日粮中添加不同水平的维生素E对小白牛肉贮存期间滴水损失率和TBA值的影响

本试验考察了饲料中添加维生素E(VE)对小白牛肉(中国荷斯坦公犊牛)贮存期间滴水损失率和TBA值的影响。试验选取16头小白牛,按体重随机分为4组,每组4头。在屠宰前30d每天添加不同水平的VE,添加水平分别为0mg/d、500mg/d、800mg/d和2 000mg/d。屠宰后将牛肉贮存14d。贮存期间选取滴水损失率和TBA值作为肉品质的考察依据。结果表明:随着贮存时间的延长,各组牛肉滴水损失率增加,而不同添加水平间差异不显著(P>0.05)。TBA值随时间延长而升高,从第4天开始,VE0组和VE500组,与VE800组和VE2000组之间差异显著(P>0.05),VE0组与VE500组,VE800与VE2000组之间差异均不显著(P>0.05)。表明饲料中添加VE800mg/d可使小白牛肉有很好的抗氧化效果。     

Differential response of zucchini varieties to low storage temperature

Several parameters related to cold damage in zucchini have been measured in fruits from different varieties cultivated in the province of Almería (south-eastern Spain). The purpose of this work is to correlate physiological parameters with commercial quality and chilling damage, in order to establish reliable criteria for selecting varieties having better genetic adaptation to low-temperature storage. The results show that, for varieties harvested during February, the variety Natura was the best adapted to storage at 4 °C, as its fruits suffered less from chilling injuries, had a lower weight loss, and the levels of metabolites malonyldialdehyde and H₂O₂ were not as high as in the other varieties. Genetic variation was detected for some of the parameters analysed. The positive correlation among the levels of MDA, H₂O_2, and chilling injury, as well as the negative correlation among catalase and chilling injury, makes these parameters good indicators of chilling damage in our system.     

Effect of antioxidant supplementation on free radical scavenging system and immune response in lindane treated scabies patients

The scabicide, lindane induces oxidative stress and immunological alterations. The present study was undertaken to assess the ameliorative effects of antioxidant supplementation in lindane treated scabies patients. Scabies patients were treated with either 1% lindane or 1% lindane along with antioxidant (Lycored or Vitamin-E). Oxidative stress and immunological parameters were evaluated in blood samples and compared with healthy controls. Lindane caused a significant increase in malonedialdehyde (MDA) levels and decrease in reduced glutathione (GSH) and ferric reducing ability of plasma (FRAP), which was attenuated by anti-oxidant therapy. The IL-1α levels were significantly enhanced in scabies patients per se and remained unaffected after lindane/anti-oxidant treatment. The TNF-α and nitroblue tetrazolium (NBT) reduction levels were not significantly different in all the groups. Topical application of lindane induces significant free radical generation and may cause immunological alterations which can be reversed by antioxidant therapy.     

Cytotoxic, cytoprotective and antioxidant effects of isolated phenolic compounds from fresh ginger

Twenty-nine phenolic compounds were isolated from the root bark of fresh (Yunnan) ginger and their structures fully characterized. Selected compounds were divided into structural categories and twelve compounds subjected to in-vitro assays including DPPH radical scavenging, xanthine-oxidase inhibition, monoamine oxidase inhibition, rat-brain homogenate lipid peroxidation, and rat pheochromocytoma PC12 cell and primary liver cell viability to determine their antioxidant and cytoprotective properties. Isolated compounds were also tested against nine human tumor cell lines to characterize anticancer potency. Several diarylheptanoids and epoxidic diarylheptanoids were effective DPPH radical scavengers and moderately effective at inhibiting xanthine oxidase. An enone–dione analog of 6-shogaol (compound 2) was isolated and identified to be most effective at protecting PC12 cells from H₂O₂-induced damage. Almost all tested compounds inhibited lipid peroxidation. Three compounds, 6-shogaol, 10-gingerol and an enone-diarylheptanoid analog of curcumin (compound 6) were identified to be cytotoxic in cell lines tested, with KB and HL60 cells most susceptible to 6-shogaol and the curcumin analog with IC₅₀ < 10 μM. QSAR analysis revealed cytotoxicity was related to compound lipophilicity and chemical reactivity. In conclusion, we observed distinct compounds in fresh ginger to have biological activities relevant in diseases associated with reactive oxygen species.     

不同处理方法对浒苔粉贮藏性状的影响

[目的]研究不同处理方法对水浒苔贮藏性状的影响。[方法]采用热风干燥、低温真空干燥、真空包装、普通包装等方法研究浒苔叶绿素含量和TBA值的变化情况。[结果]在贮藏的开始阶段,热风干燥的样品叶绿素含量低于低温真空干燥的样品。在贮藏过程中经热烫的样品比未烫的样品叶绿素损失率高,TBA值高。真空包装贮藏的样品与密封贮藏的样品相比损失率低,TBA值较小,且变化较缓慢。低温真空干燥的样品与热风干燥的样品相比,TBA值较小,且TBA值变化缓慢。[结论]真空低温干燥是一种比较理想的方式。     

