烤烟烘烤过程中烟叶淀粉酶活性变化及色素降解规律的研究

Studies on activity of amylase and degradation of starch and pigment in tobacco leaf during the process of curing

采用河南农业大学设计制造的电热式温湿度自控烤烟箱 ,研究了烘烤过程中烟叶淀粉、淀粉酶和淀粉同工酶的变化 ,及对色素降解的影响。结果表明 ,在烟叶变黄阶段 ,淀粉急剧降解 ,4 8h后基本趋于稳定 ;淀粉酶活性从烘烤开始逐渐升高 ,并于 36 h前后达到一高峰 ,随后降低 ,在叶片水分 4 0 %～ 4 5 %和环境相对湿度 70 %以上时 ,淀粉酶活性高 ,淀粉降解快 ,淀粉酶活性升高和淀粉相对降解量呈动态正相关 (r NC89=0 .75 17* ,r云烟 85=0 .4 4 79) ,在叶片水分含量降至 10 %左右时 ,淀粉酶仍保持较高的活性 ,但降解量很小 ,含量几乎趋于稳定。淀粉同工酶电泳胶板上明显可见 3条酶带 A、B、C,初步确定为α-淀粉酶、β-淀粉酶、R-淀粉酶 ;β-淀粉酶活性最高 ,且同工酶活性和生理生化酶活性测定结果相一致。烘烤过程中淀粉和色素降解规律相同 ,数量变化呈极显著正相关 r NC89=0 .96 4 9* * ,r云烟 85=0 .94 2 8*。

Changes of activity of amylase and amylase\|isoenzyme and degradation of starch and pigments in tobacco leaf during curing were studied by using the electric\|heated flue\|curing barn designed and made by Henan Agriculture University. The temperature and humidity of the barn were controlled automatically. Results indicated that the content of starch decreased rapidly and leveled off after 48h of curing. The activity of amylase increased with the proceeding of curing and there was a peak at 36 hours of curing and then decreased. But the activity of amylase still kept in a high level when the moisture of curing\|environment was very low, even the tobacco leaf has been dry. The relative contents of starch degradation showed dynamic correlation with the increase of activity of amylase(r NC89 =0.7517 ,r YY85 =0.4479).The degradation of starch and pigment had the same regulation and were highly significant correlation at 1% level r NC89 =0.9649  ,r YY85 =0.9428  . There were three amylase\|isoenzyme bands A\,B\,C mainly in tobacco leaf during flue curing. They were α\|AMY\,β\|AMY\,R\|AMY and the activity of β\|AMY was the highest.