Degradation of β-Carotene to Volatile Compounds in an Aqueous Model System to Simulate the Production of Sea Buckthorn Wine

The kinetics of β-carotene degradation were studied in different aqueous phases to simulate the production of sea buckthorn wine. The volatile compounds from degradation in model wine and an aqueous system were identified by mass spectrometry after gas-chromatographic analysis. The results showed that temperature was the major factor affecting β-carotene degradation in aqueous solution. Alcohol also showed an effect on β-carotene degradation. The speed of β-carotene degradation was slower in model wine than that in a pure water system, while it proceeded more quickly in sea buckthorn raw juice than in must and wine. The presence of extraneous oxidants altered the kinetic mode of β-carotene degradation in water. Six norisoprenoids from β-carotene degradation were found in the aqueous system, which were 3,5,5-trimethyl-2-cyclohexen-1-ol, 4-(2,6,6-trimethyl-1-cyclohexen-1-yl)-3-buten-2-ol, 2,2,6-trimethyl-cyclohexanone, 3,5,5-trimethyl-2-cyclohexen-1-one, 3,4,4-trimethyl-2-cyclohexen-1-one, and 2,6,6-trimethyl-1-cyclohexene-1-carboxaldehyde.     

Use of β-glucan from spent brewer's yeast as a thickener in skimmed yogurt: Physicochemical,textural, and structural properties related to sensory perception

Powdered β-glucan extracted from brewer's yeast (Yestimun, Leiber GmbH, Bramsche, Germany) was incorporated into skimmed-milk yogurt at varying concentrations (0.2–0.8% wt/wt) to investigate its potential application as a thickener. The effect of β-glucan fortification on the nutritional profile, microstructure, physicochemical properties, and texture of freshly prepared yogurts was investigated. Sensory evaluation was also conducted and was correlated with instrumental analysis. The addition of Yestimun significantly reduced the fermentation time of the yogurt mix from 4 h to 3 h. Scanning electron microscopy revealed that β-glucan particles formed small spherical clusters within the yogurt matrix. The majority of the physicochemical properties (syneresis, viscosity, color, and titratable acidity) remained unaffected by the incorporation of Yestimun in the recipe. Textural properties showed a gradual increment with increasing β-glucan concentration. Hardness, total work done, adhesive force, and adhesiveness increased by 19.27, 23.3, 21.53, and 20.76%, respectively, when using the highest amount of Yestimun powder. Sensory analysis (n = 40) indicated that fortifying yogurt with Yestimun at 0.8% (wt/wt) concentration may affect overall acceptance ratings, which was attributed to adverse flavor and aftertaste effects. However, the overall liking score of the yogurt (5.0/9.0) shows potential for commercialization of the product.