Abstract
Enzymatic hydrolysis is used to produce protein hydrolysates from animal- and plant-based sources, which are widely utilized in industry due to their nutritional, functional, and bioactive properties. However, these hydrolysates can exhibit unattractive sensory properties, such as off-flavors or off-odors, which limit their use in food products. The sensory properties of protein hydrolysates may stem from inherent attributes in the raw material or develop during processing-either as an intended consequence of hydrolysis or as an unintended side effect. This review summarizes key factors contributing to undesirable sensory attributes, and highlights processing steps influencing sensory properties, drawing on examples from plant- and animal-sourced protein hydrolysates. Subsequently, an assessment of recent strategies to improve sensory properties is provided. While earlier research has mainly addressed bitterness, other undesirable sensory issues remain underexplored. Several factors affect sensory properties in protein hydrolysates during pre-, peri-, and post-hydrolysis, such as choice of raw material (composition and freshness), process conditions, and microbial action. Through literature searches, 10 strategies for optimizing the sensory properties in protein hydrolysates have been identified: pretreatment of raw materials, application of antioxidants, enzymatic modification methods, use of Maillard reaction, fermentation processing techniques, solvent-assisted extraction, adsorption removal techniques, membrane filtration processes, microencapsulation technology, and use of masking agents. While these strategies may make the protein hydrolysates more palatable and acceptable for consumption, their shortcomings include additional costs, time-consuming processes, reduced nutritional value, and potential non-compliance with food-grade standards.