A functional dairy product rich in Menaquinone-7 and FeOOH nanoparticles

Abstract

Menaquinone-7 (MK-7) has been identified as an essential nutrient in enhancing bone mineral density, bone health, and reducing the risk of osteoporosis. Although there have been worthy achievements in MK-7 fermentation process using Bacillus subtilis natto, the low yield of fermentation, costly downstream extraction and purification processes remain the main challenges. In this research, a new approach was taken to study the feasibility of the production of a functional fermented dairy-based product rich in MK-7 by the use of iron oxide hydroxide (FeOOH) nanoparticles (NPs) to increase the concentration of MK-7. In this regard, milk a rich source of calcium, a necessary nutrient for bone health was chosen as the fermentation medium for MK-7 biosynthesis using B. subtilis natto. Two different types of FeOOH NPs, namely naked and biocompatible xanthan gum (XG)-coated NPs, were synthesised (with 10 nm average particle size) and used to evaluate their effect on developing a fermented dairy-based product rich in MK-7 and iron. According to the results, in the presence of 3 mg/L of XG-coated and 12 mg/L of naked FeOOH NPs, the concentration of MK-7 significantly enhanced, and approximately 27% and 35% more MK-7 biosynthesis were observed respectively as compared with control samples with only 1.9 mg/L MK-7 production.