查看更多>>摘要：Tartary buckwheat dough (120 g) was used to produce steamed tartary buckwheat bread (STB). Alterations in antioxidant capacity and alpha-glucosidase inhibitory activity levels, and the concentrations of various flavonoid compounds, were investigated after each processing stage. It was identified that aglycone (quercetin and kaempferol) levels were increased after dough formation and fermentation stages. These stages were also associated with higher antioxidant capacity and alpha-glucosidase inhibitory activity. After steaming, flavonoid compound and antioxidant activity levels were slightly decreased in comparison to those observed after dough formation and fermentation steps, although they were higher than in raw flour. To clarify the anti-diabetic potential of individual flavonoid compounds, the antioxidant and alpha-glucosidase inhibitory activities of four distinct flavonoids were investigated. The results of the present study revealed that aglycones have more potent anti-diabetic effects than their corresponding glycosides, which may explain the change in antioxidant and alpha-glucosidase inhibitory activities of samples taken after the different processing stages. Correlation analysis also indicated that flavonoids' being in their aglycone form was positively associated with higher antioxidant and alpha-glucosidase inhibitory activities. Overall, these data suggest that deglycosylation of flavonoids, which occurs during the preparation of STB, contributes to higher hypoglycemic potential in tartary buckwheat bread products.
查看更多>>摘要：Determination of the histamine level in fish is essential not only because it is an indicator of fish freshness but also because this prevents the risk of histamine intoxication in consumers. This study used the strategy of nearinfrared (NIR) spectroscopy coupled with a hybrid variable selection for rapid and nondestructive assessment of the histamine level in mackerel. To effectively identify the highly informative spectral variables, a three-step hybrid strategy, combining backward interval partial least squares, selectivity ratio and flower pollination algorithm, was developed. The optimized variables were fitted to the multivariate calibration models of partial least squares model (PLS), radial basis function neural network (RBFNN), and wavelet neural network (WNN). The best model was obtained by the optimized WNN model using the hybrid variable selection method, with Rsquared (R2P) value and root mean squared error for prediction were, 0.79 and 70 mg/kg for flesh side dataset, and 0.76 and 75 mg/kg for skin side dataset. The obtained results for the skin side dataset significantly outperformed the PLS(R2P = 0.58) and RBFNN (R2P = 0.47) calibration models.
查看更多>>摘要：The resistance of probiotics to bile salts is critical to their survive in the intestinal tract. Bile salt hydrolase (BSH) catalyzes the deconjugation of conjugated bile salts and is thought to be involved in bile salt resistance. The aim of this study was to explore the roles of different bsh genes in the bile salt resistance of Lactobacillus plantarum AR113. CRISPR-Cas9 gene editing was used to construct single, double, and triple bsh knockout strains. The functions of the bsh 1, and bsh 3 genes were found to be critical for BSH activity in L. plantarum AR113. Examination of six bile salts revealed that glycine-conjugated bile salts were the preferred substrate of BSH. The growth of strains with bsh1 or bsh3 knockout was significantly inhibited when treated with glycine-conjugated bile salts. However, strains with bsh2 or bsh4 knockout were not affected. These results suggested that bsh 1 and bsh 3 are closely related to bile salt resistance. This result will be useful for the rational, high-throughput selection of strains with high tolerance to bile salts.
查看更多>>摘要：Superheated steam (SS) was used to improve the milling characteristics of common buckwheat grains during storage. The changes in milling characteristics, pasting properties, micro-mechanical behavior and protein-starch interactions of buckwheat during storage were investigated. Results showed that the average particle size, color and pasting viscosities of untreated buckwheat decreased during storage, while the damaged starch content increased significantly. SS slowed down these deteriorations of milling characteristics by alleviating intracellular cleavage of starch during the process of buckwheat milling. SS also kept pasting properties of starch stable during the continuous heating and shearing process. X-ray diffraction showed less variation in crystallinity and stable structure of starch induced by SS. The results from SDS-PAGE and confocal laser scanning microscopy showed that these stabilizations were associated with the disulfide bonds of protein and its interaction with starch granules. It meant SS processing retarded the quality deterioration during storage and protected buckwheat starch against mechanical damage by promoting protein aggregation and letting the starch to be wrapped tightly by the protein, so as to protect the swollen starch granules from disintegration. Therefore, SS processing was potentially applicable for improving milling characteristics of buckwheat.
Casquete, RocioVelazquez, RocioHernandez, AlejandroCordoba, Maria de Guia...
10页
查看更多>>摘要：A genetic characterization of 13 species of cayenne provided by Spanish milling industries was performed, and their colour, pungency and antioxidant properties were evaluated. Colour parameters (carotenoids, reflected and extractable colour), capsaicinoids, total phenolic compounds and antioxidant activity by the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging method and 2,2 '-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid (ABTS) were determined in the cayenne samples, and the stability of cayenne properties was determined after exposure to UV light. Genetic characterization using different barcode markers (26S large subunit of rDNA, internal transcribed spacer 2, rbcL gene and matK gene) revealed close relationships among samples. However, notable differences were found for most of the quality parameters studied. Specifically, colour parameters were the most important traits for the discrimination of different samples. Samples with high colour quality presented 989.9 mu g of capsanthin/g of dry matter, 104.8 ASTA units and 26.6 units in the a* coordinate of the CIELAB space. In contrast, the lowest-quality sample presented 582.7 mu g of capsanthin/g of dry matter, 21.1 ASTA units and 15.4 units in the a* coordinate. DPPH and ABTS values ranged from 73.8 to 161.8 and from 217.1 to 325.7 mg Trolox/100 g, respectively. Pungency was highly variable among samples, with values ranging between 68.2 and 751.9 mu g of capsaicin/g and 38.7 and 273.5 mu g of dihidrocapsaicin/g. Principal component analysis indicated that capsaicinoids and total phenolic compounds are the best indices to determine the antioxidant activity of cayenne, which is highly correlated with the stability of colour and pungency. According to these findings, the desirable technological qualities and the longest shelf-life of cayenne are associated with a high content of capsaicinoids and phenolic compounds, which guarantee good colour stability and pungency associated with high antioxidant activity.
