查看更多>>摘要：The effects of two drying methods (spray drying, freeze drying) on volatile organic compounds of yak milk powder (YMP) were compared by headspace-gas chromatography-ion mobility spectrometry (HS-GC-IMS) and principal component analysis (PCA). The characteristic fingerprints of YMP after ultra-high pressure sterilization and freeze drying (YMP_UHPS_FD) the YMP after ultra-high pressure sterilization and spray drying (YMP_UHPS_SD), the YMP after thermization and freeze drying (YMP_TH_FD), and the YMP after thermization and spray drying (YMP_TH_SD) were established. In total, 46 signal peaks were identified, and 17 compounds were identified including 6 aldehydes, 5 ketones, 3 acids, 1 terpene, 1 ester and 1 heterocyclic compound. The identified compounds correspond well with the flavors of organic components. In addition, the clustering analysis and fingerprint similarity analysis, based on PCA and Euclidean distance, showed that the similarity of YMP and its corresponding volatile components in different drying methods. The results found that the content of ketones, aldehydes and acids in YMP processed by SD is higher than that of yak milk powder processed by FD, and confirmed that different drying methods confer certain influence on the flavor of YMP, and the results also provide theoretic basis of flavor changes after the deep processing of YMP.
查看更多>>摘要：Effects of different dough resting times (0, 30, 60, and 90 min) on the microstructure of gluten network along the sheeting direction (longitudinal direction) and perpendicular to the sheeting direction (transverse direction), and the textural properties of dough sheet were investigated. Dough resting for more than 30 min reduced the transverse relaxation time, increased the content of tightly bound water in dough crumbs, and significantly increased the content of glutenin macropolymer in dough sheet. Microstructure revealed that dough resting for more than 30 min made the gluten network distributed more uniformly and compactly, while the total protein length and number of protein network lines of transverse direction increased by 25.57% and 10.50%, respectively, higher than the increase rate of longitudinal direction (15.93% and 7.09%, respectively). Furthermore, compared with 0 min, resting for more than 30 min increased the transverse resistance to extension and extensibility by 9.40% and 28.31%, respectively, higher than the increase rate of longitudinal direction (5.77% and 6.43%, respectively). According to the results, in comparison with the longitudinal direction, resting was more beneficial to the formation of an effective gluten network in transverse direction, and the quantitative analysis method intended for transverse and longitudinal gluten network was feasible.
查看更多>>摘要：The world's most consumed liquor-baijiu is characterised by measuring the perturbation in the resonance condition of a cylindrical microwave cavity as a function of alcohol content. Compared with other methods, the microwave sensor described here is compact, portable, low-cost and need of a small sample size (<0.1 mL) of liquid. The dielectric properties are obtained from the shift of the resonance frequency and changes in the quality factor. The measurement accuracy is validated by comparison with standard liquid samples, where high estimation accuracy (better than 6%) is achieved. The resonant responses and permittivity of baijiu samples are evaluated, where the alcohol content has a significant effect. Six other types of alcoholic drinks and ethanolwater mixtures were also measured for comparison purposes. From all the experimental results, it is demonstrated that the alcohol by volume can be readily deduced from the regressed functions obtained. In addition, the principal component analysis is successfully applied to the classification of liquids with varied alcohol contents.
查看更多>>摘要：This investigation examines the possibility for nitrite chemical preservative to be delivered in meat cured products. Potassium nitrite was encapsulated in delignified leaf celery and spinach and placed on the surface of meat. The delignification of leaf celery and spinach produces edible tubular cellulose (ETC) with 10 fold increased pore volume. The encapsulation and delivery of nitrite using vegetable tubular cellulose has been achieved in both ETC and ETC/Starch gel (SG) composite. Specifically, 43.5% of initially encapsulated potassium nitrite remains in the tubes of ETC/SG composite for a period of 5 days and 56.5% of nitrite is diffused in the meat, reaching a depth of 5 cm. The low delivery of potassium nitrite does not reduce the antibacterial activity of the total amount of nitrite. The controlled delivery of nitrite leads to a substantial reduction in meat microbiological load which was observed for a period of 10 days. Further research is needed, in order to develop the final technology for nitrite delivery in meat and meat products.
查看更多>>摘要：Chia seed is a good source of protein, carbohydrate, fat, dietary fiber, antioxidants and contain poly unsaturated fatty acids (PUFA) higher than any other seed-based food sources. In this study, the extracted oil from chia seed by conventional and high pressure processing (HPP) extraction was used to prepare nanoemulsions. The spontaneous emulsification was approached at six concentrations (0.5, 1, 1.25, 1.5, 2.5 and 3% (w/w)) and four different surfactants to oil ratio (1,2,3 and 4 (w/w) SOR). Some characteristics such as mean droplet size, antioxidant activity, total phenolic content, peroxide value, instantaneous and long-term stability, oil-water interaction and secondary oxidation products were assessed. According to the results, formulated nano emulsions had higher phenolic content and antioxidant activity than the corresponding oil samples. The highest antioxidant activity, phenolic content and oxidative stability were associated with emulsion samples prepared with 2.5% (w/w) chia oil.
