Comparison of the Chemical and Technological Characteristics of Wholemeal Flours Obtained from Amaranth (Amaranthus sp.), Quinoa (Chenopodium quinoa) and Buckwheat (Fagopyrum sp.) Seeds

Abstract

A sound fundamental knowledge of the seed and flour characteristics of pseudocereals is crucial to be able to promote their industrial use. As a first step towards a more efficient and successful application, this study focuses on the seed characteristics, chemical composition and technological properties of commercially available pseudocereals (amaranth, quinoa, buckwheat). The levels of starch, fat, dietary fiber and minerals were comparable for amaranth and quinoa seeds but the protein content is higher in amaranth. Due to the high amount of starch, buckwheat seeds are characterised by the lowest amounts of fat, dietary fibre and minerals. Its protein content ranged between that of amaranth and quinoa. Buckwheat seeds were larger but easily reduced in size. The lipid fraction of the pseudocereals mostly contained unsaturated fatty acids, with the highest prevalence of linoleic and oleic acid. Palmitic acid is the most abundant unsaturated fatty acid. Moreover, high levels of P, K and Mg were found in these pseudocereals. The highest phenolic content was found in buckwheat. Amaranth WMF (wholemeal flour) had a high swelling power but low shear stability. The pasting profile strongly varied among the different quinoa WMFs. Buckwheat WMFs showed high shear stability and rate of retrogradation.

Recent developments and knowledge in pseudocereals including technological aspects

“…All grain amaranth plants produce small seeds, which can vary in its color. The TKW is very low with 0.69 g as determined by De Bock et al (2021) for 8 different, commercially available amaranth seeds. The grains contain the episperm, consisting of a very thin layer of cellular tissue, the endosperm, the embryo, made up of protein-rich cotyledon, and the perisperm, where in contrast to true cereal, the starch is stored (Di Fabio and Parraga, 2017).…”

“…TKW values ranged around 2.19-4.04 g in 7 commercially available quinoa seeds. The TKW of quinoa increased with a decrease in the ash content (De Bock et al, 2021). Seeds of canihua are smaller, around 1 mm, and usually brown.…”

“…Ash content was increased with TKW. As minerals and fat are also stored in the embryo, it is assumed that not the proportion but the composition of the embryo is to a large extent determinative for the TKW of amaranth (De Bock et al, 2021). Amaranth requires rather warm climate conditions and is quite adaptable to diverse environmental conditions, but it has to be considered that it is a short-day species.…”

“…Carbohydrates are the major components in pseudocereals, ranging from 48.5 to 77.0% in quinoa, 60-70% in canihua 63.1-70.0% in amaranth and 63.1-82.2% dm in buckwheat (Repo-Carrasco-Valencia et al, 2010;Mart ınez-Villaluenga et al, 2020). The main carbohydrate is present as starch, its content in amaranth ranges in average from 55 to 65%, in quinoa from 52.2 to 72% (Kringel et al, 2020, De Bock et al, 2021, in canihua from 48 to 51% (Repo-Carrasco-Valencia et al, 2010) and in buckwheat from 54.5 to 78% (Mart ınez-Villaluenga et al, 2020, De Bock et al, 2021. Compared to true cereals the amounts are slightly lower.…”

“…Total lipid content of pseudocereals are generally higher (quinoa: 4.0-7.6%, canihua: 5.0-8.0%, amaranth: 5.6-10.9%, buckwheat: 0.75-7.7%) than those found in other grains such as wheat, corn or sorghum, except for buckwheat. In all of them, the highest proportion of lipids are unsaturated fatty acids (quinoa: 71.0-84.5%; amaranth: 61.0-87.3%; buckwheat: 80.1-80.9%) from which linoleic acid and oleic acid are the most abundant (De Bock et al, 2021). Amaranth, canihua and quinoa show higher concentrations of linoleic acid, compared to oleic acid, whereas buckwheat displays similar proportions of both fatty acids.…”