薏苡仁的抗诱变性研究

应用Ａｍｅｓ试验方法，对薏苡仁的丙酮提取液进行抗诱变性研究。选用直接致突变物亚硝基胍（ＭＮＮＧ）和间接致突变物苯并（α）芘　　（Ｂ（α）Ｐ）为模型致突变物，进行诱导鼠伤寒沙门氏菌ＴＡ９８移码型、ＴＡ１００碱基置换型回复突变抑制作用实验。观察不同浓度薏苡仁丙酮提取液的抑制突变效果。结果表明：薏苡仁对ＭＮＮＧ和Ｂ（α）Ｐ诱导的鼠伤寒沙门氏菌ＴＡ９８、ＴＡ１００引起的回变菌落数随加入样品浓度增加而减少。经统计学分析呈显著性差异。提示：薏苡仁有抑制突变作用。该物作为防癌保健食品具有重要意义。     

小儿牛黄清心散遗传毒性研究

目的评价小儿牛黄清心散的遗传毒性。方法采用鼠伤寒沙门菌回复突变试验(Ames试验)、小鼠骨髓细胞微核试验和细胞染色体畸变试验对小儿牛黄清心散的遗传毒性进行研究。结果小儿牛黄清心散Ames试验中受试物8～5000μg/皿剂量范围内回复突变菌落数均未超过自发回复突变组菌落数的2倍,实验结果为阴性;细胞染色体畸变试验中受试物在250～1000μg/ml剂量范围内与空白对照组比较,染色体畸变率无明显差异(P0.05),小鼠骨髓细胞微核试验中受试物在500～2000 mg/kg剂量范围内与空白对照组比较,微核率无明显差异(P0.05),实验结果为阴性。结论在本试验条件下,小儿牛黄清心散未显示遗传毒性。     

一种微生物絮凝剂急性毒性和诱变毒性作用的研究

目的研究一种微生物絮凝剂受试物的急性毒性和诱变毒性作用。方法分别对微生物絮凝剂进行了小鼠急性经口毒性试验、Ames试验、小鼠骨髓嗜多染红细胞微核试验。结果该微生物絮凝剂的小鼠急性经口毒性试验LD_(50)≥5000 mg/(kg BW);Ames试验中,各剂量组回复突变菌落数均未见明显增加,亦无剂量-反应关系;小鼠骨髓嗜多染红细胞微核试验中,微生物絮凝剂各剂量组微核细胞率与阴性对照组比较差异无显著性。结论该微生物絮凝剂对昆明种小鼠的急性经口毒性属实际无毒,在Ames试验中未呈现致突变作用,未见诱导小鼠骨髓嗜多染红细胞微核形成的能力。     

枫糖的遗传毒性及亚慢性毒性试验研究

评价枫糖的食用安全性。急性毒性试验,采用限量法,将小鼠禁食(不禁水)16 h后,经口灌胃给予受试物,剂量为15.0 g/kg BW,灌胃后观察14 d;细菌回复突变试验,设5 000、1 000、200、40、8μg/皿5个剂量组,及未处理、溶剂、阳性对照组,采用平板掺入法,对有组氨酸营养缺陷的5株鼠伤寒沙门氏菌突变型菌株TA97、TA98、TA100、TA102和TA1535进行回变菌落计数;哺乳动物红细胞微核试验,设10.0、5.0、2.5 g/kg BW三个剂量组,环磷酰胺及阴性对照组,采用间隔24 h两次经口灌胃法进行试验,计数骨髓嗜多染红细胞在总红细胞的比例及含微核嗜多染红细胞比率;90天喂养试验,设8.0、6.0、4.0 g/kg BW三个剂量组,掺入饲料喂养90 d,空白对照组给与正常饲料,观察体重、食物利用率、血常规、血生化指标及病理检测。枫糖细菌回复突变试验、骨髓细胞微核结果均为阴性,90天喂养试验各项指标与对照组比较无显著性差异。枫糖在一定剂量范围内通过系统的体内和体外试验验证其具有食用安全性。     

