Sustainable proteins and peptides: interaction of structure and function

The increasing growth of population in the world has imposed the elevated pressure on the world's resources (Weindl et al., 2020). Especially, the increased demand for high-quality protein in particular is expected, which can lead to the generation of more greenhouse gas emissions as well as consumption of more water and land (Knorr et al., 2020). Addressing this issue will require more sustainable production of protein as well as alternative sources for direct human consumption (Henchion et al., 2017). Protein severs as a crucial food component contributing to the functionality, bioactivity and flavour in food systems. However, the functional, bioactive and flavour properties derived from some sustainable proteins/peptides remain to be investigated. Therefore, it is highly preferable to understand and modify proteins/peptides derived from sustainable food sources in order to assign them specific features. The present special issue covered a wide range of topics concerning sustainable food protein sources from plant proteins as well as animal proteins. Compared with animal proteins, production of plant protein can exert a lower environmental impact and offer a sustainable solution by reducing emissions, land usage and water consumption. Therefore, it is crucial to further understand the structure–function relationship of sustainable plant proteins before they can be employed in the food industry. Khan et al. (2022) reported that ultrasonication combined with enzymatic hydrolysis can improve the emulsifying properties of seabuckthorn seed protein concentrate, which can serve as a promising emulsifier in the food industry. Enzymatic hydrolysis of soybean meal and its protein isolate by Alcalase and Neutrase can generate numerous bioactive di- and tri-peptides with potent antioxidant activity (da Silva Crozatti et al., 2022). Moreover, soy protein isolate can be used to develop protein particle film with good mechanical properties. In addition, Zeng et al. (2022) revealed that heat-induced gel properties of pumpkin seed protein isolates exhibited better heat-induced gelation than soy protein isolate and pea protein isolate. As a novel type of plant protein, amaranth proteins are characterised by well-balanced amino acid profile, good functionality and great bioavailability. Rivero Meza et al. (2022) reviewed the recent progress in isolation, fractionation, amino acid composition and digestibility of amaranth proteins. In addition to plant proteins, collagen derived from by-products from livestock and fish have a comprehensive application as a functional food ingredient. The bone collagen recovered from yak, bovine, porcine and chicken sources have been compared in terms of structure and function (Liu et al., 2022a), which provided a theoretical basis for further utilisation in the food industry. The unpleasant off-flavour in collagen peptides from fish may hinder their application in the food industry. Wang et al. (2022) have systematically reviewed the formation, detection and removal of off-flavour compounds of fish-derived collagen peptides. In addition, several poultry and related by-products can serve as more sustainable protein sources. Cao et al. (2022) demonstrated the potential target and mechanism of duck-derived bioactive peptides with antihypertensive activity with the aid of network pharmacology and molecular docking. Liu et al. (2022b) revealed the heat-induced thinning mechanism of thick egg white in weak alkaline conditions. Even though several recent studies have revealed the great potential of sustainable protein and peptides, there are still several issues to be addressed prior to their application as a food ingredient. Therefore, further studies and research are still necessary, which contributes to the sustainable food protein system. The present special issue cannot be completed without the contributions from all the experts, peer reviewers and professional editorial teams of International Journal of Food Science & Technology. Hence, I would like to take this opportunity to appreciate our contributors for this interesting special issue. I hope the readers will enjoy reading this special issue. Yu Fu: Visualization; writing – original draft, review and editing. Ethics approval was not required for this editorial. The peer review history for this article is available at https://publons.com/publon/10.1111/ijfs.16332. There is no data in this editorial.