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.

Quantitative analysis, in vitro assessment of bioavailability and antioxidant activity of food carotenoids—A review

“…The prediction quality of Raman was poorer and NIRS had the worst prediction potential (Baranska et al, 2006). Bicanic et al (2005) proposed the use of an ''optothermistor'' as an accurate, fast and low-cost detector of lycopene in a wide range of commercial processed tomato products. The data obtained with the new device correlated with those obtained by absorption spectrophotometry and HPLC.…”

Estimation of daily intake of lycopene, antioxidant contents and activities from tomatoes, watermelons, and their processed products in Korea

“…The lycopene content of the samples was measured according to Bicanic's method with some modifications [19,20]. For each 1.0 g of samples, a small amount of deionized water and methanol was added, and the mixture was vortexed after placing Celite powder (No.…”

On the photoacoustic, photothermal and colorimetric quantification of carotenoids and other phytonutrients in some foods: a review

“…The performance of this inexpensive detection concept, was evaluated by comparing optothermistor data obtained from nineteen products (lycopene concentration ranging from 7 to 75 mg/100 g of product weight) to that determined by SP and HPLC [21]. The linear correlation was high (R = 0.98) and the repeatability (RSD 0.5-9.0%, n = 3-5) achieved by independent analyses (multiple loading) was comparable to that characteristic for SP and HPLC.…”