鼠伤寒沙门氏菌/哺乳动物微粒体酶试验检测 生命壹号口服液安全性

目的采用鼠伤寒沙门氏菌/哺乳动物微粒体酶试验(Ames)对生命壹号口服液进行安全性毒理学试验。方法实验选用鼠伤寒沙门菌TA97、TA98、TA100和TA102菌株,将生命壹号口服液配制成浓度为50000、10000、2000、400、80μg/mL的溶液,作为5个剂量组,同时设未处理对照组、溶剂对照组(二甲基亚砜)和阳性对照组(2-乙酰氨基芴、4-硝基喹啉-N-氧化物),观察各菌株的回变菌落数。结果生命壹号口服液Ames试验各剂量组的回变菌落数均未超过未处理对照组自发回变菌落数的2倍,Ames实验结果为阴性。结论在本实验条件和剂量范围内,未观察到生命壹号口服液对鼠伤寒沙门氏菌TA97、TA98、TA100、TA102的诱变作用。     

一种无溶剂饮水舱防腐涂料的毒性研究

目的 探讨一种无溶剂饮水舱防腐涂料的毒性作用。方法 急性经口毒性试验采用啮齿类动物急性固定剂量经口毒性试验一次限量法, 剂量设为20000mg/kgBW。微核试验设5000、2500、1250mg/kgBW 3个剂量组、阴性对照组及阳性对照组,采用30h给受试物法,检测骨髓嗜多染红细胞微核率。Ames试验分别设每皿200、100、40、10μl共四个剂量组,同时设阴性、阳性对照组,采用平板掺入法,观察每皿回变菌落数。结果 该种无溶剂饮水舱防腐涂料对受试动物的急性毒性(LD₅₀)＞20000mg/kgBW。与阴性对照组比较,骨髓细胞微核试验结果为阴性。三七须根各剂量组在Ames试验中未呈现致突变性。结论 在本实验条件和剂量范围内,该种无溶剂饮水舱防腐涂料对昆明种小鼠的急性经口毒性属实际无毒,未见诱导小鼠骨髓嗜多染红细胞微核形成的能力,在Ames实验中未见呈现致突变作用。     

东紫苏致突变作用的研究

目的研究东紫苏是否具有致突变作用。方法采用平板掺入法Ames试验,设每皿5000、1000、200、40、8μg剂量组,同时设阴性、阳性对照组,观察每皿回变菌落数。微核及精子畸形试验设5000、2500、1250 mg/kg·BW 3个剂量组、阴性对照组及阳性对照组。微核试验采用30 h、2次给受试物法,检测骨髓嗜多染红细胞微核率。精子畸形试验于首次染毒后第35 d处死动物,观察精子畸形率。结果与阳性对照组比较,东紫苏各剂量组在Ames试验中未呈现致突变性,骨髓细胞微核试验及小鼠精子畸变试验结果均为阴性,差异均无统计学意义(P0.05)。结论在本实验条件和剂量范围内,未发现东紫苏有致突变性作用。     

三七红曲复方制剂遗传毒性评价

目的 评价三七红曲复方制剂的遗传毒性.方法 通过细菌回复突变试验(Ames试验)、小鼠骨髓细胞微核试验和小鼠睾丸染色体畸变试验组合的方式评价三七红曲复方制剂的遗传毒性.结果 Ames试验中,在8～5000μg/皿剂量范围内,TA97a,TA98,TA100,TA102和TA1535的回复突变菌落数与溶媒对照组比较无统计...     

胡桃楸种仁壳黄酮的急性毒性和Ames试验的结果分析

通过急性毒性试验和Ames试验,研究胡桃楸种仁壳黄酮的安全性。急性毒性试验表明胡桃楸种仁壳黄酮无急性毒性作用(LD5016 g/kg);Ames试验中胡桃楸种仁壳黄酮不诱发鼠伤寒沙门氏菌组氨酸缺陷型菌株TA98和TA100的回复突变。表明胡桃楸种仁壳黄酮无致突变性,为安全无毒物。     

