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Olive Oil Technical

Information about the technical aspects of olives and olive oil.

Apostolos K Kiritsakis
Professor
School of Food Technology and Nutrition, Technological Educational Institution of Thessaloniki, Sindos Thessaloniki, Greece

ABSTRACT

The purpose of this paper is to describe the factors affecting olive oil composition and to overview the effect of its composition on nutrition and human health. It is well accepted that the high mono-unsaturation of olive oil and the presence of several other constituents such as phenols and tocopherols, chlorophyll and pheophytin, sterols, squalene, aroma and flavour compounds and others exhibit a significant role on the health. Olive oil, as a highly monounsaturated oil, is resistant to oxidation. Also the presence of phenols, tocopherols and other natural antioxidants prevent lipid oxidation within the body eliminating the formation of free radicals which may cause cell destruction. The aroma and the flavour compounds of olive oil, as well as the chlorophyll and pheophytin pigments, increase the stomach secretion and facilitate the absorption of the natural antioxidants, which furthermore protect the body tissues from oxidation. Epidemiological studies suggest that the high consumption of the monounsaturated olive oil in Mediterranean countries, is related with the low rates of cardiovascular disease (CHD), cancer of the breast and of high life expectancy.

The following is published with the kind permission of Guido Costa.

Guido has worked in the family olive farming business in Paarl (60 km from Cape Town, South Africa) since completing studies in 1987: responsibilities include processing of table olives, production of olive oil, propagation of olive trees, conversion of operation to full organic production, etc., etc. The family business (F. Costa & Sons) was founded by his Italian horticulturalist grandfather, Ferdinando Costa, in 1904 as the first olive/olive oil business in South Africa. COSTAS Olives and Olive Oils are the oldest established olive product brands in S.A. His qualifications include: BSc (Physics & Chemistry majors), BSc. (Hons.) (Chemistry), MSc (Chemistry) cum laude, MBA (University of Cape Town).

Varying fatty acid profiles in olive oils from different areas can modify the ratio of Saturated vs. Monounsaturated vs. Polyunsaturated fatty acids(SFAs, MUFAs & PUFAs). Tunisian oil, for instance, is relatively high in SFAs (specifically palmitic) and low in MUFAs (specifically oleic), whilst Australian (and South African) oils are much higher in MUFAs and lower in SFAs. From the health point of view, the latter oils are preferred, because of the proven beneficial effect of MUFAs on our serum cholesterol levels. MUFAs have been shown to lower "bad" LDL cholesterol (low density lipoproteins) yet retain "good" HDL cholesterol (high density lipoproteins). This, chemically speaking, is in fact the major benefit of olive oil over the highly polyunsaturated seed oils, wherein the PUFAs reduce both the "bad" as well as the "good" serum cholesterol levels in our blood.

One of the most contentious issues between olive oil and competing vegetable oils is the smoke point. 

When frying the oil in the pan is heated between 160-240°C. The optimal temperature is around 180°C. Lower temperatures are used in other forms of cooking – roasting, baking etc. In Asian countries where the wok is used for stir frying, temperatures higher than this can be expected.

The importance of smoke point from a chef’s point of view was brought home to me by a chef in Blenheim, New Zealand when I quizzed him about which oil he used for frying. His answer was avocado oil because of its high smoke point, and secondly he liked the flavour. Pursued as to why he didn’t use some of the locally produced extra virgin olive oil, his answer was that he was so busy in the kitchen that he could not watch the frying all the time and the lower smoke point of olive oil often caught him out with the food he was frying being spoilt. Price was not an issue.