Heat treatment of quinoa (Chenopodium quinoa Willd.) albumin: Effect on structural, functional, and in vitro digestion properties

Extraction, structural characteristics and antioxidant activity of hemp seeds glycoprotein

The extraction process of hemp seeds glycoprotein (HGP) was optimized by using response surface methodology based on the single-factor experiments, and the structure characteristic and antioxidant activity of HGP were evaluated. The optimum conditions were extracting temperature of 58.54 °C, material-liquid ratio of 1:22.21 and ultrasonic power of 344.53 W. The molecular weight of HGP was identified by SDS-PAGE to be about 35 kDa. The FT-IR results demonstrated the presence of uronic acid and pyranose in the HGP structure. UV spectral scanning results confirmed the presence of a polypeptide skeleton structure and aromatic amino acids in HGP. TGA analysis revealed two weight loss intervals for HGP, with a thermal degradation temperature of 341.6 °C. Moreover, HGP demonstrated good antioxidant activity in vitro, with IC50 values of all antioxidant indexes below 0.5 mg/mL. These findings provide a basis for in-depth exploration of functional characteristics of hemp seeds glycoprotein.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10068-024-01583-3.

Study on the Thermal Stability of the Sweet-Tasting Protein Brazzein Based on Its Structure-Sweetness Relationship

Brazzein (Brz) is a sweet-tasting protein composed of 54 amino acids and is considered as a potential sugar substitute. The current methods for obtaining brazzein are complicated, and limited information is available regarding its thermal stability. In this study, we successfully expressed recombinant brazzein, achieving a sweetness threshold of 15.2 μg/mL. Subsequently, we conducted heat treatments at temperatures of 80, 90, 95, and 100 °C for a duration of 2 h to investigate the structural changes in the protein. Furthermore, we employed hydrogen-deuterium exchange coupled to mass spectrometry (HDX-MS) to analyze the effect of heating on the protein structure-sweetness relationships. Our results indicated that the thermal inactivation process primarily affects residues 6-14 and 36-45 of brazzein, especially key residues Tyr8, Tyr11, Ser14, Glu36, and Arg43, which are closely associated with its sweetness. These findings have significant implications for improving the thermal stability of brazzein.

Development of Functional Gluten-Free Sourdough Bread with Pseudocereals and Enriched with Moringa oleifera

Celiac patients tend to have an unbalanced diet, because gluten-free products typically contain a high amount of fats and carbohydrates and a low amount of proteins, minerals, and dietary fiber. This research focused on the development of gluten-free functional breads using pseudocereals, psyllium, and gluten-free sourdough to replace commercial yeast, fortifying them with Moringa oleifera. Six different gluten-free breads were made with sourdough: three control breads differentiated by sourdough (quinoa, amaranth, and brown rice) and three breads enriched with moringa leaf differentiated by sourdough. The antioxidant capacity, phenolic compounds, nutritional composition, physicochemical parameters (color, pH, and acidity), folate content, amino acid profile, reducing sugars, mineral composition, mineral bioaccessibility, fatty acid profile, and sensory acceptability were evaluated. A commercial gluten-free (COM) bread was included in these analyses. Compared with COM bread, the reformulated breads were found to have better nutritional properties. Moringa leaf increased the nutritional properties of bread, and highlighted the QM (quinoa/moringa) bread as having increased protein, fiber, sucrose, glucose, maltose, phenylalanine, and cysteine. The AM (amaranth/moringa) bread was also shown to have a higher total folate content, antioxidant capacity, phenolic compounds, 9t,11t-C18:2 (CLA), and 9t-C18:1. Reformulated breads enriched with moringa could meet nutritional requirements and provide health benefits to people with celiac disease.

Modifying quinoa protein for enhanced functional properties and digestibility: A review

Quinoa (Chenopodium quinoa Willd.) is a pseudocereal plant that originally came from South America. The trend of consuming quinoa is propelled by its well‒balanced amino acid profile compared to that of other plants. In addition, its gluten‒free nature makes quinoa a promising diet option for celiac disease patients. Protein accounts for approximately 17% of the quinoa seed composition and quinoa protein possesses excellent quality. Quinoa protein is mainly composed of 11S globulins (37%) and 2S albumins (35%), both of which are stabilized by disulfide bonds. To date, the alkaline extraction method is the most commonly used method to extract quinoa protein. The functional properties and digestibility of quinoa protein can be improved with the help of various modification methods, and as a result, the application of quinoa protein will be extended. In this review, the extraction method, modification of functional properties and digestibility of quinoa protein are thoroughly discussed, providing insights into the application of quinoa protein in plant‒based foods.