查看更多>>摘要：To analyze structural characteristic of rabbit glycated myofibrillar protein (GMP) with different solubility in low ionic strength medium, changes in fourier transform infrared spectroscopy, Raman spectroscopy analysis, intrinsic fluorescence analysis, UV absorption spectra, surface hydrophobicity, total sulfhydryl and carbonyl contents, and sodium dodecyl sulfate polyacrylamide gel electrophoresis were determined. The results reflected that GMP with 75.07% solubility in low ionic strength medium had less a-helix and more random coil than GMP with other solubility. The difference in the tertiary structure of GMP with different solubility was also detected, including that intrinsic fluorescence intensity of GMP gradually reduced and a red shift of peak positions of UV absorption spectrum of GMP with solubility increased. Furthermore, the total sulfhydryl content of GMP with 75.07% solubility was much lower than other groups, and carbonyl content of GMP was significantly increased when solubility was above 15.10%. Results also suggested that the electrophoretic mobility of the protein chain of GMP with 75.07% solubility was minimum among all groups. In conclusion, the structure of rabbit GMP with 75.07% solubility in low ionic strength medium was different from GMP with other solubility due to glycation process, and protein oxidation may be also response for the structure changes.
查看更多>>摘要：The purpose of this study is to investigate the effects of vacuum processing on antioxidant activity and microbial growth of strawberry puree over day 10 after storage at 5, 25, and 35 degrees C. The strawberry puree was prepared under vacuum (7.2 Pa) using a specially designed grinding and packaging system. Grinding under vacuum resulted in significantly greater antioxidant activity retention (78.6-92.1%) as compared to grinding in atmospheric conditions (48.4-68.2%) during storage at all temperatures. Samples ground under vacuum showed delayed or no growth of total aerobic counts, anaerobic bacteria, and mould and yeast, while control groups showed significant microbial growth. Taxonomic composition analysis of samples at day 7 and 25 degrees C, showed the most abundant bacteria of the control group were from the genus Rahnella belonging to the phylum Proteobacteria, while those of the vacuum-processed groups were from the genus Lactobacillus belonging to the phylum Firmicutes. Consequently, vacuum grinding and packaging can be used in developing technology for preservation of nutritional quality and microbial safety of strawberry puree.
查看更多>>摘要：The effects of high pressure (HP) and ficin treatments, and their combinations on the quality characteristics of post-rigor tan mutton were investigated. HP at 150 MPa/15 min significantly increased the hardness and centrifugal loss (CeL) of meat and deteriorated the meat color, and ficin at 0.10 g/L reduced meat hardness by 8% and protected meat color but increased CeL significantly (P < 0.05). Initial ficin (0.10 g/L) injection and incubation at 55 degrees C for 60 min, followed by HP at 50 MPa/15 min and 150 MPa/15 min reduced the hardness of the treated meat by 48% and 41% respectively, and cooking loss (CL) and CeL were also significantly decreased (P < 0.05), yet ficin combined with 150 MPa markedly increased the levels of thiobarbituric acid reactive substances (TBARS), lightness (L*) and yellowness (b*) of the processed meat. Water retentiveness and tenderness enhanced by combined treatments were found to be mainly attributed to increased degradation of myofibrillar and sarcoplasmic proteins through ANOVA-Partial least squares regression (APLSR), and sensory evaluation verified the high acceptability of the meat treated by both HP and ficin in terms of tenderness, flavour and texture after cooking.
Lucila Estilarte, MariaElizabeth Tymczyszyn, E.de los Angeles Serradell, MariaCarasi, Paula...
