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Acta Alimentaria
Authors: J. Tarek-Tilistyák, J. Agócs, M. Lukács, M. Dobró-Tóth, M. Juhász-Román, Z. Dinya, J. Jekő, and E. Máthé

The nutritive value, the microbiological safety of oilseed cake (OSC) obtained from naked pumpkin seed (PuC), sunflower seed (SC), yellow linseed (LC), and walnut (WnC), and their impact on wheat flour (WF) dough and bread sensory characteristics at 5% and 10% addition ratio were investigated. The OSCs had high protein (34–50%), fat (8–15%), total dietary fibre (23–36%) content and high energy value (383–444 kcal/100 g)). The OSC samples with a minimal exception fulfilled the requirements of feed legislation in force. An increased water absorption, dough development time, and reduced elasticity were observed probably due to the enhanced fiber and protein content. Dough stability increased with WnC, and decreased with PuC or SC addition. Enrichment provided the appearance of a brown bread for WnC, of a half-brown bread for LC. PuC gave an unusual look. The appearance of OSC fortified bread similar to daily bread, was an advantage resulting the 1st rank for 10% WnC bread and the 2nd one for 10% LC bread (P=0.05). The studied OSCs are suitable for food enrichment, however, in case of PuC and SC fortified flour blends, hydrocolloid application is recommended. Our data suggest that the newly developed fortified breads could be a valuable source for healthy nutrition.

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The aim of this study was to compare efficiency of RP-HPLC (Reversed-Phase High-Performance Liquid Chromatography) and LOC (Lab-on-Chip) methods for wheat gluten protein quantification regarding clustering of wheat cultivars according to the genetic similarity (HMW-GS combinations), as well as to explore relations of these two methods to wheat quality parameters. For that purpose, wheat quality parameters (protein content, falling number, wet gluten content, gluten index, Farinograph, Extensograph, and Amylograph), as well as amounts of gliadin and glutenin fractions by RP-HPLC and LOC methods were determined in two different sets of wheat cultivars (Croatian and Serbian). The percentages of gluten proteins and the values of quality parameters were used to characterize the samples by principal component analysis (PCA). Gluten protein quantification performed by method based on the protein fraction separation by molecular weights (LOC) was better for grouping of genetically similar wheat cultivars than quantification of proteins separated by their different solubility in specified solvent gradient (RP-HPLC). LOC method showed higher potential in wheat quality prediction.

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Proximate composition and physical parameters in nine quinoa cultivars were determined in order to establish differences among them and to contribute to their characterization. Faro, Pichaman, and Baer varieties cultivars were used. The aim of this research was to evaluate the physical and chemical properties and to characterize the protein fractions. All analysed properties showed significant differences between the cultivars. The physical measurements (weight, shape, size, and density) could be used for improving the technology associated with conditioning, transport, and storage of the grain. The protein content ranged from 15 to 18%, fat 6 to 8%, carbohydrates 70 to 74%, and ash from 3.5 to 4.4%, showing an outstanding nutritional profile. The relative quantity of soluble proteins (albumins and globulins) ranged from 40 to 65%, except in Faro variety cultivar, which presented 16%. The relative percentage of insoluble protein (prolamins and glutelins) ranged from 25 to 34%. The obtained information in this research could be useful in determining seed-quality, automating production, improving cultivation practices and technologies, and developing food products with enhanced nutritional qualities.

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The primary purpose of these researches was to optimize single-cell protein (SCP) production process using Saccharomyces cerevisiae NCAIM Y.00200 and Kluyveromyces marxianus DSM 4908 strain, and then to analyse the changes in yield of single-cell protein final product using vitamin supplementation. To determine these values, the total sugar content of the fermentation medium, and the protein content of the yeast was determined. During our work, a particular attention was paid to the change of sugar content and yeast protein quantity. Besides, yield (Yx/s) values, typical of the whole fermentation, were also measured. Protein yield, as the final product of fermentation, featured the efficiency of our work. The results of our optimized trial settings that were considered as control, using S. cerevisiae NCAIM Y.00200 and K. marxianus DSM 4908 strains, were compared with the results of vitamin-supplemented fermentation processes. On this basis, we can say that during our trials vitamin supplementation did not influence the final product yield of processes. The counted protein yields during fermentation were between 0.4–0.7 g g−1.

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Acta Alimentaria
Authors: N. Parunović, M. Petrović, V. Matekalo-Sverak, D. Radojković, D. Vranić, and Č. Radović

The objective of this paper is to investigate variability in chemical composition, total fatty acid and cholesterol content in m. longissimus dorsi (MLD) of Mangalitsa, swallow-belly (LM) and white (BM), and Swedish Landrace pigs (SL). Compared to SL, the total fat content has been 14.2% higher in BM, while it has been 10.2% higher in LM. SL fatteners contained significantly less cholesterol in MLD compared to LM and BM (−13.6 and −14.8%, P≤0.05). A higher percentage of SFA (+8.5 and +10.1%, P≤0.05) and PUFA (+8.0 and +9.4%, P≤0.05) has been established in MLD, originating from SL fatteners, compared to both Mangalitsa strains. The total MUFA content was higher in LM and BM than in SL (P≤0.05). A phenotypic correlation between protein content and ashes with water content in MLD has been positive (0.81 and 0.88), while the correlation between water content and total fats has been found to be negative (−0.99). A negative phenotypic correlation between MUFA and SFA, as well as PUFA and MUFA (−0.97 and −0.98) has been established, statistically significant at the level of P≤0.001. A positive phenotypic correlation between PUFA and SFA (0.90), statistically significant at the level of P≤0.001, has been found.

