Showing papers in "European Food Research and Technology in 2005"

Aronia melanocarpa phenolics and their antioxidant activity

Abstract: The purpose of the present study was to evaluate small and high molecular phenolics (tannins) and antioxidant activity of Aronia melanocarpa berries, juice and pomace in order to find new potential sources of natural antioxidants. The fruits of Aronia melanocarpa Elliot were collected in the middle of October at a plantation near Wroclaw, Poland. The pomace has a much higher content of phenolics in comparision to juice and fruits. Results showed that polymeric proanthocyanins, predominantly of (−)epicatechin, are the major class of polyphenolic compounds in chokeberry, represent 66% of fruits polyphenols. The average concentration ranged from 1578.79 mg/100 g of DW for chokeberry juice up to 8191.58 mg/100 g in pomace. The concentration of phenolic acids (chlorogenic and neochlorogenic acids) in juice was higher than in pomace. Anthocyanins in Aronia melanocarpa are second phenolic compound group and represent about 25% of total polyphenols, mixture of four different cyanidin glycosides: 3-galactoside, 3-glucoside, 3-arabinoside and 3-xyloside. The higher antioxidant activity expressed as TEAC was measured in pomace >fruit >juice.

Heat and light stability of three natural blue colorants for use in confectionery and beverages

Abstract: The stabilities of three natural blue colorants—gardenia blue, phycocyanin and indigo—toward heat and light were studied in simple solutions of various pH. Gardenia blue was found to be stable at temperatures up to 80 °C in aqueous solution at pH 3, 5 and 7. Exposure to light of 3×105 lux for 24 hours resulted in approximately 50% degradation of gardenia blue in aqueous solution. Phycocyanin was found to be unstable to heat and light in aqueous solution. Phycocyanin is insoluble in acidic solution (pH 3) and denatures at temperatures above 45 °C at pH 5 and 7, leading to a color change. Exposure to light of 3×105 lux for 24 hours in aqueous solution at pH 5 and 7 caused ~80% degradation. Indigo was found to be stable in medium-chain-triglyceride oil for temperatures up to 90 °C, but to photodegrade (by approximately 70% after five hours of exposure to 3×105 lux), corresponding to a quantum yield of 1.8×10−4 mol Einstein−1 for visible light and 1.4×10−2 mol Einstein−1 for UV, as determined for monochromatic light of 600 and 313 nm, respectively. Exploratory studies have been carried out with the three blue colorants in application media such as soft drink, jelly gum, hard candy and sugar coating for soft candy. Despite its lower stability towards heat and light, phycocyanin was concluded to be the more versatile blue food colorant among the three studied, showing a bright blue color in jelly gum and coated soft candy.

Investigation of aromatic compounds in roasted cocoa powder

Abstract: Most of the volatile compounds identified are highly significant in determining cocoa powder flavour, and this paper demonstrates that basic sensory perceptions (undesirable, bitter pungent, repulsive, fruity, nutty, floral, vegetal, and sweet chocolate) can be totally explained by aroma compounds with R2-adjusted values of 0.85 and greater. Samples from five geographical origins of cocoa bean were characterized by chemical compounds and sensory attributes. The aroma extracts were obtained by a two-step procedure involving (1) preliminary steam distillation under reduced pressure to evaluate the methylpyrazines generated in roasted cocoa powder by spectrophotometry (flavour index), and (2) Likens-Nickerson’s simultaneous steam distillation and solvent extraction method with added NaCl. The distilled compounds were separated by adsorption chromatography in six fractions depending on the polarity. A combined total of 114 compounds were detected by gas chromatography/mass spectrometry, 110 of which were identified. About 15 components in the mean milligrams per kilogram range (1.09–4.67 mg kg−1) and 95 components in the mean micrograms per kilogram range (12–980 µg kg−1) were quantified. The major components of cocoa aroma were 2,3,5,6-tetramethylpyrazine, benzaldehyde, 2-phenylacetaldehyde, acetophenone, 3-methylbutyric acid, 5-methyl-2-phenyl-2-hexenal, ethyl phenylacetate, and 3-hydroxy-2-methyl-4-pyrone (mean greater than 1.30 mg kg−1).

