Study Of An Innovative Combination Between Microwaves And Enzymes Applied To Bakery Products

摘要

Microwave food processes offer a lot of advantages such as less start-up time, faster heating, energy efficiency, space savings, precise process control, selective heating and food with high nutritional quality. However, microwave baked products have quality problems: reduced height of the product, dense or gummy texture, crumb hardness, an undesired moisture gradient along a vertical axis in the final baked product and no browning on surface of product. The aim of this research was to combine enzymatic and microwave treatments in order to improve products baked by microwaves. For this purpose the single and interactive effects of some commercial enzymes activity (amylase, glucoamylase and protease) and processing parameters (power % and time of enzymatic pre-treatment) on production of reducing sugars, colour and structural characteristics of cookie roasted by microwaves (bulk density and breaking strength) were evaluated. This research was carried out on model system (like wafer) made up of running water and wheat flour without ingredient normally used to produce wafers in order to better understand the effect of enzyme activity on biopolymers of flour in absence of other substances that could influence enzymatic kinetic. The best operating conditions, to obtain a good colour and the lowest bulk density (0.38 g/ml) of samples, were the highest time of enzymatic pre-treatment (30 minutes) and power percentages of 90%. All enzymes had a positive effect on production of reducing sugars, colour and texture of samples only if added together and at middle amounts (0.5 g/kg protease and 0.05 g/kg amylase and glucoamylase). Moreover, the protease showed a positive and significant effect on decrease of breaking strength values.