Production of Ready-to-Reconstitute Functional Beverages by Utilizing Whey Protein Hydrolysates and Probiotics

This investigation was aimed at developing a ready-to-reconstitute beverage by utilizing probiotics and whey protein hydrolysates carrying bioactive peptides. Cheddar cheese whey was ultrafiltered. The 18% protein retentate was subjected to protein hydrolysis using Neutrase. The hydrolyzed retentate was further condensed to 35% total solids and spray-dried at $75^{\circ}C$ outlet air temperature. Different levels of sugar, citric acid and stabilizer were blended for spray-dried hydrolysates. Spray-dried hydrolysate was further inoculated with different levels of probiotics grown in a whey medium and dried in fluidized-bed drier at $40^{\circ}C$ to obtain a ready-to-reconstitute beverage. Hydrolysis was greatest at an enzyme:substrate ratio of 1:25 for 3 h. Spray-dried hydrolysate reconstituted to 1% protein and blended with 15% sugar, 0.2% citric acid and 0.15% xantham gum resulted in a superior product with no sedimentation. Accordingly, sugar, citric acid and xanthum gum were dry-blended with spray-dried hydrolysates. Bifidobacterium bifidum and Lactobacillus acidophilus that was grown separately in a whey medium, blended to produce 2% spray-dried hydrolysate and dried as described above resulted in a readyto-reconstitute beverage mix. The fluidized dried product typically exhibited a probiotic count of $10^8$colony forming units (CFU)/g. However, blending of probiotic to the retentate and direct spray-drying precipitously reduced the probiotic count to $10^4$ CFU/g of powder.