Evolution of polyphenols in red wines from Vitis vinifera L. during aging in the bottle: II. Non-anthocyanin phenolic compounds

Abstract: The evolution of anthocyanins and pyranoanthocyanins (as measured by high-performance liquid chromatography) in young red wines from Vitis vinifera L. cv Tempranillo, Graciano and Cabernet Sauvignon (vintage 2000) from Navarra (Spain) was studied during 26 months of aging in the bottle. For the anthocyanin pigments of grape origin, a progressive decrease in their concentration, corresponding to first-order kinetics, was observed during this period. Independently of the anthocyanin structure studied, grape anthocyanins in Tempranillo wine presented twofold slower kinetics than those in Graciano and Cabernet Sauvignon wines, which exhibited a very similar disappearance rate. Acylated anthocyanins presented a slightly higher disappearance rate than the nonacylated ones, indicating the possible hydrolysis of the former into the latter forms. However, no distinction was observed in the kinetics of the different anthocyanidin forms (delphinidins, petunidins, peonidins and malvidins). These results indicate that during aging under nonoxidative conditions (bottle), the chemical reactivity of grape anthocyanins in wine is influenced by the grape variety, a factor that imposes over the stability associated with the chemical structure of each anthocyanin form. In relation to the evolution of pyranoanthocyanins, anthocyanin–pyruvic acid adducts presented a similar or lower disappearance rate than their corresponding anthocyanin precursors during the first months of aging in the bottle, while anthocyanin–vinylphenol and anthocyanin–vinylflavanol adducts did not exhibit significant variations during the whole period studied.

Antioxidant potency of cumin varieties—cumin, black cumin and bitter cumin—on antioxidant systems

Abstract: Cumin is one of the commonly used spices in food preparations. It is also used in traditional medicine as a stimulant, a carminative and an astringent. In this study, we characterized the antioxidant activity of three commercially available cumin varieties, viz., cumin (Cuminum cyminum), black cumin (Nigella sativa) and bitter cumin (C. nigrum). The antioxidant capacity of cumin varieties was tested on Fe2+ ascorbate induced rat liver microsomal lipid peroxidation, soybean lipoxygenase dependent lipid peroxidation and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging methods. The total phenolic content of methanolic extracts of cumin varieties ranged from 4.1 to 53.6 mg g−1 dry weight. Methanolic extracts of all the three varieties of cumin showed higher antioxidant activity compared with that of the aqueous extract. Among the cumin varieties, bitter cumin showed the highest antioxidant activity followed by cumin and black cumin in different antioxidant systems. IC50 values of the methanolic extract of bitter cumin were found to be 0.32, 0.1 and 0.07 mg dry weight of cumin seeds on the lipoxygenase dependent lipid peroxidation system, the DPPH radical scavenging system and the rat liver microsomal lipid peroxidation system, respectively. The data also show that cumin is a potent antioxidant capable of scavenging hydroxy, peroxy and DPPH free radicals and thus inhibits radical-mediated lipid peroxidation. The high antioxidant activity of bitter cumin can be correlated to the high phenolic content among the three cumin varieties. Thus, bitter cumin with a high phenolic content and good antioxidant activity can be supplemented for both nutritional purposes and preservation of foods.

Influence of processing on the generation of γ-aminobutyric acid in green coffee beans

Abstract: A determination of the concentrations of free amino acids in differently processed green coffees indicated the nonprotein amino acid γ-aminobutyric acid (GABA), a well-known plant stress metabolite, to be present in raw coffee beans (Coffea arabica L.) in significantly varying amounts. The GABA content of unwashed Arabica beans (green coffee produced by the dry processing method) was always markedly higher than that of washed Arabicas (wet processing method) as well as that of untreated seeds. This result underlined the assumption that during postharvest treatment a significant metabolism occurs within coffee seeds. A putative relation between drought stress of the coffee seeds and postharvest treatment methods is discussed. The GABA content of green coffee beans may serve as a potent tool to characterize the type of postharvest treatment applied in coffee processing.

