查看更多>>摘要：Kefir is a health-promoting fermented drink having complex microbiota. This complex microbiota consists of bacteria and yeast association that is bound together with a polysaccharide called kefiran. To date, the complex microbiota of fermented foods was enlightened with culture-depended methods, however, recently, metagenomic studies have been started to use to reveal microbial diversity of fermented foods such as kefir. In this present study, we investigated the microbiome of two artisanal Turkish kefir grains (namely, A and G) by high throughput sequencing at the species level. Additionally, physicochemical analyses were carried out besides enumerations of lactobacilli, lactococci, total aerobic, and bifidobacteria in fermented milk kefirs. In these two kefir grains, different bacterial and fungal populations were revealed. In kefir grain A, Bifidobacterium longum was the dominant species while in kefir grain G, Lactobacillus kefiranofaciens was dominant. Concerning fungal diversity, in kefir grain A, Naumovozyma dairensis was the dominant yeast, while in kefir grain G, Zygosaccharomyces rouxii was dominant. High-throughput sequencing studies have revealed that kefir grains were typically dominated by lactobacilli. But, in this study, Bifidobacterium longum was found as a dominant bacterium in kefir for the first time.
Lucas, J. R.Velasco, R.Garcia, M. L.Selgas, M. D....
8页
查看更多>>摘要：The manufacture of restructured dry-cured hams involves a contamination risk with pathogens such as Listeria monocytogenes. This work studied the effect of E-beam, as sanitizing treatment, on the binding capacity of plasma powder (PP). For that, model systems of restructured boneless dry-cured hams were manufactured by adapting the conventional processing of dry-cured hams to their reduced size. They were contaminated with L. innocua as a surrogate and treated bilaterally with 2 kGy. The PP binding properties were determined using tensile tests. The microstructure of the binding area was studied by scanning electron microscopy. The results showed that the binding force increased progressively with the processing time and was not modified by the irradiation treatment. Scanning electron microscopy of the binding area showed increasingly compact and dense structures probably related to changes in proteins structure induced by the treatment.
De Iseppi, AlbertoMarangon, MatteoLomolino, GiovannaCrapisi, Antonella...
9页
查看更多>>摘要：Wine lees are an under-exploited sludge-like material mainly consisting of yeast cells that, upon fermentation, settle at the bottom of wine tanks. Lees from commercial red and white winemaking were processed to yield mannoprotein-rich extracts. An established autoclave-based extraction protocol, as well as a simplified version of it, were applied. The composition of the obtained wine lees extracts was determined. Extracts were tested as emulsifying and foaming agents in model food systems and benchmarked against analogues extracts derived from laboratory-grown yeast cultures of the same two strains used for red and white wines production. All ex-tracts showed good functionalities as emulsifying and foaming agents. However, some differences were noted in both composition and functionality, and these were related to the purification process used, yeast strain, and to the extract's origin (red lees, white lees, lab-grown yeasts). Extracts from real wine lees, which contained also grape-derived polyphenols, performed equally or better than the corresponding extracts derived from laboratory-grown yeast cultures of the same strains. Both red and white wine lees can be a novel and effective source of emulsifiers and foaming agents representing a valid alternative to the yeast biomass produced in bioreactors to be potentially used in the food industry.
查看更多>>摘要：Radio frequency-assisted hot air drying (RF-HAD) was carried out to produce carrot powders. Effect of electrode gap, sample thickness and sample weight on RF-HAD efficiency was investigated. 90 mm of electrode gap, 2.5 cm of sample thickness and 600 g of sample weight were selected as RF-HAD parameters in order to obtain acceptable drying rate and avoid excessive deformation. RF-HAD kinetics were studied and compared with hot air drying (HAD). RF-HAD increased drying rate and reduced drying time by 45%. Also, the quality of carrot powders obtained after RF-HAD was evaluated and compared with those produced by air and freeze drying. The results showed that the samples dried with RF-HAD had greater contents of 8-carotene, ascorbic acid, and total phenols, higher antioxidant activity and improved rehydration capacity compared to HAD. The better retention of cellular microstructure after RF-HAD also resulted in better rehydration capacity. Beta-carotene, ascorbic acid, total phenolic content and antioxidant activity retention rates were 80.26%, 45.33%, 72.42% and 67.49%, respectively, for RF-HAD. These values were 89.36%, 47.02%, 79.98% and 70.61% for freeze dried samples. The retention of bioactive compounds after RF-HAD was comparable to those achieved by freeze drying.
