Lycopene in Tomato Products
Stability and Bioavailability through Food Processing, and Extraction of Lycopene Concentrate as Food Ingredient
John Shi, Ph. D.
Food Research Center, Agriculture and Agri-Food Canada
93 Stone Road West, Guelph, ON NIG 5C9
Increasing clinical evidence suggests lycopene is an important natural anti-oxidant and it appears to provide protection against a broad range of epithelial cancers. Southern Ontario is the major tomato production area in Canada. There are over 500,000 T of processing tomatoes produced in Ontario each year. In the past three years, we launched the research project "Lycopene in Tomato Products - Stability and Bioavailability through Food Processing, and extraction of lycopene as food ingredient". This year we received funding, $5,000 from the Ontario Tomato Research Institute, and an equal amount from the Matching Investment Initiative of Agriculture Canada. The research progress shows great promise.
(1). Lycopene stability (chemical, physical and engineering properties of lycopene during processing). Thermal and mechanical treatments are often involved in food processing, which affect tomato product quality. Deep-red tomato fruits which contain high concentrations of lycopene would be processed into products with a dark red color. However, the lycopene content in concentrated tomato products is generally lower than expected due to the losses that occur during tomato processing. It is believed that the changes in lycopene content and the distribution of trans to cis isomers result in the change of biological properties. Degradation of lycopene and color loss of processed tomato products are affected by a number of factors such as high temperatures, long processing times, light, oxygen, acids, and some metal ions. Converting all trans-isomers to cis-isomers due to additional energy input results in an unstable more readily oxidizable form of lycopene. These undesirable degradations of lycopene not only affect the sensory quality of the final products, but may also reduce the potential health benefits of tomato-based foods. Determination of the degree of lycopene isomerization during tomato processing would provide a measure of this potential loss. The focus of the experiment:(a) to determine the rates of isomerization and oxidative degradation and the distribution of the all-trans- and cisisomers in the tomato products resulting from the different tomato processing methods, conditions, and steps, and (b) to improve processing technologies for the retention of lycopene in tomato-based products.
(2). Extraction of lycopene -- lycopene concentrate preparation. In the lycopene-rich concentrate development, optimum technology parameters for the extraction of lycopene by supercritical CO2 fluid - a "non-chemical solvent extraction technology" is being developed. Different physical treatments of tomato material (homogenizing, sanitation, cooking, milling, dehydration, etc.) were tested in the laboratory scale to compare the extraction yield. The material matrix effect on the Jycopene extraction from the skin has been tested, and electronic microscopies of skin after each treatment was recorded. Lycopene concentrate is used as a food ingredient in tomato-based foods and other nutritional foods, which is favored by most customers and also encouraged by Health Canada and the FDA. Extractions of lycopene from tomato skin and low-grade tomatoes is then put back into the tomato product to fortify it with lycopene-enriched concentrate, thus to enhance tomato product quality.
The research results are a direct benefit to the Ontario Tomato Industry.
(a). Studies on the effects of tomato processing conditions (physical, chemical, and engineering) on qualitative and quantitative changes in lycopene degradation are necessary for the tomato processing industry to ensure high food quality. The research on lycopene stability in tomato processing will benefit the food industry by enhancing the food quality and improving the competitiveness of tomato-based foods in global markets. Determination of the degree of lycopene oxidation and isomerization would provide better insight into the potential health benefits (and their possible reduction) of the processed tomato products.
(b). Based on the information about lycopene degradation and isomerization being effected by heat, light irradiation, oxygen, and other physical and chemical treatment, improvement of processing technology using lycopene content as a quality index will greatly improve the nutritional quality of tomato products, and enhance the health benefit for customers.
(c). Development of potential new products -- lycopene rich concentrate as a food ingredient. Tomato processing companies in Ontario have received a high reputation in product variety and quality. How is it possible to face the world marketing challenge and high competition among the European community, the US market and the South American market? With the new "lycopene-enriched tomato products", which may create potential economic benefits for further growth of the agri-food industry. A successful commercialization of lycopene-rich tomato products may improve the competitiveness of nutraceutical products in the global market, and may capture some lycopene-rich tomato product market in other parts of the world.
(d). Lycopene-rich concentrate (50% lycopene and other carotenoids in tomato paste) is a natural food ingredient, and meets the safety requirements of Health Canada and FDA policies. A lot of customers will favor such natural products, which will in turn promote production and economic development.