Escalating global protein demand necessitates the commercialization of protein rich products. Oat is a promising high-quality protein source but it requires structural and functional modifications to diversify its application. The current investigation was focused on the impact of different powers of ultrasonic waves (200, 400, and 600 W) on structural and functional characteristics of oat protein isolates to improve its techno-functional properties. Higher strength ultrasound waves generated flat sheet structures which were observed while analyzing microstructure of oat protein isolate (OPI). However, non-significant variation in molecular weight distribution were observed in different treatments. At 600 W power of ultrasonic waves the protein fragments show local accumulation, increased α-helix content. Due to uncoiling of protein structure decrease in β-sheets and β-turns was also observed at 600 W. Protein turbidity decreased significantly under low power ultrasonic treatment (200 W) which significantly increased at higher power. Moderate ultrasonic treatment (400 W) promoted protein dissolution, and maintained a good balance between β-sheets (71.04 ± 0.08), α-helix (16.27 ± 0.02) and β-turns (12.68 ± 0.03), exhibiting optimized flexibility and structural integrity. Whereas, higher strength (600 W) significantly destroyed protein structure. The amino acid content decreased significantly with increasing ultrasonic power. The thermal characteristics of OPI remained unaffected after ultrasound treatment. In conclusion, modifications of secondary and tertiary structure induced by moderate ultrasonic treatment (400 W) improved functional properties of OPI. The 400 W treatment resulted in highest essential amino acid content (EAA) i.e., 22.75 ± 0.82 mg/100 mg and total amino acid content (TAA) i.e., 64.94 ± 2.7 mg/100 mg, which are significantly higher than WHO and FAO standards, suggesting best total and essential amino acid production in comparison to other treatments.
To understand the effect of gluten on starch digestion characteristics, the structural characteristics of protein, starch, and starch digestion attributes were explored by using flours of four wheat near-isogenic lines. Protein and starch fractions from the four flours were used to form so-called recombinant flours where glutenin and gliadin protein fractions, in different ratios, were combined with starch and heated in a water slurry at 80 °C for 5 min. We found that starch digestibility of the recombinant flours could be reproducibly modified by altering the long- and short-range molecular order of starch through varying the attributes of the gluten protein by virtue of the gluten strength as well as the proportions of glutenin and gliadins. The gluten composition changes of strong-gluten flour did not improve the starch digestion resistibility, however, for the moderate- and weak-gluten flours, the proportional increase of glutenin improved the resistance of starch to digestion through the increased long- and short-range molecular order of starch. The resistance of starch to digestion could also be enhanced with increasing gliadin, and was associated with the modified short-range molecular order of starch. We propose that flour mixtures can be optimized for specified product quality by manipulating the amounts of both gliadin and glutenin.
29 November 2022 in Journal of the Science of Food and Agriculture
This paper seeks to contribute a fresh perspective meant to enrich the current limited discourse on teacher retention and attrition in Sub Saharan Africa particularly in Eritrea. Factors leading to teachers’ retention and attrition in middle and secondary schools in Eritrea are discussed. Results of an in-depth semi-structured interview with thirteen teachers in five purposefully selected schools show that low remuneration, poor school leadership, school-home distance, and placement without preference & interest are factors for teacher attrition. Conversely, meagre alternative employment opportunities, love of the profession, and love of the school children play a crucial role in teachers’ persistence in their profession. Although the study was carried out among few teachers and few schools, the findings present valuable discoveries useful for policymakers, school leaders, and stakeholders in the struggle for retaining quality teachers in the schools.
Dendrobium officinale (DO) is a well-known medicinal and edible plant, yet its impact on the quality of noodles has been infrequently reported. In this study, DO was incorporated into multi-grain flour in varying proportions (0, 2, 4, 6, 8%) to prepare noodles, and their quality was assessed. The percentage increase in DO decreased the cooking loss, whiteness, appearance, and taste of the noodles while simultaneously enhancing their water absorption, adhesiveness, smoothness, and starch digestion resistance. Lower supplemental levels of DO (2–4%) facilitated the water absorption of protein and the formation of a dense and extensive protein network surrounding the partially gelatinized starch, which was characterized by higher relative crystallinity. The highest sensory score (77.4) and greatest content of slowly digestible starch content (38%) were observed in the noodles containing 4% DO. Conversely, higher percentages of DO (6–8%) diluted and compromised the protein network in the cooked noodles, leading to water migration from protein to starch. The excessive polysaccharides from DO tended to complex with fully gelatinized starch, promoting starch aggregation and interactions between starch and non-starch components. This ultimately resulted in the highest adhesiveness and resistant starch content (34%) in the cooked noodles with 8% DO. These findings provide a reference for enhancing noodle quality by regulating the amount of DO added, thereby promoting the application of DO in cereal-based food products.