Physicochemical properties and in-vitro digestibility studies of microwave assisted chemically modified breadfruit (Artocarpus altilis) starch

Abstract

Chemical modifications (citrification, acetylation and phosphorylation) of breadfruit (Artocarpus altilis) starch were performed using dual (microwave-assisted and chemical) processes, the physicochemical properties, degree of substitution and in-vitro starch hydrolysis of the modified starches were evaluated using standard methods while changes in molecular structure was assessed using Fourier transform-infrared (FTIR) spectroscopy. The results showed that bulk density ranged from 0.22 to 0.28 g/ml, swelling power (5.89 to 6.23), solubility (0.13 to 0.17 g), water absorption capacity (WAC) (0.5 to 0.9 mg/g), and oil absorption capacity (OAC), 0.8 to 1.0 ml/g. Starch and amylose contents varied between 122 and 206 mg/g and 16 to 36%. The degrees of citrification in chemically and microwave modified starches were 0.2 and 0.31% while chemical and microwave modified acetylation were and 0.24 and 0.36%, respectively. The infrared spectra of modified starches showed characteristics band for C = O at 1754 to 1375 cm−1 for acetylated starches and at 1240 cm−1 to 1417 cm−1 belonging to P = O stretching vibration for phosphorylated starches. The in-vitro starch hydrolysis showed that modified starches recorded decreased rate of hydrolysis and glycemic index compared to native starch. Microwave-assisted chemically modified starch recorded better functional properties and low glycemic index compared to chemically modified starch. The study revealed that modification of breadfruit starch could enhance efficient utilization of breadfruit for both industrial and nutritional purposes.