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UC Cooperative Extension sensory analysis panel enhances the quality of California olive oil

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Fuente de la noticia: 
Authors Paul M. Vossen, UC Cooperative Extension Alexandra Kicenik Devarenne, Writer and Educator Publication information California Agriculture 65(1):8-13. DOI: 10.3733/ca.v065n01p8. January-March 2011.
7 years 37 weeks ago
UC Cooperative Extension sensory analysis panel enhances the quality of California olive oil


During the California olive oil revival of the past two decades, a quiescent industry has come dramatically to life (see box, page 9). Acreage planted in oil olives is increasing rapidly. By fall 2010, an estimated 28,500 acres were growing in California, a doubling of acreage from 3 years prior.

Interest in planting new orchards is still high, but the economic crisis has reduced the rate of oil-olive acreage growth. A few large producers make about 80% of the state's olive oil, but more than 90% of the farms are small scale with less than 20 acres. Production of premium olive oil in California is predicted to double in the next 3 years from 800,000 to 1.6 million gallons. Many of these oils are excellent, taking top awards in global competitions.

But this was not always the case. The improvement in California's olive oil is due largely to the efforts of a scientifically selected and trained sensory evaluation panel. Only the most rudimentary quality testing on olive oil is currently being done by laboratory chemical analysis; a group of human beings following strict tasting protocols is now the standard tool for detecting, identifying and quantifying the many positive and negative attributes of olive oil.

Although people have been making and using olive oil for thousands of years, the methodical sensory analysis of olive oil is a recent development. Its use in measuring quality was advanced significantly in the early 1980s, when sensory researchers in Spain, Italy, Greece, Portugal and France began working together with the International Olive Oil Council (now the International Olive Council or IOC) to develop the first official tasting methodology. Their work applied the principles of sensory science to olive oil. Sensory evaluation evokes, measures, analyzes and interprets the responses of tasters to the flavors they perceive.

Worldwide, sensory analysis has become a key part of how olive oils are rated for market grade, and it has been used to help growers and processors produce a higher-quality product. Since the late 1980s, many researchers have used sensory evaluation to characterize olive oil flavors attributable to cultivar (variety), fruit maturity, terroir, irrigation, tree nutrition, pest damage, fruit handling and processing methods. Researchers have also taught sensory short courses and workshops for industry professionals and consumers about olive oil styles and quality.

Uses of a sensory panel

A trained sensory panel is an invaluable tool. It provides an objective sensory evaluation of olive oil that can be used by regulators to enforce label standards that protect consumers, producers and processors from fraud in the industry. IOC quality standards are used globally to determine whether an oil should be graded and marketed as “extra virgin” or “virgin,” or refined and then sold as “olive oil” (see box, page 10). In order for an oil to be graded as “extra virgin,” it must pass several laboratory chemical analyses and be evaluated by a sensory panel. The olive oil must be free of defects and have some fruitiness.

Official IOC tastings that rate oils for compliance to trade standards note the intensity of any defects. Only three positive attributes — fruitiness (either green or ripe fruit), bitterness and pungency — are quantified on the profile sheet. The official IOC profile sheet includes five standard defects: fusty/muddy sediment, musty, winey-vinegary, rancid and metallic. Space is left to note negative attributes other than the classic defects (IOC 2006, 2007c). Beyond evaluating by defined IOC standards, sensory panels help producers make better decisions regarding variety selection, pest management, cultural practices and harvest timing. With qualitative analysis, processors can also better select processing methods to maximize quality and assess how various cultivars might contribute desirable characteristics in blends.

Sensory evaluation in research


Sensory panels define the attributes of olive varieties and rate them according to the intensity of fruitiness, bitterness and pungency, but also provide an in-depth evaluation of fruit flavor characteristics. The content of volatile aromatics (aroma compounds emanating from the oil) and polyphenols (complex phytochemicals that act as antioxidants) make up much of an oil's flavor, and are highly variable between varieties. Qualitative analysis of the fruity characteristics of an olive oil provides valuable information about the sensory contributions of different cultivars, helping producers to select varieties and market product to consumers (Cimato et al. 1996; Romero et al. 2005; Tura et al. 2000; Uceda and Aguilera 2005; Vossen 2003