优化催芽温度及CaCl_2溶液浓度提高发芽小米中γ-氨基丁酸含量

Optimization of germination temperature and CaCl_2 concentration to improve γ-amino butyric acid content in germination millet

氨基丁酸(γ-amino butyric acid,GABA)是一种非蛋白质氨基酸,具有多种生理活性。为进一步提升富含GABA食品的市场占有率,以小米为原料,通过发芽处理提高小米的营养价值,提高GABA的含量。为提高发芽小米中GABA的含量,通过单因素试验、Plackett-Burman因素筛选试验、最陡爬坡试验和响应面试验,优化发芽条件提高小米中GABA含量。在单因素试验的基础上,经过Plackett-Burman设计筛选出对GABA含量影响显著的3个因素:浸泡时间、CaCl_2溶液浓度和发芽温度。经最陡爬坡试验,确定对GABA含量影响显著的三因素在响应面中心点水平:浸泡时间13 h、CaCl_2溶液浓度3.5 mmol/L和发芽温度31℃。经响应面优化试验得出发芽小米积累GABA的最优工艺条件为:浸泡时间13 h、浸泡温度35℃、CaCl_2溶液浓度3.5mmol/L、发芽时间48h和发芽温度31℃,此时制得的发芽小米中GABA质量分数为251.46 mg/100 g,比小米中的初始GABA质量分数86.72 mg/100 g提高了2.90倍。研究结果得到了最佳小米发芽条件,为富含GABA健康小米食品的制备提供理论支持。

butyric acid of cereals.The germinated millet is a potential source of functional food.To improve the content of theγ-amino butyric acid in germinated millet,the optimal technological conditions was performed through the single factor experiment,Plackett-Burman experiment,steepest ascent path experiment and response surface methodology.Through the Single factor experiment,the optimum level of each factor was soaking time of 12 h,soaking temperature of 35℃,CaCl2 concentration of 3 mmol/L,germination time of 48 h and germination temperature of 35℃.On the base of the single factor experiment,soaking time,CaCl2 concentration and germination temperature which affected significantly the content of theγ-amino butyric acid were selected through the Plackett-Burman experiment.By use of Minitab software,a first-order model was fitted to the date obtained from the experiment.The effects of the five factors:soaking time(A),soaking temperature(B),CaCl2 concentration(C),germination time(D)and germination temperature(E)were calculated to be GABA=175.8–7.11A–0.680B+16.85C–0.365D+3.894E.At the same time,the first-order linear model of all factors and the content ofγ-amino butyric acid were formulated according to the results.Based on the formula and the three important effect factors above,the steepest ascent path experiment was carried out to determine the levels that affected significantly(P<0.05)the content ofγ-amino butyric acid at the central point of response surface experiment.It was obtained that the optimal processing for the accumulation ofγ-amino butyric acid in germinated millet.The millet was soaked in 3.5 mmol/L CaCl2 solution at 35℃for 13 h and germinated at 31℃for 48 h.The content ofγ-amino butyric acid was obtained 251.46 mg/100 g in germinated millet under optimized condition,which was 2.90 times higher than the initialγ-amino butyric acid 86.72 mg/100 g.The maximum predicted value 254.19 mg/100 g of GABA content in germinated millet obtained by Response surface methodology was close to the actual value 249.47 mg/100 g,indicating that the formula designed by Response surface methodology was close to the actual situation and the suitability of the formula to be used in optimizing the conditions of germination for the millet.It can be seen that the Single factor experiment,Plackett-Burman experiment,Steepest ascent path experiment and Response surface methodology can effectively screen and optimize the significant factors affecting the GABA content in the germinated millet,and greatly increase the GABA content.