Study On The Change Of ?-Aminobutyric Acid In Germinated Brown Rice And Its Products Processing

Germinated brown rice,the product of brown rice after germination and drying.Germination improves the content of ?-aminobutyric acid(GABA)and nutritional value significantly.GABA is an important physiologically active ingredient with multiple pharmacological effects.GABA is an important physiologically active ingredient,with multiple pharmacological effects.To obtain the germinated brown rice with high GABA content and provide theoretical guidance for the processing of GABA enriched food,this paper mainly studies on the change of GABA in germinated brown rice and its products processing.The main results are as follows:1.Amino acid analyzer and high performance liquid chromatography(HPLC)were used to determine GABA of the germinated brown rice,and the comparison of two methods were studied.The repeatability and recoveries of two methods were measured,both amino acid analyzer and HPLC were able to quantitative determination of GABA in germinated brown rice;The advantage of amino acid analyzer method was simple pretreatment,separation efficiency,high sensitivity;The advantage of HPLC method was high precision and accuracy while the derivatization was incomplete probably.The amino acid analyzer was selected for the determination of GABA in germinated brown rice.2.The relationship between glutamic acid decarboxylase(GAD)activity,glutamic acid(GA)and GABA content in brown rice during germination with ultrasonic treatment assistant were analysed.The activity of GAD increased first and then decreased with the prolongation of germination time.When the germination time was 0-48 h,the average activity of GAD was 9.2 nmol GABA/g and the GABA content increased by more than 6 times.Between 48-60 h of germinating process,GAD average activity was 7.3 nmol GABA/g,and the increase of GABA content was not obvious.The content of GABA was regulated by the activity of GAD.GABA and GA content increased obviously with the extension of the germination time,and there is a significant positive correlation between GABA and GA content(P<0.05).Compared with the control,ultrasonic treatment promoted the growth of GA content at more than 2 times,accelerated the GAD activation process,and increased GABA content in the early period of germination.The change of GABA content in brown rice germinated mainly depends on the germination and metabolism of brown rice.3.The dynamics of the GABA during rice-steamed sponge cake(RSSC)with exogenous supplementation GAD and sodium glutamate making were studied.Mixing,fermentating and microwave cooking affect the GA content and GABA of the RSSC.Yeast was involoved in the production and consumption of GA and GABA.Exogenous supplementation GAD decreased GA levels in mixed and fermented batter and increased GABA levels.The reservations of GABA in the RSSC samples increased from 16.46 mg/100 g to 36.29 mg/100 g with supplementation the highest exogenous GAD.The recipe aaddition of GAD significantly increased the content of GABA compared with the addition of sodium glutamate.The GAD was the limiting factor for GABA conversion during RSSC making.Microwave cooking resulted in large GABA and GA losses more than 30%,probably in thermal degradation during cooking,and only a small amount of GABA was retained in the RSSC.4.The nutrients in the germinated brown cooked rice with different cooking methods were annlysed.There was no significant loss of GABA of germinated brown rice cooked at normal pressure and high pressure,the retention rate was over 96%.The GABA content of germinated brown rice cooked by microwave and superheated steam was significant loss,and the maximum reached to 29%.The content of all FAAs in germinated brown cooked rice decreased during different cooking methonds.The mineral elements changed in different cooking methonds,the content of K,Cr,Ca and Fe were obviously related to the amount of water added.The comprehensive scores of germinated brown cooked rice were lower than white rice.