- Incorporation of tomato peel is an efficient mean to extract carotenoids and phenolics into the fatty substrate and to enhance their bioavailability.

- Tomato derivatives were incorporated in refined olive oil, extra virgin olive oil and refined sunflower oil.

- The enrichment of oils with tomato might be an alternative approach to elaborate new functional foods.

The protective effect of the Mediterranean diet against the risk of cancer and cardiovascular disease has been attributed to various dietary components. Recently, there has been renewed attention given to the antioxidant content of tomatoes because many epidemiological studies suggest that lycopenes and other carotenoids are related to the prevention of prostate cancer.

Tomatoes are widely consumed either raw or after processing and can provide a significant proportion of the total antioxidants in the diet. There is literature determining that tomato peel had significantly higher levels of total phenolics, total flavonoids, lycopene and ascorbic acid than the pulp and seed fractions.

The study was carried out by scientists from the University of Boumerde’s of Algeria, the Mediterranean Agronomic Institute of Chania in Crete, Greece, the National Agronomic Institute of Algeria and the Aristotle University of Thessaloniki, Greece.

A new way to get functional food

The approach is based on the lipophilic properties of carotenoids for their extraction into edible oils and phenolics to some extent in view of upgrading low quality oils and thus suggesting new functional food products. Refined olive oil was chosen because it is a low quality virgin olive oil with high acidity, which undergoes physical and chemical treatment to improve its quality.

The incorporation of tomato puree or peel did not lead to an increase of acidity and peroxide value except for the sunflower oil. The enrichment levels on lycopene and b-carotene were similar in all the types of oils after incorporation of tomato puree independently of the percentage of incorporation.

Interestingly, tomato peel incorporation in refined olive oil was more efficient to enhance for antioxidant activity. Moreover, tomato puree incorporation induced leaching of phenolic compounds, while tomato peel permitted to overcome this problem and enhance significantly the total phenol content of the refined olive oil.

The research paper has been published in 2008 in the journal Food Chemistry, specialized in the chemistry and biochemistry of foods and raw materials, under the title Valorisation of low quality edible oil with tomato peel waste.

Source: Food Chemistry

Editorial Staff: Oleociencia http://www.oleociencia.es (GDESCO)