Methyl jasmonate in conjunction with ethanol treatment increases antioxidant capacity, volatile compounds and postharvest life of strawberry fruit

Abstract: The antioxidant capacity, total anthocyanins, total phenolics, volatile compounds, and postharvest quality of strawberry fruit were evaluated after treatment with natural antimicrobial compounds and during storage at 7.5 °C. Strawberries treated with methyl jasmonate (MJ) in conjunction with ethanol (MJ-ETOH) showed higher antioxidant capacity, total phenolics, and anthocyanins than those treated with ethanol or control (non-treated). MJ-ETOH and ethanol treatments also increased volatile compounds during storage period. However, individual volatile compounds were affected differently. Methyl acetate, isoamyl acetate, ethyl hexanoate, butyl acetate, and hexyl acetate increased, while ethyl butanoate, 3-hexenyl acetate, and methyl hexanoate decreased during storage. The postharvest life was longer for those berries treated with MJ-ETOH and MJ than for those treated with ethanol or control fruit. In conclusion, strawberries treated with MJ-ETOH maintained an acceptable overall quality for the longest storage duration and retained higher levels of volatile compounds; also, berries treated with MJ showed the highest antioxidant capacity compared with other treatments during the postharvest period.

Recovery of anthocyanins from grape pomace extracts ( Vitis vinifera L. cv. Cabernet Mitos) using a polymeric adsorber resin

Abstract: Anthocyanins from a Cabernet Mitos grape pomace were extracted without sulfitation, purified and concentrated on a laboratory scale by adsorption to a styrene–divinylbenzene copolymerisate. The pigment loss during sample loading and washing of the column with water was negligible. Elution was performed with acidified methanol, ethanol and 2-propanol, respectively. The recovery rates ranged from 96 to 100% of anthocyanins when methanol was used, from 86 to 96% for ethanol and from 78 to 88% when pigments were eluted with 2-propanol. The temperature during adsorption and desorption (25 and 50 °C) did not significantly influence the pigment binding capacity. The recovery rates were not affected by the scale-up from laboratory to pilot-plant adsorption experiments. The use of polymeric resins facilitates nonthermal anthocyanin concentration since highly pigmented alcoholic eluates were obtained which can further be concentrated under mild conditions. The present study provides systematic data on adsorber technology increasingly used for the recovery of plant secondary metabolites.

Heat-induced degradation of inulin

Abstract: Dry heating of inulin from chicory for up to 60 min at temperatures between 135 and 195 °C resulted in a significant degradation of the fructan ranging from 20 to 100%. The choice of the analytical method has a significant influence on inulin quantification especially in heat-treated samples. The amount of inulin found after thermal treatment measured as fructose after acidic hydrolysis was significantly higher compared with corresponding data obtained with a method based on enzymatic hydrolysis. Using high-performance anion-exchange chromatography with pulsed amperometric detection as well as high-performance thin-layer chromatography, it was found that thermal treatment of inulin leads to a degradation of the long fructose chains and formation of new products, most likely di-D-fructose dianhydrides. These degradation products of inulin are cleavable by acid to fructose monomers, but their glycosidic bonds are no longer accessible for β-fructosidase, thus explaining the discrepancies in inulin quantification with respect to the method used. Inulin degradation must be taken into account when fructan is used as a prebiotic ingredient in thermally treated foods like bakery products.

Influence of the exposure to light on extra virgin olive oil quality during storage

Abstract: An experimental investigation was carried out to study the influence that exposure to light has on the quality of extra virgin oil during a 12-month storage period by comparing it with the quality of extra virgin oil stored in the dark. The results showed that the oils stored in the light had significantly lower tocopherol, carotenoid and chlorophyll contents than did the same oils kept in the dark. Moreover, the oils stored in the dark mainly contained primary oxidation products, while the oils kept in the light contained secondary oxidation products as confirmed by the K270 values which exceeded the legal limits even after purification by means of alumina. Overall, the results obtained showed that the shelf life of the oils exposed to light is shorter than that of oils kept in the dark, and that after only 2 months of exposure to light the oils examined could no longer be considered as extra virgin.

