Direct quantification of lycopene in products derived from thermally processed tomatoes: optothermal window as a selective, sensitive, and accurate analytical method without the need for preparatory steps.
The concept of the optothermal window (OW) is proposed as a reliable analytical tool to rapidly determine the concentration of lycopene in a large variety of commercial tomato products in an extremely simple way (the determination is achieved without the need for pretreatment of the sample). The OW is a relative technique as the information is deduced from the calibration curve that relates the OW data (i.e., the product of the absorption coefficient beta and the thermal diffusion length micro) with the lycopene concentration obtained from spectrophotometric measurements. The accuracy of the method has been ascertained with a high correlation coefficient (R = 0.98) between the OW data and results acquired from the same samples by means of the conventional extraction spectrophotometric method. The intrinsic precision of the OW method is quite high (better than 1%), whereas the repeatability of the determination (RSD = 0.4-9.5%, n= 3-10) is comparable to that of spectrophotometry.
Bicanic
Dane
D
Laser Laboratory for Photothermal Science, Biophysics Division, Department of Agrotechnology and Food Sciences, Wageningen University, Dreijenlaan 3, 6703 HA Wageningen, The Netherlands. Dane.Bicanic@wur.nl
Swarts
Jan
J
Luterotti
Svjetlana
S
Pietraperzia
Giangaetano
G
Dóka
Otto
O
de Rooij
Hans
H
D002138:Calibration; D002338:Carotenoids / Q000032:analysis*; D005504:Food Analysis / Q000379:methods*; D007834:Lasers; D000077276:Lycopene; D018551:Solanum lycopersicum / Q000737:chemistry*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013053:Spectrophotometry / Q000592:standards
D002338:Carotenoids; D000077276:Lycopene