Processing of tomato: impact on in vitro bioaccessibility of lycopene and textural properties

Human studies have demonstrated that processing of tomato can greatly increase lycopene bioavailability. However, the difference between processing methods is not widely investigated. In the current study different thermal treatments of tomato were evaluated with regard to their impact on in vitro bioaccessibility and retention of lycopene and beta-carotene as well as textural properties. Thermal treatments used were low (60 degrees C) and high (90 degrees C) temperature blanching followed by boiling.

Lycopene was relatively stable during thermal treatment, whereas beta-carotene was significantly (P < 0.05) reduced by all heat treatments except for low temperature blanching. In vitro bioaccessibility of lycopene was significantly increased from 5.1 +/- 0.2 to 9.2 +/- 1.8 and 9.7 +/- 0.6 mg kg(-1) for low and high temperature blanching, respectively. An additional boiling step after blanching did not further improve lycopene bioaccessibility for any treatment, but significantly reduced the consistency of low temperature treated samples.

Choice and order of processing treatments can have a large impact on both lycopene bioavailability and texture of tomato products. Further investigations are needed, but this study provides one of the first steps towards tomato products tailored to optimise nutritional benefits.