different pH levels

  • 文章类型: Journal Article
    三角phaeodactylum是通过其快速生长的能力来识别的,繁殖,和体外培养,以及一系列高价值活性化合物的存在,包括蛋白质,具有潜在的食品应用。这项研究的目的是研究pH值偏移处理(pH值分别为3、5、7、9和11)对三角斑藻蛋白(PTP)的结构和功能特性的影响。PTP的分子量主要分布在以下范围内:低于5kDa,5-100kDa,超过100kDa。与酸性环境相比,PTP在碱性环境中表现出更高的溶解度和更大的游离巯基含量。此外,PTP在碱性环境中具有较小的粒径和较高的热稳定性。PTP表现出优异的发泡能力(135%),乳化活性指数(3.72m2/g),和乳液稳定性指数(137.71min)在碱性环境中。该研究结果为PTP在食品工业中的未来发展和应用提供了基础。
    Phaeodactylum tricornutum is identified by its capacity for rapid growth, reproduction, and in vitro cultivation, as well as the presence of a range of high-value active compounds, including proteins, with potential food applications. The objective of this study was to investigate the effects of pH shift treatments (pH of 3, 5, 7, 9, and 11) on the structural and functional properties of the Phaeodactylum tricornutum protein (PTP). The molecular weight of the PTP was predominantly distributed within the following ranges: below 5 kDa, 5-100 kDa, and above 100 kDa. Compared to the acidic environment, the PTP demonstrated higher solubility and greater free sulfhydryl group content in the alkaline environment. Additionally, PTP had a smaller particle size and higher thermal stability in alkaline environments. The PTP exhibited superior foaming ability (135%), emulsification activity index (3.72 m2/g), and emulsion stability index (137.71 min) in alkaline environments. The results of this investigation provide a foundation for the future development and application of the PTP in the food industry.
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  • 文章类型: Journal Article
    在最近的研究中,分子生物学技术已经证实了橄榄发酵中弧菌的存在。然而,由于食用食用橄榄,没有任何由弧菌引起的食源性疫情的报告,到目前为止,它们的作用以及允许它们在食用橄榄中生存的环境条件尚未阐明。这项工作的目的是对接种的弧菌鸡尾酒在各种食用橄榄环境中的行为进行建模,并研究接种的弧菌鸡尾酒在食用橄榄中的可能行为。首先,已经进行了一项体外研究,其中使用预测模型在不同NaCl浓度(2-12%)和pH水平(4.0-9.0)下在实验室培养基和橄榄盐水中评估了弧菌混合物的微生物行为。之后,在用弧菌混合物发酵开始时接种的碱液处理的橄榄中进行了22天的挑战测试。在不同pH值的发酵过程中,未在橄榄盐水中检测到接种在食用橄榄中的弧菌混合物。然而,据观察,这种微生物在实验室培养基中可以在pH9和2%的盐下达到最佳生长,没有恒定吸光度(tA)的时间,并且观察到的最大吸光度值(y端)是在pH8和2%盐条件下。统计分析表明,盐浓度对动力学生长参数的影响高于pH(μmax,tA,和y结束)。另一方面,经证实,在碱液处理的橄榄发酵中,没有发现任何样品上的弧菌混合物的生长。因此,结论是橄榄化合物(未知)的存在不允许弧菌菌株的发展,所以它是一种非常安全的产品,因为它含有天然的抗菌化合物,而是本地弧菌的可能性。能够获得适应这种化合物的能力应该在进一步的研究中考虑。
    The presence of Vibrio species in table olive fermentations has been confirmed by molecular biology techniques in recent studies. However, there has been no report of any foodborne outbreak caused by Vibrio due to the consumption of table olives, and their role as well as the environmental conditions allowing their survival in table olives has not been elucidated so far. The aims of this work were to model the behavior of an inoculated Vibrio cocktail in diverse table olive environments and study the possible behavior of an inoculated Vibrio cocktail in table olives. First, an in vitro study has been performed where the microbial behavior of a Vibrio cocktail was evaluated in a laboratory medium and in olive brines using predictive models at different NaCl concentrations (2-12%) and pH levels (4.0-9.0). Afterward, a challenge testing was done in lye-treated olives inoculated at the beginning of fermentation with the Vibrio cocktail for 22 days. The Vibrio cocktail inoculated in table olives has not been detected in olive brines during fermentation at different pH levels. However, it was observed that this microorganism in a laboratory medium could reach an optimal growth at pH 9 and 2% salt, without time of constant absorbance (t A), and the maximum absorbance value (y end) observed was at pH 8 and 2% salt conditions. The statistical analysis demonstrated that the effect of salt concentration was higher than pH for the kinetic growth parameters (μmax, t A, and y end). On the other hand, it was confirmed that no growth of the Vibrio cocktail on any sample was noticed in lye-treated olive fermentations. Thus, it was concluded that the presence of olive compounds (unknown) did not allow the development of Vibrio strains, so it is a very safety product as it has a natural antimicrobial compound, but the possibility that a native Vibrio sp. is able to acquire the capacity to adapt to this compound should be considered in further studies.
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