الفهرس | Only 14 pages are availabe for public view |
Abstract Functional foods have recently emerged as a novel sector of health enhancing products, functional foods are diverse groups, including conventional foods, such as drinking yoghurt, or they can be specifically enhanced, such as fortified drinking yoghurt with fruit pulp as source of antioxidant. This research aims to improving the properties of plain drinking yoghurt by adding different types and ratios of stabilizers and production of new functional flavoured drinking yoghurt fortified with blueberries, guava pulp and carob extracts as source of antioxidants. Furthermore, study the potential hepatoprotective of different flavoured drinking yoghurt (fortified was blueberries, guava pulp and carob extract) as a source of antioxidants against CCL4 induced liver injury in albino rats. The study was done in three parts: The first one was planned to improving the drinking yoghurt quality (specially viscosity and serum separation properties). Drinking yoghurt made from different ratios of yoghurt (25, 50 and 75%), and different types (Pectin and Guar Gum), and ratios (0.2 and 0.4%) of stabilizers. Some chemical, microbiological, rheological and sensory properties of different drinking yoghurt samples were determined. Increasing the ratio of yoghurt base in drinking yoghurt caused significant higher in total solids, fat, protein and ash contents in final product. Addition of stabilizers such as gaur gum and pectin had significant effect on improving viscosity and serum separation in final products compared with samples made without stabilizers. Types and ratio of stabilizers used did not effect on Streptococcus thrmophilus and Lactobacillus delbrueckii ssp. bulgaricus bacteria counts of the different drinking yoghurt. There were significant differences in appearance and consistency scores between the samples made without stabilizers and all different drinking yoghurt samples. The drinking yoghurt containing 75% yoghurt base ranked higher flavor scores than using 50 and 25% yoghurt base. The second part of this study was planned to produce of functionally flavoured drinking yoghurt fortified with different types (blueberries (BP), guava pulp (GP) and carob extract (CE)) and ratios (5, 10 and 15%) of fruit as sources of antioxidant. Some chemical, functional, microbiological, rheological and sensory properties of different functionally flavoured drinking yoghurt samples were determined. Significant differences were observed in, total solid, ash, pH, TA, antioxidant activity, total phenolic, vitamin C, dietary fiber content and viscosity values of all treated samples and control (without fruit pulp). Addition of fruit pulp had significant effect on the viability of the lactic acid bacteria strains. All the functionally flavoured drinking yoghurt samples, however, contained more or less the recommended levels of (106–107 cfu /g) lactic acid bacteria at the end of the refrigerated storage. Yeasts and moulds count was higher in functionally flavoured drinking yoghurt fortified fruit pulp compared with the control sample (without fruit pulp) increased significantly during storage at 5±1oC. The functionally flavoured drinking yoghurt fortified with carob extract ranked higher flavor scores than using blueberries and guava pulp. The third part of this study was planned to hepatoprotective evaluation of functionally flavoured drinking yoghurt fortified with 15% from blueberries, guava pulp or carob extract. Thirty-six rates were divided into six main groups of six animals each. The first group control (-) rats fed a commercial diet, second group control (+) rats fed a commercial diet, group (I) rats fed a commercial diet + 5g drinking yoghurt, group (II) rats fed a commercial diet + 5g functionally flavoured drinking yoghurt fortified with 15% blueberries pulp, group (III) rats fed a commercial diet + 5g functionally flavoured drinking yoghurt fortified with 15% guava pulp, group (IV) rats fed a commercial diet + 5g functionally flavoured drinking yoghurt fortified with 15% carob extract. Biological experiment were done after 28 days of feeding. Feeding on functionally flavoured drinking yoghurt caused the significant effect in increasing body weight of rats and decreasing liver and kidney weights of rats, which approached to the normal weight of negative rats group. After feeding hepatic fibrosis rats on functionally flavoured drinking yoghurt for 28 days, lead to gradually decreased in ALT, AST, creatinine, urea and malondialdehyde (MDA) values with advancing feeding period till reached their lowest values after 28 days. Total protein, albumin and glutathione (GSH) values were gradually increased with advancing feeding period till reaching their higher values after 28 days. The histopathological changes in pretreated groups with functional drinking yoghurt fortified with blueberries, guava pulp and carob extract as compared to that induced with CCl4 alone indicated marked protective effects of these substances. Key words: Functional Food, Drinking Yoghurt, Guar Gum, Pectin, Blueberries pulp, Guava pulp, Carob Extract, Hepatoprotective |