高温高湿贮藏对玉米淀粉合成关键酶的影响

Effects of High Temperature and High Humidity Storage of Corn Grain on the Activity of Its Key Starch Synthases

选用2013年收获的"农大709"玉米籽粒,根据吉林省夏季平均气温与相对湿度设定玉米的贮藏条件,将玉米籽粒分别贮藏于室温和恒温恒湿培养箱(35℃,75%)中,并测定分析了不同贮藏时间玉米籽粒可溶性淀粉合成酶(SSS)、束缚性淀粉合成酶(GBSS)、淀粉分支酶(SBE)以及淀粉脱支酶(DBE)活性的变化,进而分析玉米在不同贮藏条件下淀粉品质的变化。试验结果表明:常温条件下,只有SBE在贮藏第30天时有显著的下降(P<0.05),其余3种淀粉关键酶(SSS、GBSS、DBE)活性均没有发生显著变化(P>0.05)。高温高湿贮藏条件下,SSS、SBE、DBE酶活性均呈极显著下降(P<0.01),且分别下降了42.1%、39.5%和33.7%。而GBSS酶活性则呈先上升后下降的趋势(P<0.01),较常温贮藏,GBSS酶活性总体呈上升趋势。

Samples of corn grain ＂Nongda 709＂ gained in 2013 have been selected to study the effects of stor- age temperature and humidity on corn starch syntheses activity. The storage conditions were set based on the average temperature and relative humidity in summer of Jilin Province. The corn grains were stored in conditions at room tem- perature and the incubator （35 ℃, 75% ） respectively with constant temperature and humidity. The activity change of soluble starch syntheses （SSS）, bound starch syntheses （GBSS）, starch branching enzyme （SBE） and starch branching enzyme （DBE） of corn grains with different storage time were measured. Then the change of starch quality in different storage conditions was studied. The results showed that： on condition of normal temperature, only the SBE had significantly decrease （ P 〈 0.05 ） on 30 d of storage. However, the activity of the other three kinds of key enzymes of starch synthesis （ SSS, GBSS, DBE） were not significantly changed （ P 〉 0.05 ）. On high temperature and humidity storage conditions, SSS, SBE, DBE enzyme activity were significantly decreased （P 〈0.01 ） , and de- creased by 42.1%, 39.5% and 42.1% respectively. However, GBSS activity first increased and then decreased （P 〈0.01 ）. Compared with normal temperature storage, GBSS increased totally.