Effect of storage temperature on survival of free and encapsulated Lactobacillus acidophilus in apple juice

In this study, effect of storage temperature on survival of free and encapsulated Lactobacillus acidophilusin in apple juice and physicochemical and sensorial properties of final products was investigated during 60 days storage at ambient (25 ± 5°C) and 5 ± 1°C. There were three treatments in two replicates, including: 1. Control apple juice (CAJ), 2. Apple juice containing Lactobacillus acidophilus in free form (FPAJ) and 3. Apple juice containing Lactobacillus acidophilus in encapsulated form (EPAJ). The results showed that the encapsulation caused an increase of 1 log in the number of L. acidophilus in both storage conditions. Moreover, the number of probiotics in the kept samples at ambient was 1.5 log cycle greater than those kept at 5 ± 1°C at the end of storage. The Lactobacillus acidophilus in encapsulated form had not significant effect in transparency and turbidity (P>0.05), but the L. acidophilus in free form decreased transparency and increased turbidity in apple juice. The results of sensorial evaluation showed that using of L. acidophilus in apple juice had not adverse effect on color and flavor in samples. At the end of the storage period, except the treatment FPAJ stored at 5 ± 1 °C, the number of L. acidophilus in the rest of samples was greater than minimum number of the recommended therapeutic products (106cfu/g). In despite of high number of L. acidophilus in treatments stored at 25 ± 5 °C, to prevent the possibility of fermentation in ambient temperature and to increase shelf-life, it is recommended to store such products at 5 ± 1°C. Therefore, L. acidophilus in capsulated form could be used successfully in apple juice not only caused no adversary affects in the physicochemical and sensorial properties, but also increased survival of it’s probiotics.