The present study aimed to produce functional heat treated milk fortified with different sources of iron ferrous sulfate(S), ferric chloride (L) and iron nanoparticles (N) and assess its Biological effects in rats. Four heat treated milk samples were prepared by heating milk at 72°C/15sec then rapidly cooled to 42 °C. The first sample was milk without any iron sources (P), while, three samples were fortified with 0.01% different sources of iron as: ferrous sulfate (T1), ferric chloride (T2) and iron nanoparticles (T3) to produced functional milk fortified with 39 ppm iron. Control sample was raw milk (C). All samples were evaluated.

Thirty male albino rats were divided into randomly 5 groups, (each group contain six rats). The first group of rats (G1) rats were fed on standard diet represent as control (-). While, the second group(G2) rats were fed on standard diet and heat treated milk without any iron sources served as control (+).The third group (G3) rats were fed on standard diet and heat treated fortified milk with ferrous sulfate. Fourth group (G4) rats were fed on standard diet and heat treated fortified milk with iron nanoparticles. Fifth group (G5) rats were fed on standard diet and heat treated fortified milk with ferric chloride. The body was weighed periodically weekly with a complete blood profile taken at the beginning and end of the experiment to notice the changes. All biochemical parameters were determined and histopathological examination.The results referred to, there were no significant differences in chemical composition among all heat treated milk samples without any iron sources or fortified with different sources iron and raw milk. Addition of iron salts led to a significant decrease in the sensory properties compared to the control milk samples (P) which were heat treated milk without any iron sources, but the least sample severe effect was the treatment fortified with iron nanoparticles (T3) when compared with other treatments fortified with iron salts during cold storage period. There is a significant increase in body weight in rats when using iron salts, especially iron nanoparticles. Fortification milk with iron nanoparticles improves the physiological and biological performance of the body in general. There were significant increases in the weights of the organs (liver and kidney) in the group rats that were fed milk fortified with iron salts in general and in particular in the iron nanoparticles group. There was significant increase in the percentage of hemoglobin (%Hb) and red blood cells (%RBCs) in the samples of the group of rats that were fed with iron nanoparticles. The group of rats that were fed milk fortified with iron nanoparticles showed the least significant activity of the kupffer cells. In conclusion, Fortification of milk with iron is considered an important means of producing functional drinking milk especially when adding iron nanoparticles. It had been several benefits for human such as: improved iron absorption which leads to increased iron bioavailability, that was important for preventing iron deficiency anemia which is a common health problem worldwide especially Egypt.