高静压力结合热处理对肉品中微生物存活性的影响

研究了压力( 30 0MPa ,15min)、温度( 5 ,2 0 ,35 ,5 0℃)共同处理灭活肉制品中微生物(细菌总数、乳酸细菌、葡萄球菌、假单胞菌和肠杆菌)的效果。实验表明,压力、温度处理可以明显降低猪肉中微生物数量;革兰氏阴性细菌对压力更敏感;当加压温度为5 0℃时,灭活微生物的效果更好;微生物对高压处理的敏感性与压力处理时的温度,微生物的类群和肉的种类有关     

超高压杀菌处理对乳品质的影响

超高压杀菌技术是一项冷杀菌技术,近年来已在食品工业中应用,叙述了超高处理技术及其对乳中微生物和乳成分的影响。     

高压食品加工技术及在乳制品中的应用

介绍了高压加工技术在食品方面应用的研究进展，其内容有：高压原理，装备和对微生物，蛋白质，酶的影响，高压乳及其制品的研究，作为国际热门食品加工方法的高压处理技术必将成为２１世纪崭新的食品加工技术，在开发新产品方面有着广泛的应用前景。     

均质压力对番茄浆料粘度的影响

采用流变仪对番茄浆料的流变性质进行测定,研究均质压力对番茄浆料粘度的影响。结果表明:番茄浆料为假塑体系,其粘度随剪切速率的增加而迅速下降。番茄浆料的粘度随均质压力的增加而增加。均质处理会影响番茄浆颗粒的大小和分布、纤维物质的性状以及番茄固形物中果胶物质的释放量,影响由番茄浆颗粒(纤维物质)聚集所形成的网状结构。     

Effect of Vitamin Supplements on Growth of Leuconostoc oenos 44.40

Media sterilization procedures were studied during the production of a starter culture, Leuconostoc oenos 40·40, for use in malolactic fermentation of wine. Heat and filter sterilization of yeast extract was compared with respect to the growth of L. oenos. Addition of a mixture of vitamins after heat sterilization of basal medium with yeast extract stimulated the growth of this organism. When used alone, each vitamin except nicotinic acid had a stimulatory effect on growth. During pilot fermentation the production of bacterial cells per hour was doubled when vitamins were supplemented after sterilization of medium. Vitamin supplementation also increased the viability of lyophilized cells.     

高压与热结合处理对鱼糜凝胶质构特性的影响

将高压处理(400MPa和600MPa,40℃,15min)作为鱼糜“凝胶化”的另一种方法,与热处理凝胶化(40℃,75min)比较,然后都作后热处理(90℃,25min)。研究了不同处理方法所得凝胶的质构特性(包括凝胶强度分析TPA和持水性),结果表明,600MPa压力凝胶化再后热处理样品质构特性均不及热处理,而400MPa压力凝胶化再后热处理样品比典型热处理样品表现出更好的质构特性:(1)凝胶强度提高了36·1%;(2)硬度提高13·7%;(3)压出水分含量减少6·0%。而且,400MPa压力凝胶化时间仅为典型热力凝胶化的1/5。所以,400MPa压力凝胶化再后热处理可以作为传统热处理方法的替代方法。     

Effect of High Pressure Treatment on Rheological Characteristics of Egg Components

The objective of this study was to evaluate the effect of high pressure treatment on rheological properties of various egg components (i.e., egg white, egg yolk, and whole liquid egg). A five-level central composite design with three independent variables (pressure, 281.8–618.2 MPa; temperature, 8.2–41.8°C; pressure holding time, 1.6–18.4 min) was employed. Samples were packed in plastic pouches, heat sealed, and subjected to pressure treatment in an isostatic press. Shear and time-dependent rheological properties were evaluated using a 3-segment (each 5 min) program with the shear rate initially increasing from zero to 100 s^?1 (upward curve), then held at 100 s^?1 (hold curve), and finally decreasing from 100 to 0 s^?1 (downward curve) using a parallel plate rheometer. Power law model was fitted to the upward (virgin) and downward curves while Weltman time dependency model was fitted for the hold curve (R² > 0.90). Rheological properties were most significantly affected by pressure followed by holding time and temperature for all egg components. In general, they showed thixotropic shear thinning behavior and reduction in time dependency, which was dependent on the level of processing treatment used (combination of pressure, time, and temperature level). The high pressure treatment resulted in a progressive transition of egg components from flowable liquid-like behavior (218–350 MPa) to semi-viscous (350–500 MPa) to highly-viscous (500–618 MPa) behavior. Rheology-based optimal conditions satisfying HP pasteurization needs were identified.     

Effects of High Pressure and Heat Treatment on Pectic Substances and Related Characteristics in Guava Juice

Effects of high pressure treatment on guava juice pectic substances and related juice characteristics were investigated and compared with heat treatment. The viscosity and turbidity of guava juice pressurized at 600 MPa and 25°C for 10 min increased slightly; whereas the viscosity of juice heated at 95°C for 5 min decreased while turbidity increased. There were no apparent changes in water soluble, oxalate soluble and alkali soluble pectin in pressurized juice. However, heat treatment of juice decreased water and alkali soluble pectins and slightly increased oxalate soluble pectin. High pressure treatment resulted in no marked changes in pectic and cloud substances of guava juice, and maintained the natural viscous of the juice.     

乳制品加工过程中热处理对营养成分的影响

乳制品生产过程中,热处理是一种经常用到的一种处理方法.不同的热处理温度,加热时间长短的不同均对乳中的营养成分有较大的影响.本文就乳制品生产中常见的热处理方式、不同热处理工艺对乳中营养成分的影响进行了综述,为乳制品的加工工艺的改进,提供一些有用的信息.     

