Curtin University of Technology research has uncovered a simple and effective way to boost the health benefits of olive oil by preserving higher levels of antioxidants in the extracted oil.
The research, conducted by Curtin food science and technology PhD student Hui Jun Chih, under the supervision of Professor Vijay Jayasena, Dr Tony James and Dr Satvinder Dhaliwal, found that the addition of citric acid during the oil production process was very beneficial.
“Phenolic compounds in olives are proven antioxidants that rid the body of the free radicals that cause oxidative stress and contribute to cardiovascular disease, diabetes and cancer,” she said.
“Normally about 90 per cent of these compounds are lost during olive oil production, but by adding a small amount of citric acid during processing, the concentration of total phenolic compounds in the extracted oil can be effectively increased.
“Results showed a135 per cent increase in phenolic compounds with the use of citric acid.
“We also found that the ability of the phenolic compounds in the extracted oil to act as an antioxidant was improved by about 46 per cent.
“The citric acid was also able to increase the yield of oil extraction with 21 per cent more oil extracted.
Ms Chih said the findings were significant because there was a strong demand for olive oil which could not be met by the industry.
“Many consumers around the world are already aware of the health benefits of consuming olive oil and this has contributed to a very high demand,” she said.
“Techniques such as the addition of citric acid help by not only increasing the yield of the oil extracted from the olives but also its likely health benefits.
“This type of research is particularly important as current production techniques used by industry are only able to extract less than 60 per cent of oil and only about 10 per cent of the beneficial phenolic compounds from olive fruits.
“Citric acid, which is low cost and natural, can be a simple and effective way to get more out of existing olive oil production.
“When compared to commercial samples, the quality and taste of the extracted oil was not affected by processing with citric acid.”
The three-year research study was conducted on Frantoio olives harvested from the Gingin, Swan Valley and Margaret River areas in Western Australia at various maturity levels.
Ms Chih expects to graduate with her PhD in February 2010.