Use of natural plant antioxidant and probiotic in the production of novel yogurt

Abstract

Low fat fermented milk (1% fat) was supplemented with green bell pepper juice as a source of antioxidant compounds, and also carotenoids was produced and the impact of this ingredient on LAB was investigated. Pepper juice, in a ratio of 1:2 and 3%, was added to the low heat reconstituted milk powder. Lactobacillus rhamnosus (2%) was used only or with yoghurt starter (2%), and the growth rate of all probiotic strains and the viable count of lactic acid bacteria (LAB) during storage in refrigerator were determined. Moreover RSA, TPC and TCC of fermented milk samples were evaluated. Pepper juice was effective in enhancing the growth rate of L. rhamnosuswhen compared to the control, while the others of LAB count in the fermented milk, which contain pepper juice, was decreased. Furthermore, it was obvious that increasing the concentration of pepper juice increased RSA (%), TPC and carotenoids of the resultant low fat fermented milk, inoculated with L. rhamnosus for fresh and stored samples. During cold storage, RSA (%) slightly increased until 7 days and then decreased especially for samples supplemented with low concentration of pepper juice (1%), while TPC was gradually decreased by a prolongation of the storage period (15 days). The TCC was highly increased during the storage until 15 days. Moreover, adding yoghurt starter with L. rhamnosus strain in preparing fermented milk fortified with pepper juice also increased the RSA (%), TPC and TCC of the media. During storage, the TPC gradually decreased, whereas TCC was inversely increased. The percentage of RSA also increased during storage until 7 days and then decreased, in which case, it could be recommended that the addition of pepper juice has no effect on viability of probiotic strain.   Key words: Lactic acid bacteria, probiotic, carotenoids.