7页
查看更多>>摘要：The present work studied the preservation of probiotic strains of Enterococcus durans by freeze-drying. The prebiotic lactulose showed to be the best protectant agent for E. durans after freeze-drying and storage at 4 and 25 degrees C for 92 days. Freeze-dried E. durans LM01C01 was resistant to acid treatment and able to grow in the presence of bile. Also, freeze-dried samples grew in the presence of preservative food ingredients: potassium sorbate and sodium chloride. After addition of dried cultures in a cream cheese, the number of viable bacteria was maintained for 3 months (shelf-life of the products). The spent culture supernatant of E. durans LM01C01 showed inhibitory effects on the pathogens E. coli and S. aureus. Although the addition of dried probiotic to cream cheese did not have any effect on contamination of food matrix with E. coli, a drastic decrease of viability of S. aureus was observed. These results demonstrated the suitability of E. durans strains to develop a dried symbiotic product (probiotic plus prebiotic) that could be added to food matrices or nutraceutical products, that could also tolerate gastrointestinal conditions and may act as biopreservative too.
查看更多>>摘要：This study aimed to determine antilisterial potential of lysozyme (LYS)-nisin (NIS) combination at temperatures and pHs optimal for LYS activity. Tests in buffers at pH 4.5 and 6.0 showed that heating at 50 or 60 degrees C combined with LYS-NIS caused higher Listeria innocua inactivation (- 6.2 to >6.6 log) than heating alone (- 0.05 to 5.5 log), or heating combined with LYS (- 4.34 to 6.0 log) or NIS (3.9 to >6.6). The antimicrobial performance of LYS-NIS in buffer at 50 degrees C was not pH-dependant (5.8-5.9 logs) while heating at 60 degrees C with LYS-NIS at pH 6.0 (>6.6 logs) caused higher Listeria reduction than that at pH 4.5 (5.7 logs). Heating at 50 degrees C for 45 min alone or in combination with LYS-NIS caused 0 and 5.5 logs Listeria reduction in milk, respectively. In contrast, Listeria inactivation in milk at 60 degrees C occurred mainly by heat (5.5 logs) with limited contribution of LYS and/or NIS. Milk heated at 50 degrees C maintained 73% of NIS and 63% of LYS activity. Application of LYS-NIS at 50 degrees C provides an opportunity to improve milk safety with less destruction of milk enzyme and microbial flora necessary to obtain desired ripening periods, and aroma and flavour in traditional cheeses.
Silva, Douglas R. G.Haddad, Gabriela B. S.de Moura, Ana P.de Souza, Poliana M....
8页
查看更多>>摘要：This study evaluated the effect of gamma radiation (0, 1.5, 3, 4.5, 6 KGy) and sodium nitrite (0, 50 and 150 mg/kg) on Clostridium sporogenes spores and on the technological and sensorial characteristics of restructured cooked hams. The number of spores recovered reduced (p < 0.05) with increasing doses of radiation but radiation sensitivity (D-values) was reduced from 1.98 kGy in uncured samples to 1.81 and 1.57 kGy in cured ones. Residual nitrite (RNO2) and pH were not affected (p > 0.05) by irradiation, but RNO2 was reduced (p < 0.05) with lower nitrite additions. CIE color measures and texture profile were affected only by nitrite levels and all sensory attributes of uncured samples were perceived (p < 0.05) as different from the cured ones. Irradiation improved > 0.05) the odor scores of cured samples. Irradiation of cooked hams at 3 kGy can be used to improve the sensory quality and ensure the microbiological safety of cooked hams elaborated with 50 mg/kg of nitrite.
Lee, Seung YunLee, Da YoungKang, Hea JinKang, Ji Hyeop...
6页
查看更多>>摘要：We aimed to determine changes in the antimicrobial activity of penicillin, cephalosporin, tetracycline, and ofloxacin present in patties cooked at 150, 200, or 250 degrees C, at different stages of in vitro human digestion, over Staphylococcus aureus (S. aureus) and Methicillin-resistant Staphylococcus aureus (MRSA). Results revealed that the antimicrobial activity of antibiotics were the same regardless of meat types and cooking temperatures. However, after small intestine digestion, some differences were observed, especially in tetracycline and ofloxacin activities. The antimicrobial activity of tetracycline was slightly higher over S. aureus than over MRSA. Besides, the activity of ofloxacin was relatively maintained, compared to the rest of the antibiotics, showing antimicrobial activity against S. aureus regardless of in vitro digestion. These results may provide an insight on antimicrobial activity changes of antibiotics under various condition. Notably, they suggest that ofloxacin residues in meat may have a higher activity than other antibiotics.
