Upcycling cheese whey into a raspberry-enriched fermented beverage with sensory characterization and assessment of phenolic compounds during simulated gastrointestinal digestion.

Background

Cheese whey valorization requires processing strategies that yield acceptable beverages while characterizing their composition and behavior during digestion. This study developed a fermented whey beverage enriched with raspberry extract and evaluated extraction conditions, sensory acceptance, and changes in phenolic markers and antioxidant responses during simulated gastrointestinal digestion.

Results

Partially deproteinized whey was fermented with Lactobacillus helveticus and formulated with raspberry extract at 100, 200, or 300 mL L-1. Steam-assisted extraction for 30 min provided the highest juice recovery, although monomeric anthocyanin concentrations were lower than after shorter extraction times. The formulation containing 300 mL L-1 extract received the highest overall acceptability score from 11 untrained panelists (6.18 ± 0.75 on a seven-point scale). Gastrointestinal endpoints were evaluated in independent digestion vessels. Mean total phenolic concentrations were 149.2 and 211.5 mg gallic acid equivalents L-1 at the oral and gastric endpoints, respectively, and ranged from 52.9 to 125.3 mg L-1 at intestinal endpoints. Monomeric anthocyanins were detected at oral and gastric endpoints but were not detected at intestinal endpoints. 2,2-Diphenyl-1-picrylhydrazyl and oxygen radical absorbance capacity assays showed distinct response patterns, with measurable antioxidant capacity throughout digestion.

Conclusion

Raspberry enrichment offers a promising route for valorizing cheese whey into a fermented beverage with favorable preliminary sensory acceptance. Detectable antioxidant capacity throughout simulated digestion supports further investigation of this formulation. These findings provide a foundation for optimizing whey-fruit beverages and validating their properties through controlled digestion studies and broader consumer evaluation. © 2026 Society of Chemical Industry.