الفهرس 
REVIEW OF LITERATUREOnly 14 pages are availabe for public view
Abstract
SUMMARY AND CONCLUSION
In this thesis a detailed study has been conducted to trace the chemical and Physical properties of dried dairy products, and the changes that may occur during storage of these products. All tests were performed according to the FDA guidelines and AOAC guidelines.
The thesis is composed of three parts:
Part I:
In this part general introduction is presented containing various definitions of dairy products, its importance, and uses. and definitions of traceability and their objective
.A review of the literature is presented indicating the researches occurred to detect the changes that may happen during storage of dried milk and other dairy products. The aim of this workwas FirstTracing chemical changes which can affect on the safety & quality of the dried dairy products. Example: the reactions between amino acids &carbohydrates, Such as Maillard reaction and outputs such as hydroxymethylfurfural, furfural which effect on physical properties and color of milk powder particles. Second Oxidation products of milk fats and protein whicheffects on consumer health seriously. Example: Free radicals which cause cancer diseases, & Alzheimer diseases.
Part II:
In this part a study had been conducted on (100) one hundred samples of different dried dairy products, which had been collected from the Egyptian market. A study of the chemical and physical properties of these products was established.
Skim milk powder, Whole milk powder, Flavored milk powder, Ice cream powder, and powder ofCereal infant formula. The results showed that chemical composition and physical properties agree with Egyptian Standard and Codex standard. The oxidation of the products determined in allsamples such as total carbonyl as indicator of protein oxidation and TBARS values and Anisidin values as indicator of fat oxidation. the data showed low increased in oxidation that ensure our theory about the changes which would happen during the shelf life of this product if stored in condition encourage the appearance of chemical changes especially the protein oxidation and their products.
Part III:
In this part fresh skim and whole milk powder were stored at 30οC for six months. And the changes on chemical and the physical properties were traced. To detect any changes that occurred during the storage period. The fresh samples properties agreed with the Egyptian and Codex Standards. But after storage there was an indication of lipid and protein oxidation in all samples which affected the quality and safety of these products.Fat and protein decreased with the increase of storage time from 0.47% to 0.27% and from 37.25% to 35.69% and from 27.3 % to 25.89 %and from 26.18% to 24.99% for SMP and WMP respectively. Also the antioxidant decreased with the increased of storage time from 0.131to 0.021and from0.981 to 0.272 in skim and whole milk powder respectively .and that explained the relationship betweenthe antioxidant and oxidation. when the antioxidant decreased the oxidation increased. Also, the physical properties affected with the oxidation such as protein oxidation products are affected on the solubility and there are relationship between the insoluble index and protein oxidation when the protein oxidation increased the insoluble index increased. Also the moisture increased from 1.79 to 3.28 and from 1.289 to 3.990 in skim and whole milk powder respectively. and it was affected on some physical properties such as wettability and dispersability.
The total carbonyl value was used as an indicator of protein oxidation Moreover TBARS and p-ansidin values were used as indicator of lipid oxidation.The data showed increased of the total carbonyl during period storage from 1.60 to 5.71nmol/ml and from 0.91 to 2.69nmol/ml in skim and whole milk powder respectively.Also, the TBARS and p-anisidin values increased from 0.018 to 0.029 and from 0.27 to 3.84 respectively in whole milk powder and that explained the reasons of changes in color of milk powder particle’s.
In this work the color parmarters were measured a-, b-, L-,chroma, hue,total color index and browning index .The L-value of fresh skim milk powder samples (95.569) , being higher than that of whole milk powder sample (92.605)as a result of removing milk fat , which contains the carotonids. L-Value of skim milk powder were fluctuated between 94.257 to 96.115 for 6 months storage according to the progress in protein oxidation and Maillard reaction. Comparison with whole milk powder. On the other hand, the a-values of skim milk powder were higher(-5.04 to -6.228) than those of whole milk powder (-6.425)as a result of removing most of carotonoids.The b-values were very close correlated to the fat content of the milk, since the b-value of fresh skimmed milk powder was 12.17 , being 33.44% lower than that of fresh whole milk powder. As a result of fat and pigments removal, the Hue-value of fresh skim milk powder was closer to the yellow color shade (-67.754◦)than did the whole milk powder sample (-70.643◦). However, during the 6 months storage, Hue-values were increased to level of (-67.372◦)due to the oxidation and Maillard reaction products. Comparing the Browning index (BI) value of whole milk powder samples.(14.076 to 14.45) and those of skim milk powder samples (8.41 to 9.87) indicate that the BI- Values of the first were 75% higher than those of the later, which indicate that the browning of milk powder depends mainly on its fat and protein content ( pigments and oxidation) as well as its free sugar and lysine and other amino acids content.
In the end of this study we advise that the dried dairy products must storage in good conditions from temperature and moisture especially after the packets was opened and the best temperature for storage is from 20-25°c the room temperature to avoid the appearance of the protein oxidation products which effect on consumer health and make it exposure for a lot of chronic diseases such as cancer diseases and Alzheimer diseases.