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Acidic and enzymatic coagulation of milk are complex processes which proceed in several phases and are dependent upon many different parameters. The formation of coagulum during lactic-acid fermentation is in fact acidic coagulation of milk. It occurs because of an increase in concentration of lactic acid, which causes a decrease in pH. Enzymatic coagulation of milk has been analytically described by means of mathematical models by many authors. Although enzymatic and acidic coagulation of milk do not proceed according to identical physical and chemical rules, it is possible to compare them kinetically. The aim of this paper was to combine the kinetics of enzymatic and acidic coagulation of milk and to mathematically present the changes that develop during lactic-acid fermentation of milk. The models presented in this paper enable a more complex mathematical analysis of the coagulation of the protein content of milk during lactic-acid fermentation. Application of the models enables the analysis and comparison of the kinetics of coagulation in different types of milk and various types of fermented dairy products manufactured with lactic acid bacteria. Mathematical combination of coagulation kinetics of the protein complex in milk with reological characteristics of the obtained fermented dairy products enables easier defining of parameters for lactic acid fermentation.

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The immobilization of enzymes has not been reported earlier on the two-dimensional crystalline bacterial cell surface (S-layer). In this study we tested S-layer isolated from Bacillus stearothermophilus PV72 for enzyme (ß-glucosidase, hexokinase and aldolase) immobilization. The carbodiimide method gave yields less than 5%. The yields of co-cross-linking method with glutaraldehyde were enhanced compared to the carbodiimide method, but the yield was higher than 10% only in the case of ß-glucosidase. Because of the fine structure of S-layer, immobilized enzymes could be removed from reaction mixtures only by centrifugation, therefore these preparations were entrapped in calcium alginate gel. The yields of entrapping procedures were between 15% and 37%. It was presumed that the new immobilized ß-glucosidase preparation could be used in a preliminary testing for flavour enrichment of wines. Efficiency of this preparation was compared to that of the immobilized ß-glucosidase on Acrylex C-100 support described earlier. We found that the immobilization of ß-glucosidase on both Acrylex C-100 support and S-layer followed by gel entrapping resulted in active enzyme preparations that could be used for flavour enrichment of wines without enhancing their protein content.

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Dietary fiber content of bulgurs prepared from different wheat varieties was investigated. Grains of 29 Turkish wheat cultivars and advanced breeding lines (23 of durum and 6 of common wheat) were used in this study. The average values for ADF and NDF (+amylase) contents of investigated durum wheats were 3.4% and 9.9%, respectively and the corresponding values of common wheats were 3.4% and 11.5%. In this study, the average values for ADF and NDF (+amylase) contents of bulgurs made of durum wheats were found to be 5.4% and 10.3%, respectively and the corresponding values of bulgurs made of common wheats were 5.8% and 11.7%. The minimum and maximum values for ADF and NDF (+amylase) contents of bulgurs made of durum wheats were found to be 4.1%-6.8% and 7.9%-11.8%, respectively and the corresponding values of bulgurs made of common wheats were 5.1%-6.4 and 10.6%-12.4%. The processing of wheat into bulgur generally increased the levels of ADF and NDF(+amylase) contents. It can be concluded that bulgur is at least as good as a raw wheat in terms of dietary fibre content. Although there is no essential change in the total protein content, ash and ß-carotene contents of the bulgurs were lower than the ones in the original wheats as a result of debranning.

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The toxic effects of cylindrospermopsin (cyanobacterial toxin) on animals have been examined extensively, but little research has focused on their effects on plants. In this study cylindrospermopsin (CYN) caused alterations of growth, soluble protein content and protease enzyme activity were studied on two aquatic plants Lemna minor and Wolffia arrhiza in short-term (5 days) experiments. For the treatments we used CYN containing crude extracts of Aphanizomenon ovalisporum (BGSD-423) and purified CYN as well. The maximal inhibitory effects on fresh weight of L. minor and W. arrhiza caused by crude extract were 60% and 54%, respectively, while the maximum inhibitory effects were 30% and 43% in the case of purified CYN at 20 μg ml−1 CYN content of culture medium. In CYN-treated plants the concentration of soluble protein showed mild increases, especially in W. arrhiza. Protease isoenzyme activity gels showed significant alterations of enzyme activities under the influence of CYN. Several isoenzymes were far more active and new ones appeared in CYN-treated plants. Treatments with cyanobacterial crude extract caused stronger effects than the purified cyanobacterial toxins used in equivalent CYN concentrations.

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The hypersensitive response (HR), a type of programmed cell death (PCD) during biotic stress is mediated by salicylic acid (SA). The aim of this work was to reveal the role of proteolysis and cysteine proteases in the execution of PCD in response of SA. Tomato plants were treated with sublethal (0.1 mM) and lethal (1 mM) SA concentrations through the root system. Treatment with 1 mM SA increased the electrolyte leakage and proteolytic activity and reduced the total protein content of roots after 6 h, while the proteolytic activity did not change in the leaves and in plants exposed to 0.1 mM SA. The expression of the papain-type cysteine protease SlCYP1, the vacuolar processing enzyme SlVPE1 and the tomato metacaspase SlMCA1 was induced within the first three hours in the leaves and after 0.5 h in the roots in the presence of 1 mM SA but the transcript levels did not increase significantly at sublethal SA. The Bax inhibitor-1 (SlBI-1), an antiapoptotic gene was over-expressed in the roots after SA treatments and it proved to be transient in the presence of sublethal SA. Protease inhibitors, SlPI2 and SlLTC were upregulated in the roots by sublethal SA but their expression remained low at 1 mM SA concentration. It is concluded that in contrast to leaves the SA-induced PCD is associated with increased proteolytic activity in the root tissues resulting from a fast up-regulation of specific cysteine proteases and down-regulation of protease inhibitors.

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