Effects of Hydrothermal Treatments on Physicochemical Properties and In Vitro Digestion of Starch

Ishita Chakraborty,Krishna Kishore Mahato,Nirmal Mazumder,Sintu Rongpipi,Indira Govindaraju

doi:10.1007/s11483-021-09687-7

Ishita Chakraborty, Krishna Kishore Mahato + Show 3 more

Open Access

https://doi.org/10.1007/s11483-021-09687-7

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Abstract

Starchy food items such as rice and potato with high carbohydrate content raise blood sugar. Hence, consuming low glycaemic foods is one tool to keep diabetes under control. In this study, potato and brown rice (Njavara rice) starches were subjected to hydrothermal treatments: heat moisture treatment (HMT) and annealing (ANN) to develop starch-based food products fit for consumption by diabetic patients. The effects of hydrothermal treatments on physicochemical properties and in-vitro enzymatic digestion of starch were determined. It was observed that hydrothermal treatments decreased the swelling power (SP)% and increased the water solubility (WS)% of the native starches. Native potato starch (PSN) showed a high SP of 80.33%, while annealed potato starch (PANN) and heat moisture treated potato starch (PHMT) showed SP reduced to 65.33% and 51.66%, respectively. Similarly, the SP % reduced from 64.33% in native brown rice (BRN) to 44.66% in annealed brown rice (BRANN) and 38.33% in heat moisture treated brown rice (BRHMT). WS % increased from 32.86% in PSN to 36.66% in PANN and 40.66% in PHMT. In BRN, the WS % increased from 14.0% to 14.66% in BRANN and 18.33% in BRHMT. Amylose content increased from 13.23% and 14.56% in PSN and BRN to 16.14% in PANN 17.99% in PHMT, 17.33% in BRANN, and 18.98% in BRHMT. The PSN crystallinity index reduced from 33.49 to 30.50% in PANN and 32.60% in PHMT. At 12 h of enzymatic digestion, it was found that the degree of hydrolysis (DoH) of PHMT (31.66%) and PANN (36.82%) reduced when compared to PSN (41.09%). Similarly, BRHMT exhibited the lowest DoH at 12 h compared to BRANN (29.24%) and BRN (35.48%). This study highlights the importance of hydrothermal treatments on starch in developing low glycaemic index commercial starch-based food products.

Highlights

Starch is a plant-derived polysaccharide with glucose units linked by glycosidic bonds
Heat moisture treatment (HMT) starch is widely popular in the food industry including products of bakery and canned food items due to their increased thermal stability compared to native starch [9, 10]
PSN and brown rice (BRN) show a decrease in swelling power post hydrothermal treatments (HMT and ANN) compared to the native starch

Summary

Introduction

Starch is a plant-derived polysaccharide with glucose units linked by glycosidic bonds It further contains two polymersamylose and amylopectin. Rice and potato are two of the most consumed sources of starch used in the food industry with total starch content ranging between 60 and 80% [3, 4]. Physical modifications by hydrothermal treatments are often used to improve the functional properties such as crystallinity, gelatinization temperature, swelling power, solubility, amylose content, and enzymatic digestibility of starch. They are preferred compared to any other chemical modifications as they are less expensive, easier to perform, produce no harmful by-products, and are environmentally neutral [8]. HMT and ANN are often considered to develop starch-based food items with low glycaemic index and promote the slow and steady release of glucose

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