Quality control of beer using high-resolution nuclear magnetic resonance spectroscopy and multivariate analysis

Abstract: High-resolution nuclear magnetic resonance (NMR) spectroscopy is introduced for the quality control and authenticity assessment of beer in official food control. Measurements were performed using a 400-MHz NMR spectrometer using flow injection technology for automatic sample changing. Only degassing and addition of buffer (pH 5.6 in D2O for locking and 0.1% TSP for referencing) is required to prepare the beer samples. Differences in the spectral profiles of beers varying in type and origin were studied by principal component analysis (PCA), considering the spectrum to be a characteristic fingerprint. For the first time, the high throughput of a Flow-Injection NMR system allowed a comprehensive database of beer spectra for PCA classification to be established efficiently. Beers made with barley malt could be distinguished from those made with wheat malt. Clustering of beers from the same brewing sites was observed, as well as significant discrimination of beers with deteriorated quality. Using the partial least squares (PLS) method to correlate NMR spectra with results from reference methods, models for calculating the original gravity, ethanol and lactic acid were established. The results obtained suggest that NMR is a useful tool in the quality control of beer samples, since quantitative determination of essential compounds as well as chemometric classification are simultaneously possible. Compared to conventional methods, 1H NMR spectroscopy is faster and requires simpler sample preparation.

Geographic origin of meat—elements of an analytical approach to its authentication

Abstract: This review article discusses recent analytical developments with respect to the determination of the geographic origin of raw meat. The main emphasis is laid on lamb, beef and poultry. So far, some methods have shown quite promising potential (e.g. stable isotope ratios, trace elements), others have remained unsatisfactory in their discriminating power to authenticate the geographic origin of meat (e.g. microbiological profile, sensory traits, volatile compounds). Other methods (e.g. animal genotype, gross chemical composition) could be auxiliary criteria as they help to determine related indicators such as feeding or housing conditions but not directly the origin. The complexity of this question is large. An integrated approach simultaneously addressing various species and production characteristics such as environment, animal husbandry conditions, breed, feeding and drinking water has to be developed. Strategies have to be different for global and micro-regional scales.

Reactive oxygen species scavenging, metal chelation, reducing power and lipid peroxidation inhibition properties of different solvent fractions from Hizikia fusiformis

Abstract: The antioxidative properties of different organic and aqueous fractions obtained by solvent fractionation of 80% methanolic extract of Hizikia fusiformis were investigated for free-radical, reactive oxygen species scavenging (O2⋅−, H2O2, HO⋅, NO⋅), metal chelation, reducing power and lipid peroxidation (conjugated diene and thiobarbituric acid reactive substances formation) inhibition assays. Of the organic and aqueous fractions tested, the organic ethyl acetate and aqueous chloroform fractions were notably effective. Almost all fractions exhibited significantly higher activities on NO⋅ and 1,1-diphenyl-2-picrylhydrazyl scavenging compared with commercial antioxidants. The organic chloroform fraction showed the highest HO⋅ scavenging activity among other counterparts. The aqueous chloroform fraction demonstrated O2⋅− scavenging and metal chelating activities that are similar to those of butylated hydroxytoluene. The lipid peroxidation inhibition was significantly higher in the organic ethyl acetate fraction than that of α-tocopherol. These data suggest that both organic and aqueous fractions are rich in hydrophobic and hydrophilic antioxidative compounds with different antioxidative properties.

Effect of incorporation of amaranth flour on the quality of cookies

Abstract: Studies were carried out on composite flour cookies by incorporating amaranth seed (Amaranthus gangeticus) flour, which is rich in protein at 0–35% levels, showed a small reduction in water absorption capacity from 58.0 to 56.5%, a considerable reduction in Farinograph stability from 3.0 to 1.5 min and increase in the mixing tolerance index from 40 to 120 BU of the dough. The pasting characteristics of the blends using rapid visco analyser (RVA) showed a reduction in peak viscosity, cold paste viscosity as well as break down viscosity from 261 to 192, 204 to 153 and 151 to 108 RVU, respectively. Incorporation of amaranth flour improved the colour of the cookies from pale cream to golden brown. The cookies became crispier which is evident from the reduction in the breaking strength value from 6.2 to 4.02 kg. Considering the colour, taste, flavour, surface appearance of the cookies, 25% incorporation of amaranth flour was found to be optimum. By the addition of glycerol mono stearate (GMS) and soy lecithin in combination at 0.5% level, the quality of the cookies further improved.

