Achieving the reuse of traditional egg by-products, salted duck egg whites (SEW), is an urgent problem to be solved. In this current work, we constructed a heat-induced gel-assisted desalination method for SEW. Subsequently, a top-down way was utilized to prepare desalted duck egg protein nanogels (DEPN) with uniformly distributed diameters and their application in the oil/water (O/W) interface system was explored. The results revealed that the increase of DEPN concentration could lower the droplet size, however, the size was negatively correlated with the oil phase fraction. Moreover, the effect of pH, ionic strength, and temperature on the emulsion stability demonstrated that the DEPN-stabilized emulsion displayed superior physical stability under different conditions. The addition of NaCl resulted in the significant decrease in droplet size of the emulsion, while further increasing the NaCl concentration, the droplet size did not decrease accordingly. Besides, heat-treatment and cold-treatment had little negative effect on the stability of the emulsion. Even if the droplet size of the emulsion increased at 80 °C for 3 h, the morphology of the emulsion remained unchanged. Our study demonstrated DEPN had great potential as a stabilizer for food-grade Pickering emulsions.

Concerns regarding sustainability have prompted the search of value in the by-products of food manufacturing. Such is the case of the cooking water (CW) of chickpeas, which has shown its potential as a vegan egg white replacement. This study aimed to characterize and compare the CW from three novel legumes (black soybeans, BSB; yellow soybeans, YSB; and small black beans, SBB) obtained from the processing of Korean soybean foods, and the widely used CW from chickpeas (CH), with regard to total polyphenol, total carbohydrate, and protein contents, and further compare their foaming and emulsifying abilities and stabilities. Compositional analysis revealed that all the studied legumes possessed higher values than CH for all parameters. Furthermore, the CW from these legumes exhibited enhanced functional properties, particularly foaming capacity and stability. Taken together, our results suggest that the CW from BSB, YSB, and SBB, sourced from the manufacturing of legume food products, has the potential of being revalorized as a plant-based functional ingredient for vegan product development.