Commercial application of high-pressure processing for increasing starter-free fresh cheese shelf-life

Different non-thermal technologies have been proposed to extend the shelf-life of solid food products, high-pressure processing (HPP) being one of the emerging technologies which has been most extensively studied. In this study, one of the first commercial industrial-scale applications of HPP on a starter-free fresh cheese, with the aim of increasing its shelf-life, is presented. The effect of 500 MPa (5 min, 16 °C) on physico-chemical, microbial, colour, microstructure, texture and sensorial characteristics of starter-free fresh cheeses during cold storage of 21 days was studied. The results showed that pressurised cheeses presented a shelf-life of about 19–21 days when stored at 4 °C, whereas control cheese became unsuitable for consumption on day 7–8. On the other hand, cheese treated at 500 MPa was firmer and more yellow than the untreated one. However, these changes, which were detected by instrumental and sensory analysis, did not affect the preference for pressurised cheese. These results may lead to practical applications of HPP in the food industry to produce microbiologically safe cheese with extended shelf-life and sensory quality.     

基于电子鼻与电子舌建立牛奶货架期预测模型

以全脂鲜牛奶为研究对象,以产品感官品质得分、电子舌样品间的差别度欧氏距离（Euclidean distance,ED）和电子鼻气味距离为指标,分析产品在4、15、23 ℃和30 ℃的贮藏温度下的变化情况。运用零级反应动力学模型,结合Arrhenius方程,利用感官品质变化临界点计算电子舌差别度ED值随时间和电子鼻气味距离临界值,构建了电子舌以及电子鼻货架期的预测方程,预测全脂鲜牛奶货架期分别为16.2 d和15.7 d,预测误差分别为8.0%和4.7%。结果表明,采用电子鼻、电子舌技术,能够有效监测牛奶保质期加速实验过程中的品质变化,并为牛奶货架期的判定提供新思路。     

Effects of non-thermal plasma treating wheat kernel on the physicochemical properties of wheat flour and the quality of fresh wet noodles

The effects of non-thermal plasma (NTP) on the physicochemical properties of wheat flour and the quality of fresh wet noodles ( FWN) were investigated. The results showed that NTP effectively decreased the total plate count (TPC), yeast and mould count (YMC) and Bacillus spp. in wheat flour. Wet gluten contents and the stability time reached the maximum when treated for 20 s. The viscosity of starch increased significantly after treatment due to the increased of damaged starch. The contents of secondary structure were altered to some extent, which was because that the ordered network structure of gluten protein broken. Furthermore, compared with the control, texture properties of FWN were enhanced significantly at 20 s, and the darkening rate of FWN was greatly inhibited due to the low polyphenol oxidase (PPO) activity. Consequently, the most suitable treatment was 500 W for 20 s, providing a basis for the application of NTP in flour products.     

火锅虾滑肠加工工艺研究

研究一种火锅虾滑肠的制作过程及工艺.通过单因素试验确定了影响火锅虾滑肠品质的主要因素及最佳水平范围.通过正交试验确定了主要影响因素的最佳配比:新鲜虾肉添加量为40％、金线鱼鱼糜添加量为14％、木薯变性淀粉添加量为2％、斩拌时间为6min,在此添加量及工艺条件下,生产出的产品经火锅水煮,结构及风味表现最佳.     