查看更多>>摘要：The synergistic effects of peptides in bovine skin gelatin hydrolysate (BSGH) on the water-holding capacity (WHC), measured as cooking loss, were studied. These peptides were isolated from the hydrolysate in fractions with different hydrophobicities by reversed-phase chromatography on C18 separation columns. Each peptide fraction was included in the meat matrix at various concentrations for the study of water retention. The fraction with the highest WHC (F5) was obtained. The experimental design consisted of a central compound design with axial points; the independent variables were X-1 (ingredient concentration in the meat sample) and X-2 (concentration of fraction F5 in the ingredient). The dependent variable was cooking loss. The WHC studies showed substantial synergistic effects occurred between the fractions within the BSGH, and the peptide fractions reduced the cooking loss by 62.96% with respect to a sample without the ingredient. However, a decrease of 42.26% was observed for the F5 fraction. This fraction corresponds to the highest WHC applied for the concentration of 3 g/100 g. The results suggest a synergistic WHC effect of the peptides present in the BSGH since this effect was significantly reduced (p <= 0.05) when the peptide fractions were separated.
查看更多>>摘要：Enzymatic hydrolysis and decoloration are indispensable processes for the production of biological peptides from microalgae materials. Herein, this study aimed to investigate the effects of enzymatic hydrolysis and activated carbon decoloration on antioxidative activities and peptidomic patterns of microalgae protein hydrolysates based on a peptidomic approach. Protein hydrolysates with different hydrolysis time (2-16 h) showed significantly different antioxidative activities based on DPPH and ABTS assays. Regarding the peptidomic pattern, principal component analysis (PCA) models revealed that hydrolysates were classified into discriminable clusters depending on the hydrolysis and decoloration processes. Protein hydrolysates contained many aromatic amino acid containing peptides, such as GDSLYPG, SADPETF, FPALN, FPGDY, and LTDWV, contributing to the classification of PCA models. Activated carbon decoloration at the concentration of 5 mg/mL significantly increased the color lightness by 38.20%, reduced antioxidative activities by 29.78% and 33.59% based on DPPH and ABTS methods, and reduced relative abundances of peptides, especially aromatic amino acid containing peptides. Fifteen selected peptides showed strong ABTS radical scavenging abilities and ten of these peptides were correlated with the antioxidative properties of hydrolysates. The monitoring of dynamic production processes at a molecular scale would contribute to the production and quality control of bioactive peptides from Auxenochlorella pyrenoidosa.
查看更多>>摘要：Utilization of pulse proteins in food products is increasingly explored, but the effect of processing on their quality and functionality is not well known. The effects of high pressure processing (HPP; 600 MPa, 5 degrees C, 4 min) and heat treatment (95 degrees C, 15 min) on the structure and functionality of pulse (lentil, pea, faba bean) proteins were evaluated, at protein concentrations characteristic for fortification of beverages (5 g/100 g) and gel formation (15 g/100 g). Structural changes were investigated by differential scanning calorimetry, rheological analyses, and surface hydrophobicity measurements. Sample solubility, water holding capacity, emulsifying and foaming properties were determined and compared to untreated controls. HPP and heat denatured pulse proteins and increased their surface hydrophobicity (p < 0.05). This led to changes in emulsifying and foaming, but the extent of these changes varied by protein type and treatment. Both treatments led to strong gels for 15 g/100 g samples, with heat-induced gels having greater strength (G') than pressure-induced gels (p < 0.05). Both treatments resulted in higher water holding capacity for 15 g/100 g samples, but lower solubility for 5 g/100 g samples (p < 0.05) compared to untreated controls. These changes can have a significant influence on pulse products and may facilitate new pulse product innovations.
