Optimization of phenolic compounds in virgin olive oil
2015
Sermet, S.O.
Phenolics are component being responsible especially for oxidative stabilities of olive oil besides to color, taste, nutritional value and organoleptic properties. In this thesis study, it was aimed to determine the effects of maturity and different malaxation conditions on yield, quality parameters, total phenolic content, ortho-diphenol, phenolic composition and free radical scavenging activity of olive oils produced from olives samples harvested at three maturity periods. Olive oil extraction was carried out according to the central composite design created using different malaxation temperature and time. Phenolic composition of extracts obtained from olive oils using high performance liquid chromatography (HPLC) was determined. The results were analyzed using response surface method for optimization.The amount of total phenolic contents, ortho-diphenols and free radical scavenging activity of oil samples were found to vary in the range of 86.11-338.94 (miligram gallic acid equavalent (GAE)/kg), 66.74-154.88 (mg GAE/kg) and 42.49-90.10 %, respectively. Main phenolic compound tyrosol, hydroxytyrosol, vanilic acid, vanilin, p-cumaric acid, ferulic acid, luteolin was determined.When olive oil extracted from Memecik cultuvar was investigated in terms of the effects of malaxation temperature and time, at high temperature and for long process time values, total phenolic content and ortho-diphenol amd free radical scavenging activity display decreases.The optimum conditions of malaxation temperature and time for oil extraction from spotted, purple and black fruits were found as 37°C / 39 min, 33°C / 42 min, and 26°C / 24 min, respectively.
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