Effect of different storage methods on the proximate composition and functional properties of cream-skinned sweet potato(ipomea batatas lam)

Abstract

In this study, the effect of different storage methods on the proximate composition and functional properties of sweet potato (Ipomoea batatas Lam.) was investigated. The sweet potato tubers were harvested from a local farm in Jukwa, a village within the vicinity of Cape Coast. For the proximate composition, sample from the fresh tubers were thoroughly sorted, washed, peeled and subjected to analysis for moisture, ash, protein, fat, fibre, carbohydrate and reducing sugars. For the functional properties the peeled samples were sliced, sun-dried, milled into flour and subjected to analysis for water absorption, oil absorption, foaming capacity and swelling power. The rest of the tubers were cured and stored in sawdust, wood ash and ambient conditions for six weeks in a storage facility. Samples were taken from various storages every two weeks, processed and subjected to proximate composition and functional properties analysis. Results of the proximate analysis carried on the fresh sweet potato samples showed 59±0.69 % moisture, 2.27±0.17 % ash, 7.85±0.08 % protein, 0.95±0.00 % fat, 0.21±0.00 % fibre, 62.68±8.00 % carbohydrate and 2.41±0.00 % reducing sugars. For the functional properties the results showed 1.95±0.14 ml/g, 1.37±0.26 ml/g, 4.03±0.05 ml/g, and 8.88±0.82 g/g for water absorption capacity, oil absorption capacity, foaming capacity, and swelling power respectively. The results of the analysis of the stored samples showed no significant variations (p>0.05) in fibre, and reducing sugar, foaming capacity and swelling power with the storage methods and time but showed that moisture, ash, protein, fat, carbohydrate, foaming capacity and swelling power varied significantly (p<0.05) with storage time In this study, the effect of different storage methods on the proximate composition and functional properties of sweet potato (Ipomoea batatas Lam.) was investigated. The sweet potato tubers were harvested from a local farm in Jukwa, a village within the vicinity of Cape Coast. For the proximate composition, sample from the fresh tubers were thoroughly sorted, washed, peeled and subjected to analysis for moisture, ash, protein, fat, fibre, carbohydrate and reducing sugars. For the functional properties the peeled samples were sliced, sun-dried, milled into flour and subjected to analysis for water absorption, oil absorption, foaming capacity and swelling power. The rest of the tubers were cured and stored in sawdust, wood ash and ambient conditions for six weeks in a storage facility. Samples were taken from various storages every two weeks, processed and subjected to proximate composition and functional properties analysis. Results of the proximate analysis carried on the fresh sweet potato samples showed 59±0.69 % moisture, 2.27±0.17 % ash, 7.85±0.08 % protein, 0.95±0.00 % fat, 0.21±0.00 % fibre, 62.68±8.00 % carbohydrate and 2.41±0.00 % reducing sugars. For the functional properties the results showed 1.95±0.14 ml/g, 1.37±0.26 ml/g, 4.03±0.05 ml/g, and 8.88±0.82 g/g for water absorption capacity, oil absorption capacity, foaming capacity, and swelling power respectively. The results of the analysis of the stored samples showed no significant variations (p>0.05) in fibre, and reducing sugar, foaming capacity and swelling power with the storage methods and time but showed that moisture, ash, protein, fat, carbohydrate, foaming capacity and swelling power varied significantly (p<0.05) with storage time