燕麦多酚对冷却猪肉的保鲜效果

研究不同添加量燕麦多酚对冷却猪肉的保鲜效果。将冷却猪肉分成4 组：不加任何保鲜剂的阴性对照组、
加入300 mg/kg茶多酚的阳性对照组、分别加入500 mg/kg和1 000 mg/kg燕麦多酚的处理组,在贮藏期间定期对各
组冷却猪肉的菌落总数、pH值、失水率、硫代巴比妥酸反应物值、挥发性盐基总氮（total volatile basic nitrogen,
TVB-N）值进行检测。结果表明,茶多酚和燕麦多酚均可以明显抑制冷却猪肉中微生物的快速繁殖,明显抑制冷却
猪肉中脂质的氧化,延缓TVB-N值的增加;燕麦多酚对冷却猪肉的保鲜效果不及茶多酚;1 000 mg/kg燕麦多酚对
冷却猪肉的保鲜效果更佳。结论：较高添加量的燕麦多酚可使冷却猪肉在较长时间内保持良好的食用品质,延长其
货架期。     

孜然精油对冷却猪肉保鲜效果的影响

为了延长冷却猪肉的货架期,将质量浓度为0、25、50、75mg/mL的孜然精油对冷却猪肉进行涂膜处理,并采用PE有氧包装形式,以pH、挥发性盐基氮（TVB-N值）、硫代巴比妥酸（TBA）、色差值和细菌总数为考察指标,评价孜然精油对冷却猪肉的保鲜效果。结果表明,质量浓度为50mg/mL的孜然精油保鲜效果最佳,显著优于对照组,在（4±1）℃条件下能将冷却猪肉保鲜期延长至14d。      

茶多酚对冷却猪肉保鲜效果的应用研究

研究了质量分数分别为0%、0.25%、0.75%、1.25%、1.75%和2.25%的茶多酚对贮藏在4℃下冷却猪肉的保鲜效果。在贮藏的过程中,分别定期对冷却猪肉的菌落总数、色泽及持水力、pH、TBA、TVB-N等理化指标进行检测。结果表明,茶多酚处理能抑制冷却肉中微生物的增长速度,明显抑制冷却肉中脂质的氧化,延缓TVB-N的增加,使冷却肉在较长时期内保持良好的食用品质,延长其货架期。     

香蕉皮多酚与双乙酸钠复配对猪肉保鲜效果研究

通过从香蕉皮提取多酚物质,并与双乙酸钠按比例进行复配,采用感官、检测pH值、对二甲氨基苯甲醛显色分光光度法,检测不同浓度的复配剂配比对猪肉保鲜的效果,得出最佳复配比例。结果表明:香蕉皮多酚物质与双乙酸钠复配剂比例为1∶3、在夏季平均室温27℃条件下,猪肉的保存期能有效延长至第2天。     

几种天然保鲜剂对冷却猪肉保鲜效果的研究

冷却肉的货架期是限制我国冷却肉发展的瓶颈所在。为了延长冷却猪肉货架期,本文对8种复合保鲜剂喷洒处理冷却猪肉在冷藏(0～4℃)条件下的保鲜效果进行了研究,结果表明:不同保鲜剂处理可不同程度降低肉表面的初始菌数,保鲜剂乙酸1g+乳酸1g+壳聚糖0.5g+茶多酚0.1g+蒸馏水100g效果最明显;保鲜剂乙酸1g+乳酸1g+壳聚糖1g+蒸馏水100g的保鲜效果最显著,可以在4℃贮存下保持冷却肉的一级鲜度15天,比不喷洒保鲜剂延长8天。     

几种天然香精油对冷却猪肉保鲜效果的比较研究

将桂皮精油、丁香精油和大蒜精油3种香精油分别配比成不同浓度的保鲜剂对鲜猪肉进行处理,于0～4℃贮藏,然后测定其肉样的理化、微生物及感官指标,并对肉样新鲜度进行综合评价,比较研究这3种天然香精油的保鲜效果。结果表明:桂皮精油及丁香精油对冷却猪肉均有较好的保鲜作用,能延长冷却猪肉的贮藏期,其中0.8%桂皮精油的保鲜效果最佳。     

