A Multi-Technique, Biophysical Approaches for the Characterization of Potato Starch Granules
Wednesday, July 28, 2021
11:30 AM - 11:45 AM
Potato is the most commonly used food crop in the world. In terms of human consumption, it is the world's third most valuable food crop, after rice and wheat. Potatoes are consumed by over a billion people worldwide in their tuber form. Potato starch is a widely used ingredient in the food and non-food sector. Potato is a rich source of dietary carbohydrates as it contains starch. Starch shows varied Physico-chemical properties in its native and hydrolyzed forms. Therefore, the current study aims to investigate the structural and functional characteristics of commercially available potato starch. Initially, enzymatic hydrolysis (α-amylase from Bacillus subtilis) of potato starch revealed that the formation of dextrose equivalent, and it was found to be maximum at 90mg of potato starch with 200 U/mL α-amylase. In vitro hydrolysis with porcine pancreatic α-amylase and amyloglucosidase revealed the resistant starch (RS) content which was found to be 81.98%. An iodine test was conducted to determine the amylose content and it was found to be 22%. Microscopic examination revealed the oval-shaped potato starch granules whose size varied between 15-30 µm. Spectroscopic analysis using X-ray diffraction (XRD) revealed the B-type crystallinity with crystallinity index 33.49%. Fourier-transform infrared (FTIR) spectroscopy confirmed the presence of –OH, C-O-C, and C-O-H bending and stretching vibrations. Thermal analysis of potato starch showed the gelatinization peak temperature at 54.35°C, onset and endset temperatures at 22.51°C and 79.77°C respectively. The lack of facts and figures regarding the use of potato starch has limited its use in the food industries. To optimize its usage, appreciation of the relationship between the molecular structure, and functionality of potato starch is necessary. Hence, a multi-technique approach for structurally and functionally characterizing starch can gain new insights into potato starch applications in the food and non-food sectors. Keywords: Potato starch, resistant starch, amylose, microscopy, X-ray diffraction, FTIR, differential scanning calorimeter.