National Food Institute, Technical University of Denmark, Kemitorvet, DK-2800 Kongens Lyngby, Denmark.
Department of Analytical Chemistry and Food Technology, University of Castilla-La Mancha, Camilo José Cela Avenue, 13071 Ciudad Real, Spain.
Int J Food Microbiol. 2022 Nov 16;381:109889. doi: 10.1016/j.ijfoodmicro.2022.109889. Epub 2022 Aug 27.
Plant-based food products are generating a growing interest as part of the ongoing transition to a primarily plant-based diet, which makes demands to the quality, functionality, and health properties of plant proteins. Microbes used for traditional food fermentations such as lactic acid bacteria (LAB) and fungi (yeasts and molds) carry out enzymatic changes on their protein substrates by which technological and sensorial characteristics can be improved. The literature on extracellular proteases targeting plant proteins, on the other hand, is scattered with only a narrow representation of plants even for traditionally plant-based products. Therefore, this review aims to explore the current state of knowledge regarding the application potential of microbial extracellular proteases targeting plant proteins, with a focus on traditional applied food microbes. Plant proteins are targeted by proteolytic microbes of both animal and plant origins, and their proteases show a wide range of activities. Extracellular microbial proteases can hydrolyze specific protein-based allergens and even reduce the toxicity of plant proteins. Additionally, microbial assisted proteolysis can improve plant protein digestibility by increasing availability of peptides and amino acids. This catabolic process will change the organoleptic characteristics of fermented plant proteins, and the release of bioactive peptides can provide additional functionalities to the plant matrix. The proteolytic activity is determined by the microbial strain, and it can be quite substrate selective, which is why proteases may be overlooked by the prevalent use of casein as substrate in proteolytic screenings. The synergetic effects of LAB and fungal species consortia can facilitate and steer plant protein hydrolysis by which co-fermentation may increase or change the properties of plant protein hydrolysates. Microbes do not necessarily require extracellular proteases because endogenous proteases in a plant-matrix may meet the microbial amino acid requirements. However, extracellular proteases have the potential to provide central properties to diverse food-matrixes by which the full proteolytic potential of food microbes needs to be explored in order to facilitate the development of high-quality plant-based food products.
植物性食品作为向主要以植物为基础的饮食转变的一部分，越来越受到关注，这对植物蛋白的质量、功能和健康特性提出了要求。用于传统食品发酵的微生物，如乳酸菌 (LAB) 和真菌（酵母和霉菌），通过对其蛋白质基质进行酶促改变，可以改善其技术和感官特性。另一方面，关于靶向植物蛋白的细胞外蛋白酶的文献分散且狭窄，即使对于传统的植物性产品，也只有很少的植物被代表。因此，本综述旨在探讨靶向植物蛋白的微生物细胞外蛋白酶的应用潜力的现有知识状态，重点关注传统的应用食品微生物。植物蛋白是动物和植物来源的蛋白酶解微生物的靶标，其蛋白酶显示出广泛的活性。细胞外微生物蛋白酶可以水解特定的基于蛋白质的过敏原，甚至降低植物蛋白的毒性。此外，微生物辅助蛋白水解可以通过增加肽和氨基酸的可用性来提高植物蛋白的消化率。这种分解代谢过程将改变发酵植物蛋白的感官特性，而生物活性肽的释放可以为植物基质提供额外的功能。蛋白酶解活性取决于微生物菌株，并且它可以具有相当的底物选择性，这就是为什么在蛋白酶解筛选中，普遍使用酪蛋白作为底物时，蛋白酶可能会被忽视。LAB 和真菌种属的协同作用可以促进和引导植物蛋白水解，从而共发酵可以增加或改变植物蛋白水解物的特性。微生物不一定需要细胞外蛋白酶，因为植物基质中的内源性蛋白酶可能满足微生物的氨基酸需求。然而，细胞外蛋白酶有可能为多种食品基质提供核心特性，因此需要探索食品微生物的完整蛋白酶解潜力，以促进高质量植物性食品产品的开发。
