The Effect of Free and Microencapsulated Extract of Nepeta Binaludensis on Sensory and Microbial Properties of Doogh

The current study was carried out with the purpose of investigating the antimicrobial properties of free and microencapsulated extract of Nepeta Binaludensis. For this purpose, the Nepeta extract was extracted by assisting pulse electric field process (6000 v and pulse number 60). Then the effect of free extract (0.2 and 0.6 %) and encapsulated extract with 4 different types of wall material (wall contain mixture of maltodextrin 7 (26.97%) with Arabic gum (29.36%) and maltodextrin 20 (43.69%), wall contain mixture of 1% sodium alginate and 1% chitosan, wall contain mixture of 1% sodium alginate and 1% Inulin and wall contain mixture of 2% sodium alginate) at two concentrates (1 and 3 %) in comparison with synthetic potassium sorbate preservative (0.1%) on sensory, total phenolic content and microbial properties of doogh during 28 days storage at refrigerator temperature was evaluated. Results demonstrated that free and microencapsulated extract was able to control the growth of mold and yeast with preservation of sensory and phenolic properties in the doogh. The lowest growth rate of mold and yeast after 28 days of refrigeration was respectively observed in the sample containing 1% sodium alginate, 1% inulin at 1 and 3% concentration and 2% sodium alginate at 3% concentration and there was no statistically significant difference with the the sample containing 0.1% potassium sorbate (P>0.0.5). The results of sensory analyze showed that doogh samples containing encapsulated extract with 4 types of wall compositions mentioned were not statistically significant in terms of sensory characteristics with doogh samples containing potassium sorbate (P>0.0.5). Also, doogh samples containing microcapsules with wall composition (1% Sodium alginate and 1% inulin) and (1% sodium alginate with 1% chitosan) and 2% sodium alginate with a concentration of 3% after 28 days of storage had more phenolic compounds.