Influence of Maillard reaction conditions and solvent extraction on the surface activity and foaming characteristics of black cumin protein concentrates

Enhancing the foaming properties of brewer's spent grain protein by ultrasound treatment and glycation reaction

The denaturation state and relatively poor solubility of brewer's spent grain protein (BSGP) have limited its industrial application. Ultrasound treatment and glycation reaction were applied to improve the structural and foaming properties of BSGP. The results showed that all ultrasound, glycation, and ultrasound-assisted glycation treatments increased the solubility and surface hydrophobicity of BSGP while decreasing its zeta potential, surface tension and particle size. Meanwhile, all these treatments resulted in a more disordered and flexible conformation of BSGP, as observed by CD spectroscopy and SEM. After grafting, the result of FTIR spectroscopy confirmed the covalent binding of -OH between maltose and BSGP. Ultrasound-assisted glycation treatment further improved the free SH and S-S content, which might be due to -OH oxidation, indicating that ultrasound promoted the glycation reaction. Furthermore, all these treatments significantly increased the foaming capacity (FC) and foam stability (FS) of BSGP. Notably, BSGP treated with ultrasound showed the best foaming properties, increasing the FC from 82.22% to 165.10% and the FS from 10.60% to 131.20%, respectively. In particular, the foam collapse rate of BSGP treated with ultrasound-assisted glycation was lower than that of ultrasound or traditional wet-heating glycation treatment. The enhanced hydrogen bonding ability and hydrophobic interaction between protein molecules caused by ultrasound and glycation might be responsible for the improved foaming properties of BSGP. Thus, ultrasound and glycation reactions were efficient methods for producing BSGP-maltose conjugates with superior foaming properties.

Effect of Black Cumin Cake Addition on the Chemical Composition, Glycemic Index, Antioxidant Activity, and Cooking Quality of Durum Wheat Pasta

Pasta is a good carrier for plant enrichment substances due to its popularity among consumers. The purpose of the study was to investigate the functional potential and optimize the recipe of pasta made from durum semolina with the addition of black cumin cake at the level of 5, 10, 15, 20, and 25%. The use of black cumin cake resulted in a statistically significant (p ≤ 0.05) increase in the content of protein, fat, ash, and fiber, including both the insoluble and soluble fractions. A reduction in the digestible carbohydrate content, in vitro starch hydrolysis index (HI), was observed. Pasta with a reduced glycemic index (GI) compared to the semolina control was obtained. The content of polyphenols, including flavonoids, in the cake-enriched pasta increased significantly (p ≤ 0.05), which resulted in higher antioxidant activity against DPPH. The increase in the iron content was over 2.5 times higher in the sample with the 25% addition of black cumin cake than in the control sample. The functional addition significantly (p ≤ 0.05) increased the loss of dry matter and influenced the cooking time of pasta.

Black Cumin (Nigella sativa L.) Seed Press Cake as a Novel Material for the Development of New Non-Dairy Beverage Fermented with Kefir Grains

In recent years, there has been a growing interest from the food industry in new products that are increasingly desired by consumers because of the functional ingredients they contain. This category certainly includes fermented plant-based beverages, which combine the properties of plant substrates with the beneficial effects of fermentation on human health. In our study, two trial variants containing 20% and 30% black cumin (Nigella sativa L.) seed press cake (BCPC) were inoculated with kefir grain cultures and then incubated at 25 °C for 24 h. The resulting beverages were stored under refrigeration (6 °C) for 28 days. During storage, pH, total free amino acids, reducing sugars, changes in the microbial population, viscosity, textural parameters, and color were measured on days 1, 5, 7, 14, 21, and 28. Throughout the storage period, the number of lactic acid bacteria, as well as yeasts, exceeded the recommended minimum level. Numerous changes in product parameters were observed in the tested beverages as a result of fermentation compared to non-fermented products. This study indicates the possibility of using BCPC as a valuable matrix for the production of a functional kefir-like beverage.