Search

The interaction between whey protein isolate (WPI) and saponins plays a key role in regulating and improving foam properties. In this study, the influences of Xanthoceras sorbifolium Bunge leaves saponins (XLS) on the foaming properties of WPI were characterized. Results revealed that 0.2 or 0.3% XLS could significantly increase the particle size and turbidity, as well as significantly decrease the protein solubility. The spectrum results showed that there was an interaction between WPI and XLS, which caused the change in protein structure and exposed more hydrophobic groups. Importantly, WPI with 0.3% XLS significantly increased the surface hydrophobicity and decreased the surface tension, resulting in better foaming ability and foam stability. Moreover, the rheological determination suggested that WPI with XLS increased both the apparent viscosity and viscoelasticity. The best foaming performance of WPI was achieved with 0.3% XLS at pH 3, along with the formation of the most compact, smallest, and densest bubbles. According to the classification of mixed conditions suggested by principal component analysis and hierarchical clustering analysis, WPI had good scores in the presence of both 0.2% and 0.3% XLS at pH 3, suggesting that XLS is a promising acidic foam additive applied to WPI food foam. • Both pH and XLS can change the interface properties of WPI. • XLS improved both foaming ability and stability of WPI. • XLS improved rheological properties of WPI by change the state of water. • Quantative associations between foam and physicochemical properties were studied. • WPI-XLS dispersions can be used for the development of acidic food foam in dairy industry. [ABSTRACT FROM AUTHOR]

The utilization of agro-industrial residues is an interesting issue contributing to sustainable development and environmental protection. Lycium barbarum leaves (LBL) are agro-industrial residues of the L. barabrum berry cultivation and seriously underutilized, leading to resource waste and environmental pollution. In this study, we prepared cost-effective enzyme cocktails with high xylanase activity from a novel soil-derived fungal strain Aspergillus costaricensis LS18. The xylanase activity of these on-site produced enzyme cocktails was 3.49 ± 0.55 U/mL. Through the hydrolysis using the enzyme cocktails with 6% substrate loading at 45 °C for 12 h, 86.57 ± 1.81% of total reducing sugars (RS) from LBL was released. The concentration of RS in the hydrolysates reached 8.17 ± 0.33 mg/mL. In this study, LBL were added values by two mutually independent bioprocess ways. On the one hand, LBL were used as the only nutrients in the medium for the on-site production of enzyme cocktails by fermentation. On the other hand, through hydrolysis using this enzyme cocktail, LBL biomass was efficiently hydrolyzed and fermentable monosugars were gained. This study could benefit to the exploitation of LBL resources and provide the references for utilization of other agro-industrial residues. [Display omitted] • Composition and enzymolysis characteristics of LBL were investigated. • A novel high-producing xylanase fungal strain LS18 was isolated from ancient forest soil. • Underutilized LBL and LS18 were employed for preparation of cost-effective enzyme cocktail. • LBL were efficiently hydrolyzed by self-prepared enzyme cocktails. • A new protocol of cost-effective conversion of biomass into fermentable sugar was established. [ABSTRACT FROM AUTHOR]