September 09, 2006
Do you love the smell of fresh pressed olive oil, the smell of the produce aisle of the supermarket or the local Farmer's market? Your nose may be telling you what foods are heavy in nutrients. Animals evolved the sense of smell and taste to find nutritious foods and to avoid toxins. Many plants such as the tomato depend on their fruit being eaten by animals for seed dispersal. The most successful varieties of wild tomatoes have developed nutrients that are important to animals and therefore smell better. We are attracted to them for our benefit and the benefit of the tomato. According to a recent study in Science magazine, plants produce many volatile compounds but only a small of subset of these are sensed by animals and humans. In many plants almost all of the important flavor-related volatiles are derived from essential nutrients.
Plants produce different volatiles at different stages of maturation. The "flavor fingerprint" that helps animals and humans discriminate healthy foods from poor or dangerous ones is made up of a small number of volatiles. These volatiles are produced in highest proportion when the fruit is ripe, the seeds are mature and the nutrients at are at their peak.
The authors of the article describe how domestication of plants has had a negative effect on flavor production. In the case of the tomato, breeding programs have focused on yield, color, shape and disease resistance. Flavor has not been a high priority to breeders. Highly bred tomatoes do not have as strong a flavor as the wild plant and studies show that the essential nutrient level of the wild plants are several times higher. By breeding out the flavor, nutrients have been lost. The same has been found in strawberries. It is not your imagination that many fruits today don't smell like the wild or heirloom varieties.
It is interesting to extrapolate the author's findings to the olive. The most domesticated olive trees are the clone dwarf varieties. Just as with tomatoes, characteristics such as early maturity, fecundity, and disease resistance have been selected. The oil from these varieties tend to be more mellow and have a lower level of antioxidants. Less is known about other essential nutrients than more studied plants such as the tomato. It will be a challenge for tree breeders to develop olives that have high yield characteristics and also a high level of nutrients and volatiles desirable for smell and taste.
Plant Volatile Compounds; Sensory Cues for Health and Nutritional Value?, Stephen A. Goff and Harry j. Klee Science Vol 311, 10 February 2006