Proximate composition, amino acid profile, pasting and process characteristics of flour from different Tartary buckwheat varieties

Authors: BHINDER, SEERAT - Guru Nanak Dev University; KAUR, AMRITPAL - Guru Nanak Dev University; SINGH, BALWINDER - Khalsa College; Yadav, Madhav; SINGH, NARPINDER - Guru Nanak Dev University

Submitted to: Food Research International
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/21/2019
Publication Date: 12/26/2019
Citation: Bhinder, S., Kaur, A., Singh, B., Yadav, M.P., Singh, N. 2019. Proximate composition, amino acid profile, pasting and process characteristics of flour from different Tartary buckwheat varieties. Food Research International. 130:108946. https://doi.org/10.1016/j.foodres.2019.108946.
DOI: https://doi.org/10.1016/j.foodres.2019.108946

Interpretive Summary: Buckwheat is a less utilized cereal crop but is rapidly gaining popularity due to its high contents of bioactive materials, including antioxidants, resistant starch, vitamins, proteins, minerals and dietary fibers. Buckwheat flour has superior nutritional quality and its proteins possess superior functional properties like higher nitrogen solubility index, water holding, foaming and emulsification capacities. Buckwheat, therefore, has potential for use in many food formulations. To make a good use of Tartary buckwheat flour, a detailed study of its functional properties is needed. The successful incorporation of Tartary buckwheat in a food system will depend on various properties, e.g. foaming, oil and water absorption capacities, emulsification and pasting properties. A comparative study of the amino acid composition and pasting and functional properties of Tartary buckwheat flour obtained from twenty-three different varieties recently was completed. The study showed that protein contents in Tartary buckwheat flour from different varieties varied significantly and there was a good relationship between their protein contents and their emulsion stability. Emulsifying and foaming properties increased with increase in pH, which could be due to enhanced protein solubilities at high pH and exposure of oil-loving group. Good emulsifying and foaming properties are an indication of their potential for use in gluten-free eggless cakes with high specific volume. All varieties were found to possess all essential amino acids with particularly high contents of leucine, phenylalanine, lysine, and threonine. They also were found to have a low shear thinning behavior, making them suitable for use as a thickener in the processed foods like soups and sauces. The results of this study are very helpful to the US and Indian agricultural and food processing industries and also beneficial to buckwheat growers.

Technical Abstract: The flour from twenty-three Tartary buckwheat varieties were analysed for determining their proximate and mineral composition, amino acid profile, functional, and pasting properties. Ash, protein and fat contents of the flours ranged between 1.76 - 2.80%, 9.06 to 14.88%, and 2.02 - 3.60%, respectively. Buckwheat flours from all varieties had abundant K, Mg and Ca content, with the highest in B-121, and IC-274439, respectively, while IC-109237 had the lowest K content and Sanga B-117 had the lowest Mg and Ca content. All essential amino acids were detected in all varieties with leucine present in abundance. Isoleucine, cystine and asparagine were limiting. Emulsifying and foaming properties of flour from all varieties were better as the pH increased from 4 to 10. Their emulsion activity index (pH 10) showed a significant positive correlation with hydrophobic amino acids. Water and oil absorption (2.25 - 2.73 g/g and 0.82 to 1.40 g/g, respectively) of the flours correlated positively with their hydrophobic and acidic amino acids, respectively. The flours from most of the buckwheat varieties had unique pasting properties with very low set back and breakdown viscosities indicating paste stability and lower retrogradation tendency, making them suitable for thickening of sauces and soups.