Finger millet porridges subjected to different processing conditions showed low glycemic index and variable efficacy on plasma antioxidant capacity of healthy adults

Disna Kumari,Fereidoon Shahidi,Anoma Chandrasekara,Prisko Athukorale

doi:10.1186/s43014-020-00027-9

Abstract

Finger millet porridges (FMP), rich in nutrient and non-nutrient compounds have been used in the traditional food cultures in Asia. The aims of the study were to determine the effect of different processing conditions of finger millet grains on glycemic response, phenolic content and the antioxidant activities of FMP and to determine the short term and long term efficacy of its consumption on plasma antioxidant levels of healthy adults. Twelve types of FMP were prepared combining different processing conditions. Phenolic content of porridges as well as antioxidant activities were determined. The glycemic index (GI) and glycemic load (GL) values of FMP were also evaluated. The long term efficacy of FMP consumption on plasma glucose (PG), total cholesterol (TC) levels and plasma antioxidant capacity (PAC) of 18 subjects were investigated using a 24 weeks randomized cross-over study. The short term efficacy of porridge consumption on AC was determined. PAC was measured by trolox equivalent antioxidant capacity (TEAC) and ferric ion reducing antioxidant power (FRAP). All FMP exhibited low GI values (< 55) except the raw roasted flour which showed high and medium GI values for both particle sizes used. Parboiling of finger millet grains with 15 min steaming produced FMP with low glycemic response and possessed high PAC. Compared to baseline, PAC measured using FRAP and TEAC assays increased after 8 weeks consumption of porridge though significant changes were not observed for PG and TC levels. Furthermore, PAC was increased by 23 and 14% after 2 h of porridge consumption as measured by TEAC and FRAP, respectively. FMP consumption increased the plasma total antioxidant capacity of healthy adults. Further research on examining the potential of FMP on improving the antioxidant capacity in patients with diabetes is warranted.Graphical abstract

Highlights

Oxidative stress is known to contribute to the development of several chronic ailments such as obesity, hypertension, diabetes, certain types of cancers, cardiovascular diseases, arthritis, and neurodegenerative disorders associated with unhealthy diet and sedentary lifestyle
Epidemiological evidences have shown that consumption of whole grains with fruits, vegetables, and legumes is protective against the occurrence of a multitude of disease states
In the present study, roasting of raw finger millet flour significantly increased the total phenolic content (TPC) of soluble phenolic extracts of Finger millet porridges (FMP) preparations compared to those prepared using unroasted flour

Summary

Introduction

Oxidative stress is known to contribute to the development of several chronic ailments such as obesity, hypertension, diabetes, certain types of cancers, cardiovascular diseases, arthritis, and neurodegenerative disorders associated with unhealthy diet and sedentary lifestyle. The recent knowledge of millets as a rich source of antioxidant phenolic compounds and essential nutrients have attracted the interest of consumers to its potential health benefits in preventing and managing a myriad of chronic disease conditions (Shahidi and Chandrasekara 2013; Devi et al 2014; Bora et al 2019). Finger millet (Eleucine coracana) ranks fourth in importance among coarse grains, after sorghum, pearl millets and foxtail millets and is grown by subsistent farmers in the semi-arid tropics in South Asia and Africa (Gupta et al 2012). Due to their small seed size, finger millets grains are processed as whole grains. Locally known as Kurakkan, is the most popular type among other underutilized cereals in Sri Lanka and has been a part of a variety of cuisines in traditional food culture

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