Optimization and characterization of nutrient-fortified milk beverages using conjoint analysis and response surface methodology

In this study, we developed fortified milk beverages (FMB) with varying ingredient levels and optimized both ingredient levels and retort processing conditions using conjoint analysis and response surface methodology (RSM). The optimal retort processing conditions were determined through a Box–Behnken design in RSM, identifying 100 °C for 10 min as the preferred combination. This optimized condition yielded FMB with desirable properties, including pH values from 6.57 to 6.30, titratable acidity from 0.140 to 0.170%, total soluble solids from 15.55 to 17.07° Brix, peroxide values from 0.64 to 2.07 meq O₂/Kg, and viscosity from 1.68 to 1.46 cp over 90 days. Significant differences (P < 0.05) were observed between control and fortified samples in terms of moisture, fat, crude fiber, crude protein, and caloric value. During storage, concentrations of docosahexaenoic acid and vitamin A in the FMB decreased to 6.22 and 3.38 mg/200 mL, respectively. Sensory evaluations were conducted on both control and fortified samples throughout their shelf life.