Evaluation of Ghee Processing Methods on Shelf Stability and Yield
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Date
2012-06
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Addis Ababa University
Abstract
The aim of this study is to evaluate three different Ghee processing methods, namely Direct Cream Method (DCM), Creamery Butter Method (CBM) and modified Ethiopian Butter Method (EBM). Yield and shelf stability were major criterion for comparison. Shelf stability of samples was estimated by using the accelerated shelf-life testing method. The Arrhenius kinetic model was used using a successive two step ordinary linear least squares fit. Samples were stored at 45 and 70 oC in dark place for 26 days. Then peroxide values, free fatty acid values and sensory qualities were measured and used to monitor deterioration. Furthermore, the effect of two traditional additives, Lippia adoensis and Aframomum corrorima, on the shelf stability of EBM Ghee was analyzed. The Ghee samples made by EBMwa (Ethiopian Butter Method without additives) and CBM had lowest (0.16±0.03mEq/Kg)and highest (1.29 ± 0.06mEq/Kg) peroxide value after 26 days storage at 45 oC. The Ghee samples made by EBMa (Ethiopian Butter Method with additives) and CBM had lowest (0.46±0.04mEq/Kg)and highest (6.11±0.29mEq/Kg) peroxide value after 26 days storage at 70 oC. DCM Ghee exhibited the maximum shelf life (7.5 month) followed by EBMa Ghee samples (3.45 months) and then CBM Ghee (2.7 months). On the other hand, yield was highest for CBM Ghee (91%) followed by EBMwa Ghee (83%), EBMa Ghee (80%), and DCM Ghee (73%). To conclude, it is advisable to process Ghee by Direct Cream Method. The addition of the aforementioned additives had positive effect in retarding oxidation process, which resulted in less formation of peroxides in EBMa (0.46±0.04mEq/Kg) in comparison to EBMwa (1.04±0.09mEq/Kg) after 26 days of storage at 70 oC. Finally, a preliminary techno-feasibility analysis for DCM and/or EBMa processing unit was also carried out.
Keywords: Accelerated Shelf Life Testing; CBM; DCM; EBM; EBMa; EBMwa; Peroxide Value; Shelf Stability; Yield.
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Keywords
Accelerated Shelf Life Testing; CBM; DCM; EBM; EBMa; EBMwa; Peroxide Value; Shelf Stability; Yield