Work

Refrigerated storage stability, probiotic survivability and techno-economic feasibility of dragon-fruit-enriched synbiotic buttermilk

Year: 2026

Type: article

Abstract: This study evaluated the refrigerated-storage behaviour, probiotic survivability, packaging response and production economics of an optimized synbiotic buttermilk containing 10% red dragon fruit (Hylocereus polyrhizus) pulp. Cow milk was fermented with 2% mixed lactic starter and 2% Bifidobacterium bifidum, blended with fruit pulp, packed in pre-sterilized bottles and stored at 4 ± 1 °C for 8 days. Microbial quality and viable populations were assessed at 2-day intervals. The general lactic acid bacterial count declined from 4.45 × 108 CFU/mL on day 0 to 3.85 × 108 CFU/mL on day 8. In the selective survivability assessment, LAB and Bifidobacterium counts decreased only slightly, from 7.75 to 7.50 × 107 CFU/mL and from 8.92 to 8.62 × 107 CFU/mL, respectively. Coliforms remained undetected throughout storage, whereas yeast and mould were undetected through day 6 and appeared at 1.12 × 104 CFU/mL on day 8. Post-acidification occurred in both glass and PET bottles: pH changed from 4.40 to 4.00 in glass and from 4.50 to 3.90 in PET, while titratable acidity increased from 0.51% to 0.70% and 0.69%, respectively. The estimated production cost was ₹71.10/L or ₹14.22 per 200-mL serving. These findings indicate that the dragon-fruit-enriched beverage retained probiotic populations above commonly cited desirable levels over the evaluated period and was economical to produce. However, yeast and mould detection on day 8 suggests that, under the tested conditions, a conservative refrigerated shelf life should not exceed 6 days unless further validation establishes an acceptable microbiological limit.

Source: International Journal of Advanced Biochemistry Research

DOI: 10.33545/26174693.2026.v10.i9saf.10217