Phase Behavior and Mechanical Properties of TripaImitin/Butterfat Mixtures

The functionality of butterfat can be improved by fractionation, a process that can be considered as enrichment of butterfat with long-chain saturated fatty acids. Model hard fractions were produced by adding tripalmitin to butterfat, in ratios from 0.9:0.1 through 0.1:0.9. The model system had very similar thermal behavior and mechanical properties to true fractions. The phase behavior of tripalmitin/butterfat mixtures was determined. Such butterfat fractions have potential as a moisture barrier in edible films and coatings. Tripalmitin-enriched butterfat is an alternative to hard butterfat fractions in some applications.     

基于紫外可见光谱技术和色素组成区分橄榄油与其他食用油

目的 通过紫外可见光谱技术和色素组成,探究区分橄榄油与其他食用油的方法。方法 选择市售橄榄油(特级初榨橄榄油、混合橄榄油)和其他食用油(菜籽油、玉米油、葵花籽油、大豆油、花生油、调和油)作为研究对象,分别在220~800 nm的波长范围内进行全光谱扫描以及在波长为450 nm和670 nm处进行光度测量;通过比较不同食用油的紫外可见吸收光谱并结合主成分分析(principal component analysis, PCA)和偏最小二乘法判别(partial least squares discriminant analysis, PLS-DA)对不同橄榄油和其他食用油进行比较区分。结果 通过观察比较各食用油紫外可见吸收光谱的最大吸收波长所在位置,可以对不同食用油进行初步区分。并且PCA和PLS-DA结果显示,以波长450 nm和670 nm处的吸光度A450和A670以及A450/A670为变量,可用于区分不同橄榄油和其他食用油。结论 基于紫外可见光谱技术对不同食用油中色素的检测结果可以对食用油进行分类,并且A450、A670和A450/A670可以作为区分橄榄油与其他食用油的标记。     

全自动固相萃取净化-高效液相色谱法测定食用植物油中苯并(a)芘含量

为提高工作效率,降低误差,建立分子印迹柱全自动固相萃取净化-高效液相色谱法测定食用植物油中苯并(a)芘含量的方法。样品经正己烷提取,采用全自动固相萃取仪进行分子印迹柱净化,C18色谱柱分离,高效液相色谱-荧光检测器检测。结果表明：苯并(a)芘在0.5～20.0 ng/mL质量浓度范围内与峰面积线性关系良好,相关系数为0.999 9,方法检出限为0.09μg/kg,定量限为0.30μg/kg,加标回收率为91.7%～111.8%,相对标准偏差为2.0%～8.2%,与国标方法的检测结果不存在显著性差异;对市售38份食用植物油样品进行检测发现,苯并(a)芘的检出率为76.3%。该方法准确度高、重复性好,可批量自动化前处理样品,提高工作效率,并降低人员操作误差风险,适用于食用植物油中苯并(a)芘含量的测定。     

基于嗅觉可视化技术的食用植物油分类识别

为实现山茶油与3种常见食用植物油(菜籽油、大豆油和玉米油)的区分,制备可视化传感器阵列,采用嗅觉可视化技术对4种不同种类的食用植物油进行分类识别。采用主成分分析(PCA)对4种油样的特征数据进行降维,然后将降维后的数据导入K近邻(KNN)、极限学习机(ELM)、支持向量机(SVM) 3种分类模型中进行模型参数优化,对比了3种分类模型的分类结果。结果表明：建立的SVM分类模型性能最优,当输入主成分向量数为7、c=1.741 1、g=4.549 8时,SVM分类模型的测试集分类识别准确率为95.8%,五折交叉验证准确率为89.6%。制得的可视化传感器阵列可以实现4种食用植物油的分类识别,嗅觉可视化技术用于食用植物油检测是可行的。     

Chitosan Acetate as an Active Coating Material and Its Effects on the Storing of Prunus avium L.