Cell wall anthocyanin adsorption by different Saccharomyces strains during the fermentation of Vitis vinifera L. cv Graciano grapes

Abstract: This work reports the adsorption of anthocyanins by the cell walls of different strains of Saccharomyces during the production of red wine from Vitis vinifera L. cv Graciano grapes. The anthocyanin derivative contents of the yeast cell walls were substantially different to those of their corresponding wines. Cinnamoyl derivatives (6-p-coumaroyl and 6-caffeoyl) were strongly adsorbed while vitisins (adducts of pyruvic acid and acetaldehyde) were weakly adsorbed. The mean total anthocyanin concentration of the wines was 507.64 mg L−1 with the following distribution: 3-glucosides (3G), 82.2%; vitisins, 0.97%; 6-acetyl derivatives, 7.44%; 6-caffeoyl derivatives, 1.81%; and 6-p-coumaroyl derivatives, 7.54%. A mean of 18.57 mg of anthocyanins were adsorbed by the lees corresponding to 1 L of wine; this quantity was distributed: 3G, 52.60%; vitisins, 0.15%; 6-acetyl derivatives, 4.06%; 6-caffeoyl derivatives, 6.61%; and 6-p-coumaroyl derivatives, 36.58%. Large differences were seen between the different yeast strains examined with respect to the quantities of anthocyanins adsorbed. The mean adsorption percentage was 3.67%, but this varied between 1.60% (strain 3VA) and 5.85% (strain 9CV). The adsorption percentage of 6-p-coumaroyl derivates for strain 3VA (7.61%) was fourfold less than that of 9CV (28.37%). Strains 2EV and 3VA showed no vitisin adsorption.

The effects of concentration on electrical conductivity of orange juice concentrates during ohmic heating

Abstract: Ohmic heating is an alternative heating technique, using an electrical current passing through the food product. It can be specially used in pumpable food lines as an alternative heating unit. In this study, orange juice concentrates having 0.20–0.60 mass fraction soluble solids were ohmically heated by using five different voltage gradients (20–60 V/cm). The dependence of electrical conductivity on temperature, voltage gradient and concentration were measured. The ohmic heating system performance coefficients were calculated by using the energies given to the system and taken by the orange juice samples. The mathematical model results, taking system performance coefficients into account, were compared with experimental ones. The predictions of the mathematical model were found to be very accurate.

Total and individual tocopherol contents of sunflower oil at different steps of refining

Abstract: The contents of total and individual tocopherols of sunflower oils at different stages of industrial chemical and physical refining processes were determined by high-performance liquid chromatography (HPLC). According to the results, total and individual tocopherol contents gradually decreased until the end of the refining processes. The average losses of total tocopherol content during the chemical and physical refining processes were found to be 30.2% and 35.5%, respectively. The steam distillation stage of the physical refining process caused greatest overall reduction (average 24.6%) in total tocopherol content. In contrast to the physical refining process, the degumming-neutralizing stage in the chemical refining process caused greatest overall reduction (average 14.7%) in total tocopherol content. An additional average loss of 11.0% occurred during deodorizing in the chemical refining process. In both chemical and physical refining, the bleaching stage caused similar effects. The physical refining process caused higher loss in the total and individual tocopherol contents when compared with the chemical refining process. The conditions of the refining processes should be carefully evaluated to reduce the loss of tocopherols.

Antioxidant activity of enzymatic extracts from a brown seaweed Ecklonia cava by electron spin resonance spectrometry and comet assay

Abstract: The potential antioxidant activity of enzymatic extracts from Ecklonia cava was evaluated by 1,1-diphenyl-2-picrylhydrazyl (DPPH), hydroxyl and alkyl radical scavenging using a electron spin resonance (ESR) spectrophotometer compared with ESR signal intensity and inhibitory effect of DNA damage on comet assay. E. cava was enzymatically hydrolyzed with five food industrial carbohydrases (AMG, Celluclast, Termamyl, Ultraflo and Viscozyme) from Novozyme Nordisk. All the tested extracts exhibited strong radical scavenging activities and the values were dose-dependent. The DPPH and hydroxyl radical scavenging activities of the enzymatic extracts were compatible with the vitamin C, which the alkyl radical scavenging activity was even higher than that of vitamin C. Also in the present study, the enzymatic extracts showed strong inhibitory effect against DNA damage in a dose dependent manner. These results indicated that the E. cava might be valuable natural antioxidative source.

