5075
HAMDY ABD EL-HADY ZAHRAN
MAXIMIZING THE UTILIZATION OF OLIVE OIL PROCESSING WASTES
Olive wastes, Extraction technology, Phenolic compounds, Antioxidants assay, Ultrasound-assisted extraction, Microwave-assisted extraction, Oxidative stability, Sunflower oil, Soybean oil, Frying process, Schaal oven test
This study aims to examine the potential benefits for phenolic compounds (PC) extraction from olive mill wastes and leaves using novel extraction technologies compared to conventional extraction methods for two reasons: first, to reduce pollution and second, to regain an economically important by-product. The production of olive oil has seen an increase in recent years due to a broader understanding of the health benefits of the Mediterranean Aliment Culture. With this expanding industry we also see an increase in the waste products associated with olive oil production. Given the high polluting content of the waste streams and the economic costs associated with its removal and processing, waste remediation and disposal has become a significant point of interest for both producers and local bodies. In this study, different olive mill waste types i.e. solid and liquid wastes from traditional, 3-phase and 2-phase processing of olive oil extraction were used for phenolic compounds extraction under different conditions such as solvent type, temperature, extraction time and using some assisted extraction method (dynamic ultrasonic, microwave). The wastes of the olive oil production industry were examined for their use as a raw material for producing a novel product used in the control of oxidative stability of vegetable oils and other food products, as well as, examining the effect of extraction protocols on the activity of this final product. The PC of olive wastes were identified in this study as providing the majorityof the active fraction, so protocols were developed for the recovery of these compounds. Standard solvent extraction and assisted extraction method (dynamic ultrasound, microwave) were examined for their effectiveness of bio-phenolic recovery and their effect on product quality. It was found that the action of ultrasound during extraction provided a greater degree of recovery of PC, with minimal loss of product quality; also, the use of ultrasound and microwave dramatically accelerated the extraction rate, as well as, reducing the time of extractionby 83 %.. This increase in recovery was due primarily to the destruction of cellular material resulting in higher yields of recovery. The crude olive leaf extract (ethanol/water at 1:1) showed an antioxidant effect on stabilizing of oil samples against control (antioxidant free sample) during deep-fat frying at 180±5°C for 5 h / day, for 4 consecutive days. The results exhibited the efficiency of olive leaves extract (OLE) in reducing the changes in the physicochemical properties of all oil samples during deep-fat frying at 180±5°C/20 h. Some evidence exists that there is an opportunity for the economic recovery of olive polyphenols for use as a novel product, but more work is required to determine specific applications and/or targets of use, as well as optimization of the extraction and purification protocol. The novel olive phenolics will allow the examination of particular compounds activity, and hence a better understanding of the action of olive wasteextracts.
2015
Ph.d
Ain Shams
Agriculture