Physical treatment synergized with natural surfactant for improving gas-water interfacial behavior and foam characteristics of α-lactalbumin

Multiscale approach to the characterization of the interfacial properties of micellar casein and whey protein blends and their effects on recombined dairy creams

In this study, whipped cream with blends of micellar casein (MCN) and whey protein (WPI) in different ratios were prepared to investigate the role of protein interfacial behavior in determining foam properties at multiple scales, using theoretical modeling, and microscopic and macroscopic analysis. Fluid force microscopy has been used for the first time as a more realistic and direct means of analyzing interfaces properties in multiphase systems. The adsorption kinetics showed that the interfacial permeability constant of WPI (4.24 × 10-4 s-1) was significantly higher than that of the MCN (2.97 × 10-4 s-1), and the WPI interfacial layer had a higher modulus of elasticity (71.38 mN/m) than that of the MCN (47.89 mN/m). This model was validated via the mechanical analysis of the fat globules in real emulsions. The WPI-stabilized fat globule was found to have a higher Young's modulus (219.67 Pa), which contributes to the integrity of its fat globule morphology. As the ratio of MCN was increased in the sample, however, both the interfacial modulus and Young's modulus decreased. Moreover, the rate of partial coalescence was found to increase, a phenomenon that decreased the stability of the emulsion and increased the rate of aeration. The mechanical analysis also revealed a higher level of adhesion between MCN-stabilized fat globule (25.16 nN), which increased fat globule aggregation and emulsion viscosity, while improving thixotropic recovery. The synergistic effect of the blended MCN and WPI provided the highest overrun, at 194.53 %. These studies elucidate the role of the interfacial behavior of proteins in determining the quality of whipped cream and provide ideas for the application of proteins in multiphase systems.

Characterization of fruit pulp-soy protein isolate (SPI) complexes: Effect of superfine grinding

Superfine grinding (SG), as an innovative technology, was conducted to improve the physicochemical and structural properties of fruit pulps. Nectarine, apple, and honey peach were selected as the materials. With the increase in SG frequency, the soluble solids content, viscosity, D[4, 3], D[3, 2], G' and G″ of fruit pulps were evidently decreased, whereas the turbidity was increased. The smallest D[4, 3] (294.90 µm) and D[3, 2] (159.67 µm) were observed in nectarine pulp under SG at 50 Hz. The highest turbidity (266.33) was shown in honey peach pulp under SG at 50 Hz. The active groups of the fruit pulps with SG were exposed by Fourier transform infrared spectroscopy (FT-IR). Notably, the excessive destruction in structure was confirmed in SG with 50 Hz. With soy protein isolate (SPI) addition, D[4, 3] and D[3, 2] of complexes decreased, whereas G' and G″ increased. The formation of new fruit pulp-SPI complexes was demonstrated by FT-IR and LF-NMR analysis. The dense and uniform structure was found in complexes prepared by SPI and fruit pulp with 30 Hz SG. Especially, apple-SPI complex with 30 Hz SG showed the highest water-holding capacity (WHC) (0.75) and adhesiveness (7973.00 g s). A significant correlation between fruit pulps and the complexes was revealed. Taken together, the impact of SG modification on fruit pulps would enhance WHC, rheology, and textural properties of the fruit pulp-SPI complexes, especially for SG with 30 Hz. PRACTICAL APPLICATION: This research provided a comprehensive exploration of the potential of SG technology to modify fruit pulps, solving the diversity of textural customization problems and offering valuable insights for the development of semisolid food products.

Insight into the physicochemical characteristics, functionalities and digestion behavior of protein isolate derived from Lactarius volemus (L.volemus): Impacts of microwave-assisted extraction

The impacts of microwave assisted-extraction (MAE) on the physicochemical characteristics, functionalities, and digestion behavior of Lactarius volemus (L. volemus) protein isolate (LPIs) was investigated. Compared with the conventional water bath assisted-extraction method (WAE), MAE significantly enhanced the extraction rate of LPIs by 30.00% and 47.98% at 20 and 60 min, respectively. Also, MAE unfolded the spatial structure of LPIs, promoting the transformation from ordered structure to disordered structure, exposing its hydrophobic groups and increasing free sulfhydryl content. In addition, LPIs obtained by MAE showed better solubility, emulsifying and foaming characteristics than that by WAE. MAE method can improve the digestibility and the degree of hydrolysis of LPIs compared to WAE, which were increased by 6.06% and 19.78% after 20 min extraction in the small intestine digestion, respectively. This study can provide a potential strategy to produce L. volemus protein isolate with high efficiency and quality.

Evaluating the role of glycyrrhizic acid on the dynamic stabilization mechanism of the emulsion prepared by α-Lactalbumin: Experimental and silico approaches

The role of glycyrrhizic acid (GA) on the dynamic stabilization mechanism of the α-Lactalbumin (α-La) emulsion was evaluated in this study. Smaller particle size and higher zeta potential value were observed in the α-La/GA emulsion as compared to the α-La emulsion. Ultra-high-resolution microscopy revealed that the interfacial film formed around oil droplets by α-La/GA complex was thicker compared to that of either α-La or GA. The appearance of a new peak at 1679 cm-1 in FTIR of the α-La/GA emulsion attributed to the stretching vibration of CO, providing evidence of the formation of a stable emulsion system. The results from dynamic molecular simulation showed GA induced the formation of an interfacial adsorption layer at the oil-water interface, reducing the migration ability of GA. The findings indicate that the presence of GA in the α-La emulsion effectively enhances its stability, highlighting its potential as a valuable emulsifying agent for various industrial applications.

Non-thermal techniques as an approach to modify the structure of milk proteins and improve their functionalities: a review of novel preparation

BACKGROUND

Milk proteins (MPs) have been widely used in the food industry due to their excellent functionalities. However, MPs are thermal-unstable substances and their functional properties are easily affected by heat treatment. Emerging non-thermal approaches (i.e., high-pressure homogenization (HPH), ultrasound (US), pulsed electric field (PEF)) have been increasingly popular. A detailed understanding of these approaches' impacts on the structure and functionalities of MPs can provide theoretical guidance for further development to accelerate their industrialization.

SCOPE AND APPROACH

This review assesses the mechanisms of HPH, US and PEF technologies on the structure and functionalities of MPs from molecular, mesoscopic and macroscopic levels, elucidates the modifications of MPs by these theologies combined with other methods, and further discusses their existing issues and the development in the food filed.

KEY FINDINGS AND CONCLUSIONS

The structure of MPs changed after HPH, US and PEF treatment, affecting their functionalities. The changes in these properties of MPs are related to treated-parameters of used-technologies, the concentration of MPs, as well as molecular properties. Additionally, these technologies combined with other methods could obtain some outstanding functional properties for MPs. If properly managed, these theologies can be tailored for manufacturing superior functional MPs for various processing fields.