Studies On The Process Technology And Changes Of The Quality During Storage Period Of Fermented Rice Cake

Fermented rice cake is the most authentic and the most ancient traditional fermented rice food in China. It has a unique flavor and high nutrition health care function. Quality good fermented rice cakes with the characteristics of white color, soft texture, no sink and non-stick teeth. However, traditional folk manual produced by the fermentation of fermented rice cakes have long production cycle, complex microbial system lead to the products have unstable quality. Now for production process optimization and strains purification is put forward higher requirements. Therefore, to investigate the stable fermentation strains and excellent processing technology of fermented rice cakes production is a general tendency. Fermented rice cakes are rice products wit high moisture content and eutrophy. In many physical and chemical changes have taken place in the process of storage, which leads to change the senses of their eating, quality and structure characteristics.Facing the increasing need of fermented rice products, it is necessary to provide theoretical basis on the study of fermented rice cakes correlation between the quality indexes during storage for large storage.Main contents and results in this paper are as follows:1、Adopt Box-Behnken method to explore the optimal test conditions of fermented rice cake which is used to design experiment and response surface analysis, with deformation degree and deformation rate were selected as research objects, to study the effect of structure test conditions on hardness, adhesiveness, springiness, cohesiveness and resilience of fermentation rice cakes. The results showed that deformation degree had a very significant impact on textural parameters(p<0.01); deformation rate had a very significant impact on hardness, adhesiveness, springiness(p<0.01), had a significant impact on cohesiveness and resilience(p<0.05). Through the response surface picture we know that the interactions of deformation degree and deformation rate had a very significant impact on hardness(p<0.01), had a significant impact on springiness and cohesiveness(p<0.05). In order to make stable results and test more convenient and quick, the optimal test condirions wre deformation degree of50%and deformation rate of1mm/s.2、Analysis and comparison of volatile compositions of fermented rice cake by using gas chromatography-mas spectrometry(GC-MS), which made by different brands of yeast and lactic acid bacteria and old plasma, chose the optimal combination.84Volatile compositions were identified from fermented rice cakes which were made by Danbaoli yeast and Youbaisheng lactic acid bacteria, Anqi yeast and Chuanxiu lactic acid bacteria, Yanzi yeast and Youbite lactic acid bacteria(baking agent4%, yeast:lactic acid bacteria1:1), old plasma. Esters in fermented rice cakes, which were made by Yanzi yeast and Youbite lactic acid bacteria, was68.12%, and had the most abundant lower threshold compounds, aroma-producing substances67.6%, ethyl caprylate56.3%, better than fermented rice cake which were made by old plasma. Yanzi yeast and Youbite lactic acid bacteria is the optimal group.3、In order to get stable quality fermented rice cake by using the result from experient (2), exploring the optimal fermentation technology. The study researched the influence of fermentation temperature, time, starter additive amount and the proportion of yeast and lactic acid bacteria on adhesiveness, springiness, cohesiveness and hardness. Through orthogonal test and fuzzy mathematics we can conclud the optimal fermentation technological conditions.Appropriate fermentation conditions were as following:starter additive amount3%, the proportion of yeast and lactic acid bacteria was3:1and fermented at a temperature of36℃for6h. The texture texture properties of fermented rice cakes under these conditions were:springiness0.928, adhesiveness137.891g·s, cohesiveness0.762, hardness3629.038g.4、Using two way of packing by plastic wrap and vacuum package and storaging under-18℃,4℃and25℃conditions, the fermented rice cakes’ moisture, total bacterial count, texture characteristic after cooking and sensory evaluation were measured in every two days. Make a comprehensive analysis, to determine the correlation between the quality indexes during storage. As the extension of storage time, the total bacterial count, hardness, and adhesiveness increased; moisture content, sensory characteristics, springiness and resilience decreased. Sensory evaluation value had very significant positive correlation with moisture content, springiness and resilience (p<0.01), had very significant negative correlation with hardness and adhesiveness(p<0.01). Moisture content had very significant positive correlation with springiness and resilience(p<0.01), had very significant negative correlation with hardness and adhesiveness(p<0.01). Under the premise that the total number of colonies accord with a standard in day6, moisture loss rate of fermented rice cake under-18℃vacuum packaging is only10%, was the lowest for all storage conditions. It’s the most optimal condition to maintain fermented rice cakes.