Functional characteristics and protein quality of selected commercially obtained brown and yellow canary seed flours and prepared isolates

Abstract

Background and ObjectivesCanary seed is a true cereal crop and classified as a “novel” food for human consumption. To explore potential food applications, the current study focused on evaluating the functional and nutritional properties of flours and protein isolates from glabrous (yellow and brown) canary seed.FindingsThe proximate composition, total starch and total amylose contents of the flours from both brown and yellow seeds were not significantly different. Both flours shared similar pasting properties and started developing viscosity at ~90°C. All the protein isolates showed >75% purity although were obtained in low yield (<5%). Most of the functional properties of the canary seed flour were significantly lower than those of the protein isolates. Similarly, lower digestibility of the flours (<32% in vitro protein digestibility‐corrected amino acid scores—PDCAAS) was evident in comparison with the isolates (>50% in vitro PDCAAS).ConclusionsThere are no significant differences between the yellow and brown canary seed proteins in terms of their composition, and functional and nutritional properties. However, marked differences were observed between the flours and protein isolates. The selection of yellow seed over the brown seed could be based on the color attributes of the flour or isolates for the intended product application.Significance and noveltyThis study provides insight on the protein quality, that is, functional and nutritional properties, of flour and protein isolates from yellow and brown canary seed. The findings provide prospects of selecting yellow seeds versus brown seeds for product applications based on their protein quality.

Techno‐functional and nutritional properties of full‐bran and low‐bran canaryseed flour, and the effect of solvent‐de‐oiling on the proteins of low‐bran flour and isolates

“…Similar to canaryseed, lower number of polypeptide bands were visible in the gluten sample compared to the wheat flours, showing evidence of protein loss during processing. The polypeptide profiles of canaryseed isolates evaluated by Achouri et al (2020) and Moura et al (2020) showed clear differences in the polypeptide profiles to the current study, especially in high molecular weight glutelin and globulin region and lower molecular weight region <10 kDa, mainly representative of albumins. In these two studies, the canaryseed protein isolates were prepared using alkali extraction and isoelectric precipitation processes at different extraction pH levels whereas, a completely different process was used to prepare isolates in the present study.…”

“…However, they showed strong stability once formed. Overall, both whole and white canaryseed flour showed low solubility (~50% or less) and shared similar solubility trend with each other (Figure 5a, Moura et al, 2020). The maximum solubility of 50.5% and 45.2% was obtained for whole and white four, respectively at pH 2 whereas, the minimum solubility was observed at pH 5-7 (2%-5.6%) for both canaryseed flours.…”

“…The polypeptide profiles of different fractions were evaluated using SDS-PAGE as described in Moura et al (2020) with modifications. The modifications include addition of Dithiothreitol (DTT, bioWorld chemicals) as the reducing agent to provide 50 mM final concentration and utilizing FroggaBio™ BLUelf prestained protein ladder as the molecular weight markers.…”

“…The water holding capacity (WHC), oil holding capacity (OHC), foaming capacity (FC), foaming stability (FS), emulsifying capacity (EC), emulsion stability (ES), and solubility were determined as the techno-functional properties of different canaryseed fractions obtained. The WHC and OHC, FC and FS were determined as illustrated in Moura et al (2020) and the foams were prepared using a polytron homogenizer (Kinematica Polytron™ PT 10-35 GT homogenizer, Kinematica Inc.) with PTA 10 TS probe (Kinematica Inc.) for 5 min at 16,000 rpm. The EC was determined according to the method described by Stone et al (2015) that involves monitoring the electrical conductivity (Model HI8733, Hanna Instruments) of series of emulsions until the inversion point, that is, the point in which the oil-in-water emulsion is converted to a water-in-oil emulsion.…”

“…In this process, ethanol was used as the solvent to de‐oil canaryseed flour, and the resulting protein isolate was evaluated for its techno‐functional properties. Moura et al (2020) also studied the techno‐functional and nutritional properties of hexanede‐oiled canaryseed whole flour (full‐bran flour), and derived protein isolates. However, information on the effect of using different solvents on canaryseed protein quality, and oil extraction efficiency is limited.…”