Application of Raman Spectroscopy for Non-Destructive Determination of Qualitative Parameters of Tomato

Non-destructive methods yield a great deal of importance in agriculture since the tested product can return to the market process، together with simplicity compared to destructive ones. Therefore، the major challenge in industrial on/in line quality evaluation is to eliminate damages in fruits and vegetables. Every visible or invisible damage can be followed by problems in storage، processing and diseases. During recent years، machine vision، optical techniques such as Raman، NIR، NMR spectroscopies، acoustics and ultrasonic techniques are the main methods which have gained worldwide attention. In order to sort and grade fruits، several methods are implemented which are mostly slow، time consuming، and destructive. Yet، a rapid، non-destructive and precise measurement of qualitative factors including pH، SSC and color in tomato fruit yields a great deal of importance. For such a purpose، Raman spectroscopy is implemented to measure qualitative parameters in tomato non-destructively. Sugar components in tomato were investigated with HPLC test and spectroscopy was conducted on pure sugars. Results showed that Raman spectra highlight the major bands related to the fruit components. Lycopene and Carotene as the major cartenoeids in tomato fruit were detected explicitly through the spectra، in the way that all the three characteristic regions indexing such pigments (C-C and C=C stretching vibrations) are peaked as strong bands. Also carbohydrates could be shown by a medium band assigned to C-H vibration together with strong bands in 2300 cm-1 – 3000 cm-1 range. Thus it can be concluded that the technique is capable enough to be used in recognizing non-destructively both the external factors (e. g. color) and internal parameters (e. g. SSC) in tomato fruit.