Basic aspects of food preservation by hurdle technology

Hurdle technology is used in industrialized as well as in developing countries for the gentle but effective preservation of foods. Previously hurdle technology, i.e., a combination of preservation methods, was used empirically without much knowledge of the governing principles. Since about 20 years the intelligent application of hurdle technology became more prevalent, because the principles of major preservative factors for foods (e.g., temperature, pH, a(w), Eh, competitive flora), and their interactions, became better known. Recently, the influence of food preservation methods on the physiology and behaviour of microorganisms in foods, i.e. their homeostasis, metabolic exhaustion, stress reactions, are taken into account, and the novel concept of multitarget food preservation emerged. In the present contribution a brief introduction is given on the potential hurdles for foods, the hurdle effect, and the hurdle technology. However, emphasis is placed on the homeostasis, metabolic exhaustion, and stress reactions of microorganisms related to hurdle technology, and the prospects of the future goal of a multitarget preservation of foods.     

酶制剂在食品保鲜中的应用

现将酶制剂的一般特性 ,酶制剂保鲜的特点 ,以及主要酶制剂 (溶菌酶、葡萄糖氧化酶 )在食品保鲜中的新应用作一介绍 ,并展望酶制剂作为保鲜剂的发展前景。     

辐照保鲜技木及其在动物性食品中的应用

阐述了辐照保鲜技术及其在动物性食品中的应用,探讨了辐照对动物性食品保鲜处理的优势、安全性以及对产品品质的影响,提出了动物性食品在辐照时质量控制的措施.     

植酸的食品保鲜机理及应用

通过植酸的分子结构,分析了植酸的理化特性及高效螯合金属离子的作用机理。介绍了植酸在食品行业中作为抗氧化剂、护色剂、沉淀剂的理论研究和应用概况,并对植酸食品保鲜技术进行了展望。     

植酸的食品保鲜机理及应用

本文通过植酸的分子结构,分析了植酸的理化特性及高效螯合金属离子的作用机理。介绍了植酸在食品行业中作为抗氧化剂、护色剂、沉淀剂的理论研究和应用概况,并对植酸食品保鲜技术进行了展望。     

MAP技术在鱼类保鲜中的应用

ＭＡＰ保鲜技术延长易腐败的食品如新鲜蔬菜,鲜肉,鱼类等的货架期。本文从基本原理,应用现状和将来的发展趋势等方面综述了ＭＡＰ技术在鱼类保鲜中的应用。     

双轮底丢糟二次串蒸工艺的研究及应用

将质量等级较低的原酒通过双轮底丢糟的二次串蒸,可将双轮底糟中的微量成份充分提取出来,又使串蒸酒质量有很大提高,减少资金和库存占用,提高酒质,损失较少,有一定推广价值。     

臭氧技术在食品加工中的应用

臭氧技术作为一种现代高新技术正日益受到重视 ,它可应用于空气、水和食品的消毒灭菌处理 ,与传统的方法相比较有独特的优点。本文主要探讨了臭氧杀菌的原理和特点以及存在的问题 ,展望了其发展前景 ,以期加速其在食品中的应用     

应用UPLC-Q-TOF-MS鉴定白酒酒糟中的水溶性多肽

以白酒酒糟为研究对象,采用超滤、反相高效液相色谱法(reverse phase high-performance liquid chromatography, RP-HPLC)分离制备酒糟中的水溶性多肽组分,并利用超高效液相色谱-四极杆飞行时间质谱联用技术(ultra-performance liquid chromatography-quadrupole-time-of-flight-mass spectrometry, UPLC-Q-TOF-MS)共分离鉴定出30种多肽,包括6种血管紧张素转换酶(angiotensin converting enzyme, ACE)抑制肽AAPK、KAGP、TVPK、YE、VPGK、TPF,2种抗氧化肽VPSGK、LH和1种抑制紫外线引起红斑的功能短肽HP。研究结果表明,白酒酒糟中含有多种生物活性肽。     

微波技术在食品水分检测中的应用

利用普通的微波设备,对食品中水分含量进行快速检测,将检测的数据进行工艺分析并及时地作出调整,应用于生产实际。对保证产品的质量和提高企业的效益都具有一定的现实意义。．     

中性蛋白酶水解啤酒槽中蛋白质的研究

以啤酒厂主要副产物啤酒糟为主要的原料,利用中性蛋白酶对其蛋白质进行水解,研究了酶解的pH温度、固液比、时间和加酶量对水解程度的影响,确定了最佳的影响因素。     

Profiling brewers' spent grain for composition and microbial ecology at the site of production