苹果枝条多酚对草鱼保鲜效果的研究

将分离纯化得到的纯度为79%的苹果枝条多酚用于草鱼的保鲜,以pH、细菌总数、TBA值、TVB-N值、色度和感官质量评价等为鲜度指标,研究苹果枝条多酚的保鲜效果。结果表明:苹果枝条多酚浓度为0.1%时能够有效地控制鱼肉因蛋白质降解而引起的pH以及TVB-N值的升高,降低鱼肉微生物总数和丙二醛含量,保持鱼肉品质,其保鲜效果好于同浓度的山梨酸钾,是一种应用潜力较大的营养型鱼肉保鲜剂。     

苹果枝条多酚对草鱼保鲜效果的研究

将分离纯化得到的纯度为79%的苹果枝条多酚用于草鱼的保鲜,以pH、细菌总数、TBA值、TVB-N值、色度和感官质量评价等为鲜度指标,研究苹果枝条多酚的保鲜效果。结果表明:苹果枝条多酚浓度为0.1%时能够有效地控制鱼肉因蛋白质降解而引起的pH以及TVB-N值的升高,降低鱼肉微生物总数和丙二醛含量,保持鱼肉品质,其保鲜效果好于同浓度的山梨酸钾,是一种应用潜力较大的营养型鱼肉保鲜剂。      

苹果幼果多酚对草鱼片保鲜效果的研究

本论文研究了冷藏条件（0⁴℃）下,不同浓度苹果幼果多酚对草鱼片的保鲜效果,采用电子鼻技术获取不同保藏时间草鱼片的气味信息,通过主成分分析（PCA）,对感官评价,挥发性盐基氮（TVB-N）和菌落总数的测定结果进行验证。结果表明,采用1g/L苹果幼果多酚溶液处理后草鱼片的TVB-N及菌落总数显著低于对照组（p<0.05）,且电子鼻分析结果与感官、TVB-N和菌落总数结果基本一致。苹果幼果多酚作为一种安全可食用的保鲜防腐剂具有广阔的开发应用前景,电子鼻作为一种方便快速检测鱼片新鲜度的方法是可行的。      

苹果幼果多酚对草鱼片保鲜效果的研究

本论文研究了冷藏条件(0~4℃)下,不同浓度苹果幼果多酚对草鱼片的保鲜效果,采用电子鼻技术获取不同保藏时间草鱼片的气味信息,通过主成分分析(PCA),对感官评价,挥发性盐基氮(TVB-N)和菌落总数的测定结果进行验证。结果表明,采用1g/L苹果幼果多酚溶液处理后草鱼片的TVB-N及菌落总数显著低于对照组(p<0.05),且电子鼻分析结果与感官、TVB-N和菌落总数结果基本一致。苹果幼果多酚作为一种安全可食用的保鲜防腐剂具有广阔的开发应用前景,电子鼻作为一种方便快速检测鱼片新鲜度的方法是可行的。     

Nisin对冷却猪肉冷藏保鲜效果的影响

研究Nisin对冷却猪肉保鲜效果的影响.研究中对比Nisin与山梨酸钾两种保鲜剂对冷却猪肉冷藏过程中6项鲜度指标(细菌总数、挥发性盐基氮、pH值、球蛋白、硫化氢以及感官指标)的变化情况.结果表明:Nisin在0.03 g/L～0.06 g/L浓度范围内可延长冷却猪肉货架期,其中以0.05 g/L Nisin保鲜液浸泡猪肉120 s保鲜效果最佳,货架期可延长6d,且与山梨酸钾保鲜剂(0.05 g/L)保鲜效果无明显差异.     

大孔吸附树脂对苹果渣中苹果多酚吸附性能的研究

研究了8种大孔吸附树脂对苹果渣中苹果多酚的吸附与解吸性能,其中AB-8、NKA、X-5、D4006树脂具有较大吸附量和解吸率,其静态吸附量:AB-8>X-5>D4006>NKA,解吸附率:X-5>NKA>AB-8>D4006,吸附速率:AB-8>X-5>NKA>D4006,从中选出AB-8树脂对苹果多酚进行纯化。动态吸附实验研究了提取液浓度、pH、流速对AB-8树脂吸附量的影响,适合的上柱浓度为1.1528mg/mL,pH为4.80,吸附流速为2BV/h,4倍树脂床体积的70%乙醇以1BV/h的流速进行洗脱即可基本将苹果多酚从AB-8树脂上解吸下来。     