查看更多>>摘要：In this work, we observed the effect of grape juice (% concentrated juice/% concentrated camel milk: GJ20/80, GJ50/50) and pomegranate juice (PJ20/80, PJ40/60) fortification on camel milk (CM) protein solubility and digestibility. Proteins were dissolved in sodium phosphate buffer to 50 mg/ml and defatted prior Bradford assay of protein concentration, then analyzed by Size Exclusion-Ultra High-Performance Liquid chromatography (SE-UHPLC). The CM protein aggregation and their stability were further monitored at different pH 2.0, 4.0, and 7.5 via sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). Freeze dried CM (FDCM) was the reference sample and our results showed that GJ50/50 and PJ40/60 with the highest fruit juice ratio had the lowest protein content in the supernatant, hence the decreased solubility. SE-UHPLC of supernatants showed a slight decrease in retention times of 11 kDa and 62 kDa proteins for GJ50/50 and PJ40/60 suggesting a pos-sibility of adduct formation due to fortification leading to higher molecular weight. The simulated static in vitro gastrointestinal digestion of samples revealed that most soluble proteins were readily digested by pepsin, trypsin and chymotrypsin enzymes leading to small peptides. However, the SDS PAGE of pellets showed the partial resistance of casein and alpha-lactalbumin against peptic digestion.
查看更多>>摘要：Grape stem and vine-shoot extracts have been studied in cooked pork model system as alternative preservatives to prevent oxidation reactions. After cooking, samples were stored in refrigeration and analyzed at 0, 10 and 20 d. Winery extracts addition (3 g/100 g) preserved better redness loss and reduced lipid and protein oxidation during chilled storage, being more effective than the traditional additive sodium ascorbate. A significant increase of total phenolics content and catechins, and the subsequent greater antioxidant capacity, were observed in samples added with winery extracts, being particularly noticeable in those treated with vine-shoot extract. Furthermore, volatile organic compounds (VOCs) concentration derived from lipid oxidation during chilled storage were lessen inhibited thanks to the extracts addition. Nonanal, some unsaturated aldehydes and octanoic acid showed high odor activity values (OAVs) in control samples after storage, evoking rancid odors. In this sense, winery by-products samples did not exhibit these flavors whereas distinguished pleasant sensorial features described as "herbaceous" or "woody" were found.
查看更多>>摘要：Since Baijiu, a traditionally distilled Chinese spirit, is widely consumed, the health risks of the ethyl carbamate (EC) content are of significant concern. To assess the EC content and evaluate dietary exposure risk to Chinese Baijiu, 2039 Baijiu samples, including 715 Strong-flavor Baijiu (SFB), 702 Jiang-flavor Baijiu (JFB), and 622 Light-flavor Baijiu (LFB), were collected from 16 provinces. The mean EC concentration was 62.26 mu g/L, ranging from n.d. to 382.33 mu g/L. Moreover, SFB exhibited higher EC content (113.94 mu g/L) than JFB (58.10 mu g/L) and LFB (12.02 mu g/L). The EC content varied between different geographic areas and was especially evident between East China and other regions. Based on Baijiu consumption data, the daily exposure to EC was calculated as 40 ng/kg bw/day for regular consumers, while SFB drinkers displayed a higher intake (73.2 ng/kg bw/day). The margin of exposure (MOE) indicated that the EC in SFB and JFB posed various health risks, necessitating the development of stricter supervision while reducing consumption to regulate the EC level in SFB and JFB. In addition, this study identified safe drinking limits for consumers, recommending 0.46 L/month for SFB, 0.96 L/ month for JFB, and 4.66 L/month for LFB.
NSTL
Elsevier