Department of Consumer and Food Sciences and Institute for Food, Nutrition and Well-being, University of Pretoria, Pretoria, South Africa.
Department of Food Science and Post-Harvest Technology, Gulu University, Gulu, Uganda.
J Sci Food Agric. 2021 Dec;101(15):6347-6354. doi: 10.1002/jsfa.11305. Epub 2021 May 22.
Vacuum package storage is commonly applied to reduce postharvest deterioration in minimally processed cassava roots. However, the influence of vacuum packaging conditions on root end-use quality is poorly understood. Hence, the effects of vacuum packaged storage at ambient, refrigerated and freezing temperatures on microflora, cassava tissue structure and starch extraction by wet milling were studied.
Vacuum packaged storage temperature strongly affected cassava root quality. Minimal adverse effects were obtained with frozen storage. With refrigerated storage, there was negligible microbial growth but some disruption of the parenchyma cell wall structure suggestive of chilling injury. With ambient temperature storage, there was considerable Lactobacilli dominated fermentation. This caused substantial cell degradation, probably due to the production of extracellular cellulolytic and other cell wall degrading enzymes. A benefit of this cell wall breakdown was that it substantially improved starch extraction with wet milling from the stored cassava pieces; by 18% with pieces that had been ambient vacuum packaged and wet milled using a 2000 μm opening screen. However, ambient temperature storage resulted in some starch granule pitting due to the action of extracellular amylases from the fermenting microorganisms.
The best vacuum packaging storage conditions for minimally processed cassava depends on application and cost. For short-term storage, refrigeration would be best for vegetable-type products. For several months storage, freezing is best. For wet milling applications, this could be combined with subsequent short-term ambient temperature storage as it improves starch extraction efficiency and could reduce distribution energy costs. © 2021 Society of Chemical Industry.
真空包装储存通常用于减少鲜切木薯根的采后劣变。然而，真空包装条件对根末端用途质量的影响知之甚少。因此，研究了在环境、冷藏和冷冻温度下真空包装储存对微生物群、木薯组织结构和湿磨淀粉提取的影响。
真空包装储存温度对木薯根质量有很大影响。冷冻储存效果最小。冷藏储存时，微生物生长可忽略不计，但部分薄壁细胞壁结构受到破坏，提示存在冷害。在环境温度下储存时，存在大量的乳杆菌主导的发酵。这导致了大量细胞降解，可能是由于细胞外纤维素酶和其他细胞壁降解酶的产生。细胞壁破裂的一个好处是，它大大提高了用湿磨从储存的木薯块中提取淀粉的效率；用环境真空包装并使用 2000 μm 开口筛湿磨的块，提高了 18%。然而，由于发酵微生物的胞外淀粉酶的作用，环境温度储存会导致一些淀粉颗粒凹坑。
鲜切木薯的最佳真空包装储存条件取决于应用和成本。对于短期储存，冷藏最适合蔬菜类产品。对于几个月的储存，冷冻最好。对于湿磨应用，可以与随后的短期环境温度储存相结合，因为它可以提高淀粉提取效率，并可以降低分配能源成本。© 2021 化学工业协会。
