Probiotic Milk Enriched with Protein Isolates: Physicochemical, Organoleptic, and Microbiological Properties

Area of Science:

• Food Science and Technology
• Microbiology
• Dairy Science

Background:

• Plant protein isolates can improve probiotic culture growth and modify fermented milk properties.
• Understanding these interactions is crucial for developing functional fermented foods.

Purpose of the Study:

• To evaluate the impact of soy, pea, and whey protein isolates on probiotic growth (Lacticaseibacillus casei, Lactobacillus johnsonii).
• To assess the effects on physicochemical (acidity, syneresis, color) and organoleptic properties of fermented milk.
• To determine the influence of protein isolate concentration (1.5% and 3.0%) and storage duration (21 days).

Main Methods:

• Fermented milk was prepared with varying concentrations of soy, pea, and whey protein isolates.
• Probiotic viability, pH, syneresis, color, and sensory attributes were analyzed during refrigerated storage.
• Monocultures of Lacticaseibacillus casei and Lactobacillus johnsonii were used.

Main Results:

• Pea protein isolate (PPI) at 1.5% and 3.0% increased milk pH.
• Whey protein isolate (WPI) at 1.5% and 3.0% reduced syneresis in L. casei fermented milk.
• Soy protein isolate (SPI) and 1.5% PPI initially reduced L. casei counts, while increased PPI concentration enhanced L. casei growth. WPI concentration affected L. johnsonii and L. casei growth differently. Probiotic populations declined over storage.
• Protein isolates significantly influenced color and organoleptic properties.

Conclusions:

• Protein isolates can be utilized to create diverse and potentially health-promoting fermented dairy products.
• Specific isolates and concentrations differentially affect probiotic survival and fermented milk characteristics.
• Further research into isolate-probiotic interactions can advance functional food development.