Effect Of Selenium-enrich Upon Endogenous Enzyme Activities In Process Of Brown Rice Germination

This paper focuses on the dynamic activity changes of glutamate decarboxylase(GAD) activity and proteinase activity in brown rice (Liao Jing294)during germination and after adding selenium(Se). Endogenous enzyme is gradually activated with the germination. Different culture conditions and Se solution soaked are carried out to investigate the changes of the partial component content during germination under the endogenous enzyme treatment. The main results can be summarized as follows:1The effects of soaking time(3,6,9,12,15,18h), germination temperature(20,25,30,35,40,45℃), germination time(12,24,36,48h) and concentration of sodium selenite(0,5,10,20,30,40mg/L) on proteinase activity in brown rice are investigated. The change of proteinase activity shows that it increase first and then decrease subsequently after the treatment of these four factors during germination.2On the base of single factor investigation, the effects of germination time(X1), soaking time(X2), germination temperature(X3)and concentration of sodium selenite(X4)on proteinase activity in brown rice by using central composite design are studied. The predictive polynomial quadratic equations model is developed by response surface analysis(RSM):Y=3.66+0.82X1+0.59X2-0.88X3-0.27X4-0.59X2X4+0.51X3X4-0.57X42, and the regression coefficient of the model is3.66, p<0.0001, R2=91.55%by analysis of variance(ANOVA), which suggest the model is extremely significant, and fit well with actual experiments. The effects of X1、 X2、X3、X4、X2X4、X3X4and X42on proteinase activity are significant. Optimal condition dynamic changes of proteinase activities in brown rice during sprouting period can be concluded as follows:soaking time9h, germination time24h, germination temperature30℃, concentration of sodium selenite20mg/L, on these conditions, the protease activity is up to5.09U, and meanwhile the content of γ-Aminobutyric acid (GABA) is144.33mg/100g determined by HPLC, the results shows that the content of GABA in brown rice after germination is much higher than before germination (5.12mg/100g) organic-Se is0.376mg/kg.3The effects of germination temperature, soaking time, germination time and concentration of sodium selenite on GAD activity in brown rice during germination are investigated. The results shows that these four factors have a significant influence on the activity of GAD during germination.9h soaking time is suitable, germination temperature could be25℃, final consumption demands determined germination time48h germination time for high content GABA, and24h for general. Brown rice germination of0.5～1mm is the best state.20mg/L sodium selenite solution could be used in germinated rice.4The effects of germination temperature, soaking time, germination time and concentration of sodium selenite on the content of reducing sugar, soluble protein and amino acid are also studied. The results shows that the content of reducing sugar, soluble protein and amino acid present a rising tendency under the treatment of germination time, and the others treatments bring the tendency that is increased firstly and decreased subsequently. The content of reducing sugar,soluble protein and amino acid are737.6mg/100g,139.694mg/100g and2.49mg/100g, respectively in the condition of6h soaking time. The content of reducing sugar, soluble protein and amino acid are737.6mg/100g,155.154mg/100g and2.19mg/100g, respectively, in the condition of35℃germination temperature. And the content of reducing sugar, soluble protein and amino acid are723.08mg/100g,344.956mg/100g and2.58mg/100g, respectively, in the condition of30mg/L sodium selenite.