ABSTRACT: In this article, chitosan acetate (CA) was prepared by the method of solid–liquid reaction. CA was a stable faint yellow powder with water solubility. CA kept the same backbone in the chemical structure as the raw material of chitosan, and it also had the similar antibacterial properties with chitosan. CA could form a coating film on the outside surface of the sweet cherries, could effectively retard the loss of the water, titratable acidity, and ascorbic acid of sweet cherries, and could induce a significant increase in the peroxidase and catalase activities in the fruit. The CA coating could also increase the ratio of the total soluble solids and titratable acidity in the fruit. The application of CA effectively maintained quality attributes and extended postharvest life of the sweet cherries. The results revealed that the CA salts had potential application in active edible coating materials in the storage of fresh fruit.     

Antimicrobial effectiveness of oregano and sage essential oils incorporated into whey protein films or cellulose‐based filter paper

BACKGROUND: In this study the antimicrobial effectiveness of oregano and sage essential oils (EOs) incorporated into two different matrices, whey protein isolate (WPI) and cellulose‐based filter paper, was analysed. RESULTS: Antimicrobial properties of WPI‐based films containing oregano and sage EOs were tested against Listeria innocua, Staphylococcus aureus and Salmonella enteritidis. Oregano EO showed antimicrobial activity against all three micro‐organisms. The highest inhibition zones were against L. innocua. However, sage EO did not show antimicrobial activity against any of the micro‐organisms. Antimicrobial activity was confirmed for both EOs using cellulose‐based filter paper as supporting matrix, although it was significantly more intense for oregano EO. Inhibition surfaces were significantly greater when compared with those of the WPI films. This finding is likely due to the higher porosity and diffusivity of the active compounds in the filter paper. CONCLUSION: The interactions between the EOs and the films have a critical effect on the diffusivity of the active compounds and therefore on the final antimicrobial activity. As a result, to obtain active edible films, it is necessary to find the equilibrium point between the nature and concentration of the active compounds in the EO and the formulation of the film. Copyright © 2010 Society of Chemical Industry     

含花青素大豆蛋白可食膜对油脂贮藏的影响

研究了含花青素可食性大豆蛋白膜(BEF)对油脂贮藏中品质的影响。使用保鲜膜、大豆蛋白膜以及分别含有VE、BHA和花青素大豆蛋白膜等包装油脂,检测贮藏过程中油脂酸价、过氧化值和羰基价等变化。与大豆蛋白膜相比,BEF具有较强抑制油脂氧化、延缓油脂酸败的能力;同时,BEF还具有最强的抗拉强度[(3.80±0.782)MPa]以及较低的水蒸气透过率[(15.7±0.113)g.m-2.d-1.MPa-1]和透氧率[(17.0±0.474)mL.m-2.d-1.MPa-1],也比目前常用的PE保鲜膜具有更好的阻隔能力。因此,BEF作为包装材料可以有效延长油脂贮藏期。     

大通犊牦牛肉食用品质研究

从肉色、大理石纹、pH、失水率、系水力、熟肉率、肌纤维直径、剪切力来比较成年牦牛肉与犊牛内品质差异.结果表明犊牛的肉色、大理石纹均低于成年牦牛.犊牛的系水力、熟肉率均高于成年牦牛,并且失水率、肌纤维直径、剪切力均低于成年牦牛,说明犊牛肉比成年牦牛肉食用品质高.同时测定犊牦牛内和成年牦牛肉中重金属残留均远低于标准要求,磺胺类、呋喃唑酮在成年牦牛和犊牦牛肉中也均未检出,说明大通牦牛肉是安全优质的.     

燕窝及其伪品鉴定方法研究

分别利用性状、电泳、紫外光谱法及唾液酸含量HPLC分析等方法,研究燕窝及其伪品的鉴定技术。结果表明,真燕窝在278nm有最大紫外吸收,含有唾液酸,电泳谱图与伪品差异明显等特点,利用上述方法可以综合鉴定燕窝真伪及不同品质的燕窝,为制定燕窝国家标准提供依据。     

食用植物油返色原因及其防止对策

返色现象是植物油精炼后会经常遇到问题,如何有效控制返色现象,提高油脂品质稳定性,是油脂行业迫切需要解决难题。该文论述食用植物油返色原因及其防止对策研究进展。