The physicochemical properties, sugar compositions and sweetness indexes in sweet potato (Ipomoea batatas Lam) tubers cultivated in Malaysia

Nurul Afza, K.^1,2*, Aziz, A.², Thiyagu, D.¹ and Khairunizah, H. K.³

Abstract
Sweet potatoes' physicochemical properties and taste are the main factors in determining the eating quality that leads to
consumer acceptance. However, little information is available about these characteristics, which making it challenging
for breeders to develop new sweet potato varieties with good eating quality. The purpose of this study is to determine
the physicochemical properties, sugar compositions, and sweetness index of sweet potato tubers [Ipomoea batatas (L.)
Lam] grown in Malaysia. MIb19 had the highest TSS (14.06 °Brix), while MIb11 had the lowest (7.80 °Brix). The pH
values ranged from 5.81 to 6.55, with MIb33 having the lowest pH and MIb23 having the highest. TTA was highest
in MIb16 (9.63%) and lowest in MIb29 (1.30%). MIb26 has the highest hardness value (12.74N), followed by MIb12
(12.45N). MIb11 sweet potato varieties with the lowest hardness value were mild, soft, and tender (7.66N). In terms of
total sugar, sweetness index and total sweetness index, MIb11 is significantly better than other genotypes. Due to the
high cumulative value of glucose and sucrose, SI revealed that MIb11 had the highest amount of sweetness index (5.76)
as well as the total sweetness index, TSI (4.10). This study demonstrated that there is a wide variation among sweet
potato accessions in terms of physicochemical properties, sugar composition, and sweetness index. Furthermore, it is
possible to select among the accessions to improve sweet potato genetics through the breeding of new quality varieties.

Keywords: sweet potato, physicochemical properties, sugar compositions, sweetness index

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