真空预冷结合微孔膜包装对鲜枸杞贮藏品质的影响

为了延长鲜枸杞贮藏保鲜期,该研究通过真空预冷结合微孔膜包装对鲜枸杞的贮藏品质进行研究,设置不同预冷终温(2、4、6℃)和终压(800～1 000、1 000～1 200、1 200～1 500Pa)对鲜枸杞进行真空预冷处理,通过比较真空预过程中鲜枸杞失重率、蜡质层和呼吸强度指标来确定较优工艺参数;之后将真空预冷较优工艺参数下的鲜枸杞用微孔膜包装后在(-1±0.5℃)的冷库中进行贮藏,以微孔膜包装处理和未经任何处理的鲜枸杞作为对照组,比较贮藏过程中硬度、可溶性固形物(Total Soluble Solids,TSS)、色差、呼吸强度、过氧化氢酶(Catalase,CAT)活性指标来综合分析不同处理对鲜枸杞贮藏品质的影响。结果表明:终温6℃和终压800～1 000Pa对鲜枸杞失重率影响较小;终温6℃和终压1 200～1 500Pa对鲜枸杞内表皮结构损伤较小;终温2℃和终压800～1 000Pa鲜枸杞呼吸强度最低,综合考虑3个指标,终温6℃,终压1 200～1 500 Pa为鲜枸杞真空预冷较优工艺参数;在贮藏期间,真空预冷结合微孔膜包装与其他两组相比较,可有效延缓鲜枸杞硬度和TSS下降,降低呼吸强度,抑制色差变化和CAT活性的下降(P0.05)。该研究为鲜枸杞贮藏保鲜提供新方法。

Storage quality of fresh Lycium barbarum by vacuum precooling and microporous membrane packaging

Abstract: "Three increases" in the production, storage and import of grain industry have triggered the continuous advance in the current harvest-storage system in recent years. At the same time, there is a highly serious loss of grain in the harvest and postharvest stages. Specifically, the annual loss of grain only in the storage, transportation and processing is up to about 3.5×1010 kg. Among the main grain storage entities, the loss rate of the farmers'' grain harvest-storage is the highest, which reduces food supply and farmers'' income level. Furthermore, new types of operation entities, such as farmer cooperatives, are widely expected to cope with the planting and storage dispersion since 2006. However, some current cooperatives only share simple harvest-storage technology, failing to formulate the production on a large scale, where the facilities and equipment are still lacking. In this study, an attempt was made to deal with the present situation of harvest and postharvest links in the farmer cooperative, such as simple technology, high loss rate, high energy consumption, and technology mismatch. The field data was collected in 130 farmer cooperatives covering 7 provinces in China. An integrated scheme of grain harvest-storage technology was also established for the farmer cooperatives integrating various engineering technologies. An evaluation was made on the typical technology pattern of grain harvest-storage in farmer cooperatives using hierarchical analysis, Delphi, and case study. The whole link, operation entities, and grain types were also considered during the evaluation. Three representative patterns were constructed, including the mechanical drying with clean energy for corn in northeast China, natural drying with green energy in annual double cropping areas of Central Plains, and rice mechanized drying and classified collection in southern China. These designs were assessed from the aspects of pattern connotation, suitable scope, and pattern scheme. Taking the harvest-storage pattern of a farmer cooperative in Liaoning Province as an example, the score shifted from the medium to excellent grade, after the cooperative pattern was optimized. The specific operational indicators showed that the loss rate of harvest-storage link decreased from 9% to 5%, the mildew rate of corn decreased from 4%-8% to less than 2%, and the drying energy consumption was reduced by more than 15%. It inferred that the well-established pattern was feasible to optimize the grain harvest-storage scheme for the farmer cooperative in specific regions. Nevertheless, some possible constraints also need to be considered, such as the state-of-the-art technology, market prospect, acceptance degree, and policy system, when the pattern is applied to optimize the current cooperative harvest-storage scheme. Therefore, it is strongly recommended that the optimization of the harvest-storage pattern should be further strengthened in the follow-up study, where the marginal effect of cooperative scale, harvest-storage pattern, and economic output should be further explored to determine the best balance. The finding can provide potential support to reduce grain loss, while keeping grain quality in modern highly mechanized agriculture.