湿球温度对烟叶密集烘烤过程中酶促棕色化反应及烤后质量的影响

Effects of Wet Bulb Temperature on Enzymatic Browning Reaction and Quality of Flue-Cured Tobacco Leaves During Intensive Curing

为调控烟叶的酶促棕色化反应,提高烤后烟叶质量,以云烟87为材料,研究烘烤过程中酶促棕色化反应敏感期不同湿球温度对烟叶水分、PPO活性、叶绿素和总酚含量的影响,并对烤后烟叶的经济性状、外观质量、物理特性及感官质量进行测定和评价。结果表明:①不同湿球温度条件下烟叶水分、PPO活性、叶绿素含量、总酚含量的变化规律基本一致。②随湿球温度升高,烟叶含水率和叶绿素含量表现为持续下降;PPO活性表现为“降-升-降”的变化规律;总酚含量表现为先升高后降低再升高趋势。③在酶促棕色化反应敏感期,PPO活性表现为T2处理较低,叶绿素降解较快。④在40~54℃(变黄后期至定色期)后使湿球温度稳定在37~38℃条件下,PPO活性较低,总酚含量高,烤后烟叶质量高,感官质量较好。棕色化反应敏感期通过改变湿球温度有利于抑制烟叶酶促棕色化反应,防止烟叶发生褐变,提高烤后烟叶的外观和内在品质。

To regulate the enzymatic browning reaction and improve the quality of tobacco leaves, the effects of different wet bulb temperatures on moisture, PPO activity, chlorophyll and total phenol contents of tobacco leaves during the curing process were studied using Yunyan 87 as material. The economic properties, appearance quality, physical properties and sensory quality were measured and evaluated. The results showed that:(1) The changes of moisture, PPO activity, chlorophyll content and total phenol content under different wet bulb temperatures were basically same.(2) With the increase of wet bulb temperature, the contents of moisture and chlorophyll decreased continuously, PPO activity showed "decrease-rise-decrease", the total phenol content showed a trend of increase-decrease-increase.(3) In the sensitive period of enzymatic browning reaction, the PPO activity of T2 treatment was lower and chlorophyll degradation was faster.(4) After the wet bulb temperature was stabilized at 37~38℃ after 40~54℃(late yellowing to fixation period), PPO activity was lower, total phenol content was high, flue-cured tobacco quality was high, and sensory quality was better. Changing the wet bulb temperature during the sensitive period of browning reaction was beneficial to inhibiting the enzymatic browning, preventing the browning of tobacco leaves, and improving the appearance and internal quality of flue-cured tobacco.