查看更多>>摘要：The effect of salt ion on the freeze-thaw stability of protein-polysaccharide emulsions remains controversial. In this study, we investigated the effects of two salts, CaCl2 and NaCl, on the freeze-thaw stability and digestion characteristics of soybean lipoprotein-hydroxypropyl methyl cellulose (LP-HPMC) emulsions. Analysis of the particle size, protein adsorption, and zeta-potential showed that addition of salt ions led to an increased extent of interfacial protein adsorption. The best oxidation stability and emulsification were observed when 100 mM salt was added. Analyses of the microstructure, creaming index, oiling off, and coalescence degree revealed that the presence of salt ions significantly improved the freeze-thaw stability of the emulsion, and addition of monovalent ions of NaCl to the emulsion to showed better interface protein crack resistance performance during the freezethaw cycle, low oiling off (8.75 +/- 0.5 %), and coalescence degree (43.67 +/- 2.5 %) compared to adding divalent ions of CaCl2. Moreover, Fourier infrared spectroscopy data revealed that the alpha-helix content in the secondary structure of LP was closely related to the freeze-thaw stability of the emulsion. Addition of salt ions delayed the release rate of internal oils in the LP-HPMC emulsion. These results provide a foundation of producing new emulsified foods with favorable freeze-thaw stability.
Na-Nakorn, KuenchanHamaker, Bruce R.Tongta, Sunanta
6页
查看更多>>摘要：The effect of soy protein isolate (SPI) and dietary fibers [maize bran (MB), resistant maltodextrin (RMD)] on cooked extruded rice quality-related parameters and relating rheology to the human gastric emptying measurement of Lag phase were investigated. DSC onset temperature (T-o) and peak temperature (T-p) of extruded rice substituted with 20 % SPI (20SPI-ER) were higher than of extruded rice substituted with 20 % MB (20MB-ER) and substituted with 20 % RMD (20RMD-ER). Peak viscosity of 20SPI-ER was lower than that of 20MB-ER and 20RMD-ER, indicating that SPI delayed starch gelatinization. Hardness and stickiness values of cooked 20SPI-ER were significantly higher than those of the control, 20MB-ER, and 20RMD-ER. Storage modulus (G') value of cooked 20SPI-ER was also higher than the control. It is possible that the swelling of starch granules was decreased when 20%SPI was supplemented. For human gastric emptying, cooked 20SPI-ER resulted in the highest lag phase, indicating that the time of grinding and mixing in the stomach took longer for this reformed rice. Overall the soy-containing cooked extruded rices were somewhat harder than the fiber-containing rices, which may not be as appealing to consumers, though they had a slightly longer Lag phase in the stomach which could relate feeling of fullness.
查看更多>>摘要：Pixian broad bean paste (PBBP) is a well-known fermented condiment in China. Herein, the water-soluble peptide extracts of PBBP were isolated by two sequential separations, ultrafiltration and reverse-phase high performance liquid chromatography (RP-HPLC). Ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS) analysis resulted in the identification of peptides. Four novel bioactive peptides: RGLSK, NKGPR, DNLLN, and TPCPPQ, were found firstly based on our knowledge. Among them, RGLSK showed the strongest ACE inhibitory activity with IC50 value of 87 mu mol/L, and TPCPPQ exhibited the highest antioxidant capacity (ABTS(center dot+) assay, 535 mu mol TE/g, DPPH center dot assay, 62.62 %). The electrospray ionization with triple-quadrupole mass spectrometry (ESI-QQQ-MS) was developed for the quantitative analysis of these peptides. The molecular docking suggested that RGLSK formed hydrogen bonds with S1 active sites (Ala354, Tyr523, Glu384) and made coordinate bonds with Zn2+ (His383, Glu411) of ACE. This study showed that PBBP was a good source of bioactive peptides.
查看更多>>摘要：Red currants, berries usually consumed fresh, are prone to fast quality deterioration, due to microbial spoilage. This study evaluates diffuse coplanar surface barrier discharge cold atmospheric pressure plasma (DCSBD CAPP) treatment as a potential decontamination technique for red currants and investigates its effects on microbial load and quality. Red currants were treated with air- and nitrogen-generated CAPP for 0, 5, and 10 min and stored for 10 d at 7 degrees C. The microbial load and physicochemical quality parameters were measured before and after treatment and during storage. Air-generated CAPP reduced yeasts and moulds load up to 1.28 log CFU g(-1), whereas nitrogen-generated CAPP had a significant effect on aerobic mesophilic total viable count (initial reduction of 1.11 log CFU g(-1)) and not on yeasts and moulds load. Both treatments did not have significant impact on most quality parameters. Results indicated that CAPP could be an effective decontamination technique for red currants, which also ensures the preservation of their antioxidant properties and high nutritional value during storage.
