查看更多>>摘要：Tea water-insoluble protein nanoparticles (TWIPNs) can be used as Pickering particles. However, Pickering emulsions stabilized by heat-treated TWIPNs (TWIPNPEs) were not characterized clearly. Therefore, the effect of heat-treated TWIPNs on the characteristics of Pickering emulsions was analyzed. TWIPNs became small at 60 degrees C and reassembled at 100 and 120 degrees C. Disulfide bonds and noncovalent bonds synergistically participated in the intermolecular forces of heat-treated TWIPNs. The random coil content of heat-treated TWIPNs decreased from 0.24 to 0.13 and the contents of alpha-helices and beta-sheets increased from 0.11 to 0.27 to 0.19 and 0.30 in the proportion of secondary structure with the increase in heat-treated TWIPN temperature. High temperature (100 degrees C/120 degrees C) on TWIPN accelerated the flocculation of emulsion droplets. A potential mechanism for the changes occurring in TWIPNPEs based on heat-treated TWIPNs was proposed to exhibit the instability of TWIPNPEs stabilized by heat-treated TWIPNs due to the structural rearrangements and enhanced intermolecular forces of TWIPNs at 100 and 120 degrees C. Besides, heat-treated TWIPNs at 30 and 40 g/L decreased the gel-like behavior of TWIPNPEs. These results can broaden our understanding of the characteristics of TWIPNPEs stabilized by heat-treated TWIPNs for utilizing tea by-products.
查看更多>>摘要：Although 1-deoxynojirimycin (DNJ) is an efficient alpha-glucosidase inhibitor, its lower yield limited its application. In this study, the integration of DNJ synthase genes gabT1, yktC1, and gutB1 into Bacillus amyloliquefaciens HZ-12 genome promoted DNJ production, resulting in 19.11%, 13.40%, and 16.70% increase in DNJ yield, respectively. Furthermore, the strain of B. amyloliquefaciens HZ-12/TB integrated with gabT1 and gutB1 was more conducive to improve DNJ production than the strain simultaneously integrated with gabT1, yktC1, and gutB1. Overexpression of glcP not only promoted the synthesis of DNJ efficiently, but also reduced the production of byproduct acetoin. Then, the strain of B. amyloliquefaciens HZ-12/TBP integrated with gabT1, gutB1, and glcP was resulted in 32.52% increase in DNJ production compared with B. amyloliquefaciens HZ-12. In addition, 20 g/kg lactose and 10 g/kg malt extract added into soybean solid medium were more beneficial for DNJ yield (1135.60 mg/kg). This study demonstrated that enhancing the synthesis pathway and glucose transport, and optimization of medium effectively improved the yield of DNJ in B. amyloliquefaciens, respectively, which provide an effective method to produce high level of DNJ.
查看更多>>摘要：Previous studies on the application of a novel multifrequency ultrasound washing treatment have proven to be effective in guaranteeing microbial safety, and enhancing the quality of cherry tomato. Nevertheless, there is still a need to evaluate the effect of these treatments on the metabolic activity, volatile profile, and sensorial quality of the fruit. This study evaluated the above parameters of cherry tomato treated with optimized assisted and unassisted multifrequency ultrasound. The treatments slightly enhanced the enzyme activities and inhibit ethylene production and respiration rate. The results indicated that the treatment with 20/40 kHz and aqueous ozone (0.85 +/- 0.2 mg/L) for 10 min enhanced and maintained the volatile compounds (VC). Out of the 44 identified VC, one had odor activity value > 1 and thereby considered as active aroma compound contributing significantly to the aroma of the sample. E-nose analysis indicated that alcohol, terpenes, and some aromatic compounds are the core indicators of the significant sensors. PCA showed that the processing methods had an influence on the flavor indexes of the tomatoes. The result verified that all the washing techniques did not result in a substantial negative effect on the tomato, and the treatment with ultrasound and ozone proved to be the best.
Mukilan, M. T.Ghanghas, NeerajPrabhakar, Pramod K.Sharma, Shikha...
