Quality of Olive Oils
A short essay about the quality of olive oil.
Date: 6/7/2007 3:01:12 PM ( 14 y ) ... viewed 3792 times
Olive oil obviously comes from olives which are cultivated, harvested, pressed, bottled, transported and ultimate sold. This process affects the quality of the olive and consequently not all olive oil is the same. It should be chosen in the same that you chose a good wine or fruit juice.
In some parts of the world olive trees are grown traditionally on land that is fertilised naturally, without artificial irrigated or watering. It is harvested with care and by hand when the olives are mature (golden read) and transported without damage to be milled within 24 hrs and stored in ideal condition until it is required. Very ripe olive damage easily and mechanically harvested olives are contaminated by old putrid apples, twigs and unwanted material. To obtain a litre of oil of first extraction, approximately, five kilos of olives are required.
Olive oil should be bottled, transported and retailed in a way that preserves its purity; in cool condition away from light and air. During storage in depots, stores and in the home keep olive oil in a cool and dark place, tightly sealed. Oxygen promotes rancidity, light affects the flavour s and plastic bottles can react with the oil in time so it is often bottle it in green glass. Buy quality oil from an outlet with a rapid turnover or guaranteed quality. How long has that bottle of very expensive olive oil been sitting on the shelf of the health store? Check the label to find out when it was bottled.
Olive oil can be kept over two years, longer than any edible oil. Olive oil can be refrigerated but this will make it cloudy. The cloudiness will disappear when the oil returns to room temperature.
Olive oil is classified by its “acidity level”; the lower the acidity level, the better the quality and taste. Consequently, oil from the first cold pressing of olives without using any chemicals must have an acidity level less than 1%.
Types of olive oil
The International Olive Council (IOC) has a United Nations charter to develop quality and purity criteria for olive oil. The International Olive Council and the California Trade Standards for Olive Oil have 9 categories of olive oil as follows:
1. Extra Virgin Olive Oil - is produced from the very first pressing, olives which takes place within 24 to 72 hours of the harvest. The only two types of pressing allowed are mechanical or hand pressing. No heat or chemical processes are used. The acidity level of the olive oil is less than 0.8%.
Premium Extra Virgin olive oil is the best possible in terms of acidity, quality, aroma, and flavour. Some oils have natural acidity rates as low as 0.225% but always less than 0.8%.
2. Virgin olive oils - are produced in the way as extra virgin grades and the oil is not refined or processed after pressing. The natural acidity levels less than 2% but the flavour and is still of the highest quality. The oil obtained from the first pressing is the only olive oil that can be classified as virgin or extra virgin depending on the natural acidity.
Fine Virgin oils - are produced in the way as extra virgin grades and the oil is not refined or processed after pressing. They are a high quality olive oil with a maximum acidity level of 1.5%. It is less expensive than extra virgin grades, which makes it an excellent substitute when budget is a consideration.
3. Ordinary Virgin Olive Oil - has a maximum acidity level of 3.3%. It has good flavour, but it is less tasty than higher grades. It has the same health benefits as any of the higher grades and is best used for cooking.
4. Lampante virgin oil - is a low grade of virgin olive oil not for human consumption. It’s natural acidity is above 3.3% and may also have an unpleasant taste and aroma. Lampante virgin olive oil is made into refined olive oils.
Refined Olive Oil
5. Refined Olive Oil – Not Fit for Human Consumption - Refined Oil is obtained from refining virgin olive oil that has a natural acidity higher than 3.3%, poor flavour, and an unpleasant odour. This lampante oil is treated with heat, filtration, and/or chemicals to produce the refined oil, which has no taste or colour. It has an acidity level is below 0.3% when refined.
6. Olive Oil or Pure Olive Oil - usually a ratio of 85% refined oil to 15% virgin or extra virgin olive oil. The maximum acidity level may not exceed 1.5% (after the addition of the virgin or extra virgin oil). It has the same health benefits of the higher quality virgin and extra virgin grades. It also has a higher smoke point than virgin or extra virgin oil, making it an excellent choice for cooking.
7. Crude Olive-Pomace Oil – Not Fit for Human Consumption - Pomace is the waste product from the milling process and pomace oil is obtained by treating olive pomace with solvents. It does not include oils obtained in the re-esterification processes or any mixture with oils of other kinds (seed or nut oils). This is the solvent extracted crude oil product as it comes out of the pomace extractor after distillation to separate and recover most of the solvent.
8. Refined Olive-Pomace Oil – Not Fit for Human Consumption - Oil obtained from crude pomace oil by refining methods that do not alter the initial glyceride structure. Refining includes the same methods used for “refined olive oil” except that the source of the raw product comes from pomace by means of solvent extraction.
