Modelling, Phytochemical, Aroma and Antioxidant Capacity of Tamarillo Fruits Dried With Convective Oven Equipped With Programmable Logical Control (PLC) at Different Temperatures: A Comparative Study

Abstract

The tamarillo or tree tomato fruit (Solanum betaceum Cav.) is one of the most consumed fruits in the tropical countries. This fruit contains a numerous health benefits for human consumption. However, this fruit is perishable and its compositions are degraded under different heat conditions. Therefore, this study is sought to evaluate the mathematical modeling of dehydration and rehydration kinetics, antioxidant properties, and aroma profiles of the tamarillo fruits dried using convective oven dryer equiped with Programmable Logical Control (PLC) at 40, 50, 60, 70, 80, and 90 degrees C with an air velocity of 1.5 m/s. The obtained drying curves were processed to find the most suitable mathematical modeling among the different moisture rate expressions. Total phenolic, total anthocyanins, total flavonoids, vitamin C, Ferric Reducing Antioxidant Power (FRAP), and 2,2-diphenyl-1-picrylhydrazyl (DPPH) were analysed.; The phenolic compounds profile and anthocyanins compounds profiles were identified using High Performance Liquid Chromatography (HPLC), while the aroma profile was analysed using gas chromatography-MS. Page, Newton and Logistic models precisely were used to describe the dehydration methodology at all mentioned temperatures whereas the coefficient of determination(R-2) was 0.99. On the other side, the Weibull and Peleg models precisely were used to describe the rehydration modeling of the used drying methods with the coefficient of determination (R-2) of 0.99. The tamarillo fruits dried at 90 degrees C had the highest amount of total phenolic contents, especially epicatechin which was a predominant phenolic compound (3.388 +/- 0.009 mg/g). Hexanoic acid ethyl ester and eucalyptolwere among the most abundant aroma compounds found in the tamarillo fruits after dryingat the overal result of this study found the the mild temperature drying (40-50 degrees C) to be the best temperature which may preserve the most antioxidants and physical properties of tamarillo fruits.