Researchers at the Universitat Politècnica de València’s (UPV) Food Development Engineering Institute (IUIAD) and the Advanced Centre on Food Microbiology (ACFM) have found that certain antioxidants in tomatoes–phenolic compounds and lycopene–have a positive impact on the performance of the probiotic microorganism L reuteri throughout the digestive process.

In the study, published in the Journal of Functional Foods, the team confirmed that the presence of antioxidant compounds protect L reuteri against the loss of viability that takes place during digestion. Probiotic performance was found to increase when tomatoes were fried to make tomato sauce compared to using raw tomatoes.

Researchers also advised that enhancing the probiotic effect of bacteria should be considered when designing personalised diets by pairing complementary foods together.

IUIAD researcher Ana Belén Heredia said: “We have evaluated the viability of the probiotic strain along the digestive process individually and the presence of antioxidants from vegetable sources, as well as the impact of the probiotic strain on the changes suffered by antioxidant compounds and the resulting bioaccessibility.

“We worked with raw and fried tomato to determine the impact of processing and among the results, we found that serving meals rich in probiotics with fried tomato sauce boosts its probiotic effect, as well as causing a progressive isomerisation of the lycopene of the tomato, from form cis to trans throughout digestion, which positively results in an increased final bioaccessibility of this carotenoid.”

The research highlighted the importance of not only identifying chemical changes experienced by bioactive compounds during food processing, but also during digestion. This is especially significant when designing function food products, ensuring that probiotic performance and bioaccessibility to bioactive compounds is optimised during both processing and digestion.

ACFM researcher Jorge García Hernández added: “Viability throughout the gastrointestinal tract, and the gastro-resistance of Lactobacillus reuteri, is affected by a parallel supply of antioxidant compounds from tomatoes. And we have shown that fried tomato is better than raw tomato in both cases.”