红曲发酵夏秋茶毒理学评价

目的 利用红曲发酵夏秋茶, 探究其急性毒性和遗传毒性。方法 通过急性经口毒性试验评价其食用毒性, 通过细菌回复突变试验、哺乳动物红细胞微核试验和体外哺乳动物细胞染色体畸变试验对红曲发酵夏秋茶进行遗传毒性评价。结果 经过急性经口给药的受试动物未见明显中毒症状及死亡, 且雌雄小鼠急性经口半数致死量(median lethal dose, LD50)大于10 g/(kg BW), 属于实际无毒级, 哺乳动物红细胞微核试验的阴性对照组、阳性对照组及红曲发酵夏秋茶各剂量组嗜多染红细胞/红细胞(polychromatic erythrocytes/red blood cells, PCE/RBC)比例无明显差别, 细菌回复突变试验中各剂量组回变菌落数均未超过自发回变菌落数的2倍, 体外哺乳动物细胞染色体畸变试验中红曲发酵夏秋茶无细胞毒性。结论 在本试验研究剂量和条件下, 通过红曲发酵的夏秋茶既无食用毒性也无遗传毒性, 该结论能为其食用安全提供依据。     

Lycopene degradation, isomerization and in vitro bioaccessibility in high pressure homogenized tomato puree containing oil: Effect of additional thermal and high pressure processing

In the present study, the effect of equivalent thermal and high pressure processes at pasteurization and sterilization intensities on some health related properties of high pressure homogenized tomato puree containing oil were investigated. Total lycopene concentration, cis-lycopene content and in vitro lycopene bioaccessibility were examined as health related properties. Results showed that pasteurization hardly affected the health related properties of tomato puree. Only the formation of cis-lycopene during intense thermal pasteurization was observed. Sterilization processes on the other hand had a significant effect on the health related properties. A significant decrease in total lycopene concentration was found after the sterilization processes. Next to degradation, significant isomerization was also observed: all-trans-lycopene was mainly converted to 9-cis- and 13-cis-lycopene. High pressure sterilization limited the overall lycopene isomerization, when compared to the equivalent thermal sterilization processes. The formation of 5-cis-lycopene on the other hand seemed to be favoured by high pressure. The in vitro lycopene bioaccessibility of high pressure homogenized tomato puree containing oil was decreased during subsequent thermal or high pressure processing, whereby significant changes were observed for all the sterilization processes.     

Ohmic heating: A promising technology to reduce furan formation in sterilized vegetable and vegetable/meat baby foods

Occurrence of furan, classified as carcinogen 2B by the International Agency for Research on Cancer, in heat-processed foods, especially sterilized baby foods, is of a health concern. On this account, innovative processing practices ensuring microbial safety, acceptable sensorial features, and, at the same time, minimizing furan formation have to be searched. In this study, the potential of ohmic heating to mitigate furan formation was demonstrated. Compared to conventional retort sterilization, significant mitigation (70–90%) of furan was achieved, assumingly due to reduced degradation of furan precursor under faster terms heating conditions. In purees containing meat, approx. two times less furan was formed, regardless of the processing technology. In addition to furan, also other headspace volatiles were measured and statistically evaluated. Compounds originated through fatty acids oxidation and Maillard reaction products were more abundant in conventionally sterilized samples compared to those treated by ohmic heating.Industrial relevanceOhmic heating is an emerging technology being employed in the field of food processing which applies a direct electric current to food products, providing rapid and uniform heating throughout the product. Shorter heating times used in ohmic heating, as compared to conventional retort sterilization, reduce potential losses of valuable nutrients and as well as reduce the formation of undesirable processing contaminants, in particular furan.The presented work examines furan concentrations across various stages of baby food production, in order to compare ohmic heating and retort sterilization processes. Volatile compound fingerprints for baby food purees processed via both sterilization methods, both prior and post sterilization were assessed. The results presented in this work are of high potential interest to the baby food industry to reduce both heat induced chemical changes and exposure of infants and babies to hazardous processing contaminants such as furan.     

非热杀菌技术特点及在肉制品加工中的应用

非热杀菌技术是指利用非加热的方法杀灭食品中特定的致病微生物,使微生物的总量符合标准的杀菌技术。该技术具有产热低或不产热,能最大程度地保持食品的香味、色泽和营养成分的特点,有效地避免了传统热杀菌技术影响产品品质的缺点,因而具有良好的应用前景。目前应用较为广泛的非热杀菌技术主要包括超高压杀菌、微波杀菌、高压脉冲电场杀菌、超声波杀菌以及辐照杀菌五种。本文根据近年来的研究成果综述了上述五种非热杀菌技术的原理、影响因素以及对肉品质的影响,并对非热杀菌技术的未来进行了简要展望。     

