Effect Of Transport Vibration On Three Kinds Of Fresh-cut Vegetables

Fresh-cut lettuce, fresh-cut green pepper and fresh-cut cucumber were used as the experimental materials. First of all, the process of cold-chain transportation in Beijing was investigated, in order to analyze the effect of vibration intensive and accumulated transportation time on three kinds of fresh-cut vegetables. Then the impact test was simulated in laboratory, in order to figure out the effect of variable impact strength on the quality of fresh-cut vegetables. Then some kinds of improvement packages were researched in order to find out a good way to remain the quality of fresh-cut products and make the deterioration slown down. The summaries of this research are as followed.1. The results of real cold-chain transportation are shown below:(1)The vibration in different position were various. The strength in rear-top was higher than that in front-top higher than that in rear-bottom higher than that in front-bottom. Basically, more damages of fresh-cut vegetables can be caused by stronger vibration.(2)The quality of fresh-cut lettuces was much more worse after continuous 5 hours transport under the acceleration vibration of 1.21±.111 g than that after 2 hours transport. The quality of fresh-cut green pepper was worse after continuous 5 hours under acceleration vibration of 1.20±0.134 g rather than that after 2 hours, however, the external quality was not quite obvious. For fresh-cut cucumber, a remarkable damages was caused after continuous 5 hours under acceleration vibration of 1.16±0.099 g, the result was significantly different from the treatment of 2 hours.(3)The resistant ability of fresh-cut green pepper was was higher than that of fresh-cut lettuce higher than that of fresh-cut cucumber after the transport vibration.2. Consequences of impact-simulated experiment are shown below:(1)Four different areas of impact intensity were seperated from drop tests. A grade (0～ 200 g), B grade (200～400 g), C grade (400～600 g) and D grade (600～800 g). The more damages of products can be caused by the more impact strength.(2)The quality of fresh-cut vegetable was not quite obvious after the impact strength from A and B grades in initial stage of storage. However, the effect from the impact of B grade can be saw gradually during the later storage when compared with control.(3)As for the three subjects, severe changes of quality can be caused by the impact strength of C and D grades. After the treatments of 2-30 and 2-10, the external quality of fresh-cut lettuce and cucumber slices were unacceptable immediately.(4)The resistant ability of fresh-cut green pepper was higher than that of fresh-cut lettuce higher than that of fresh-cut cucumber.3. The results of different kinds of improved packages are shown below:(1)The improvement of MAP and plastic box were unsatisfied when doing the drop tests. Plastic box could easily be broken when the load was high.(2)For extending the shelf life, the packages of vacuuming and (vacuuming+buffer) were the most efficient methods. However, vacuum was not a suitable method for fresh-cut green pepper and cucumber.(3)The package of (Vacuuming+buffer) was a good way to protecting fresh-cut lettuce. The shelf life of fresh-cut lettuce in this kind of package can be extended to 10 days, while that in vacuuming package method can last to 9 days, that in hot-seal package can last to 7-8 days, and that in MAP and plastic container can only last to 4-5 days.(4)Hot-seal was a good package for fresh-cut green pepper and fresh-cut cucumber in this research.