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Subject: Agricultural Biochemistry × Author: Aranha, Deena Lyrisha × Start date: 2013 × Type: Thesis ×
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    ThesisItemOpen Access
    STARCH DIGESTIBILITY AND ESTIMATED GLYCEMIC INDEX OF RICE DIFFERING IN AMYLOSE CONTENTS
    (2021) Aranha, Deena Lyrisha; Baishya, Samindra
    Rice (Oryza sativa L.) is the most important cereal crop worldwide and serves as the major energy source in human nutrition. Starch digestion rate is an important consideration for rice consumers, particularly for diabetics. In the present study, eleven rice varieties differing in amylose contents were assessed for their variation in starch digestibility. An in vitro enzymatic starch digestion method was applied to estimate the glycemic index of rice varieties based on the kinetics of starch hydrolysis. Moisture content in the studied varieties ranged from 11.2% to 13.56%, reducing sugars from 0.33 to 0.65g/100g and starch content from 62.33 to 88.17%, with amylose content from 1.6% to 24.34% and amylopectin content from 75.65 to 98.39% on a dry weight basis. In vitro starch digestion resulted in readily available glucose (RAG) content from 44.96 to 95.4% and free glucose (FG) from 0.102 to 0.211%. The digestible and available starch fractions were calculated. Rapidly digestible starch (RDS) ranged from 40.33 to 85.72% and slowly digestible starch (SDS) from 2.59 to 41.99%. The resistant starch (RS) varied between 6.09% and 20.01%. The kinetics of in vitro starch digestion was determined and used for the calculation of hydrolysis index (HI) with which the glycemic index (eGI) was finally estimated. Starch digestibility and eGI varied widely among the rice varieties. The hydrolysis index ranged from 35.88 to 90.25 and with the lowest HI value of 35.88, Gitesh had the lowest eGI of 59.41, followed by Bahadur and Ranjit with eGI of 62.79 and 63.27 respectively. All these three varieties along with Prafulla, Numali, and TTB Black rice were found to be medium glycemic index rice. Sam Chakuwa, Lahi Chakuwa, Betguti, Joha Bora, and Ronga Bora were the high glycemic index rice.