超高压对酱料食品中微生物指标的影响

由于超高压杀菌技术实现了常温或较低温度下杀菌和灭酶,保证了食品的营养成分和感官特性,因此被认为是一种最有潜力和发展前景的食品加工和保藏新技术。广泛的应用于含液体成分的固态食品或液态食品的杀菌。本实验尝试以酱料食品为样本,研究超高压杀菌技术对半固体膏状调味品的微生物卫生指标的影响,探讨非热力抑菌技术在半固体膏状调味品生产的应用。分别对压力、保压时间、温度进行单因素实验,结果为300MPa为最佳压力,20min为最佳保压时间,32℃为最适温度。     

Quantifying Enhancement in Heat Transfer Due to Natural Convection During Canned Food Thermal Sterilization in a Still Retort

Thermal sterilization of canned viscous liquid foods using saturated steam is enabled by natural convective heat transfer. However, the governing equations for two-dimensional convective heat transfer may be only rigorously solved by numerical calculations. On the other hand, if conduction is assumed to be the only mode of heat transfer, the thermal sterilization problem has analytical solutions for simple boundary conditions. However, the conduction model may not be appropriate in describing thermal sterilization of even viscous liquid foods and may cause considerable error in the prediction of the important parameters such as slowest heating zone (SHZ) temperature and lethality. The longer time for sterilization recommended by the conduction model may lead to overprocessing and an unacceptable food product. The objective of this work is to quantify the faster temperature rise in the food can due to natural convection when compared to the temperature rise obtained by only conductive heating. The consequent enhancement in lethalities is also reported. In addition, this work’s objective is to investigate how quickly the natural convective heat transfer effects begin to dominate over the solely conduction heating mode. The volume-averaged temperature as well as the SHZ temperature variations with time was calculated for the convection-augmented mode using computational fluid dynamics (CFD) simulations. Lethality values were then calculated based on volume-averaged temperature as well as the SHZ temperature. Food cans of different aspect ratios and food medium thermal conductivities are considered in this analysis. For the food system investigated, the critical Fourier number at which the transition to convection-augmented mode of heat transfer occurred is identified and explained from scaling considerations. In the conduction-dominated mode, it was possible to use analytical solutions to predict the volume-averaged and SHZ temperatures of the liquid food undergoing thermal sterilization. The Nusselt number correlation developed by Kannan and Gourisankar (2008) was used in the lumped parameter transient heat transfer model to predict the volume-averaged temperatures in the convection-dominated region. The volume-averaged temperatures from this approach were found to be in good agreement with the CFD simulation results. The time predicted for the SHZ to reach the minimum sterilization temperature was significantly lower when convective heating was also considered. The volume-averaged temperature and SHZ temperature enabled an estimation of overall sterility levels attained and minimum sterility levels prevalent inside the can, respectively. Even though the volume-averaged temperature increase due to convection was only about 10 K, the resulting accumulated lethality values were higher by an order of magnitude. The increase in SHZ temperatures was much higher in the convection-augmented mode, and consequently greater integrated lethalities were attained. The simple conduction model that is amenable to analytical solution cannot be used to approximate the heat-transfer-related phenomena even for “quick estimation” purposes when convection effects are significant. This precaution is found necessary even for the reasonably high viscous carboxy methyl cellulose system, whose average viscosity values ranged between 13 and 3 Pa s during the course of the sterilization process.     

超高压在涮肉调料中抑菌处理的应用

对于半固体膏状调味品,常规热力抑菌措施很难有效保障产品的安全。但是超高压杀菌技术实现了常温或较低温度下杀菌和灭酶,保证了食品的营养成分和感官特性。本实验尝试以涮肉调料为样本,探讨非热力抑菌技术在半固体膏状调味品生产的应用。采用Box-Behnken响应曲面法分析压力、温度、保压时间等三因素的交互影响,得出影响的主次顺序为:压力>温度>保压时间,压力330MPa,保压时间16min,温度37℃的条为最佳参数。其结果为菌落总数为18000cfu/g,大肠菌群数<3.0(MPN/100g)。本次试验大肠杆菌均未检测出超标情况,大肠菌群阴性,MPN/g<3.0。     

