StatusThe thesis was presented on the 5 December, 2008
Approved by NCAA on the 26 February, 2009
Abstract– 0.97 Mb / in romanian
3.01 Mb /
The main objective of this study was the investigation of the principles of food fortification with micronutrients: iodine, iron and calcium. It was researched the opportunity of molecular iodine incorporation in vegetable oil, physical and chemical properties of iodized vegetable oil and other food products fortified with iodized oil. There were established the principles of fortification of bread and bakery products with iron, added as inorganic compounds directly during the technological process, allowing receiving products with high iron bioavailability. These results were obtained by the administration of iron enhancers and by application of a lactic acid fermentation stage during bread making, which contributes to the decrease of the demineralising effect of the phytates present in wheat flour. On the basis of the experimental data, there were elaborated some technologies of iron and calcium fortification of bakery products, which is based on traditional principles of moldavian bread making and does not demand the additional equipment and expensive capital investments. By physical and chemical methods it was established the presence of iodine-triglyceryde compounds in iodized oil, formed by fixing the molecular iodine at the double bound of the unsaturated fatty acids, with the participation of the π electrons of the donor group (the double bound of the unsaturated fatty acid). There were established the thermodynamic and kinetic parameters of the reaction of formation of the iodine-triglyceryde compounds. It was researched the stability and the validity term of storage and technological treatments. The researches concerning the iodine fixing capacity of the sunflower oil as iodine-triglyceryde compounds allowed generalizing the incorporation technology of a significant amount of iodine (1-100 ), without sensitive changes of the product’s physico-chemical properties. Carried out researches have shown, that lipids represent a suitable matrix-carrier for iodine fortification of food products. It was elaborated the scientific basis and the technology of fabrication of lactic acid products and margarine, iodine fortificated by the addition of iodized oil. The results of the investigations of the physico-chemical, microbiological and organoleptic properties, the oxidation stability of iodine fortified products compared to the control samples, indicate the absence of sensitive difference during the maturation and storage processes. The iodine bioavailability in fortified lipid products has been investigated in vitro and in vivo (on white rats Wistar) conditions. It was established, that the recovery percent of iodine represents 57-92% (in vitro). In vivo researches have proved that iodized lipid products are influencing the metabolic processes by accumulation of iodine in animal’s body, as a result of an efficient digestion and a high iodine bioavailability from the present complexes.
For iron and calcium as fortification matrix products were used bread and bakery products. It was researched the interactions between the added micronutrients and the food product, and the possible interferences. There were calculated the stability constant values of the complexes of type iron-phytate and calcium-phytate chelates, there were appreciated the possible structures of these complexes. It was researched the interference of some cations of nutritional interest on in vitro bioavailability of micronutrients in fortified products. The kinetic model for enzymatic hydrolisis of phytates was elaborated. It was investigated the influence of the chemical nature and the concentration on the fortifying agent, the influence of the flour extraction degree and of the bread making method on iron and calcium bioavailability (in vitro). Researches allowed to establish the best fortifications conditions and represented the basis for the elaboration of the technologies for the fabrication of fortified bread products.
Iron and calcium fortification of bread requires the development of a sourdough stage of on the basis of wheaten bran which promotes hydrolysis of 55-70 % from total phytate amount, with further fortifying agent introduction. Iron fortification requires the utilization of an enhancer, capable to protect iron during technological processes. The employment of the dry hip-rose additive in iron fortified bakery products, leads to the increase of iron solubilization degree (1,4-2,5 times). By mathematical modelling of the experimental data there were perfected the technological conditions of manufacturing fortified products. The obtained results were patented. Iron bioavailability in fortified products was researched in vivo conditions. It is established, that the consumption of iron fortified bread products promotes improvement of the basic haematological parameters. In the presence of induced experimental anaemia, the serum iron concentration was restored entirely in groups that received iron fortified sourdough bread, and in proportion of 45-45 % in the case of groups that received iron fortified bread prepared by the diphase procedure.