Shelf life and quality of probiotic yogurt produced with Lactobacillus acidophilus and Gobdin

• Published in: International journal of food science & technology Vol. 53; no. 3; pp. 776 - 783
• Main Authors: Ertem, Hatice, Çakmakçı, Songül
• Format: Journal Article
• Language: English
• Published: Oxford Wiley Subscription Services, Inc 01.03.2018
• Subjects: Acceptability; Gobdin; Lactobacillus acidophilus; Lactobacillus bulgaricus; Lactobacillus delbrueckii subsp. bulgaricus; Morus alba; probiotic food; Probiotics; Sensory properties; Shelf life; storage time; Streptococcus thermophilus; therapeutics; Walnuts; Yogurt
• ISSN: 0950-5423; 1365-2621
• DOI: 10.1111/ijfs.13653

Summary This study evaluated the effect of dry white mulberry and walnut paste (Gobdin, a traditional Turkish food) in probiotic yogurt on the survival of Lactobacillus acidophilus and yogurt properties. Six different yogurts were produced with 0%, 5% and 10% Gobdin using Lactobacillus bulgaricus + Streptococcus thermophilus and with 0%, 5% and 10% Gobdin using L. bulgaricus + S. thermophilus + L. acidophilus. The physical, chemical, microbiological and sensorial properties of the yogurts were evaluated based on storage at 4 ± 1 °C. Probiotic shelf life and the most suitable combinations were determined. The highest L. acidophilus count (8.65 log cfu g−1) was found in the 5% Gobdin‐supplemented yogurt on the 7th day of storage, while the lowest count (8.11 log cfu g−1) was found in the probiotic control yogurt on the 21st day. Although the L. acidophilus counts in the probiotic yogurts declined during storage, all values found throughout the 21‐day storage period were >8 log cfu g−1. This is above the level necessary to provide the desired therapeutic effect in probiotic products (106–107 cfu g−1). The highest overall acceptability score was obtained on the first day from the yogurt with 5% Gobdin. However, all yogurt samples had general acceptability scores between 7 and 8 points from a 9‐point maximum. Thus, this study determined that a new functional yogurt can be produced using L. acidophilus with 5% Gobdin. Gobdin (dry white mulberry and walnut paste; a traditional Turkish food) addition to milk before yogurt fermentation did not influence the growth and survival of starter culture and Lactobacillus acidophilus. Gobdin revealed a positive effect on L. acidophilus. This study demonstrated that a new functional yogurt can be produced by adding 5% Gobdin and using L. acidophilus.