机械去梗对荔枝损伤及保鲜性能影响的研究

荔枝在收获季节依赖人工成串采收,但出口的荔枝要求分成单果,为了实现成串荔枝的去梗分离,设计了一种机械式荔枝去梗机,该去梗机利用梳振法将成串荔枝分成单果。使用当天采购的成串新鲜荔枝,分别对人工去梗和4种振动频率下的去梗机去梗进行分离效率试验,试验表明,振动频率20 Hz时,机械去梗效果最好,其去梗效率约为人工去梗的3倍,破损率低于6%。分别对人工去梗和去梗机去梗得到的荔枝果实进行损伤测试和贮藏保鲜试验,试验表明,机械去梗果实的弹性模量未出现明显变化,即分离过程中机器对果实造成的机械损伤不明显,人工去梗和20 Hz机械去梗得到的果实在保鲜过程中,褐变指数、失重率、可溶性固形物含量等参数在大部分节点差异无显著差性,所以机械去梗对果实的保鲜性能影响较小。

Effects of Mechanical Stemming on Litchi Damage and Preservation Performance

Litchis are harvested by hands in bunches during harvesting seasons. However, litchis for exportation are required to be separated. In order to realize the separation of litchi bunches, a mechanical litchi stemming machine was designed, in which a combing vibration method was used. Fresh litchi bunches were purchased and on the same day, separation efficiency tests were carried out respectively by hand stemming and machine stemming under four vibration frequencies. The results showed that 20 Hz was the best vibration frequency for mechanical stemming, and the separation efficiency was about 3 times more than that of hand stemming. The damage rate of the fruits was less than 6%. The mechanical damage tests and the storage tests were conducted with the litchis separated by hands and machine. The modulus of elasticity was measured and showed no change after the fruits were separated by the machine, which indicated that no serious mechanical damage was caused by the machine during the separation process. During the preservation process, the browning index, weight loss rate and soluble solid content of litchis separated by hands and machine under the frequency of 20 Hz showed no significant difference, indicating mechanical stemming had no significant influence on the preservation of the litchis.