11页
查看更多>>摘要：This work aimed to functionalize fenugreek seed protein using microfluidization treatment. The color, oil binding capacity, emulsion stability, and viscoelastic property of Kasuri and Ajmer fenugreek seed proteins (KF and AF) were considerably improved after microfluidization. The oil binding capacity of AF and KF significantly increased 9.99-12.92 mL/g and 10.72-11.32 mL/g, and similarly, emulsion stability also increased 76.32%90.51% and 68.28-87.50%, respectively (p < 0.05), whereas microfluidization reduced foam formation and water-binding capacity. The color change (.E*) was 17.11 +/- 0.29 and 6.71 +/- 0.73 for AF-C and KF-C, respectively. Microfluidized samples were lighter in color compared to the control samples. Microfluidization increased denaturation temperature (Tm) of KF from 54.8.C (KF-C) to 57.4. C (KF-M) while it reduced Tm of AF from 61.2. C (AF-C) to 56.0.C (AF-M). Microfluidization increased the linear viscoelastic range (strain %) of fenugreek seed proteins (16% for KF-M & 25.2% for AF-M), signifying increased stress tolerance. The frequency sweep test showed a higher storage modulus of microfluidized samples. The effect of microfluidization on the functional groups and morphology of fenugreek seed proteins was observed in the Fourier-transform infrared spectroscopic (FT-IR) and scanning electron microscopic (SEM) analyses, respectively.
查看更多>>摘要：Blue mussel (Mytilus edulis L.) is a shellfish with high nutritional and economic value. Free amino acids (FAAs), 5'-nucleotides, and lipids that affected the nutritional value and flavor of blue mussels varying with the seasons were analyzed using stable isotope labeling-liquid chromatography coupled with tandem mass spectrometry (SIL-LC-MS/MS) and ultra-performance liquid chromatography-Q-Exactive orbitrap tandem mass spectrometry (UPLC-Q-Exactive Orbitrap-MS). FAAs and 5'-nucleotides were most in the summer. Changes in FAAs between seasons were more obvious than those between genders, except in spring, when females were in the reproductive period. A total of 413 lipids were annotated in blue mussels for one year. Seasonal variation in triacylglycerols (TAGs) was the most evident. TAGs were dominant in females, while phosphatidylcholines (PCs) and phosphatidylethanolamines (PEs) were dominant in males. Overall, blue mussels in summer were more delicious and nutritious. Thus, such findings are of great significance to the seasonal preference of deep processing and consumption of mussel products.
查看更多>>摘要：'Bask in daytime and dewed at night' technique is traditionally used in doubanjiang fermentation, however, the underlying mechanism behind this technique is still unrevealed. This study aimed to elaborate the roles of three key indexes in this technique, that are air, sunlight, and mash turnover, on doubanjiang quality through the design of doubanjiang fermentation. The results showed that the exposure to air or sunlight was beneficial for doubanjiang to yield reddish-brown luster color, less acidity and balanced flavor. On the contrary, blocking of air and sunlight could accumulate higher acidity (4.75 +/- 0.01 g/100gdw), amino nitrogen (2.08 +/- 0.07 g/100gdw), alcohols (36.9 g/kg) and esters (26.9 g/kg). Regular mash turnover was mainly involved in making different mash layers exposure to air or sunlight equally through homogenizing mash layers. Different conditions also have been suggested to affect the microbiota dynamics by amplicon sequencing and RT-qPCR. Based on RDA analysis, Pediococcus, Meyerozyma, Bacillus and Zygosaccharomyces were predicted to be related to the changes of physicochemical properties or volatile compounds in different conditions, and their function was validated by simulated fermentation. This study would unravel the underlying scientific meaning of 'bask in daytime and dewed at night' technique in doubanjiang fermentation.
查看更多>>摘要：This work aimed at exploring the potential of partial substitution of the back-fat with fat mimetic, a novel polysaccharide-protein complex of xanthan gum and succinylated chicken liver protein, to improve the physicochemical characteristics and fatty acid composition of emulsified sausages. The quality characteristics of the sausages demonstrated that low-fat emulsified sausages with the addition of fat mimetic or its sunflower oil preemulsion presented similar microstructure and texture to high-fat sausages, while pre-emulsion increased the gel strength and whiteness of products. The rheological behavior characterization indicated that fat replacers caused a significant increase in storage modulus and loss modulus, explaining well the decreased cooking loss and the improved emulsification stability, water holding capacity (WHC) and heating stability. Although the back-fat replacement led to a great decrease in fatty acids, the nutritional values of fatty acids were optimized due to the incorporation of sunflower oil, as revealed by a 10% increase of polyunsaturated fatty acids and the decreased TBARS values within the storage. This study suggests the technological feasibility to simultaneously improve the quality and nutritional features of emulsified sausages with partial back-fat replacement by the proposed polysaccharide-protein complex, as well as the way to achieve chicken liver valorization.