Consumer Acceptance of Model Soup System with Varying Levels of Herbs and Salt

Although herbs have been reported as one of the most common saltiness enhancers, few studies have focused on the effect of herbs on reducing added sodium as well as the impact of herbs on consumers’ overall liking of foods. Therefore, the objectives of this study were to determine the effect of varying levels of herbs on reducing added sodium and consumers’ overall liking of soups and identify the impact of salt levels on consumers’ overall liking of soups. Overall liking of freshly prepared and retorted canned soups with varying levels of herbs was evaluated before and after adding salt by consumers ad libitum until the saltiness of the soup was just about right for them. The results of the study demonstrated that when the perceived herb flavor increased, the amount of salt consumers added to fresh soups decreased (P ≤ 0.006); however, consumers’ overall liking decreased (P ≤ 0.013) as well for the highest level of herb tested in the study. Although overall liking of all canned soups was not significantly decreased by herbs, the amount of salt consumers added was also not significantly decreased when herbs were used. Overall liking of all soups significantly increased after more salt was added (P ≤ 0.001), which indicates that salt level was a dominant factor in affecting consumers' overall liking of soups with varying levels of herbs. These findings imply the role of herbs in decreasing salt intake, and the adequate amount of herbs to be added in soup systems.     

Effect of varying oxygen concentrations on the shelf-life of fresh pork sausages packaged in modified atmosphere

A total of 105 fresh pork sausages were packaged in atmospheres varying in oxygen concentration, using the following mixtures (%O₂/%CO₂/%N₂): 0/20/80, 0/20/80 + O₂ scavenger, 20/20/60, 40/20/40, 60/20/20, and 80/20/0. In addition, two batches were subjected to vacuum packaging or over-wrap with O₂-permeable film. They were stored for 20 days at 2 ± 1 °C in the dark. Values of pH, CIE L*, a* and b* color parameters, surface metmyoglobin percentage, TBA-reactive substances, psychrotroph aerobe bacterial numbers and sensory discoloration and off-odor were assessed throughout storage. Packaging in the absence of O₂, either under vacuum or in atmosphere with O₂ scavenger, led to extension of shelf-life in terms of both color and odor stability due to low oxidation rates. Increase of O₂ caused a significant enhancement of oxidation, decrease of shelf-life due to discoloration and off-odor development. The highest O₂ concentration gave rise to a significant color improvement, though only for a limited period of 8 days.     

配米加工鲜湿米粉工艺研究

为提高用配米加工的鲜湿米粉的品质,以珍桂矮与株两优39两者混合所得的配米为原料,以鲜湿米粉品质综合得分为评价指标,研究了大米浸泡温度、浸泡时间、磨浆粒度、蒸粉时间对鲜湿米粉品质的影响。在单因素试验基础上通过正交试验优化得到配米加工鲜湿米粉最佳工艺条件,即大米浸泡温度为20 ℃,浸泡时间为3 h,磨浆粒度为100目,蒸粉时间为100 s,在此条件下鲜湿米粉品质综合得分最高,为5.36。     

QuEChERS结合超高效液相色谱串联质谱法测定花椒中烯效唑残留量及贮藏稳定性

该研究建立超高效液相色谱-串联质谱法(ultra performance liquid chromatography tandem mass spectro-mentry,UPLS-MS/MS)测定花椒中烯效唑残留量的检测方法,并测定花椒样品中烯效唑残留量以及低温条件下烯效唑在花椒中贮藏稳定性研究.样品经0.1％(体积...     

复合生物保鲜技术及其在生鲜食品中的应用研究进展

近年来复合生物保鲜技术在生鲜食品上的应用,引起了越来越多的研究者的关注,研究结果层出不穷。本文介绍了复合生物保鲜技术及其原理,针对生鲜食品的品质变化特点,列举了复合生物保鲜技术在生鲜食品保鲜中的诸多应用与进展,为生物保鲜技术发展和生鲜食品产业发展提供有益参考和理论依据。      

石榴籽的袋装保鲜技术

利用消毒剂高锰酸钾、过氧乙酸、酒精杀菌、消毒和加入抗氧化剂苯甲酸或其他助剂，真空包装石榴籽，使其在不同的温度、湿度、一定气体组分下进行保鲜。通过不同的方法对比实验，确定最佳的保鲜方法，即袋内加入铁粉和食盐混合的．小袋，在低温条件下冷藏的保鲜效果最好，可以达到两个月的保鲜时间。从而延长石榴的货架期，满足市场需求。