Quantification of Lycopene, β-Carotene, and Total Soluble Solids in Intact Red-Flesh Watermelon (Citrullus lanatus) Using On-Line Near-Infrared Spectroscopy

Abstract

A great interest has recently been focused on lycopene and β-carotene, because of their antioxidant action in the organism. Red-flesh watermelon is one of the main sources of lycopene as the most abundant carotenoid. The use of near-infrared spectroscopy (NIRS) in post-harvesting has permitted us to rapidly quantify lycopene, β-carotene, and total soluble solids (TSS) on single intact fruits. Watermelons, harvested in 2013–2015, were submitted to near-infrared (NIR) radiation while being transported along a conveyor belt system, stationary and in movement, and at different positions on the belt. Eight hundred spectra from 100 samples were collected as calibration set in the 900–1700 nm interval. Calibration models were performed using partial least squares (PLS) regression on pre-treated spectra (derivatives and SNV) in the ranges 2.65–151.75 mg/kg (lycopene), 0.19–9.39 mg/kg (β-carotene), and 5.3%–13.7% (TSS). External validation was carried out with 35 new samples and on 35 spectra. The PLS models for intact watermelon could predict lycopene with R2 = 0.877 and SECV = 15.68 mg/kg, β-carotene with R2 = 0.822 and SECV = 0.81 mg/kg, and TSS with R2 = 0.836 and SECV = 0.8%. External validation has confirmed predictive ability with R2 = 0.805 and RMSEP = 16.19 mg/kg for lycopene, R2 = 0.737 and RMSEP = 0.96 mg/kg for β-carotene, and R2 = 0.707 and RMSEP = 1.4% for TSS. The results allow for the market valorization of fruits.

Monitoring strategies for quality control of agricultural products using visible and near-infrared spectroscopy: A review

“…In the case of in-line applications the situation is similar: the predominant acquisition modes are reflectance, used in all in-line applications with olives (Salguero-Chaparro et al, 2012, and the transmittance mode in the case of pears (Xu et al, 2012;Sun et al, 2016). Examples of both acquisition modes were found in in-line applications with watermelon (Jie et al, 2014;Tamburini et al, 2017) and apple (McGlone et al, 2005;Shenderey et al, 2010;Ignat et al, 2014), but nectarines were the only example found that employed the interactance mode (Golic & Walsh, 2006).…”

“…The spectra were pre-treated using baseline offset correction (BOC). Recently, Tamburini et al (2017) developed an NIR in-line system to determine lycopene, β-carotene, and total soluble solids content in red-flesh watermelons in the selected wavelength range from to 1,700 nm in reflectance mode. Watermelons were transported along a conveyor belt system at different speeds (2,100, 2,400 and 2,700 rpm).…”

Application of Visible to Near-Infrared Spectroscopy for Non-Destructive Assessment of Quality Parameters of Fruit

“…Moreover, they preserve the sample fruit that would be wasted if destructive methods were used. In postharvest storage, visible and near-infrared spectroscopy (Vis-NIRS) can be applied in various forms where fruit would be passed under a radiation chamber and be analysed for physical, chemical and organoleptic properties whilst rolling on sorting belts [8]. The Vis-NIRS holds many advantages over destructive or contact techniques.…”

Effects of a Watermelon Extract Beverage on Canine Lipid Metabolism and Urine Crystals

“…The remaining components is a rich source of bioavailable compounds, including lycopene, vitamins A and C, and the amino acid L-citrulline. Lycopene has been shown to exhibit anti-tumor, anti-inflammatory and anti-obesity effects and L-citrulline is known to have diuretic effects [7,8].…”