Determination of the survival rate of probiotic bacteria in doogh enriched with shallot and gingko extract

Doogh is widely used as a healthy dairy product in Iran which is a suitable alternative to soft drinks in the society. Ginkgo biloba is an ancient plant species on earth which is also known as the living fossil. The leaves of these tree have several nutritional and therapeutic properties and therefore the Ginkgo - enriched doogh has a high nutritional value. In this study, the impact of the addition of Ginkgo extract at the levels of 0, 1, 2, 3 and 4 percent on some attributes plus the survival rate of probiotic bacteria containing 0.2 g/l shallot extract during 21 days of storage at the temperature of 4°C was explored. According to the results, by enhancing the concentration of Ginkgo extract, acidity, population of Lactobacillus acidophilus LA-5 and Bifidobacterium lactis Bb-12 plus the antioxidant activity and total phenol level were significantly enhanced (p<0.05). Also, with the increase in the level of Ginkgo extract, the sensorial score of the samples were reduced considerably (p<0.05). Storage of the samples during 21 days resulted in the reduction of Lactobacillus acidophilus LA-5 and Bifidobacterium lactis Bb-12 population as well as antioxidant activity, total phenol content and sensory acceptability considering odor,taste and color (p<0.05). Overall, the sample containing 2 g/l Ginkgo extract was selected as the best sample and can be prepared as a healthy product in the dairy industry.