超高压处理对大蒜风味的影响

大蒜经过200、400和600 MPa保压处理20 min后,采用评分法进行感官评定,同时,采用顶空固相微萃取(SPME)富集,气相色谱-质谱联用仪(GC-MS)检测挥发性风味物,探讨超高压处理对大蒜风味的影响。结果表明:处理后大蒜中的挥发性风味成分的种类、含量都发生显著的变化,其中硫醚类物质的相对含量由处理前的54.46%变化为处理后的59.39%、41.38%和22.73%,导致感官评定中大蒜风味强度随压力增大而减弱。     

Effects of High Hydrostatic Pressure on Heat-Resistant and Heat-Sensitive Strains of Salmonella

Salmonella senftenberg 775W, a heat-resistant strain (D_57.5°C= 15.0 min) and Salmonella typhimurium ATCC 7136, a heat-sensitive strain (D_57.5°C=3.0 min), were subjected to hydrostatic pressures of 2,380 to 3,400 atmospheres (atm) at 23°C in phosphate buffer (63 mM, pH 7.0) and chicken medium (strained baby food). Survivor curves showed that cell death occurred in this pressure range and increased as pressure increased. Death was greater in buffer than in the chicken medium. S. senftenberg 775W was more sensitive to pressure than S. typhimurium 7136. Injury occurred over the range of pressures for both species. Recovery at 37°C was possible following pressurization for salmonellae in chicken but not in buffer.     

精氨酸产生菌的代谢机制及选育进展

L-精氨酸是氨基酸的一种,是蛋白质和肌酸的重要组成成分.作为一种条件必需性氨基酸,L-精氨酸在营养生理、医药工业和饲料工业方面有重要作用和良好的应用前景,本文综述了精氨酸的代谢机制及精氨酸产生菌的选育研究进展.     

精氨酸产生菌的代谢机制及选育进展

L-精氨酸是氨基酸的一种,是蛋白质和肌酸的重要组成成分.作为一种条件必需性氨基酸,L-精氨酸在营养生理、医药工业和饲料工业方面有重要作用和良好的应用前景,本文综述了精氨酸的代谢机制及精氨酸产生菌的选育研究进展.     

The Effect of Inhibitors and High Pressure Treatment to Prevent Melanosis and Microbial Growth on Chilled Prawns (Penaeus japonicus)

ABSTRACT: Ascorbic acid, citric acid, sodium benzoate, kojic acid, and 4-hexylresorcinol were evaluated alone and in combination as inhibitors of melanosis and microbial spoilage in prawns ( Penaeus japonicus ) under non-pressure and high-pressure conditions. Sodium benzoate and kojic acid was an effective combination for the inhibition of prawn melanosis. Alone and in combination with ascorbic or citric acid, 4-hexylresorcinol proved the most effective as inhibitors of melanosis and microbial spoilage in prawns. High-pressure treatment appeared to increase the melanosis process, but it did not alter the effect performed by inhibitors. Lower total count of microorganisms seemed to be obtained with the presence of ascorbic and citric acids under high-pressure treatment.     

均质压力和温度对南瓜粉质量的影响

研究了均质压力和温度对南瓜粉质量的影响。结果表明随着均质压力和温度的上升,溶解度逐渐增大,而营养成分损失呈上升趋势;在均质压力25～35MPa之间Vc保留率变化明显,而还原糖含量主要在均质温度为40～60℃之间变化。因此需在压力30MPa左右、温度50℃上下选择水平进一步优化试验。     

超高压处理对柚子酒香气成分的影响

通过气相色谱-质谱(Gc-MS)分析,研究柚子酒经超高压处理后,其香气成分的变化情况.结果表明:将柚子酒在400MPa压力、25℃温度条件下处理30min后,柚子酒的香气成分有较明显变化,其醇类物质的相对含量由64.37%降低至61.02%,酯类物质由21.14%升高至22.69%,酸类和醛酮类也有不同程度的提高,而长链烷烃类化合物消失,同时产生芳樟醇,乙酸异戊酯等新物质,感官评定表明:超高压处理不仅能很好地保持柚子酒特征香气,而且使柚子酒的刺激性减小,变得饱满柔和,香气沉实厚重,这与柚子酒中香气成分检测结果相一致.     

高压中温协同处理对猕猴桃果汁流变特性影响初探

对不同条件超高压处理对猕猴桃果汁流变特性的影响进行了初步探讨。实验结果表明:不同条件处理后的猕猴桃果汁均呈假塑性非牛顿流体特征,符合Herschel-Bulkley方程。在处理压力提高到400 MPa之后,猕猴桃果汁表现出触变性。同时,随着处理压力的增大,体系损耗模量(G″)值增加而诸能模量(G′)值降低,说明高压处理有明显的增加粘性和降低弹性的作用。同时,温度也会影响高压处理对猕猴桃果汁流变学性质作用的效果。     

超高压对苹果汁微生物和多酚氧化酶的影响

研究不同处理压力和保压处理时间对鲜榨苹果汁的杀菌和钝酶效果.结果表明,随着处理压力升高和保压时间延长,菌落总数、大肠菌群数和多酚氧化酶活性均下降显著.在压力达到400MPa,保压时间25 min时,菌落总数由9750 cfu/mL降低到80 cfu/mL,降低达2.5个对数,大肠菌群数由30 cfu/mL降低到0cfu/mL,多酚氧化酶活性降低了100％,符合美国FDA鲜榨果蔬汁非热力加工的安全营养要求和国家饮料食品卫生标准.