Environmental Characteristics of Palestinian Olive Oil. A Case Study: Northern West Bank
2011
Amarna, M. | Marei, A. | Al-Rimawi, F.
We investigated the quality of olive oil produced in the northern West Bank. Forty samples were collected from two villages: Assera Al Shamalia (located in the western foothills) and Bet Dagan (eastern foothills). The samples were analyzed for iodine number, peroxide value, refractive index and free acidity using official AOAC analytical methods for fats and oils. Nitric acid test was also performed to determine olive oil purity. Steradiene content was determined using ISO method 171588-2. Factors that may affect olive oil quality were investigated, including: use of fertilizers and pesticides, fruit-collection and oil-extraction methods and some meteorological factors. Average iodine number of the studied olive oil samples was 91.8 cg/g with refractive index of 1.4696, free acid value of 1.22% and peroxide value of 19.1 meq O2/kg. All samples were negative in the nitric acid test. These parameters are within the range of virgin olive oil characteristics. Average total steradiene content was 0.45 mg/kg, comprised of stigmastadiene (0.13 mg/kg), cholestadiene (0.28 mg/kg), stigmastatriene (0.01 mg/kg), and campestadiene (0.03 mg/kg). Based on the established stigmastadiene limit (0.15 mg/kg), the olive oil from the northern West Bank is virgin olive oil. The differences in meteorological factors and harvesting times between the two villages led to differences in olive oil quality, e.g. higher stigmastadiene content in Bet Dagan vs. Assera olive oil.
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