9. Olive-Pomace Oil - A blend of about 90% refined olive-pomace oil the remainder virgin olive oil to provide flavour and aroma that is suitable for human consumption. It has a free acidity of not more than 1%. It is not called “olive oil.” And is used commercially for example in tined fish products.
Miscellaneous Olive Oils
Mild in Taste Olive Oil – So called “Lite” oils are not low in calories but have a mild flavour. All types and grades of olive oil contain 120 calories per tablespoon. The finer flavoured is derived from a special filtration process. Some of the names given to these products include:
| Lite Olive Oil
| Mild Olive Oil
| Mild in Taste Olive Oil
| Light in Taste Olive Oil
| Mild in Taste Virgin Olive Oil
| Light Extra Virgin Olive Oil
| Lite in Taste Olive Oil
Flavored Olive Oils - Lower quality grades of olive oil are enhanced by heating the oil while infuse it with flavouring agents. Citrus extracts herbs and spices such as garlic, basil, rosemary, and pepper are used.
An olive oil consists of 98% lipids and 2% unsaponifiable volatiles, polyphenols, pigments, aromas, & flavors. The lipids consist of glycerides and fatty acids such as palmitic, linoleic, and oleic. Linoleic acid increases with olive maturity, palmitic decreases with maturity. Oil viscosity is low (thick) with low linoleic acid content. The water soluble (unsaponifiable) flavor components of oil typically consist of terpenes 300 to 700 mg/kilo, chlorophyll 0-10 PPM = color & antioxidant, tocopherols - vitamin E & antioxidant, esters - flavor, and phenols & polyphenols 50 to 500 mg/kilo = flavor & antioxidant properties.
Climate has very little influence on olive oil fatty acid composition (palmitic, linoleic, oleic, etc.). Polyphenol content can be 3-5 times different, however, in one area compared to another. This can have a dramatic effect on flavor. In fertilizer studies in Spain and other Mediterranean countries, there is no influence from soil nutrient content on oil quality or composition.
The increasing demand for olive oil has resulted in the use of more automated methods in its production to reduce cost and maximise profits. Modem large oil processing factories extract more oil more cheaply, but at a reduced quality of the oil.
Antioxidant polyphenols are reduced by the need to wash mechanically harvested olives thereby lowering the shelf life to perhaps only a few months because of a loss in oil stability by up to 50%. The nutritional quality of the oil is also lower. Washed olives generally have a lower bitterness, lower Piquant and a less fruity flavour and can be more appealing. Small quantities of leaves are not detrimental to the oil and sometimes leaves are added to produce a greener colour and more intense flavour. Quantities of twigs, soil and bad olives can taint the oil.
As much as 20% hazelnut oil can be added to olive oil without it being detected by the average palate. At one time it was alleged that more oil was produced in California than harvested and although honest growers are trying hard to comply with quality requirements it gives the impression that olive doesn’t contain the nutritional criteria we expect. People have a right to assume that a label stating extra virgin is a guarantee of quality but this is not always the case. The laws in Europe are very clear but in the U.S. it is more complicated and there are no federal regulations governing the use of the "Extra Virgin" designation in the American marketplace. The California Olive Oil Council (COOC) has adopted the international standards. In 1997, Bill SB 920 makes it a crime to sell imitation olive oil or to sell olive oil labelled as "California" olive oil that contains oil from any other source.
Like wine, no two olive oils are not alike. Each is a unique product of soil, climate, olive varieties and age, and processing methods. Oils can be fruity or flowery, nutty or spicy, delicate or mild, and can range from clear to pale green to golden to deep olive green in colour. When properly processed olive oil can fully maintain the flavour, aroma and vitamins of the olives from which it came. Fully mature black fruit yield sweeter oil, but during harvest they are soft and easily damaged. Immature olives that are green or straw coloured are sometimes processed because of the unique flavour that less mature fruit impart to oil.
Bulk storage of olive in vats allows the oil to mature and stabilise and eliminates the problems of sediment in bottles. "New" oils bottled and sold immediately after processing must be consumed quickly (within a few weeks) to avoid flavour changes within the bottle.
Tasting olive oil is a much more accurate quality test (100 times) as aroma and taste are very complex and can not be determined in the laboratory. Olive oil should have a fruity olive flavour; there should be no vinegary or fermented odour or flavour. Bitterness and pungency (piquant) are often present in olive oils, especially when newly made but will mellow as the oils age. They are positive aspects of oil because they are related to keeping quality or shelf life. Astringent, bitter, and or pungent oils have higher polyphenol content and will store much longer than sweet oils with little or no bitter or piquant flavour. Blending different olive oils together masks astringency, add longevity to a low polyphenol oil, and creates depth.
In Spain and Italy is around 47 cups of olive oil is consumed per person per yaer. As a comparison, the UK consumes 0.88 cups, Germany 0.66 cups, and the USA 0.002 cups per person. The Spanish and Italians consume 24,000 times more olive oil than Americans do.
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