Abstract In order to regulate the level of carbon and nitrogen metabolism during airing of tobacco leave and improve the quality of cigar tobacco leaves, the changes of water content, chemical composition and the activity of key enzymes related to carbon and nitrogen metabolism in cigar tobacco leaves were studied by using Dexue No.1 as the test material. The results showed that the changes of the chemical composition and the activity of key enzymes related to carbon and nitrogen metabolism in tobacco leaves were basically the same under different air curing humidity. The contents of water, total sugar, reducing sugar, starch, total nitrogen, protein and plastid pigment showed a downward trend, but the contents of amino acid and nicotine increased first and then decreased. The activity of amylase(AL) and neutral invertase(NI) showed a single peak curve, but the time to peak was slightly different. The activities of nitrate reductase (NR) and glutamine synthetase (GS) showed a downward trend. During air curing of cigar tobacco leaves, when the humidity was controlled within the range of 80%-85% in withering period, 75%-80% in yellowing period, 70%-75% in browning period, 65%-70% in fixing color period and 45%-50% in dry gluten period, the activities of AL, NI, NR and GS were the highest, the chemical components were suitable and the overall physical characteristics and quality were good. Therefore, controlling the air curing humidity within a certain range can improve the carbon and nitrogen metabolism of ciar tobacco leaves, promote conversion of tobacco leaf contents, and improve the quality and availability of cigar tobacco leaves.
LU Shaohao, ZHANG Jiawen, ZHAO Zhe, ZHONG Qiu, WANG Jun, SONG Zhaopeng, ZOU Yuhang, ZHANG Huashu, ZHAO Mingqin. Effects of air-curing humidity on key enzyme activities related to carbon and nitrogen metabolism and quality of cigar tobacco leaves[J]. Acta Tabacaria Sinica, 2020, 26(4): 26-34.