The principles of ultra high pressure technology and its application in food processing/preservation: A review of microbiological and quality aspects

Consumers have a growing preference for convenient, fresh-like, healthy, palatable, additive-free, highquality and microbiologically safe food products. However, as food deterioration is constant threatalong the entire food chain, food preservation remains as necessary today as in the past. The food industry has responded by applying a number of new technologies including high hydrostatic pressurefor food processing and preservation. In addition, food scientists have demonstrated the feasibility of industrial-scale high pressure processing. High pressure processing is one of the emergingtechnologies to be studied as an alternative to classical thermal processing of food. This ‘clean’ technology offers an effective and safe method of modifying protein structure, enzyme inactivation, andformation of chemical compounds. In addition the study of the effects of high pressure on biological materials has received a great deal of attention in recent years. During the last decade, numerouspublications that describe the influence of pressure on various constituents and contaminants of foods such as spoilage microorganisms, food pathogens, enzymes and food proteins have appeared in the literature. This paper reviews the literature on high pressure application in food industry most notably it covers various facets of high pressure technology, which is, history, concepts and principles underlying the application of this technology,  hysicochemical, chemical, microbiological aspects of high pressurein the viewpoint of food technology

Influence of ultrasonic stimulation on the germination of barley seed and its alpha-amylase activity

In this study, the influence of ultrasonic stimulation was investigated on the germination of barley and alpha-amylase activity grains in the dry state before steeping. All experiments have been performedusing an ultrasonic horn operating at a fixed frequency of 20 KHz in 3 different ultrasonic power (20, 60 and 100% setting from total electrical power of device (460W) and time (5, 10 and 15 min) at constant temperature (30oC). For determining the effects of these parameters, the enzymatic activity was assayed by measuring the reducing sugars released as a result of the alpha-amylase action on soluble starch using 3,5-dinitrosalicylate regent (DNS). The results of these assays were analyzed by Qualitek4 software using Taguchi statistical method to evaluate the factor’s effects on the amount of enzyme activity. The results of assays showed that the activity of this enzyme was increased as a result of the increasing germination rate in the sonicated seeds. Also the findings indicated that both ultrasonicpower and treatment time with a contribution percentage as high as 48.456% and 45.273% respectively, had the dominant effects on overall performance