title: Optothermistor as a breakthrough in the quantification of lycopene content of thermally processed tomato-based foods: verification versus absorption spectrophotometry and high-performance liquid chromatography.
abstract: This study reports on the first use of the "optothermistor" as a novel, precise, fast, and low-cost detector of lycopene in a wide range of commercially available processed-tomato products. The quantitative performance of the new device was evaluated by comparing data obtained to that acquired by conventional methods, namely, absorption spectrophotometry and high-performance liquid chromatography (HPLC); the linear correlation was high (R = 0.98). The variation of data obtained with the optothermistor in a series of consecutive measurements performed with the same loading of the sample was better than 1%. However, the repeatability (RSD 0.5-9.0%, n = 3-5) achieved with the optothermistor by independent analyses (multiple loading) is comparable to that of HPLC and spectrophotometry. Results of the studies performed on the 19 products derived from tomatoes demonstrated that the optothermistor is suitable for selective, accurate, precise, and simple determination of lycopene (range = 7-75 mg/100 g of product weight) without the need for a sample pretreatment step. The estimated sensitivity of the present optothermistor is 2 mg of lycopene/100 g of product.
authors.affiliation: Laser Laboratory for Photothermal Science, Biophysics Division, Agrotechnology and Food Sciences, Wageningen University, Dreijenlaan 3, Transitorium, 6703 HA Wageningen, The Netherlands. dane.bicanic@wur.nl
authors.forename: Dane
authors.initials: D
authors.lastname: Bicanic
authors.forename: Jan
authors.initials: J
authors.lastname: Swarts
authors.forename: Svjetlana
authors.initials: S
authors.lastname: Luterotti
authors.forename: Per
authors.initials: P
authors.lastname: Helander
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Fogliano
authors.forename: Monica
authors.initials: M
authors.lastname: Anese
mesh_terms: D002338:Carotenoids / Q000032:analysis*; D002851:Chromatography, High Pressure Liquid; D005504:Food Analysis / Q000379:methods*; D005511:Food Handling / Q000379:methods*; D006358:Hot Temperature; D000077276:Lycopene; D018551:Solanum lycopersicum / Q000737:chemistry*; D012680:Sensitivity and Specificity; D013053:Spectrophotometry
chemical_list: D002338:Carotenoids; D000077276:Lycopene