Phytochemical Characterization of Twenty-Seven Peruvian Mashua (Tropaeolum tuberosum Ruíz & Pavón) Morphotypes and the Effect of Postharvest Methyl Jasmonate Application on the Accumulation of Antioxidants

Abstract

Tropaeolum tuberosum Ruíz and Pav. “Mashua” is a crop from the Andean region associated with preventing chronic degenerative diseases. This study evaluated the content of bioactive compounds (phenolics, glucosinolates, carotenoids, and ascorbic acid) in twenty-seven Peruvian mashua morphotypes. Furthermore, three morphotypes (MAC 067, MAC 092, and MAC 123) were selected to evaluate further the effect of methyl jasmonate (MeJA) on the accumulation of bioactive compounds. Phenolic content in the mashua morphotypes ranged from 2990.76 ± 273.5 mg/kg to 24,217.36 ± 1144 mg/kg; whereas carotenoids ranged from 12.8 ± 0.6 mg/kg to 85.8 ± 3.1 mg/kg. Moreover, total glucosinolate content ranged from 65 ± 11 mmol/kg to 1289 ± 65 mmol/kg. The different mashua morphotypes showed low levels of ascorbic acid (lower than 5 mg/kg) compared with other crops. Except for glucosinolates, MeJA application augmented the level of bioactive compounds, showing increases of up to 150.1%, 535.0%, and 542% for total phenolics, carotenoids, and ascorbic acid, respectively. Results indicated that mashua is an excellent source of phenolics and glucosinolates, whereas it contains adequate levels of carotenoids and low levels of vitamin C. MeJA application during postharvest represented a simple approach to increase the content of bioactive compounds in mashua.

Characterization of carotenoids, proximal analysis, phenolic compounds, anthocyanidins and antioxidant capacity of an underutilized tuber (Tropaeolum tuberosum) from Bolivia

“…The coloration of the different varieties of T. tuberosum ranging from yellow to purple and black, these were presumed to contain natural pigments such as anthocyanins and carotenoids. The presence of carotenoids in Isaño was con rmed by several spectrophotometric studies revealing carotenoid concentration between 1 to 25 µg g − 1 [21], 2.6 to 96.7 µg g − 1 [22], 12.8 to 85.8 µg g − 1 [23] and 70 to 132 µg g − 1 [24] expressed in β-carotene equivalents. In this study it was found that the cultivars studied present similar concentrations since they are between 57.3 to 144.0 µg ß-carotene/g.…”