Assessing the Impact of Cooking on Bioactive Compounds in Tomato Sauces with Added Tomato Pomace: A Chemometric Study

Abstract

The disposal of waste from widely consumed foods, such as tomatoes, poses a considerable challenge for the agro-industry. Tomato pomace (TP), a by-product of tomato processing consisting of peels and seeds, is an underutilized source of bioactive compounds with potential application in the food sector. In this work, a factorial experiment was designed to compare three culinary techniques, Thermomix® and Roner® food processing and traditional pan-frying, for the preparation of tomato sauces, enriched or not with TP, applying two temperatures and two cooking times. A multivariate analysis was performed on all the results obtained for the studied metabolites. The addition of TP significantly increased the content of bioactive compounds in the tomato sauce, especially phenolic compounds. OPLS-DA models were generated, using cooking technique, temperature, and time as discriminant factors. The culinary technique had a greater effect on the phenolic content than cooking temperature or duration time. During processing in the Thermomix®, but not the Roner®, bioactive components were released from tomato into the sauce to a similar extent as traditional pan-frying. Although no significant increase in bioactive compounds was found when using the Roner®, this technique proved effective in preserving the volatile fraction of the sauce. The two new cooking home technologies evaluated, comparing with the classical pan frying, have different effect on the tomato sauce preparation; while the Thermomix ®, increased significatively the amount of bioactive compounds, the Roner® increased the amount of volatile compounds.