Brewers' spent grain (BSG) is a readily available, high volume low cost byproduct of brewing and is a potentially valuable resource for industrial exploitation. The variation in BSG composition and the implications for microbiological spoilage by a resident microflora might affect the potential to use BSG as a reliable food-grade industrial feedstock for value-added downstream processing. Fresh samples of BSG from a range of 10 breweries have been analysed for their microbial and chemical composition. The results show that a resident microflora of mainly thermophilic aerobic bacteria (<10⁷ g^-1 fresh weight) persists on BSG. This population is susceptible to rapid change but at the point of production BSG can be considered microbiologically stable. Chemically, BSG is rich in polysaccharides, protein and lignin. Residual starch can contribute up to 13% of the dry weight and BSG from lager malts has higher protein content than that from ale. In general, at the point of production, BSG is a relatively uniform chemical feedstock available for industrial upgrading. Differences between breweries should not present problems when considering BSG for industrial exploitation but susceptibility to microbial colonisation is identified as a potential problem area which might restrict its successful exploitation.     

膜技术在食品工业中的应用

膜技术与酶催化合成、遗传工程、超临界流体萃取被称为21世纪食品、医药等工程的四大重要技术。本文对膜技术在食品工业中的应用进行了综述。     

红外技术在食品工业中的应用

介绍了红外技术在食品工业应用及其原理，着重讲述了近红外的检测技术应用和远红外加热和杀菌技术应用，并分析了光波炉的工作原理、干燥原理以及近红外技术的特点。并给出了一些比较实例，指出了红外技术应用的发展趋势。     

栅栏技术在膏状肉类香精防腐中的应用

栅栏技术在膏状肉类香精防腐中有明显作用,膏状香精体系中水分活度、包装、保藏温度、辐照、防腐剂均应作为栅栏应用,水分活度Aw为主要栅栏因子,在充分运行HACCP体系的情况下,反应型产品以Aw<0.76为安全,酶解物Aw<0.74,不需添加防腐剂。     

Continuous production of pectinase by immobilized yeast cells on spent grains

A yeast strain secreting endopolygalacturonase was used in this work to study the possibility of continuous production of this enzyme. It is a feasible and interesting alternative to fungal batch production essentially due to the specificity of the type of pectinase excreted by Kluyveromyces marxianus CCT 3172, to the lower broth viscosity and to the easier downstream operations. In order to increase the reactors' productivity, a cellulosic carrier obtained from barley spent grains was tested as an immobilization support. Two types of reactors were studied for pectinase production using glucose as a carbon and energy source--a continuous stirred tank reactor (CSTR) and a packed bed reactor (PBR) with recycled flow. The highest value for pectinase volumetric productivity (P(V)=0.98 U ml(-1) h(-1)) was achieved in the PBR for D=0.40 h(-1), a glucose concentration on the inlet of S(in)=20 g l(-1), and a biomass load in the support of X(i)=0.225 g g(-1). The results demonstrate the attractiveness of the packed bed system for pectinase production.     

The application of computational fluid dynamics codes to simulate heat and moisture transfer in stored grains

An aim of stored-grains technologists has been to develop robust and flexible mathematical analyses of the heat and moisture transfer phenomena that occur in bulks of stored grains. A requirement has been that the models are able to simulate the wide range of storage geometries and operating conditions that occur in practice. Software packages developed from the discipline of computational fluid dynamics offer these possibilities. Such packages can be used to attack an extremely wide range of problems by solving the equations that govern the conservation of heat, mass and momentum. However, they need to be customised if they are to calculate velocity, temperature and moisture distributions in bulk stored grains. This paper demonstrates how these modifications can be made and how the results can be portrayed graphically in a way that permits insights into the processes that occur in grain stores.     

Utilisation of press water from brewer's spent grains

Brewer's spent grain press water contains 3% solids, half of which can be removed by centrifugation. The clarified press water (CPW) obtained can be recycled to recover significant quantities of fermentable material. The beers obtained from adding CPW at 5, 10, and 20% levels to wort prior to boiling were judged indistinguishable from the control beer. This process constitutes an efficient recovery of soluble solids, saves water, and eliminates a serious water-pollution problem. Drying the sediment from centrifugation yielded a tan powder containing 50–55% protein which had a PER of 1.22 (casein 2.5). When this protein concentrate (PC) was extruded in combinations with soy, gluten, and/or wheat flour, it gave products that were suitable for extending hamburger meat. When it was used in cookies, (biscuits), the cookie spread and the quality of the top grain of the cookie was decreased. In bread, the PC increased the water absorption of the dough and substantially decreased overall bread quality.     

非加热灭菌技术在食品工业上的应用

介绍国外目前主要使用的对食品的非加热灭菌方法,如:亚、超临界二氧化碳微气泡连续灭菌、臭氧冰的保存和灭菌特性、光脉冲灭菌技术和冲击波对粉末食品的灭菌等。这些方法既能达到对食品灭菌的目的,又能最大限度地保存食品原有的风味和营养。