin 3-glucoside and cyanidin 3-rutinoside) and two flavonols (quercetin 3-glucoside and rutin) were isolated, together with caffeic acid and other hydroxycinnamic and ellagic acid derivatives. Their chemical structures were identified by spectral analyses with diode array detection (DAD), but also with alkaline saponification and acid hydrolysis of the mulberry phenolics. Good correlations ( r 2 = 0.6229) were observed among total flavonols contents and the IC 50 radical scavenging capacities of mulberry fruits. Anthocyanins are the major flavonoids present in mulberry. It would be expected that anthocyanins contribute significantly to their antioxidant activity; nevertheless, alcohol generated during fermentation may also contribute to antioxidant activity. Our results provide useful antioxidant nutritional information of fresh and fermented mulberry fruits.

Carotenoid and flavanone content during refrigerated storage of orange juice processed by high-pressure, pulsed electric fields and low pasteurization

Abstract: The impact of different processing technologies, including non-thermal technologies, on bioactive compounds of orange juice was investigated. Freshly squeezed orange juice was treated by high pressure (HP) (400 MPa/40 °C/1 min), pulsed electric fields (PEF) (35 kV cm−1/750 μs) and low pasteurization (LPT) (70 °C/30 s). The stability of main carotenoids and flavanones was studied just after treatment and during 40 days of refrigerated storage at 4 °C. Just after treatment, HP juice showed a significant increase on total carotenoid and flavanone content extracted (45.19 and 15.46%, respectively) and on vitamin A value (30.89%) with regard untreated juice, whereas no significant changes were observed for PEF and LPT juices. For all treated orange juices, flavanone content decreased significantly (around 50%) during the first 20 days of storage at 4 °C while carotenoid content showed a moderate decrease (less than 11%) that took place during the last 20 days. In general, during refrigerated storage, carotenoids and flavanones remained higher in HP juice than in LPT and PEF juices. Hence, HP and PEF technologies were as effective o even more than LPT to preserve bioactive compounds in orange juice during refrigerated storage.

Spray drying of the mountain tea (Sideritis stricta) water extract by using different hydrocolloid carriers

Abstract: The water extract of the mountain tea was spray-dried by using different food hydrocolloids viz. β-cyclodextrin (BCD), arabic gum (AG), and maltodextrins (MD19 and MD12) as carrier materials. Powdered samples were then subjected to product yield, moisture content, water activity, bulk density, solubility, color (Lab) and SEM particle microstructure analyses. Furthermore, color (Lab), turbidity (NTU), total phenolic content (TPC), total antioxidant activity (TAA) and volatile compound (β-pinene) analyses were performed on the reconstituted mountain tea samples. The product yield increased with the addition of the carrier materials whereas decreased at higher drying temperatures. The inlet air temperature of 155 °C provided the better retention for β-pinene. Almost all physicochemical properties of the spray-dried mountain tea samples were significantly (P