Production of nano-encapsulated vitamin D
polydispersity
The nano-encapsulated formulation was produced by components included: Precirol (glyceryl palmitostearate) as the solid lipid, poloxamer 188 as the non-ionic surfactant, oleic acid as the liquid lipid, vitamin D as the bioactive fatty core, and deionized water. The first three components mentioned above are inactive ingredients approved by the Food and Drug Administration. All components were mixed by homogenization with high tensile stress and ultrasound. The prepared Nano-Lipid Carriers (NLCs) had an average size of 126.3 ± 10.81 nm and a negative charge of − 17.2 ± 1.65 mv. Also, a polydispersity index (PDI) value of 0.107 ± 0.002 to 0.209 ± 0.017 was detected, indicating a narrow distribution of particle size for NLCs.Production and the fortification process of low-fat dairy products were carried out at the Salamat pilot dairy product factory under the supervision of the Faculty of Food Sciences and Technology, Ferdowsi University of Mashhad, Iran. Each 100 g of milk and yogurt in this study includes 56 kcal, 7 gr protein, sugar-free, 3 g fat, and 0.04 g trans fatty acids. Delivery and consumption of products were done on production day or the next day after.