Lotfy, Shereen N.Saad, RashaEl-Massrey, Khaled F.Fadel, Hoda H. M....
9页
查看更多>>摘要：The enzymatically hydrolyzed quinoa protein (E-HQP) was used as a main precursor of a wide range of thermal process flavours. Identification of the volatile compounds generated from the reaction of E-HQP-xylose model mixture at different initial pH values (5, 6, 7, 8 and 9) was performed using a solid phase microextraction GC MS technique. The content of free amino acids, colour intensity and radical scavenging activity of the Maillard reaction products (MRPs) formed at each pH were determined. The results revealed a great influence of the pH values on chemical composition and odour profile of the generated volatiles. The studies showed that low pH favoured formation of furans, furanones and cyclopentanones. In contrast, the pyrazines comprised the highest yield of the total volatiles at pH 9. A positive correlation was found between increasing the pH values and browning intensity of MRPs. The antioxidant activity of MRPs and total content of free amino groups showed a gradual decrease by increasing the pH. A correlation was found between the antioxidant activity of MRPs and the volatile compounds generated at each pH. Principle component analysis clearly elucidated a distinct separation among the investigated E-HQP-xylose model mixtures based on the volatile compounds generated at different pH.
查看更多>>摘要：Yak milk dreg (YMD) is a traditional homemade fermented daily food in Tibet. In this study, we characterized the amino acid profiles and bacterial community diversities of nine different YMD samples collected from Nyingchi region of Tibet. The results showed that Glu and Pro were the major amino acid, Proteobacteria and Firmicutes were the predominant phylum, Lactobacillus was the predominant genus. The taxonomic composition and abundance of bacterial community were distinct with the YMD samples of three regions (B, G, and M) based on the principal component analysis. Metagenomic prediction based on PICRUSt analysis revealed that amino acid metabolism, carbohydrate metabolism, membrane transport were the most abundant KEGG pathway. Moreover, we constructed a related relationship of heatmap to explain correlations among the bacterial community and amino acids. This study descripted the bacterial community diversity of the YMD and enable us to develop traditional daily products resources derived from YMD.
查看更多>>摘要：The aim of the work was to compare lc-carrageenan and iota-carrageenan (in concentrations 0.025-0.150 g/100 g) application to cream desserts (dry matter content 44 g/100 g and fat content 38.5 g/100 g) and evaluate their viscoelastic properties and sensory quality. Sample properties were monitored during 28 d (6 +/- 2 degrees C). During storage a slight decrease in the pH of the samples was monitored. Furthermore, the increasing addition of lc- and iota-carrageenan resulted in complex modulus (G*) and gel strength (AF) values increase (P < 0.05). In all samples, regardless of the type and concentration of carrageenan, a significant increase in the values of firmness was observed during storage. In general, the G* and AF were higher in the samples with lc-carrageenan compared to products to which iota-carrageenan was applied (P < 0.05). Moreover, all samples were characterised as homogenous and no water release and no off-flavour (P >= 0.05) were detected. The suggested concentration of both tested carrageenans in order to obtain products with desired properties lies in the range of 0.050-0.125 g/100 g.
Barrios-Rodriguez, Yeison FernandoReyes, Cristhian Andres RojasCampos, Joan Sebastian TrianaGiron-Hernandez, Joel...
7页
查看更多>>摘要：Sensory evaluation provides subjective information about characteristics related to the crop management and post-harvesting of coffee. Fourier Transform Infrared Spectroscopy (FTIR) quickly and easily detects additional coffee characteristics to those obtained through sensory analysis. This work aimed to complement the sensory evaluation of Specialty coffee by using FTIR and chemometrics. Samples from all three post-harvest methods (dry, semi-dry, and wet) were sensory analysed using the protocol of the Specialty Coffee Association (SCA). Infrared spectra were obtained from samples of green beans, medium roast coffee, and dark roast coffee, previously processed by the three post-harvest methods. Sensory evaluation, according to the SCA quality criteria, classified the coffee obtained from semi-dry process as excellent specialty coffee, and coffees obtained by wet and dry processing methods as very good specialty coffees. PCAs discriminated the post-harvest treatments based on the FTIR data. Recognition based on prediction of samples of the post-harvest treatments by LDAs was over 95%. Results demonstrated that FTIR in combination with multivariate analysis complemented the information obtained from the sensory analysis, and allowed to discriminate and identify the post-harvest treatments for green beans, medium roast coffee, and dark roast coffee.
查看更多>>摘要：The use of non-conventional yeasts could be an interesting source of biodiversity for developing innovative fermented beverages. Here, 43 wild yeast strains belonging to different genera such as Lachancea, Kluyveromyces, Torulaspora, Metschnikowia, Kazachstania, Brettanomyces, Pichia, Candida, Hanseniaspora, Rhodotorula, Rodospor-idobolus and Saccharomyces, previously evaluated for their probiotic traits, have been tested for craft beer pro-duction. Different experimental lines were carried out to develop a new beverage which could combine increased aromatic characteristics and improved nutritional properties: i) beers produced from pils wort (PW); ii) beers from pils wort enriched with lentil (PLW) or chickpea flour extracts (PCW).
NSTL
Elsevier