Functional and Antioxidant Evaluation of Two Ecotypes of Control and Grafted Tree Tomato (Solanum betaceum) at Different Altitudes

Abstract

Tree tomato (Solanum betaceum) is susceptible to nematode attack; for this reason, grafting is used as an alternative to reduce this impact. In this study, the bioactive compounds of the fruit (shell, pulp, and seed jelly) of two tree tomato ecotypes (‘giant orange’ and ‘giant purple’) were evaluated in both control and grafted plants grown at different altitudes (2010–2250, 2260–2500, 2510–2750 and 2760–3000 masl). Commercial quality, vitamin C, organic acids, phenolics, carotenoids and antioxidant activity were determined by microextraction and quantified by liquid chromatography (RRLC) or spectrophotometry (microplate reader). The results showed high concentrations of vitamin C, organic acids and antioxidant activity in the seed jelly, organic acids in the pulp and phenolic compounds, carotenoids, and antioxidant activity in the shell. The main phenolics were ferulic acid, caffeic acid and luteolin, while the main carotenoids were lutein, B-cryptoxanthin and B-carotene. Multivariate analysis showed that tree tomato quality was mainly influenced by altitude and fruit part and that grafting positively affected soluble solids for both ecotypes and all altitudes.

Evaluation of Bioactive Compounds and Antioxidant Activity in 51 Minor Tropical Fruits of Ecuador

“…For the second portion, the edible part of the fruits was removed, cut into small pieces, and placed in plastic tubes to be frozen at −80 • C before freeze-drying using a Christ Alpha 1-4 LDplus (GmbH, Osterode am Harz, Germany). The freeze-dried sample was hermetically sealed in amber glass jars under a nitrogen atmosphere and stored at −21 • C until analysed for bioactive compounds and antioxidant activity [2].…”

“…The liquid portion was measured for pH using a SevenMultiTM S47 pH meter (Mettler Toledo, Greifensee, Switzerland) [28], and the soluble solids were determined using a handheld refractometer (Boeco, Germany). In the whole pulp, total titratable acid was determined by titration [29], while moisture and ash were determined by gravimetry using a Be20 oven with air circulation (Memmert GmbH Co.KG, Schwabach, Germany) at 70 °C and a Thermolvne muffle (Thermo Fisher Scientific, Waltham, MA, USA) at 550 °C [2]. In whole fruit, fruit weight was accurately recorded using a Mettler Toledo ML204T/00 balance (Mettler Toledo, Greifensee, Switzerland), while the size was assessed using a Titan 23175 digital calliper (Titan, Kent, WA, USA) [27].…”

“…A calibration curve was used with a 1 mg/mL solution of L-(+)-ascorbic acid standard, constructed with different injection volumes (3,5,10,15, and 20 µL) for quantification. Vitamin C was expressed as milligrams per 100 g of dry matter (mg/100 g DM) [2].…”

“…The carotenoids were quantified according to the protocol of Coyago [2] with some modifications. A 3 × 2 experimental design was used to select the extraction solvent, considering different solvents (hexane: acetone (1:1), methanol: acetone: dichloromethane (1:1:2) and methanol: trichloromethane: water (1:2:1)) and ultrasonic extraction times (1, 2 and 3 min).…”

“…In the regions where they are produced, under-consumed tropical fruits play a crucial role in food and nutrition security and are a source of income for local producers. They account for about 75% of the total income of small rural households [1][2][3].…”