Resistant starch from five Himalayan rice cultivars and Horse chestnut: Extraction method optimization and characterization

Adil Gani,Farooq Ahmad Masoodi,Idrees Ahmed Wani,Asima Shah,Gazalla Akhter,Asir Gani,Bilal Ahmad Ashwar

doi:10.1038/s41598-020-60770-4

Adil Gani, Farooq Ahmad Masoodi + Show 5 more

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https://doi.org/10.1038/s41598-020-60770-4

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Abstract

In this study resistant starch (RS) was extracted from five Himalayan rice cultivars and Indian Horse chestnut (HCN) using porcine pancreatin enzyme following which it was subsequently characterized for its physicochemical, structural and functional properties. In vitro digestibility test showed that RS content of the rice cultivars and HCN was in the range of 85.5 to 99.5%. The RS extracted from the rice cultivars and HCN showed significant difference in the apparent amylose content (AAC), ranging between 31.83 to 40.68% for rice and 45.79% for HCN. Water absorption capacity (WAC), swelling and solubility index of RS ranged from 112–133.9%, 5.28–7.25 g/g and 0.033–0.044 g/g, respectively. The rice RS granules were polyhedral and irregular shaped with granular length in the range of 4.8–5.9 µm. The HCN RS granule morphology showed smooth surfaced, round, elliptical, irregular and oval shapes with average granular length of 21 µm. Pasting behavior also varied significantly between rice RS and HCN RS with later showing the lower values of pasting properties. Thermal properties (T0, Tp, Tc) and ΔH gel also varied considerably between the rice RS and HCN RS, wherein the highest values for peak gelatinization temperature and gelatinization enthalpy were seen for CH-1039. X-ray diffraction pattern of rice RS and HCN RS showed the characteristic A type of pattern in consonance with cereal starches.

Highlights

The growing importance for functional foods has led to an intense awareness among individuals for healthy foods
The apparent amylose content (AAC) of the rice resistant starch (RS) samples varied significantly (p ≤ 0.05) with the values ranging from 31.83% (SK-338) to 40.68% (CH-1007), the RS extracted from Horse chestnut (HCN) showed the highest value of AAC (45.79%) (Table 2)
In this study RS was extracted from the five Himalayan rice cultivars and HCN using porcine pancreatin enzyme following which it was subsequently characterized for its physicochemical and structural properties

Summary

Introduction

The growing importance for functional foods has led to an intense awareness among individuals for healthy foods. Starch being one of the most important food components serves as an efficient and prime dietary source of energy contributing 60–70% of the total energy[1]. RS2 is inaccessible to enzymatic action due to its crystalline nature such as high amylose maize starch (HAM). Both RS1 and RS2 belong to the category of native RS. Rice with its high starch content is of particular interest for extraction of RS as it will implement in www.nature.com/scientificreports the dietary prevention of obesity, diabetes and cardiovascular diseases, Indian horse chestnut (Aesculus indica) with about 38.3% starch content[6] serves as an important source for extraction of RS.

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