Viability of Lactobacillus Plantarum Incorporated with Sourdough Powder-Based Edible Film in Set Yogurt and Subsequent Changes During Post Fermentation Storage

Abstract

Introduction: Due to the advantages of sourdough, its film production for food packaging could be interesting. This study aimed to evaluate the influence of probiotic sourdough based edible film covered on set yogurt and subsequent changes during post fermentation storage. Materials and Methods: The parameters examined included changes to the fermentation characteristics (pH, and viable counts of probiotic bacteria), synersies, and sensory evaluation during 21-d storage at 4°C. lactobacillus plantarum was supplemented with sourdough films and yogurt produced by commercial yogurt starters (Streptococcus thermophilus and Lactobacillus delbrueckii ssp. bulgaricus) then films placed on yogurt containers, and a panel of parameters reflecting product quality was subsequently monitored along with 21-d post-fermentation storage. Results: Results demonstrated that the pH value of yogurt decreased slowly during the storage and no significant difference was observed between the control and the samples with the films. Although the number of viable cells decreased during storage, it did not lower than the minimum requirement for probiotics (> 107 log CFU / g). The synersies of the film-treated samples were significantly (P ≤ 0.05) lower than the control samples. The yogurt with the film without bacteria had the least synersis. Film-treated yogurts had acceptable sensory properties in comparison with control. Conclusion: Sourdough films can be an optimizing candidate to enter the food industry as a bioactive edible film and also could improve the delivery of probiotic bacteria.

Keywords

• edible films
• sourdough
• yogurt
• lactobacillus plantarum.