Changes in β-carotene, dry matter, sugar and starch content in two orange-fleshed sweetpotato (Ipomoea batatas (L.) Lam) cultivars as influenced by curing and household-level storage methods

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Abstract

The effects of three curing and two household-level storage methods (sand box and heap) on the compositional quality of two orange-fleshed sweetpotato cultivars were investigated for two successive years. The curing treatments were: in-ground/dehaulming, field-piling and uncured. Roots from the curing treatments were stored in either sand box or heap methods. The β-carotene content of “Apomuden†and “Nangungungu†respectively ranged from 13.80 to 28.29 mg/100 g and 11.33 to 17.20 mg/100 g for both years with “Apomuden†having a significantly (p < 0.001) higher β-carotene content. “Apomuden†also had significantly higher (p < 0.05) fructose, glucose and sucrose content compared to “Nangungunguâ€. However, “Nangungungu†had higher starch (54.86 to 56.16% vs. 46.16 to 46.30%, respectively) and dry matter content (30.43 to 32.89% vs. 25.05 to 25.62%, respectively) than “Apomudenâ€. Curing did not have a significant (p = 0.352) influence on the β-carotene content of roots except for the second year where field-piled cured roots in storage had a significantly higher β-carotene content (24.96 mg/100 mg; p = 0.007) compared with stored roots from the dehaulmed (22.26 mg/100 g) and uncured (21.01 mg/100 g) treatments. The sand box and the heap storage methods respectively resulted in 10% and 19% decline in β-carotene after 2 months of storage. This indicates that, β-carotene retention is better in the sand box relative to the heap storage and should be recommended for small scale storage of sweet potato in Ghana.