Study on the Effect of Jujuba ziziphus Hydro-Alcoholic Extract on Probiotic Yoghurt Quality and Survival of Lactobacillus acidophilus in this Product

Probiotic products have tremendous effects in improving the health of
consumers and the medicinal herbs have shown to exhibit antioxidant, anticancer and other
properties. The aim of this research work is to study the possibility of yoghurt production
using hydro-alcoholic extract of jujube fruit and Lactobacillus acidophilus probiotic bacteria
and evaluate the effect of extract on the organoleptic characteristics of product and the
survival of Lactobacillus acidophilus in the probiotic yoghurt. Low-fat raw milk was heated to 85-90ºC for 5min. Traditional yoghurt starter, Lactobacillus acidophilus and jujube extract (0, 0.2, 0.4, 0.6, 0.8 gr/Lit) were
added at 40ºC. All the treatments were incubated at 37ºC to reach the acidity of 80-85 ºD,followed by storing at refrigeration temperature. The population of Lactobacillus acidophilus was evaluated with standard methods on the 1,7,14 and 21 days after production. All samples were examined for sensory evaluation by a test panel on the 21th day after storage. The data
were analyzed using by SPSS-19 software. In all the treatments the growth of Lactobacillus acidophilus was reduced during 21 days of storage and the concentration of jujube extract did not have significant effect on this decline (P>0/05) and none of treatments showed the number of probiotic bacteria less than
106cfu/gr . The best quality was obtained in the yoghurt containing 0.6 gr/Lit of jujube extract and in terms of organoleptic properties and survival of probiotic bacteria this treatment showed the highest score. The results of this research showed that we can use 0.6gr/Lit of jujube extract with Lactobacillus acidophilus in the production of probiotic yoghurt as a new functional product