Auxiliary technologies in the modulation of enzymatic hydrolysis, bioactivities, and allergenicity of whey proteins: a systematic review and meta-analysis

Auxiliary technologies have been employed to enhance enzymatic hydrolysis of whey proteins and modulate the bioactive properties of the resulting hydrolysates. However, methodological variability among studies limits the comparability of results and the establishment of standard operating conditions for industrial application. This systematic review and meta-analysis provides a quantitative synthesis of the evidence on the use of these technologies, focusing on the degree of hydrolysis (DH), bioactivities, and allergenicity of whey protein hydrolysates. Based on searches of the Scopus and Web of Science databases, 32 studies published between 2014 and 2026 were included in the qualitative synthesis, of which 17 met the inclusion criteria for meta-analysis. Ultrasound (US) and high hydrostatic pressure (HHP) accounted for the largest body of evidence and promoted significant increases (p < 0.05) in DH, depending on the enzyme used. Under US, papain showed the highest point estimate, and only the papain subgroup reached statistical significance. Under HHP, bromelain and papain showed the largest significant increases. In contrast, trypsin exhibited a non-significant effect (p > 0.05) under HHP, suggesting limited potential for this application. Both technologies favored the release of peptides with antioxidant, antihypertensive, antidiabetic, anti-inflammatory activities and cellular antioxidant activity, depending on the operating conditions and enzymatic system employed. HHP reduced the allergenicity of whey proteins, whereas US showed variable effects. A single study on microwave treatment reported a reduction in in vitro degranulation response, an observation that requires confirmation. These results provide evidence to guide the selection of auxiliary technologies and enzymatic systems for producing whey protein hydrolysates with defined bioactivities and reduced allergenicity, contributing to future research and industrial applications.