查看更多>>摘要：The effects of yeast fermentation on the contents of reducing sugar and gamma-aminobutyric acid (GABA), the protein size distribution, peptide molecular weight distribution, free amino acid (FAA) composition, antioxidant activity, and tyrosinase and xanthine oxidase inhibitory activity of defatted adlay (DFA) were investigated in this study. Fermentation decreased reducing sugar content but increased GABA content. During fermentation, proteins were degraded, and large quantities of peptides with low molecular weights were produced. The total amount of FAAs increased by 9.9 times after 60 h of fermentation, and most of the FAAs gradually increased with fermentation time. Meanwhile, fermentation increased the total phenolic content, ferric reducing antioxidant power (FRAP) and 2, 2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging activity by 70.7%, 32.1%, and 35.4%, respectively. Furthermore, the tyrosinase and xanthine oxidase inhibitory activity of DFA increased by approximately 120% and 150%, respectively, after fermentation. Therefore, yeast fermentation was effective for improving the nutritional and biological properties of DFA.
Lopes de Macedo, Isaac YvesGil, Eric de SouzaSousa Mendes, Dianiny de CassiaAsquieri, Eduardo Ramirez...
10页
查看更多>>摘要：The objective of this study was to evaluate the microencapsulation of jabuticaba Myrciaria cauliflora extracts and verify the stability under application in manioc starch fermented biscuits processed at 180 degrees C for 20 min. Experimental design was performed varying the amount of sodium alginate and volume of the extract, with a total of 11 treatments. The result showed that the highest content of microencapsulated polyphenols was in treatment 2, with 16.02 +/- 0.06 mgGAE/g, but after thermal processing treatments 3, 4 and 6 showed lower losses of polyphenols, with approximately 20% and ideal morphological conditions in scanning electron microscopy. Treatment 3 showed better antioxidant potential after thermal processing with 3055.01 +/- 0.39 EC50 (mg/mL) for DPPH and 773.50 +/- 1.26 mu M trolox/g for ARTS. According to Fourier transform infrared spectroscopy (FT-IR) measurements, peaks at 3300 and 1600 cm(-1) were observed and it can be said that all 11 treatments have the presence of polyphenolic and polysaccharide compounds. The microcapsules presented similar diameters in the formulations and morphologies of heterogeneous surfaces in spongy and wrinkled form. It is worth mentioning that the biscuits became products with bioactive properties that they did not have.
查看更多>>摘要：Rice beverage is one of the most consumed plant-based milk alternatives and it is considered a healthy food. However, many products have in its composition food additives that could change the beverages characteristics. In this study, for the first time, the applicability of near infrared spectroscopy (NIR) and multivariate analysis were evaluated for additives detection (starch, maltodextrin, polydextrose, soy soluble extract) in powder rice beverages (PRB). The vibrational spectra did not present relevant differences for samples of PRB pure or with additives. An exploratory analysis (PCA) distinguished the samples according the rice brands used for beverage processing. Moreover, PLS-DA methods performed were able to go further the discrimination of rice brands and reach the main differences between a PRB with or without additives, by applying variable selection according the loadings, iPLS and VIP scores. The best models were obtained with MSC + MC and loadings variable selection with sensitivity and specificity higher than 92%. The results showed that NIR associated to chemometric tools was appropriate for discrimination of PRB added or not with additives and could be used to quality control related to beverages composition and safety associated to presence of allergenic, with ability to replace the traditional methods, especially in a screening step.
NSTL
Elsevier