Supercritical fluid extraction of tea seed oil and its comparison with solvent extraction

Abstract: Supercritical fluid extraction (SFE) of tea seed oil was performed to study the effects of various parameters such as pressure, temperature, extraction time (dynamic) and modifier (ethanol) on the yield and composition of the oil. The results were also compared with those obtained by Soxhlet extraction, ultrasonic extraction, and DGF (Deutsche Gesellschaft fur Fettwissenschaft) standard method B-I5 (87) in lab conditions. The yield of tea seed oil obtained using SFE was similar to or higher than the other methods. The results from SFE showed that the modifier and pressure have significant effects on the extraction efficiency. The oil extracted by SFE in the absence of modifier was clearer than the oils obtained in other conditions. The fatty acid composition of each extract was determined by gas chromatography. Palmitic (C16:0), stearic (C18:0), oleic (C18:1), linoleic (C18:2) and gadoleic (C20:1) fatty acids were observed in the oil samples. Since it contains high-unsaturated fatty acids (UFA) and low saturated fatty acids (SFA), edible tea seed oil is also relatively healthy.

Antioxidative activity of a low molecular weight peptide derived from the sauce of fermented blue mussel, Mytilus edulis

Abstract: In order to identify nutraceutical functions of fermented fish and shellfish sauces, which are highly appreciated in food products in South-East Asia, the antioxidative activity of fermented blue mussel sauce (FBMS) was investigated. The blue mussel was fermented with 25% NaCl (w/w) at 20±0.5 °C for 12 months and the fermented sauce was passed bimonthly through a 40-mesh sieve, desalted using an electrodialyzer, and then lyophilized. The antioxidative activity of FBMSs was investigated and compared with that of a natural antioxidant, α-tocopherol standing as a reference. Using consecutive chromatographic methods, the antioxidative peptide with a molecular mass of 620 Da was purified from 6-month-fermented sauce, and its sequence of the peptide was FGHPY. In addition, 64.8 μM of the purified peptide could scavenge 89.5% of hydroxyl radical in radical scavenging assay using electron spin resonance spectroscopy.

Texture evolution of “Amaretti” cookies during storage

Abstract: The results of a study on texture evolution during 35 days of storage of “amaretti”, a typical Italian cookie, packaged in two different ways are reported. Amaretti cookies were wrapped in polyvinylchloride (PVC) film or aluminium foil (ALL), to simulate two different permeability conditions and stored at controlled temperature and humidity. Evolution of texture (such as hardness) and a w were tested instrumentally by a texture analyser and a hygrometer, respectively. Texture was assessed by a cut and puncturing test. Indices for hardening were the area under the curve (N mm) and gradient (N/mm) for the puncturing test and maximum force (N) for the cut test. Both textural tests showed significantly higher hardening of PVC cookies, compared to the ALL cookies. The latter retained good sensorial properties at the end of the storage period, although their internal structure changed from soft and moist to mealy, while the PVC cookies were no longer edible only 10 days after baking. a w values decreased and increased in PVC and ALL lots, respectively. The results suggest that hardening may be explained by water loss in PVC and moisture redistribution in ALL.

Effects of batters containing different protein types on the quality of deep-fat-fried chicken nuggets

Abstract: The effects of soy protein isolate (SPI), whey protein isolate (WPI) and egg albumen (EA) on the quality of deep-fat-fried chicken nuggets were studied. Batter without protein addition was used as a control. Batter pickup and moisture content, oil content, texture, porosity and colour of the nuggets were determined for 3, 6, 9 and 12 min of frying at 180 °C. Additionally, the rheological properties of batters were studied. SPI (3%) provided the highest apparent viscosity and coating pickup. All the batters showed shear-thinning behaviour except EA-added batter. Addition of different proteins to the batter formulation decreased the oil content of the final product. EA reduced the oil content of chicken nuggets significantly but yielded softer products. WPI (3%) was found to be the most effective ingredient on improving quality parameters of deep-fat-fried chicken nuggets. WPI (3%) added batters provided the hardest and crunchiest product with the darkest colour and also significantly reduced the oil content of the fried nuggets.