红外加热技术及其在食品杀菌中的应用研究进展

介绍红外加热技术的工作原理、特点以及对食品主要成分的影响,并总结红外加热技术在食品产业中的应用,结合实例,对红外加热技术在食品杀菌等方面的应用和研究进展进行分析。     

High hydrostatic pressure inactivation of vegetative microorganisms, aerobic and anaerobic spores in pork Marengo, a low acidic particulate food product

To prolong the shelf-life of particulate food products, high pressure processing is one of the emerging technologies to be studied as an alternative to classical pasteurization and sterilization by heat. Pork Marengo (a low acidic, partially prepared stew of pieces pork, carrots and peas) was inoculated with several strains of sporulating and vegetative microorganisms. The microbial spoilage of the product was evaluated after a high pressure treatment of 400 MPa during 30 min at, respectively, 20 and 50 °C. Several Clostridium spp. and Bacillus spp. survived the treatment, and the Gram-positive cocci Enterococcus faecalis and Staphylococcus aureus were revealed to be more pressure resistant than Saccharomyces cerevisiae and the Gram-negative bacteria Pseudomonas fluorescens and Escherichia coli. The high pressure treatment at 20 °C demonstrated that high pressure processing (HPP) of neutral-pH foods cannot rely on pressure alone as a pasteurization/sterilization process. Another physical agent like heat is needed. High pressure treatment at 50 °C demonstrated that heat transfer limitations in particulate food products still can trouble their successful pasteurization/sterilization.     

Research progress and application of ultrasonic- and microwave-assisted food processing technology

Microwaves are electromagnetic waves of specific frequencies (300 MHz–3000 GHz), whereas ultrasonic is mechanical waves of specific frequencies. Microwave and ultrasonic technology as a new processing method has been widely used in food processing fields. Combined ultrasonic and microwave technology is exploited by researchers as an improvement technique and has been successfully applied in food processing such as thawing, drying, frying, extraction, and sterilization. This paper overviews the principle and characteristics of ultrasonic- and microwave-assisted food processing techniques, particularly their combinations, design of equipment, and their applications in the processing of agricultural products such as thawing, drying, frying, extraction, and sterilization. The combination of ultrasonic and microwave is applied in food processing, where microwave enhances the heating rate, and ultrasonic improves the efficiency of heat and mass transfer. The synergy of the heating effect of microwave and the cavitation effect of ultrasonic improves processing efficiency and damages the cell structure of the material. The degradation of nutrient composition and energy consumption due to the short processing time of combined ultrasonic and microwave technology is decreased. Ultrasonic technology, as an auxiliary means of efficient microwave heating, is pollution-free, highly efficient, and has a wide range of applications in food processing.     

EFFICACY OF HIGH HYDROSTATIC PRESSURE AND MILD HEAT TO REDUCE GEOBACILLUS STEAROTHERMOPHILUS AS 1.1923 SPORES IN MODEL FOOD SYSTEMS

The objective of this investigation was to evaluate the efficacy of high hydrostatic pressure and mild heat against spores of Geobacillus stearothermophilus AS 1.1923 in model food systems. The pressure-processing conditions were fixed at 625.0 MPa and 86C for 14 min, which have been determined as the optimum processing conditions considering six-log-cycle reductions of G. stearothermophilus spores. Based on the results, response surface methodology was performed in the present investigation, the effects from food ingredients, such as soybean protein, soybean oil and sucrose, as well as pH of the food matrix on the inactivation of G. stearothermophilus spores by high pressure and mild heat was explored, and a quadratic predictive model for the effects of food ingredients and pH on the reduction levels of G. stearothermophilus spores by high-pressure processing was built. The predictive model is significant because the level of significance was P  < 0.0001 and the calculated F value is much greater than the tabulated F value. Moreover, the adequacy of the model equation for predicting the reduction of G. stearothermophilus spores was verified effectively.

PRACTICAL APPLICATIONS

This paper clearly demonstrated the contributions to pressure resistance from food ingredients such as soybean protein, soybean oil, sucrose and pH of the food matrix to the inactivation of Geobacillus stearothermophilus spores by high hydrostatic pressure and mild heat. The predictive model for predicting the reduction of G. stearothermophilus spores in model food systems was built which can be beneficial to targeted process development toward high-pressure sterilization of foods.