Abstract:
Sweet potato (Ipomoea batatas) is a vital food security crop globally recognized for its
high nutritional value, adaptability, and versatility. To promote sustainable food applications,
this study evaluated four different drying techniques such as freeze drying, cabinet drying,
microwave drying, and oven drying, on the proximate composition and bioactive properties of
sweet potato. Freshly cleaned sweet potatoes were dried using each drying technique, and the
resulting dried powders were nutritionally characterized, with statistical analysis performed
using R software (version 4.2.1). The fresh sweet potato showed a moisture content (MC) of
70.64±0.70%, ash content (AS) of 2.48±0.02%, crude protein (CP) of 0.58±0.25%, crude fat
(CF) of 0.12%, crude fiber (CFI) of 1.66±0.34%, total phenolic content (TPC) of 37.64±1.44 mg
gallic acid equivalents (GAE)/100 g, and total flavonoid content (TFC) of 1.64±0.06 mg
quercetin equivalents (QE)/100 g (wet basis). After drying, MC was reduced to 4.00±0.69%,
5.13±0.21%, 6.72±0.37%, and 8.52±0.39% for freeze dried (FD), microwave dried (MD),
cabinet dried (CD), and oven dried (OD) sweet potato samples, respectively. Among the
different drying methods (dry basis), AS was highest in OD samples (4.43±0.24%) and lowest in
CD samples (2.71±0.01%), with no significant differences (p>0.05) between MD and FD. The
CP was highest in FD (4.08%) samples and lowest in CD (2.77%) samples (p<0.05). The FD
samples showed the highest CF (0.74%) content, while CD showed the lowest (0.35%) (p<0.05).
No significant differences (p>0.05) were observed in CFI content among different drying
methods studied. The MD samples showed the highest value for both TPC and TFC (67.58±7.39
mg GAE/100 g and 3.3±4.39 mg QE/100 g, respectively (p<0.05)). Overall, microwave drying
proved to be the most efficient drying technique, ensuring superior retention of bioactive
compounds and nutritional quality, thereby supporting sustainable, health-oriented sweet potato
innovations.
