Improvement of functional and sensory properties of fermented dairy drink Narine using raw apricot gum

Abstract

Background: It has been proven that natural apricot gum and the functional sour milk drink “Narine” fermented by L. helveticus MDC 9602, possess health-promoting and healing properties. The combined use of L. helveticus and apricot gum in dairy fermentation can create a new functional product with enhanced healing and organoleptic properties. Objective: To create a new functional fermented milk product by combining Apricot gum (AG) and L. helveticus, with improved health-promoting and sensory properties. Methods: For joint fermentation, 0.125%, 0.25%, 0.5%, and 1.0% of raw AG were dissolved in milk preheated to 60°C, pasteurized at 85°C for 15 minutes, and cooled to 45°C. Subsequently, the samples were inoculated with L. helveticus culture at a concentration of 5% and incubated at 37°C. The clotted samples were then transferred to 5°C for ripening. Analysis of the samples was carried out at 1, 14, and 28 days of storage. Antioxidant capacity was determined by the DPPH-scavenging assay. The total phenolic content and total flavonoid content were quantified by the Folin-Ciocalteu and AlCl3 colorimetric methods, respectively. Results: Apricot gum significantly stimulates the growth of the probiotic L. helveticus starter culture in microbiological medium and in milk. The stimulation of L. helveticus growth leads to a significant increase in the rate of coagulation and acidification of milk, improving the consistency and viscosity of Narine. The addition of AG extends the shelf life of the product in refrigerated storage, maintains a high viability count of the starter culture, and reduces syneresis and acidification. AG also significantly increases the antioxidant activity, which correlates with the viable cell count of L. helveticus. A synergistic increase in the viscosity of milk enriched with AG was discovered, depending on the degree of acidification. Conclusions: The high total phenolic content plays a key role in the biological activity of raw apricot gum. Most of the AG-induced changes, such as increased milk coagulation rate, enhanced antioxidant activity, and improved acidity, were found to be due to the promotion of starter culture growth. Raw AG can be used to increase the yield of bioactive peptides in LAB cultures and to improve the functional and sensory properties of yogurts. Keywords: Sour milk Narine, apricot gum, milk joint fermentation, synbiotic, sensory properties, antioxidant capacity.