Cysteine proteases from plants: Utilization in foods and nutraceuticals and characterization approaches for quality management

In recent years, the demand for plant-based products has emerged driven by consumers' desire for natural options that reduce their environmental footprint. Plant proteases, which play a vital role in breaking down proteins and generating amino acids in all living organisms, have become prominent in this market being cysteine proteases the most used in the nutraceutical sector. Although these enzymes are widely popular, there is a significant gap in the control and analysis of commercial proteolytic products available on the market, particularly regarding their characterization and quantification. This review article addresses this key point by examining the origin, catalytic properties, production process and the techniques available to analyse them, offering new possibilities for quality control analysis in the industry. Additionally, we will explore the characteristics of some of these enzymes and the key factors that influence the effectiveness of cysteine protease preparations as human digestive aids. Finally, we will discuss future perspectives and suggest actions to move forward into the industrial applications of plant-based proteases in food supplements and digestive aids.