Characterization of β-glucan gum for food applications as influenced by genotypic variations in three hulless barley varieties

Abstract

Three hulless barley varieties were grown under normal conditions during 2017/2018 and 2018/2019, to improve their agronomic yield, and to assess how the genotype influences β-glucan contents, and its structural, thermal, rheological, and functional properties, as intended to be used in food applications. The extracted gums with hot water at 55 °C and pH 8.0, showed contents from 5.75% to 6.41% (w/w), and concentrations from 68.55% to 79.29% of β-glucan, with some starch and protein impurities. The results of the agronomic trail indicated the highly significant (P ≤ 0.01) influence of the genotype on all studied characteristics, and on the β-glucan contents (0.28^** and 0.33^** ) at both seasons. The morphology of the three gums was significantly different in the distribution and structure of networks. Peak intensities of the -OH and -CH groups and CH₂ stretching were higher and wider in Giza129 and Giza131. β-Glucan networks melt from 71.5 to 87.18 °C, and Giza131 exhibited the highest thermal stability. The aqueous dispersions (1%) of β-glucan gums exhibited a non-Newtonian behavior, and Giza130 presented the highest significant (P ≤ 0.05) apparent viscosity (η) and foaming stability. Giza129 showed the highest significant water and fat binding capacities, whereas Giza131 showed the highest significant foaming capacity. β-Glucan gums showed different potentials in food applications as fat replacers, stabilizers, thickeners, and foaming agents in food systems. This study suggests planting the proper barley variety in breeding and genetic improvement programs to supply the food industry with the expected β-glucan content with consistent structural, thermal, rheological, and functional properties. PRACTICAL APPLICATION: β-Glucans play an important technological role in processed foods. Little current information is available on β-glucan contents, and its potentiality on food applications, as influenced by variability among hulless barley genotypes. Accordingly, knowledge of β-glucan levels in barley varieties is a valuable attribute for both consumers and food processors, and it will create an opportunity for scientific cooperation between food technologist and breeders to identify the suitable barley varieties to be used in breeding programs, to obtain barley with required β-glucan contents, targeted for specific end uses.

Keywords: barley β-glucan; genotypic factor; rheological and functional properties; structural characterization; thermal.