Novel Application of Hydrocolloids in Food System

The production of animal protein usually leads to higher carbon emissions than that of plant protein. To reduce carbon emissions, the partial replacement of animal protein with plant protein has attracted extensive attention; however, little is known about using plant protein hydrolysates as a substitute. The potential application of 2 h-alcalase hydrolyzed potato protein hydrolysate (PPH) to displace whey protein isolate (WPI) during gel formation was demonstrated in this study. The effect of the ratios (8/5, 9/4, 10/3, 11/2, 12/1, and 13/0) of WPI to PPH on the mechanical properties, microstructure, and digestibility of composite WPI/PPH gels was investigated. Increasing the WPI ratio could improve the storage modulus (G′) and loss modulus (G″) of composite gels. The springiness of gels with the WPH/PPH ratio of 10/3 and 8/5 was 0.82 and 0.36 times higher than that of the control (WPH/PPH ratio of 13/0) (p < 0.05). In contrast, the hardness of the control samples was 1.82 and 2.38 times higher than that of gels with the WPH/PPH ratio of 10/3 and 8/5 (p < 0.05). According to the International Organization for Standardization of Dysphagia Diet (IDDSI) testing, the composite gels belonged to food level 4 in the IDDSI framework. This suggested that composite gels could be acceptable to people with swallowing difficulties. Confocal laser scanning microscopy and scanning electron microscopy images illustrated that composite gels with a higher ratio of PPH displayed thicker gel skeletons and porous networks in the matrix. The water-holding capacity and swelling ratio of gels with the WPH/PPH ratio of 8/5 decreased by 12.4% and 40.8% when compared with the control (p < 0.05). Analysis of the swelling rate with the power law model indicated that water diffusion in composite gels belonged to non-Fickian transport. The results of amino acid release suggested that PPH improved the digestion of composite gels during the intestinal stage. The free amino group content of gels with the WPH/PPH ratio of 8/5 increased by 29.5% compared with the control (p < 0.05). Our results suggested that replacing WPI with PPH at the ratio of 8/5 could be the optimal selection for composite gels. The findings indicated that PPH could be used as a substitute for whey protein to develop new products for different consumers. Composite gels could deliver nutrients such as vitamins and minerals to develop snack foods for elders and children. Full article

In order to improve the water solubility and stability of lutein, soy protein isolates (SPI) and their hydrolysates via pepsin (PSPI) and alcalase (ASPI) were used as nanocarriers for lutein to fabricate the lutein-loaded nanoparticles (LNPS) of SPI, PSPI, and ASPI. The encapsulation properties, light, and in vitro digestive stability of lutein in nanoparticles, and protein–lutein interactions were investigated. Compared with SPI-LNPS and ASPI-LNPS, PSPI-LNPS was characterized by uniform morphology (approximately 115 nm) with a lower polydispersity index (approximately 0.11) and higher lutein loading capacity (17.96 μg/mg protein). In addition, PSPI-LNPS presented the higher lutein retention rate after light exposure (85.05%) and simulated digestion (77.73%) than the unencapsulated lutein and SPI-LNPS. Fluorescence spectroscopy revealed that PSPI had stronger hydrophobic interaction with lutein than SPI, which positively correlated with their beneficial effects on the light and digestive stability of lutein. This study demonstrated that PSPI possessed significant potential for lutein delivery. Full article