INHIBITION OF β-GALACTOSIDASE OF APPLE BY FLAVONOIDS AND OTHER POLYPHENOLS

The inhibition of a purified β-galactosidase from "Spartan" apples by flavonoids and related compounds has been studied with a fluorimetric assay using the substrate 4-methylumbelliferyl β-D-galactoside. Certain flavonoids, flavonoid glycosides, phenolic acids, and polyphenols (quercetin, fustin, rutin, p-coumaric acid, and catechol) gave classical noncompetitive inhibition at moderate substrate concentrations. Others (kaempferol, chlorogenic acid) gave nonlinear Dixon plots. The best inhibitors were flavones. In general, the degree of inhibition increased with the degree of hydroxylation and glycosylation of the phenol. Correlation of the structure of these substances with the observed inhibition suggests that the trans-3-(4-hydroxyphenyl)-propenoyl group, common to 4'-hydroxyflavones and p-hydroxyphenolic acids, is important for effective inhibition.     

INHIBITION OF SPOILAGE AND PATHOGENIC BACTERIA ASSOCIATED WITH FOODS BY COMBINATIONS OF ANTIMICROBIAL AGENTS

The antibacterial activity of combinations of lysozyme, monolaurin (ML), triglycerol 1,2 laurate (TGL) and butylated hydroxyanizole (BHA) against 7 Gram-positive and 8 Gram-negative bacteria was studied at different pH, NaCl and EDTA concentrations by the spiral gradient end point test. The inhibitory effect of lysozyme in combination with ML was slightly greater for Gram-positive than for Gram-negative bacteria, but their combined effect was not markedly more inhibitory than ML alone. Lysozyme and TGL together were only inhibitory at low pH and high NaCl concentrations in the presence of EDTA. There was an increase in inhibition when lysozyme and BHA were combined. For Gram-positive bacteria, inhibition by ML and BHA together was more marked than when either was present singly. However, ML decreased the antibacterial activity of BHA against Gram-negative bacteria. Similarly, TGL was antagonistic to BHA action against both Gram-positive and Gram-negative bacteria. In general, the inhibition produced by all combinations was greater as the pH decreased and the NaCl concentration increased, especially in the presence of EDTA .     

苹果多酚的提取及其在食品中的应用现状分析

苹果多酚是一种新型的天然抗氧化剂，在未成熟的苹果和果渣中含量丰富。主要介绍了目前国内外对苹果中多酚类物质的研究现状，并概述了苹果多酚的各种提取方法，以及其在食品领域的应用现状。     

三种保鲜剂在冷却猪肉保鲜中的应用研究

将乳过氧化物酶体系（LPS）、臭氧与乳酸链球菌素（Nisin）三种保鲜剂直接用于冷却猪肉的保鲜研究，通过对冷却猪肉在冷藏过程中微生物、感官和理化指标的测定，结果表明实验组的保鲜效果都显著地优于对照组，而实验组的保鲜效果依次是LPS处理组优于Nisin处理组优于臭氧处理组。     

THE ACTION OF NISIN ON BEER SPOILAGE LACTIC ACID BACTERIA

Within one minute of adding nisin to suspensions of Lactobacilli clumping of cells was observed. This happened with all the strains assayed, irrespective of their sensitivity or resistance to nisin. There was, however, no evidence of cell lysis. Two different assays for cell viability were used to show that the vast majority of cells of sensitive strains were killed within one minute of contact with nisin. The time needed to kill all the cells depended on the concentrations of both nisin and cells. One strain was more resistant and only 50–60% of the cells died within one minute of nisin addition . Using an ATP-bioluminescence assay it was shown that the addition of nisin to both Lactobacilli and Pediococci caused a rapid fall in intracellular ATP levels, which was reflected in a simultaneous appearance of ATP in the extracellular medium. Actively growing cells lost ATP more rapidly than did those in stationary phase. The amount of intracellular ATP lost was affected both by the concentration of nisin used and the sensitivity of the bacteria. It appears that an initial effect of nisin is to make the cell membrane ‘leaky’ as happens with many antibiotics, yeast killer factors (zymocins), colicins, and other gram-positive bacteriocins .