Cooking for longer time and adding onion could improve beneficial effects of tomato sofrito

May 23 2017

Cooking tomato sofrito for a longer time -around an hour- and adding onion to this typical sauce of the Mediterranean diet, benefits the production of beneficial molecules for our health due their high antioxidant capacity, according to a study published in the journal Food Research International, carried out by a team of researchers from the Faculty of Pharmacy and Food Sciences of the University of Barcelona and the Physiopathology of Obesity and Nutrition Networking Biomedical Research Centre (CIBERobn).

For the first time, the scientific team has verified the positive effects of the synergy between different ingredients in tomato sofrito and its effects on the isomerization -isomers are molecules with the same molecular formula but with different features- in the lycopene, the most present carotenoid in tomato and its products.

According to the study, onion is the most important ingredient when making sofrito, due its potential in the lycopene isomerization. Moreover, if apart from adding onion, the cooking takes longer, this can lead to a higher production of cis isomers (5-Z lycopene, 9-Z lycopene, and 13-Z lycopene), molecules with a high bioavailability which are beneficial due their antioxidant potential.  

According to Rosa Maria Lamuela Raventós, researcher from the Department of Nutrition, Food Sciences and Gastronomy of the UB and CIBERobn, "this is an innovative study because there is almost no scientific research covering the subject of cooking effects in health. Our objective was to evaluate how the sofrito home cooking process and synergies between different ingredients used in this sauce -such as extra virgin olive oil, onion and garlic- interact and increase the presence of these carotenoids".

To study the synergies of the ingredients, researchers used a full factorial design to analyze the contribution of each ingredient to the carotenoid composition of sofrito and determine whether it was possible to improve its presence regarding the cooking time and the ingredients synergism.

The analysis revealed the presence of new types of carotenoids and their isomers, that reach the highest level with onion and a cooking time of 60 minutes, according to the study led by Lamuela, director of the Institute for Research on Nutrition and Food Safety (INSA-UB). This new scientific article has as is first author the doctoral student José Fernando Rinaldi de Alvarenga, member of INSA-UB and doctoral intern of the National Council for Scientific and Technological Development (CNPq) in Brazil.

Tomato, onion and garlic, key factors for the PREDIMED study

The Mediterranean diet is efficient in the primary prevention on cardiovascular diseases, as seen in the conclusions of the known study of Primary Prevention of Cardiovascular Diseases with a Mediterranean Diet (PREDIMED), a clinical trial carried out from 2003 to 2011 which counted with the participation of Rosa Maria Lamuela.

Homemade sofrito, rich in carotenoids associated with lipid regulation and inflammatory biomarkers, is one of the most classic sauces in the Mediterranean diet. Also, polyphenols in onion and garlic, which are also part of this recipe, show beneficial effects to fight cardiovascular diseases, hypertension, diabetes and certain cancers.