Chapter Twenty-Three - Influence of evaporative cooling, refrigeration, and traditional underground storage methods on the physicochemical properties of amadumbe starch

Abstract

This study aimed to investigate the effects of different storage conditions, including evaporatively cooled environments, on the functional and morphological attributes of amadumbe starch. Amadumbe starch was derived from corms subjected to five storage conditions: low-cold storage, high-cold storage, CoolBot and evaporative cooler storage, underground storage, and ambient storage as a control. The corms were stored in three replications using a randomized complete block design. Three different experimental designs were used in this study. The first two experimental designs had two treatments: storage conditions and storage period. However, sampling was carried out on every 14th day for 70days in experiment one and on days 0 and 70 in experiment two. The third experimental design had three treatments: storage conditions, storage period, and temperature, and sampling was carried out on every 14th day for 70days. The data were analyzed using Duncan’s multiple range test at a 5% level of significance. The results obtained in this study showed that both storage conditions and storage period had a significant impact (P<.05) on reducing the granular starch size, swelling power, solubility, and L* and on increasing the water-holding capacity, oil-holding capacity, and a*. High-cold storage resulted in the lowest reduction in starch yield (10.37%), granular starch size (6.21%), swelling power (12.31%), solubility (20.99%), and L* (1.08%). It also resulted in the highest increase in the water-holding capacity (60.02%) and oil-holding capacity (107.17%). Ambient storage resulted in the highest decrease in starch yield (10.37%), granular starch size (6.21%), swelling power (12.31%), solubility (20.99%), and L* (1.08%). It also resulted in the highest increase in the water-holding capacity (60.02%) and oil-holding capacity (107.17%). A starch morphology study revealed that the granules of amadumbe starch are predominantly irregular and polygonal-shaped with a smooth texture. These granules were densely packed and large on day 0; however, after 70days of storage, they became loosely packed and reduced in size. This study revealed that high-cold storage, followed by CoolBot and evaporative cooler storages, was the best storage method for preserving the quality attributes of amadumbe starch. In contrast, ambient storage conditions, including evaporatively cooled environments, had the worst ability to maintain the quality attributes of amadumbe starch. Therefore, for short-term storage, ambient storage is not recommended.