利用中温α-淀粉酶BAN 480L的转糖基活性,对甜菊糖分子进行改性。实验结果表明,以马铃薯淀粉和甜菊糖为底物,转糖基反应主要发生在味质需要改善的组分甜菊苷上,而味质最好的组分莱鲍迪苷A几乎不发生转糖基反应。经优化得到反应的最佳条件:甜菊糖20 g/L,马铃薯淀粉160 g/L,温度70℃,pH 6.5,酶添加量2 KNU/g淀粉,反应6 h。甜菊苷的转化率为38.9%。反应液经大孔吸附树脂分离纯化,得到了脱除淀粉糖的产品。感官评定结果表明,产品后苦味明显改善,甜度和口感均优于原料。

Enzymatic modification of steviol glycosides using the glucosyl transfer activity of medium-temperature α-amylase BAN 480L has been investigated in this paper.Experimental results showed that,with potato starch and steviol glycosides as the substrates,transglycosylation reaction occurred mainly on stevioside that in need of improvement of the taste quality,while rebaudioside A,the component with the best quality of taste,was rarely transglycosylated.Under the optimized reaction conditions of steviol glycosides 20 g/L,potato starch 160 g/L,temperature 70 ℃,pH 6.5,enzyme loading 2 KNU/g starch,and reaction time 6 h,the conversion yield of stevioside was 38.9%.The removal of starch sugar and the purification of products were carried out by macroporous resin separation.Evaluation of the organoleptic properties of the product revealed the significant improvement for both the intensity and quality of the taste.