Research And Modeling Optimization Of Water Absorption And Disinfection Techniques For Germinated Brown Rice

Germinated brown rice is rich in nutrients and plays health protection function,as a result,it is favored by consumers.Moisture absorption procedure of brown rice before its germination is the fundamental reason for kernel cracking,which restricts quality and taste of germinated brown rice.In addition,growth of microorganism in moisture absorption and germination stage of brown rice brings potential safety hazard to germinated brown rice.In order to maintain safety,as well as improve edible and nutritional quality of germinated brown rice,a further study of new production technique has the practical guide meaning.The non-soaking moisture increase technique,disinfection technique for brown rice before its germination,and germination technique for disinfected brown rice are studied comprehensively.In first part,divide the humidification interval until germination of brown rice into several intervals.In each interval,investigate the effect of humidification rate on cracked kernel additional rate of brown rice and obtain the optimal humidification plan.Then,optimized humidification technique with variable humidification rate is proposed,which reduces the cracked kernel additional rate of germinated brown rice significantly.In second part,use brown rice after optimized humidification treatment with variable humidification rate as target,and select moisture of humidified brown rice,initial concentration,treatment time and temperature of ozonated water as processing parameters.Finally,the optimized ozonated water treatment technique is proposed,which disinfects efficiently,increases germination rate and accumulates gamma aminobutyric acid content.In third part,use ozonated water disinfected brown rice as target,and select moisture of disinfected brown rice,environmental temperature and relative humidity,germination time as germination processing parameters.Finally,the optimized germination technique that further increase germination rate and accumulate gamma aminobutyric acid content is proposed.The main results obtained in this paper are listed as below:(1)With humidification rate increases from low to high level,cracked kernel additional rate of brown rice firstly decreases and then increases in each humidification interval.This variation tendency follows the Exponential Linear Combination model function,and regression equations established are found to be extremely significant(P<0.01).With initial moisture content of brown rice increases gradually in whole humidification interval,the optimal humidification rate increases slowly-rapidly-slowly for DN sample and first slowly and then rapidly for SN sample.These variation tendencies follow the Sigmoidal model function and the Exponential Growth model function,respectively,and fitting equations established are extremely significant(P<0.01).In thewhole humidification interval,an optimized humidification technique featured by applying the optimal humidification rate in each interval is thus proposed.Compared to segmented moisture conditioning technique,this technique reduces cracked kernel additional rate of brown rice and germinated brown rice significantly,and germination rate of brown rice and gamma aminobutyric acid content of germinated brown rice both increase.(2)The optimized processing parameter of ozonated water treatment affects germination rate,disinfection rate in total bacterial counts and yeast counts of brown rice significantly.The proper oxidation stress by ozonated water can promote accumulation of gamma aminobutyric acid content in germinated brown rice,but high moisture adding target of brown rice,long treatment time and high temperature of ozonated water all play inhibition effect.Under each initial concentration and temperature,fitting equations for concentration of ozonated water during treatment are established based on the Polynomial model function,which are extremely significant(P<0.01).Furthermore,it is shown that consumption percentage of ozonated water concentration deceases with increase in its initial concentration and increases with increase in its temperature.Changes in concentration of total bacterial counts and yeast counts that affected by initial concentration and temperature follow the Linear model function,and coefficient of determination of fitting equations are 0.8728~0.9909.Changes in amount of total bacterial counts and yeast counts that affected by initial concentration and temperature follow the Polynomial model function,and coefficient of determination of fitting equations are 0.9025~0.9967.(3)Regression models for disinfection rate in total bacterial counts and germination rate of brown rice,gamma aminobutyric acid content in germinated brown rice are established,which are extremely significant(P<0.01).The optimal combination of ozonated water treatment parameters is listed as follows: moisture of humidified brown rice is 25.7%,initial concentration,treatment time and temperature of ozonated water are 5.2 mg.L-1,6.5 min and 29.5°C.Under this condition,the concentration of total bacterial counts for ozonated water treated brown rice decreases from5.17±0.28 lg CFU/g to 3.39±0.36 lg CFU/g,while germination rate of brown rice,concentration of total bacterial counts and gamma aminobutyric acid content of germinated brown rice are found to be 92.94±0.33%,3.57±0.18 lg CFU/g,31.88±0.21 mg.100 g-1.Compared to sodium hypochlorite treatment,the safety and functionality of germinated brown rice improved significantly.(4)The processing parameter for germination after disinfection affects germination rate of brown rice and gamma aminobutyric acid content of germinated brown rice significantly.On the other hand,there is an inhibition effect on germination rate and gamma aminobutyric acid content when the high level of each germination processing parameter is applied.In addition,regression models for germination rate of brown rice and gamma aminobutyric acid content of germinated brown rice are established,which are extremely significant(P<0.01).The optimal combination of germination parameters after disinfection listed as follows: moisture of disinfected brown rice is28.4%,environmental temperature and relative humidity are 30.0°C and 61.0%,germination time is 46 h.Under this condition,the germination rate of brown rice and gamma aminobutyric acidcontent of germinated brown rice are increased to 94.64±0.17% and 34.20±0.12 mg.100 g-1?...