Inventors: Prof. Dr. Kifaah Saeed Abass/Department of Food Science, College of agriculture, University of Baghdad
Abstract
Dairy industries became in an urgent need to master method to developing low or free fat dairy products with low calorie to meet customer requirements after it showed a close relationship between animal fat intake and the incidence of many chronic diseases, although the manufacturing process of such products is not easy due to the role play by fat in improving dairy products texture and taste. A clear defects appearance in low fat food products in texture and taste, thus; a method to solve this issue is used in this study represented by using texture and test enhancements called by fat replacers which are inulin, whey protein concentrates ( WPC). which was added in different ratios to manufacturing non fat low calorie yogurt from completely skimmed milk by adding inulin in four ratios 0.5, 1.0, 1.5, 2.0 % or WPC in four ratios 0.5, 1.0, 1.5, 2.0 % beside the positive control treatment made from whole milk and the negative control treatment made from skim milk without any addition, the most important concluded results are:
1-Non fat yogurt treatments were characterized by the highest moisture content than the positive control treatment which was 87.05 %as well as the negative control treatment which was 89.00%, respectively. while the inulin treatments ranged from 88.61 to 88.98% and the WPC treatments ranged from 87.27 to 88.98% . At the follow- up values of moisture during storage on temperature of ( 5+1) Co and a duration of 14 days found that there are slight reduction in their values for all treatments during storage.
2- Protein percentage was converged in all yogurt treatments except the WPC treatments that featured a higher percentage. protein percentage for all treatments were increased during storage.
3- Fat content was significantly decreased in all skimmed milk treatments compared to the positive control treatment, there is an increase in fat content for all treatments during storage.
4- Carbohydrates percentage was increased in all fat replacers addition treatments compared to the positive and negative control treatments.
5-Ash percentage was increased in all skimmed milk treatments compared to the positive control treatment with difference in this elevation for the fat replacers addition treatments.
6- Non-protein nitrogen values were converged in all treatments with no significant differences.
7- The pH values were converged in all treatments and ranged between 4.44 and 4.58 directly after yogurt manufacturing while the pH value decrease observed during storage. Higher total acidity percentage directly after yogurt manufacturing was observed in WPC yogurt treatments compared to addition treatments. T.A percentage was increased in all treatments during storage periods.
8- The additives improved the rheological characteristics involving the viscosity, spontaneous whey separation and water holding capacity. inulin treatment converged the positive control treatment it had excelled all the addition and the negative control treatments followed by the WPC treatments then the CMC treatments.
9- Scanning electron microscopy ( SEM ) test showed that the fat replacers improved microstructure of non fat yogurt treatments.
10- Energy calculations revealed that manufacturing low fat yogurt is attributed to decrease energy values, inulin treatment had the lowest energy value followed by WPC treatments respectively.
11-Nutritional experiment results shown the active role of fat replacers in maintaining normal body weight and decrease the levels of cholesterol ,triglycerides and bad lipoproteins (LDL,VLDL) and elevate the good lipoproteins ( HDL) and lowering blood suger level in comparison with the treatment of high fat without fat replacers, in addition of there role in enhancing the immune system and maintain the function of liver enzymes.