Induced accumulation of individual carotenoids and quality changes in tomato fruits treated with pulsed electric fields and stored at different post-treatments temperatures

Abstract

Pulsed electric fields (PEF) have been proposed to elicit an increase in the content of health-related compounds in plant-based products. It has been previously demonstrated that PEF treatments may be applied to significantly increase the content and bioaccessibility of carotenoids in tomatoes. Nevertheless, the metabolic response of tomato is known to be greatly affected by postharvest storage conditions, which have a determinant impact on the quality characteristics of the product. The effects of PEF processing and post-treatment storage temperature on both carotenoid profile and the main physicochemical properties of tomato fruits were evaluated. Different specific energy inputs (0.02 kJ kg-1 and 0.38 kJ kg-1) and storage temperatures (4, 12 and 20 ºC) were studied. The application of PEF treatments significantly improved the accumulation of carotenoids in tomato fruits. Nevertheless, the concentration of total and individual carotenoids during storage was differently influenced by the storage temperature depending on the applied PEF treatment. The increased concentration of carotenoids was noticeably higher in tomatoes stored at 12 ºC than in those fruits stored at 4 or 20 ºC. The mildest PEF treatment (0.02 kJ kg-1) promoted the greatest accumulations of total carotenoids (58 %) and lycopene (150 %) in tomatoes stored during 5 d at 12 ºC without compromising the fresh-like quality of tomato fruits. However, the most intense PEF treatment (0.38 kJ kg-1) triggered a fast accumulation of carotenoids, leading to the greatest increase of β-carotene (77 %), γ-carotene (200 %) and lutein (238 %) concentration in tomatoes stored at 12 ºC for 1 d. Nonetheless, irreversible damage was caused to tomato tissues, thus leading to deleterious quality effects. The results obtained provide valuable information for the future application of PEF in the development of tomato derivative products with increased health-related properties.

This research has been funded by the Ministerio de Economía y Competitividad (Spain) reference AGL2013-44851-R. S.G.C. thanks the Agència de Gestió d'Ajuts Universitaris i de Recerca (AGAUR) for the predoctoral grant.