Impact of the fungal protease produced by Fusarium culmorum on the protein quality and breadmaking properties of winter wheat

Abstract: Samples artificially infected by Fusarium culmorum were analyzed to assess the effects of Fusarium infection on the protein quality of winter wheat (Triticum aestivum L.). The Fusarium infection did not noticeably influence either the crude protein content or the water absorption ability of the wheat flour. The protease activity found in the wheat flour was inversely correlated to the sedimentation value. In contrast, it was positively correlated to both the free amino acid content and the degree of infection as expressed in Fusarium protein equivalents (FPE) quantified by an enzyme-linked immunosorbent assay. A distinct reduction in the content of both total glutenin and high molecular weight glutenin subunits was detected in the seriously infected samples (FPE>20 µg g−1). The infection with Fusarium impaired the dough quality and led to a deformed loaf shape. The fungal protease was active over both a wide range of temperatures (from 10 to 100 °C) and a wide range of pH values (from 4.5 to 8.5). The maximum protease activity was displayed at 50 °C in the pH range 6.0–8.0. This property indicates that the protease produced by F. culmorum may impair storage proteins throughout all the processing procedures associated with wheat flour, thereby causing weak dough properties and, consequently, unsatisfactory bread quality.

Determination of folate in some cereals and commercial cereal-grain products consumed in Poland using trienzyme extraction and high-performance liquid chromatography methods

Abstract: A trienzyme treatment (rat plasma conjugase, α-amylase, protease) followed by affinity chromatography (with folate-binding protein from bovine milk) and reversed-phase high-performance liquid chromatography with UV and fluorescence detections was performed for quantification of different folate derivatives in some commercial cereal-grain products and cereals cultivated in Poland. The method described allowed good separation of the main folate vitamins. Of the commercial cereal-grain products analyzed, buckwheat groats (30 μg/100 g) had the highest content of total folate, followed by rye flour (29 μg/100 g), barley groats (21 μg/100 g) and wheat flours (19–20 μg/100 g). Two of the ready-to eat breakfast products were found to be fortified with folic acid with the level slightly exceeding the label declaration. The total folate content of whole-grain wheat flours was more than half as much as in white flours (33–40 μg/100 g), and the highest folate content was found in rye whole grains (123–135 μg/100 g). 5-Formyltetrahydrofolate was the predominating folate form in the cereal products analyzed, above all in rye flour.

The maceration process during winemaking extraction of anthocyanins from grape skins into wine

Abstract: The rate of anthocyanin extraction from skins of Monastrell grapes into wine during the maceration process has been studied by following anthocyanin accumulation in wine and its decrease in crushed skins. The most important changes occurred during the first 7 days of maceration; the following 7 days saw very little variation in the levels of the anthocyanins found in the wine or the crushed skins. The anthocyanin profile of the wines was quite different from that of the grape skins, whereas the crushed grape skins had a profile very similar to the profile of the grape skins at the time of harvest. Any differences in the proportions of the different anthocyanins found in Monastrell grapes and wines cannot therefore be attributed to different rates of extraction for each of the anthocyanins during winemaking. Other explanations, such as degradation or yeast cell wall adsorption, must be sought.

Impact of dairy protein powders on biscuit quality

Abstract: The effects of whey protein concentrate and sodium caseinate (NaCas) on a short dough biscuit formulation were investigated with respect to dough characteristics and final product quality. Dairy powders were added at levels of 5, 10 and 15% of flour weight. Addition of 5 and 10% dairy protein powders reduced dough hardness. Doughs containing 10 and 15% NaCas had significantly higher springiness and cohesiveness values compared with the values of the control (p<0.05). Addition of both protein powders increased surface brownness, indicated by an increase in L* value. Whey protein concentrate resulted in biscuit shrinkage during baking, whereas biscuits containing NaCas powders were significantly larger than the control (p<0.05). In general, biscuits containing protein powders were harder than the control and hardness increased as the level of protein powder was increased. Confocal laser microscopy showed that doughs with NaCas had an extensive protein network and NaCas appears to interact with the flour proteins.