查看更多>>摘要：Sensory tests involving taste-sensitive individuals provide the food industry with valuable information. However, the traditional evaluation of 6-n-propylthiouracil (PROP) tasters, which is assumed to reflect general taste sensitivity, is controversial. Therefore, the present study aimed to develop a rapid method for the classification of an individual's sensitivity to chemesthetic sensation, and to investigate the relationship between taste and chemesthetic sensation sensitivity at the suprathreshold level. In all, 72 young adults were screened and participated in the tests. The intensity of the pungency, heat, bitterness and saltiness that were presented via five concentrations of Sichuan pepper oleoresin (Spo), capsaicin, PROP and NaCl, respectively, were rated using generalized Labeled Magnitude Scales (gLMS). The method, namely 20% relative standard deviation (RSD), was developed for the classification of an individual's sensitivity. The results of ordinal multinomial logistic regression showed that the sensitivity to bitterness could be partly predicted by the sensitivity to saltiness, as well as the heat and pungency sensations. Furthermore, it was found that threshold should be used in conjunction with suprathreshold intensity ratings for classifying individuals. These findings regarding panelist sensitivity will be most useful in sensory evaluations of pungent food and in large-scale consumer studies.
查看更多>>摘要：The in vitro development of representative gut microbiota from obese individuals has been approached in the present study by using a three-stage dynamic simulator of the human gut microbiota (BFBL Gut Model). During the stabilization period, aimed to reach the microbiota steady state, initial differences found between normal-weight (Nw) and obese (Ob) faecal samples were reproduced. The differentiation included lower values of Akkermansia, Enterococcus and Faecali-bacterium and higher values of Lactobacillus for the Ob microbiota when compared with the Nw microbiota. The change of food ingredients to simulate a high consumption of readilyfermented carbohydrates and fructose-enriched beverages maintained these differences and additionally produced a decrease of Bifidobacterium in the Ob microbiota. Related to obesity metabolic signatures, a lower capacity to produce propionate was characteristic of the Ob microbiota under all the tested conditions. This could be useful in the selection of food ingredients for targeted production of propionate by the human gut microbiota prior to their assessment in nutritional intervention studies related to obesity.
查看更多>>摘要：Hop is a plant with several biological properties. Many factors affect both the presence and concentration of hop compounds, such as cultivar, location and growth conditions. Recently, the interest of hop cultivation in Brazil has grown despite the tropical weather and it has been possible to obtain hop completely cultivated in Brazilian soil. This study analyzed the chemical composition and verified the antioxidant and antimicrobial activities of Brazilian hop hydroethanolic extracts in comparison to a commercially available hop cultivar. Brazilian hops were a good source of flavonoids (5.72-12.82 mg CE/g dw), and presented a high content of phenolic compounds, in particular the Canastra cultivar (35.1 mg GAE/g dw). The Brazilian cultivars showed interesting antioxidant and antimicrobial proprieties. Gram-positive and Gram-negative bacteria were susceptible to hop hydroethanolic extracts and Staphylococcus aureus was inhibited by the extracts of all cultivars. The extracts presented antifungal activity against Byssochlamys nivea and significant growth inhibition at the higher concentration tested (20 mu l/ml). The hydroethanolic extracts exhibited a high content of alpha- and beta-acids, mainly the Vitoria, Columbus and Canastra cultivars, reaching almost 60% (w/w). These characteristics evidenced the potential application of Brazilian hops as raw materials in both pharmaceutical and food industries.
查看更多>>摘要：The current study focused on how matrix ratio affected the gel properties and microstructures of sugar beet pectin (SBP)/soy protein isolate (SPI)-based gels with and without emulsion. Roles of emulsion stabilized by Tween 20 and different ratios of matrices in gelation induced by laccase and heat treatment were evaluated. The textural, rheological and thermal stability properties of either gels or gels containing emulsion were enhanced with increasing level of SBP and weakened with increasing concentration of SPI. With the increase of SBP concentration, the emulsion addition showed no significant influence on the textural parameters of gels. However, the thermal stability of gel was weakened because of the emulsion addition. The E/P212 showed improved textural and rheological properties compared with the gel without emulsion. All gels exhibited a frequency-independent behavior, and the water holding capacity of each gel was about 90%. Moreover, microstructure analysis indicated that the well-filled honeycomb gel was formed in E/P212. The gelation behavior was mainly dominant by SBP, and the underlying gelation mechanism was that the SBP was cross-linked to promote the gelatinization reaction and rate of SPI.
查看更多>>摘要：Fresh-cut fruit products have dramatically increased in market share, because of their convenience and freshness, but have the drawback of a greatly reduced shelf life, compared with fresh fruit. The effects of curcumin-based photodynamic (CBP) treatment on the quality attributes of fresh-cut pineapple were investigated in this study. Results showed that individual 100 mu M curcumin treatment slightly inhibited microorganisms but illumination (10 or 20 min) had limited bactericidal efficacy on fresh-cut pineapple. Interestingly, combining the curcumin and illumination treatments resulted in a stronger, synergistic antimicrobial effect on fresh-cut pineapple. In addition, the growth of E. coli during storage at 4 degrees C was suppressed by CBP treatment, with a reduction of 0.19-1.24 log from day 0 to day 5. Visual appearance and color analysis showed that pineapple slices were well-preserved, with good control of browning for 5 days at 4 degrees C, after CBP with 100 mu M curcumin and 10 min illumination. The texture and sensory qualities of fresh-cut pineapple after CBP treatment for 10 min were better maintained than the longer illumination time of 20 min for 5 days at 4 degrees C. Overall, curcumin-based photodynamic treatment effectively preserved the quality attributes of fresh-cut pineapple for 5 days at 4 degrees C and this approach has clear potential as a preservation method for fresh-cut pineapple.
NSTL
Elsevier