抗氧化剂TBHQ、VE和TP对罗非鱼非漂洗鱼糜的抗氧化作用

【目的】研究抗氧化剂特丁基对苯二酚(TBHQ)、维生素E (V_E)和茶多酚(TP)对罗非鱼非漂洗鱼糜的抗氧化作用,为其在非漂洗鱼糜生产中的应用奠定基础。【方法】选取3种抗氧化效果较好的抗氧化剂TBHQ、V_E和TP,以不同量(TBHQ为0.2,0.4和0.6 g/kg;V_E为0.2,0.4,0.6和0.8 g/kg;TP为0.4,0.8,1.2和1.6 g/kg)添加至罗非鱼非漂洗鱼糜中,于-20 ℃冰箱中冷冻保藏,定期取样测定样品的2硫代巴比妥酸值（TBA值）作为判定鱼糜氧化程度的指标,筛选出TBHQ、V_E和TP的最适添加量;通过对比试验,筛选出抗氧化效果最好的抗氧化剂;通过协同试验探究抗氧化剂之间的协同作用。【结果】TBHQ、V_E和TP的最适添加量分别为0.2,0.6和0.8 g/kg;3种抗氧化剂的抗氧化效果大小为0.8 g/kg TP＞0.2 g/kg TBHQ=0.6 g/kg V_E。协同试验结果显示,0.6 g/kg V_E＋0.8 g/kg TP的抗氧化效果最好,表明天然抗氧化剂V_E与TP之间存在很强的协同作用。【结论】在制作罗非鱼非漂洗鱼糜过程中,添加0.6 g/kg V_E＋0.8 g/kg TP组合抗氧化剂,可显著提高其抗氧化能力。     

赤星菌弱毒株孢子制剂PCF1对烟草赤星病的控制作用

本文研究了赤星菌(Alternaria alternata)弱毒株TBA16的灭活孢子制剂PCF1对烟草抗赤星病的诱导作用,及在田间控制赤星病的效果和对烟叶产量、品质等性状的影响。在温室内幼苗上,PCF1可明显诱导烟草对赤星病的系统抗性,抗性诱导效应为57％—89％。在山东5个主要产烟县进行的田间试验表明,PCF1有3种作用:①可以明显控制赤星病的发生程度,效果与用作对比的化学农药菌核净相当或略低,在烟草生长后期防治效果可达76％;②增强烟株生长和叶片扩展能力,使烟叶(烘烤后)产量提高7％—38％;③明显改善烟叶内在品质、增加上中等烟叶的比例,使产值提高17％。     

海产鱼油PUFA保健品的TBA价与过氧化值问题的探讨

海产鱼油ＰＵＦＡ保健品的ＴＢＡ价与过氧化值问题的探讨ＳＴＵＤＩＥＳＯＮＴＢＡＶＡＬＵＥＡＮＤＴＨＥＰＥＲＯＸＩＤＡＴＩＯＮＶＡＬＵＥＯＦＭＡＲＩＮＥＦＩＳＨＯＩＬＰＵＦＡＰＲＯＤＵＣＴＳ张利民孙玉增宋丽辉张秀珍李烟芬王际英于光溥（山东省海洋水产研究所...     

热泵冷风干燥鲢鱼的挥发性盐基氮和脂质氧化品质模型

为深入了解带热泵的冷风干燥机干燥鱼类产品的特点,以鲢鱼为研究对象,确定冷风干燥工艺参数对风干鱼品质劣变的影响,并建立相关模型,通过U10*（103）均匀设计试验,在不同热泵干燥工艺参数（温度、空气旁通率、风速）下,对决定风干鲢鱼品质劣变的挥发性盐基氮（total volatile basic nitrogen,TVB-N）和脂质氧化硫代巴比妥酸（thiobarbituric acid,TBA）值变化情况进行研究,并以TVB-N和TBA值作为风干鲢鱼制品品质判断指标。经统计分析,分别得到冷风干燥鲢鱼样品中TVB-N和TBA的回归方程。结果表明：在试验水平范围内,温度是影响风干鲢鱼制品中TVB-N和TBA的主要因素。由模型方程确定腌制鲢鱼冷风干燥工艺的最优参数分别为温度15.5℃、空气旁通率0.6（考虑能耗）、风速1.65 m/s,此条件下干燥的鲢鱼TVB-N和TBA值最小,品质最好,能耗较低。研究结果为控制热泵冷风干燥过程中鲢鱼的质量品质提供参考。     

全脂奶粉的脂肪氧化动力学研究

[目的]研究全脂奶粉在不同贮存温度下的脂肪氧化行为。[方法]选用硫代巴比妥酸值(TBA值)为评价指标,考察了温度和时间对全脂奶粉脂肪氧化的影响,并分别对脂肪氧化程度和脂肪氧化速率进行了动力学分析。[结果]当保存温度在30～40℃时,脂肪氧化随时间的变化符合一级反应动力学;当温度为50℃时,脂肪氧化随时间的变化同时符合一级和零级反应动力学,但是零级反应动力学更准确。全脂奶粉脂肪氧化一级反应动力学的活化能Ea为29.81 kJ/mol。[结论]利用脂肪氧化速率随温度变化的动力学模型,可以预测30～50℃任意温度下的全脂奶粉脂肪氧化速率常数。