Classification of South African red and white wines according to grape variety based on the non-coloured phenolic content

Abstract: The phenolic content of South African wines was investigated for the purpose of their classification according to variety or cultivar. Twenty-two phenolic compounds were quantified by liquid chromatography in 55 red wines of five varieties and in 38 white wines of three varieties. Data were compared to literature values reported for wines from across the globe. ANOVA was used to determine significant concentration differences between the different varieties. Further grouping of the data was investigated by principal component analysis and cluster analysis. Finally, linear discriminant analysis was used to derive classification functions for the effective recognition of red and white wine varieties which allowed 100.0% and 97.4% correct recognition of red and white wines, respectively.

Chemical, sensory and rheological properties of some commercial German and Egyptian tomato ketchups

Abstract: The rheological behaviour of eight tomato ketchups measured in the shear rate range from 0.1 to 100 1/s and with oscillatory tests was studied over a wide range of temperatures (0–50 °C) using a Physica UDS 200 rheometer. The results indicated that these tomato ketchups behave as non-Newtonian fluids semi-solid and have a definite yield stress. The relationship between ηeff and temperature of all the tomato ketchup brands under investigation was examined. Significantly higher correlation was found between ηeff and temperature. The ηeff values decrease with an increase in temperature. Oscillatory test data revealed weak gel-like (dispersion structure) behaviour of the ketchup: the magnitudes of G′ were higher than those of G″, and both increased with oscillatory frequency. The effect of temperature on the viscosity can be described by means of an Arrhenius-type equation. The flow activation energy for viscous flow depends on the chemical composition; the flow activation energy increases with the total solids contents. Chemical, physical and sensory tests for tomato ketchups were made.

Determination of astaxanthin and canthaxanthin in salmonid

Abstract: Total carotenoid (astaxanthin, cantaxanthin) content were determined in 60 traditionally cultured salmons (ICL, N1CL, N2CL) (Salmo salar), 10 natural salmons (NWL) (S salar), 20 ecological cultured salmons (IECL) (S salar), 20 ecological cultured rainbow trouts (NECR) (Oncorhynchus mykiss), 20 traditional cultured rainbow trouts (NCR) (O mykis) Quantitative and qualitative carotenoid determination was carried out using spectrophotometric method and thin layer chromatography method, respectively For pigmentation, astaxanthin was determined as the most important carotenoid Total carotenoid concentration in traditional cultured salmon, natural salmon, ecologically cultured salmon, ecologically and traditionally cultured rainbow trout was determined as 673–1014, 644–708, 714–904, 56–57, and 291–391 Eg/100 g respectively Carotinoid concentration in traditional cultured salmon was higher than the carotenoid concentration in natural salmon and ecological cultured salmon The lowest carotenoid concentration was determined in the ecological cultured rainbow trout (O mykiss)

Modelling of drying and rehydration of carrots using Peleg’s model

Abstract: The drying and rehydration process of conventionally and organically cultivated carrots was studied and the resulting data were fitted to the Peleg’s model. Carrots were fluid-bed and halogen dried and after that soaked in water at room temperature. The Peleg’s model gave a good prediction of water removal and water uptake in all experiments (R>0,994). During the drying process the Peleg’s rate constant (K 1) was affected by temperature. K 1 values decreased with the increase of the drying temperature. This relation was linear for fluid-bed drying and exponential for halogen drying, which implied a higher impact of the drying temperature on the dehydration kinetics during halogen drying. The lower K 1 values for fluid-bed drying suggested higher initial drying rates in comparison with halogen drying at all drying temperatures. The temperature dependence of 1/K 1 followed an Arrhenius-type relationship. Both Peleg’s rehydration constants (K 1 and K 2) increased with the increase of the drying temperature. This implied regular decrease of initial rehydration rate and water uptake with the increase of the drying temperature.