S. Goisser, S. Wittmann, Michael Fernandes, H. Mempel, C. Ulrichs
Comparison of colorimeter and different portable food-scanners for non-destructive prediction of lycopene content in tomato fruit
Postharvest Biology and Technology, vol. 167, no. September
Lycopene, the red colored carotenoid in tomatoes, has various health benefits for humans due to its capability of scavenging free radicals. Traditionally, the quantification of lycopene requires an elaborate extraction process combined with HPLC analysis within the laboratory. Recent studies focused simpler methods for determining lycopene and utilized spectroscopic measurement methods. The aim of this study was to compare non-destructive methods for the prediction of lycopene by using color values from colorimeter measurements and Vis/NIR spectra recorded with three commercially available and portable Vis/NIR spectrometers, so called food-scanners. Tomatoes of five different ripening stages (green to red) as well as tomatoes stored up to 22 days after harvest were used for modeling. After measurement of color values and collection of Vis/NIR spectra the corresponding lycopene content was analyzed spectrophotometrically. Applying exponential regression models yielded very good prediction of lycopene for color values L*, a*, a*/b* and the tomato color index of 0.94, 0.90, 0.90 and 0.91, respectively. Color value b* was not a suitable predictor for lycopene content, whereas the (a*/b*)² value had the best linear fit of 0.87. In comparison to color measurements, the cross-validated prediction models developed for all three food-scanners had coefficients of determination (r²CV) ranging from 0.92 to 0.96. Food-scanners also can be used for additional measurements of internal fruit quality, and therefore have great potential for fruit quality assessment by measuring a multitude of important fruit traits in one single scan.
Beitrag (Sammelband oder Tagungsband)
S. Goisser, Michael Fernandes, C. Ulrichs, H. Mempel
Non-destructive measurement method for a fast quality evaluation of fruit and vegetables by using food-scanner
Short Communications of the DGG and BHGL Annual Conference 2018 (Geisenheim, Germany), vol. 8/13
Recent reports estimate the volume of food loss along the supply chain to 1,3 billion tons globally per year, which equals one-third of food produced for human consumption (FAO, 2011). Further studies conducted for the German food supply chain estimate the quantity of annual food loss between 11 million (Universität Stuttgart, 2012) and 18 million (WWF, 2015) tons. Fruits and vegetables, with a percentage of 44 of the total food loss, are commodities most frequently thrown away (BMEL, 2012). In recent years, a lot of attention is given to so-called food-scanners. Food-scanner are miniaturized near-infrared (NIR) spectrometers, which allow a fast and noninvasive determination of food quality. They can be used as a multidimensional predictor to determine the chemical and physical composition of agricultural and food products (e.g. soluble solids, dry matter, moisture, firmness). Due to their small size and portability these devices can be used for in-field application as well as for researchers andend-consumers (Santos et al.,2013). Studies of Flores et al. (2009) and Kim et al. (2013) indicate that NIRS is suitable for predicting quality attributes of various tomato varieties. The experiments described in this study are conducted on tomatoes and focus on the performance of a food-scanner compared to a benchtop NIR-spectrometer. Important quality parameters of tomato, such as sugar content and firmness, are evaluated with respect to their predictability in order to validate the performance of this new kind of non-destructive measurement method.