查看更多>>摘要：To ensure food security for the continuously growing worldwide population, it is necessary to promote the use of underutilized foods in food products. In this context, we evaluated the effect of a protein defatting process, which was performed using n-hexane, on the physicochemical characteristics, thermal stabilities, and aromatic profiles of proteins extracted from an edible insect, Protaetia brevitarsis. The defatting process decreased the color values (L*, a*, b*; P < 0.01) and apparent viscosities of the solutions of the extracted proteins and increased their pH values (P < 0.01), but did not affect their thermal stabilities. Additionally, defatting reduced the cohesiveness, gumminess, and chewiness (P < 0.01), but did not affect the hardness or springiness of the product. Furthermore, it lowered the levels of alcohols, aldehydes formed by lipid oxidation, and some hydrocarbons that have a negative physiological effect or impart an off-flavor to this food. Moreover, a simultaneous increase in the number of hydrocarbons with a pleasant flavor was observed. Collectively, the defatting process had a beneficial effect. It altered the properties of the insect proteins, and could potentially promote the use of edible insects as a protein source in the food industry.
查看更多>>摘要：The effect of replacing mechanically deboned chicken meat (MDCM) with collagen and plasma on the physicochemical, and sensory properties of a salchichon was evaluated. Four formulations were developed: control (SO), and three levels of MDCM replacement: 15% (S15), 30% (S30), and 50% (S50) (a combination of collagen, plasma, and water). Treatments (S15, S30, and S50) showed improvement in their texture properties, as well as higher moisture content and a lower fat and protein content than SO (p < 0.05). Sensory analysis showed that treatments did not add any significant disadvantages compared to SO and also showed similarity with the results obtained from physico-chemical analyzes. Although substitution of collagen and plasma resulted in a color alteration, animal source proteins such as collagen and plasma can be used as a potential substitute alternative for MDCM in the studied salchichon without negatively affecting the texture, physico-chemical, and sensory properties.
查看更多>>摘要：In this study, based on homology modeling and molecular docking, the key residues involved in substrate recognition in the active center of NADH-dependent D-lactate dehydrogenase (LF-d-LDH0653) from Lactobacillus fermentum were analyzed. The site-directed saturation mutagenesis of the key Tyr53 site was carried out to study the substrate specificity of mutants. 19 variants were obtained, of which the most significant change in substrate specificity was observed for variant Y53A. The Michaelis-Menten constant (Km), turnover number (kcat), and catalytic efficiency (kcat/Km) of Y53A to alpha-ketoisocaproate were 0.13 mM, 112.60 s- 1, and 856.67 mM-1 s- 1, respectively. The Michaelis-Menten constant (Km), turnover number (kcat), and catalytic efficiency (kcat/Km) of Y53A to phenylpyruvate were 0.16 mM, 78.17 s-1, and 481.62 mM-1 s- 1, respectively. The results indicated that Tyr53 was the key site that determines the substrate specificity of the enzyme, and single-point mutagenesis can dramatically affect the catalytic efficiency for various other substrates.
查看更多>>摘要：The purpose of this study was to compare the physicochemical properties and flavor components of rose jam from different regions to evaluate the quality of rose jam. The LC-ESI-MS analysis showed that the cyanidin was the main anthocyanin and quercetin was the main flavonoid in rose jam. The VOCs of rose jam in different regions were analyzed by HS-GC-MS and HS-GC-IMS, and the flavor fingerprint of rose jam was established with principal component analysis. The VOCs content in rose jam was different in different regions, but the VOCs content in the same region was similar. Alcohols, esters and aldehydes were the main flavor substances in rose jam. The HS-GC-IMS technology can be used to distinguish the volatile flavor compounds in rose jam and identify the true and false of Pingyin rose jam, and has high feasibility in the quality evaluation and identification of rose jam. Moreover, the rose jam samples from different regions can be well distinguished by principal component analysis. This study deepened the understanding of the physicochemical properties and VOCs of rose jam, and provided reference for the identification of rose jam in different regions.
de Paula, Igor LimaScaldini Teixeira, Eduarda BarbosaFrancisquini, Julia d'AlmeidaStephani, Rodrigo...
9页
查看更多>>摘要：Buffalo milk is the second most consumed type of milk in the world, behind only bovine milk. However, expertise in the production and physicochemical characteristics of buffalo milk powder products are not yet widely explored. Characterization techniques of three products were carried out in order to understand their composition of them after production. Raman spectroscopy accompanied by chemometrics was essential to understand the crystallization process of lactose in different environments with varying relative humidity. Finally, hydrolyzed products showed worse browning and rehydration rates as well as a worsening of rehydration when compared to the product without hydrolysis, in addition to the fact that maltodextrin served to circumvent these problems in the hydrolyzed product in two storage conditions in this work.
NSTL
Elsevier