Tomato quality assurance

Several quality parameters of processing tomatoes can be measured by FTIR spectroscopy on a handheld instrument, providing flexible on-site testing. IR spectroscopy has been applied previously to the analysis of various food and agricultural products and now Luis Rodriguez-Saona and co-researchers from Ohio State University have extended the technique to tomatoes intended for the processing industry, as they described in the Journal of Agricultural and Food Chemistry.

Tomatoes representing 40 processing varieties grown in California were converted into juice using a microwave break method to simulate a hot break process and were analysed by FTIR spectroscopy using benchtop, handheld and portable instruments. The levels of soluble solids, glucose, fructose, citric acid and glutamic acid were determined with the help of a partial least squares regression model. Soluble solids are an important parameter in the production of tomato pastes.

All of the instruments gave accurate results for these parameters when compared with standard reference methods. The good performance of the portable unit opens up the potential for flexible, on-site and in-plant assessment of tomato quality, without resorting to the time-wasting removal of samples to labs for analysis.