查看更多>>摘要：This study investigated the effect of beeswax concentration and cooling temperature on the properties of rapeseed oil oleogels, and the effects of using the oleogels to replace 100% beef fat on the physico-chemical and oxidative stability of beef heart patties stored at 4 degrees C for 14 days. The results indicated that the 10% beeswax oleogel cooled at 4 degrees C was in a gel state, and it had higher lightness (L*), melting points, and melting enthalpies than that cooled at 25 degrees C. Beef heart patties, prepared with the oleogel had a reduction in SFA from 54.08 to 8.34, and an increase in PUFA from 8.88 to 34.37 g/100 g patties. During cold storage, compared with the beef fat patties, the raw oleogel patties had higher moisture and lower fat contents, while the cooked oleogel patties had lower hardness and gumminess values over time. However, in the oleogel patties, the thiobarbituric acid (TBARS), peroxide (POV), and carbonyl values increased until day 14. In conclusion, the oleogel addition improved fatty acid profiles and nutritional index of beef heart patties, but the texture and oxidative stability of patties still need further improvement.
查看更多>>摘要：The physical and oxidative stability of soybean protein hydrolysate-stabilized oil-in-water (O/W) emulsions created via limited hydrolysis using Alcalase (15, 30, 45, 60, 90, 120, and 180 min) was investigated. The extracted emulsion protein exhibited significantly lower surface hydrophobicity, higher antioxidant properties, and a greater proportion of beta-sheet and alpha-helix structures than soybean protein isolate. The physical stability of the emulsions was characterized by particle size, zeta-potential, rheological property, and multiple light scattering. The emulsion obtained by enzymatic hydrolysis for 90 min (90 min-E) had the highest physical stability, showing the smallest droplet size, uniform droplet distribution, lowest zeta-potential, lowest Turbiscan stability index, and larger G ' and G ' values. It also exhibited the highest oxidative stability, as evidenced by the thiobarbituric acid-reactive substances test. Due to the good physical and oxidative stability of 90 min-E, LC-MS/MS analysis and bioinformatic tools (Chou-Fasman secondary structure prediction and the BIOPEP database) were conducted on the protein extracted from 90 min-E. These data provided insight into the mechanism of emulsionstabilizing action by the emulsion protein (peptide) and identified potential bioactive peptides. This new strategy of producing stable O/W emulsions will likely expand its application to nutrient components or effective wall materials.
查看更多>>摘要：Dioscorea opposita Thunb., an edible and pharmaceutical plant, is usually consumed after heating processing, such as steaming, boiling, and frying with bran. In order to determine the effect of heating temperature on Maillard reaction products (MRPs) of polysaccharides from Dioscorea opposita (DOP), DOP-MRPs at 90-120 degrees C were prepared. The characterisation including colour, pH, FT-IR, XRD, fluorescence, UV-vis spectroscopy, and volatile compounds by GC-MS and GC-IMS were investigated. Results showed that the major volatile compounds of DOP-MRPs were acids, esters and ketones. Esters were generated the most (approximately 65.80%) at 90 degrees C, and acetic acids were produced approximately 25.70%. According to principal component analysis, flavours in DOP-MRP-90 and DOP-MRP-120 showed significant differences. Additionally, antioxidant activities including hydroxyl radical (HRS), DPPH scavenging and ferric ion reducing antioxidant power (FRAP) were conducted. The DOP-MRP-90 presented highest antioxidant activities, indicating that it donated more hydrogen atom to stabilize free radicals. This study provides a scientific basis for the application of the Maillard reaction in foods for Chinese yam polysaccharides.
NSTL
Elsevier