Development of a carotenoid enriched probiotic yogurt from fresh biomass of Spirulina and its characterization

Abstract

Incorporation of Spirulina in milk as thermally dried powder has the disadvantages of non-uniform distribution with undesirable odor and flavor. Through homogenization (200 ± 10 bar), complete dispersion of fresh Spirulina biomass (7% w/w) in milk was achieved and thereafter a carotenoid enriched probiotic yogurt was developed. Confocal microscopy revealed porous Spirulina-milk protein matrix integrated with smaller fat globules in the yogurt. Spirulina led to a 29.56% increase in Lactobacillus acidophilus count, a 20% reduction in fermentation time and a total probiotic count of 1.2 × 10⁷ CFU mL⁻¹. The protein, total chlorophyll, total carotenoid and β-carotene content (on dry w/w basis) were 3.58 ± 0.08 g 100 g⁻¹, 0.407 ± 0.018 mg g⁻¹, 0.235 ± 0.016 mg g⁻¹ and 13.28 ± 0.08 µg g⁻¹, respectively. During storage (18 days at 6–8 °C), the L. acidophilus count reached 8.83 ± 0.11 log CFU mL⁻¹ with 103.03% increase in the viability by day three and the yogurt retained 71.5% carotenoids. The probiotc Spirulina yogurt was found to be acceptable to consumers as evaluated by affective consumer test.