Tesfaye, Yared (2013) Effect of Oat Flour Addition on the Physico-Chemical and Microbiological Quality of Probiotic Bio-Yoghurt. Masters thesis, Addis Ababa University.
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PDF (Effect of Oat Flour Addition on the Physico-chemical and Microbiological Quality of Probiotic Bio-yoghurt)
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Abstract
This research was conducted with the aim of studying the effect of oat flour addition on the physico-chemical and microbiological quality of probiotic low fat bio-yoghurts. The low fat bioyoghurts were prepared through mixing of liquid skimmed milk with oat flour, starter culture, corn starch stabilizer, skimmed milk powder and sugar according to the basic formulation for bio-yoghurt production. The effect of mixing of oat flour (8%, 12 % and 16%) and storage days (7days, 14 days and 21days) on physico-chemical properties, microbiological qualities, proximate composition, and sensory qualities of the low fat bio-yoghurt has been studied. The oat flour (Avena sativa) variety had a nutritional composition of 5.62% moisture, 16.94% protein, 6.12% fat, 1.82% ash, 4.94% crude fiber and 64.65% carbohydrate, and the skimmed milk contained 0.31% fat, 3.51% protein and 0.86% ash. After fermentation, the proximate composition of the control bio-yoghurt, and the 8% Oat flour,12% and 16% Oat flour added bioyoghurts was; moisture (86.66%, 76.01%, 72.82% and 66.09%), crude protein (3.05%, 6.30%, 10.29% and 7.30%), crude fat (0.30%, 1.21%, 3.72% and 4.77%), crude fiber (0%, 4.03%, 4.80% and 4.97%) and ash (0.61%, 0.99%, 1.31% and 1.30%); respectively. The physicochemical results of the control bio-yoghurt and 16% oat flour added bio-yoghurts was; pH (4.49 and 4.55), syneresis (8.31% and 3.2%), TA (0.87% and 0.62%), App. Viscosity (0.66 pa.s and 0.83 pa.s) and proteolysis (0.34 and 0.48); respectively. Addition of corn starch stabilizer had reduced the effect of spontaneous whey separation which, was more significant (p<0.05) during higher amounts but because of other quality factors 2% was selected for processing of low fat bio-yoghurts. Aerobic plate count was found to be the predominant micro flora count of the final products and reached more than 8.3 log cfu/g. The sensory assessment result of the low fat bio-yoghurt was relatively acceptable by panelists in decreasing order of oat flour composition percentage comparing to that of the control. However, the most acceptable color, mouth feel, appearance, flavor and the highly preferred was the control low fat bio-yoghurt followed by samples blended with 8% and 12 % oat flour. In general, the low fat bio-yoghurt processed by mixing of partially skimmed milk with 8%, 12% and 16% oat flour and stored for 21 days gave promising results. Thus, it is possible to produce low fat bio- yogurts by incorporating oat flour to skimmed milk with additional ingredients and at a 42 o c for 4-6 hr., fermentation temperature and time.
| Item Type: | Thesis (Masters) |
|---|---|
| Uncontrolled Keywords: | Bio-yoghurt, Law fat, Oat flour, Probiotic |
| Subjects: | Q Science > Q Science (General) Q Science > QC Physics Q Science > QD Chemistry T Technology > TP Chemical technology |
| Divisions: | Africana |
| Depositing User: | Andriamparany Edilbert RANOARIVONY |
| Date Deposited: | 04 Jul 2018 09:10 |
| Last Modified: | 04 Jul 2018 09:10 |
| URI: | http://thesisbank.jhia.ac.ke/id/eprint/6577 |
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