Royal jelly improves the physicochemical properties and biological activities of fermented milk with enhanced probiotic viability

Royal jelly (RJ) is a highly valued natural product which has long been used as a functional food in various parts of the world. The aim of this study was to evaluate the effects of RJ supplementation (0.5%, 1%, and 1.5%, w/w) on physicochemical properties (i.e., viscosity, chemical composition, water holding capacity, antioxidant activity), organoleptic characteristics, culture viability, and biological activities (i.e., anticancer and antibacterial activities) of fermented milk. Results showed RJ supplementation could reduce the fermentation time, increase the viscosity and water holding capacity, and also enhance the antioxidant acitivity of fermented milk. Compared to the fermented milk without RJ addition, fermented milk with 1% RJ had significantly more probiotics Lactobacillus helveticus Lh-B02, approximately 9.73 log CFU/g during 21 days of cold storage. Additionally, RJ supplementation could greatly boost the bioactivities of fermented milk. Fermented milk with 1.5% RJ had the highest anticancer and antibacterial properties, whereas the one with 1% RJ had the best sensory attribute score. Overall, RJ has a great potential to be a viable dietary additive for the development of innovative dairy products with multifacet nutritional and bioactive properties.

Automated summary

The study showed that supplementation of royal jelly can improve the quality of fermented milk by increasing viscosity, water holding capacity, prolonging shelf life, enhancing antioxidant activity, boosting probiotic content, and improving bioactivity.