| Abstrakt: |
Yogurt drink is one of the fermented dairy products. Probiotic yogurt drink has special health properties due to the presence of probiotics. Also, adding herbalmedicinal plants including chavil to this product can make it more attractive. However, the shelf life of probiotic bacteria in yogurt drink is not very long. This research was therefore carried out to increase the shelf life of Lactobacillus rhamnosus in yogurt drink by nanoencapsulation technique with Persian gum and whey protein isolate. Particle size and SEM was used for determination nanoencapsulated bacteria (bead) characteristics. In this regard, three samples of yogurt drink containing free Lactobacillus rhamnosus, its bead and the control were produced. Some characteristics including pH, acidity, sensory including color, taste, consistency and overall acceptability of yogurt drink were measured as well as the shelf life of probiotic bacteria under gastrointestinal conditions and storage in the refrigerator. The results showed that the beads had a size from 246.98 to 356.2 nm. The efficiency of nanoencapsulation was 87.2%, and the SEM images showed that the bacteria were covered well. At the end of the storage time, the decrease in pH (3.41) and increase in acidity (97.3 °D) of the sample containing beads was highest. The counting of free and beads also showed that the shelf life of bead was greater than free bacteria in yogurt drink. In the 21st day of storage, the product was eligible for probiotics. Moreover, the bead survival in simulation gasterointestinal condition was 3.33 log cfu/ml. The evaluation of the sensory parameters also showed that the sample containing bead had the lowest score among the panellist in all the sensory components except the texture. In conclusion, it can be stated that the yogurt drink containing the bead sample can qualify as a probiotic product during 21 days of storage time. [ABSTRACT FROM AUTHOR] |
