Development of Lactic Acid-Fermented Tomato Products.

BACKGROUND: lactic acid fermentation was recently proposed to produce fruit and vegetable beverages with high nutritional value. In this study, a wide screening of strains and fermentation parameters was carried out to develop fermented tomato-based drinks containing viable cells and potentially bioactive metabolites. METHODS: six different products (three extracts, two tomato juices and one tomato puree) were used as substrate for fermentation. After preliminary testing, eight fermentation conditions for each tested product were selected. The final products were stabilized with pasteurization or refrigeration and further characterized in terms of (i) antioxidant activity and (ii) total polyphenols. RESULTS: selected strains were able to grow in almost all tomato-based products except for one extract. Antioxidant activity and total phenolic content depend on products and fermentation conditions used and, except for tomato puree, an overall increase was observed. The best nutritional profile was reached in fermented samples stored at refrigerated temperature without thermal stabilization. CONCLUSION: an integrated data vision allowed to choose, for each substrate, the best combination of strains to produce novel fermented tomato-based products with different application perspectives.

Health-promoting substances and heavy metal content in tomatoes grown with different farming techniques.

BACKGROUND: Organic farming is a production technique that imposes major restrictions on the use of fertilizers, pesticides, feed additives and veterinary drugs and for this reason consumers perceive organic foods to be healthier. The content of health-promoting molecules such as ascorbic acid, beta-carotene, lycopene and salicylic acid are important aspects of the nutritional quality of organic foods. AIM: To evaluate health promoting substances and the heavy metal content of tomato berries grown using conventional, integrated pest management (IPM) and organic farming techniques. METHODS: Moisture was determined by drying, crude protein by the Kjeldhal method, and ashes by incineration at 550 degrees C. Ergosterol, ascorbic acid, beta-carotene, lycopene and salicylic acid were determined by HPLC. The levels of heavy metals were measured by atomic absorption spectroscopy. RESULTS: Compared to crops grown using conventional and IPM methods, organic tomatoes contained more salicylic acid but less vitamin C and lycopene. Organic tomatoes had higher Cd and Pb levels but a lower Cu content. Organic fruits had a slightly higher protein content than conventionally cultivated fruits, but the difference was minimal and consequently the nutritive significance was poor. CONCLUSIONS: Farming techniques may have an impact on the quality of tomatoes. Their higher salicylate content supports the notion that organic foodstuffs are more wholesome. However, the lower lycopene and ascorbic acid levels of organic tomatoes are not to be regarded as positive. No residues of pesticides and ergosterol were detected.