采收时间对不同保鲜环境荔枝耐贮藏能力的影响

Impact of harvest times to anti-aging ability of litchi stored in different environments

为探究商业采收期内不同采收时间对荔枝采后耐贮藏特性是否具有影响,试验分别在荔枝商业采收期初期(B1)和末期(B2)对荔枝进行采摘后,采用目前常用的常温、冷柜和气调3种贮藏环境对荔枝进行贮藏。采用感官识别、色差仪识别和电子鼻识别技术分别对荔枝贮藏过程中的褐变指数、果皮颜色和气味信息进行监测。荔枝果皮褐变规律表明,在常温、冷柜和气调3种贮藏条件下的B2荔枝褐变速率均比B1荔枝快。常温和冷柜贮藏下的B2荔枝分别在4、16 d内有霉变发生,B1荔枝均未发现霉变。随着贮藏时间的增加,常温、冷柜和气调贮藏荔枝的果皮色差L*和a*值均逐渐减小,且B1荔枝减小速率较B2荔枝慢;色差b*值的变化规律不明显。B2荔枝的色差值在整个贮藏过程中均小于B1荔枝。电子鼻传感器R6、R7、R8和R9对荔枝气体挥发物响应值较大。随着贮藏时间的增加,传感器响R2、R4、R6、R7、R8、R9和R10均呈增大的趋势,传感器R1、R3和R5呈减小的趋势。呈增大趋势的传感器在0 d对B1荔枝的响应值比对B2荔枝的响应值小,呈减小趋势的传感器在0 d对B1荔枝的响应值比对B2荔枝的响应值大。线性判别分析(LDA)对B1和B2荔枝在不同贮藏环境下的贮藏时间识别结果表明,各贮藏环境下的B2荔枝的贮藏时间识别效果均明显优于B1荔枝。综合上述试验结果,B1荔枝较B2荔枝具有更好的品质特征与耐贮藏能力。

In order to explore the influence of harvest times during commercial harvest period to anti-aging ability of litchi, litchi samples were harvested at the beginning （B1） and end （B2） of commercial harvest period then stored in room temperature, refrigerator, and controlled atmosphere environments, separately. Sensory detection, colorimeter and electronic nose were applied for browning indexes, pericarp color, and volatile monitoring during storage. The browning speed of B2 litchis was faster than browning speed of B1 litchis in all 3 storage environments. Litchis stored in room temperature and refrigerator got mold within 4 days and 16 days, however B1 litchi didn＇t get mold. With the increasing of storage time, color indexes L＊ and a＊ of pericarp were decreased gradually for litchis stored in room temperature, refrigerator, and controlled atmosphere environments, and the decrease speed of B1 litchis was slower than B2 litchis. The changing rule of color index b＊ was not obvious. The value of color indexes of B2 litchis were lower than that of B1 litchis during all the way of storage. The responses of electronic nose sensors R6, R7, R8, and R9 to litchi volatiles were relative larger than other sensors. With the increasing of litchi storage time, responses of sensors R2, R4, R6, R7, R8, R9 and R10 were increased, responses of sensors R1, R3, and R5 were decreased. The response values of sensors which keeping increase during storage to B1 litchis were lower than that to B2 litchis, and the response values of sensors which keeping decrease during storage to B1 litchis were larger than that to B2 litchis. The recognition results of linear discriminant analysis to storage times of B1 and B2 litchis stored in three different environments showed that the storage time recognition effects of B2 litchi were apparently better than B1 litchi. Thus, the experimental results indicated that early harvested litchi has better food quality and anti-aging ability during commercial harvest period.