Phenolic, flavonoid and anthocyanin contents of local sweet potato (Ipomoea batatas)

N Shaari,N Hashim,Rosnah Shamsudin,M.Z Mohd Nor

doi:10.26656/fr.2017.4(s1).s01

Abstract

The sweet potato (Ipomoea batatas) is an annual herb of the family Convolvulaceae and ranked as the world's seventh most important food crop with a major contribution to energy and phytochemical source of nutrition. Three different conditions of sweet potatoes are unpeeled tuber (UPSP), peeled tuber (PSP) and skin of tuber (SSP). The objective of this study is to evaluate the phytochemical availability (total phenolic contents (TPC), total flavonoid contents (TFC) and anthocyanin content) in the different parts of the sweet potato tuber. Folin-Ciocalteau (FC) assay showed that phenolic contents for UPSP (41.14±1.69 mg GAE/100 g dry basis) and PSP (42.24±2.19 mg GAE/100 g dry basis) were significantly (50%) higher than SSP (26.01±2.04 mg GAE/100 g dry basis). In terms of flavonoid content, the highest value was retained in PSP (9.55±0.82 mg quercetin/100 g dry basis) followed by UPSP (3.30±0.19 mg quercetin/100 g dry basis) and SSP (1.43 ± 0.03 mg quercetin/100 g dry basis). PSP (9.43±0.08 mg/100 dry basis) had a higher anthocyanin content compared to UPSP (5.21±0.02 b mg/100 g dry basis) and SSP (5.21±0.02 b mg/100 g dry basis). The phytochemical properties were available in all conditions of the sweet potato. However, PSP was suggested to be the most preferable condition for further processing in the sweet potato industry.

Highlights

The sweet potato or ‘Ubi Keledek’ (Ipomoea batatas) is a staple food throughout the world
The sweet potato has a significant supply in terms of energy supplement and as a phytochemical source of nutrition (Shekhar et al, 2015)
The phenolic content for each analysed sample in the study was observed for UPSP (41.14±1.69 mg GAE/100 g dry basis), PSP

Summary

Introduction

The sweet potato or ‘Ubi Keledek’ (Ipomoea batatas) is a staple food throughout the world. The sweet potato is well-known globally because of its desirable properties. The shape of the sweet potato can be in fusiform globular, round or ovate with a smooth, ridged or rough surface. According to Woolfe (1993), the most abundant compounds in the sweet potato are minerals, vitamins, dietary fibre, and antioxidants such as phenolic acids, anthocyanins, tocopherol and betacarotene. The phenolic contents and total flavonoids of sweet potato range from 10.13 – 80.78 mg GAE per 100 g and 22.02 – 35.47 mg quercetin per 100 g, dry matter respectively (Huang et al, 2005). Huang et al (2005) reported that the content of anthocyanin ranges from 0.36 – 8.99 mg per 100 g, dry matter

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