Changes in bioactive compounds and antioxidant activity during homogenization and thermal processing of tomato puree

The effect of homogenization and thermal processing on a number of bioactive compounds (carotenoids, total phenolics, ascorbic acid and folates) in both raw tomato puree (RTP) and “hot break” tomato puree (HTP) was investigated. RTP and HTP were homogenized in either one or two-steps, followed by pasteurization at 98 °C for 40 s. Additionally, HTP was pasteurized in parallel at 98 °C, 108 °C and 128 °C. In general, homogenization had no effect, but changes were observed after pasteurization (98 °C for 40 s). Carotenoids were relatively resistant to thermal degradation, whereas total phenolic content and ascorbic acid significantly decreased. However, a higher content of folates was determined in the homogenized and pasteurized samples due to their higher extraction from the subcellular compartment. The increase in pasteurization temperatures of the HTP up to 128 °C led to a decrease of ascorbic acid, total phenolic compounds and folates. In conclusion, homogenization and pasteurization at 98 °C for 40 s improves the nutritional value of tomato puree, increasing the extractability of the folates and maintaining the carotenoid content.Industrial relevanceUnlike other vegetables, the tomato is a staple food that is not frequently homogenized by the processing industry, although homogenization could improve product quality. This is why we explored this technique, using one-step and two-step homogenization. The tomato and vegetable processing industry frequently pasteurizes at a constant flow rate, meaning constant heating time. In this study, we employed three different temperatures, using the same time of exposure, to cover different situations in the food industry. Depending on the product’s thickness, an increase in the temperature might be needed to reduce any microbiological hazard in the final product. Homogenization followed by pasteurization at 98 °C for 40 s resulted in a greater improvement of the nutritional value of tomato puree in all situations tested.