Impact of cold storage followed by drying of mashua tuber (Tropaeolum tuberosum) on the glucosinolate content and their transformation products

Mashua (Tropaeolum tuberosum), an Andean crop used in traditional medicine, has become of interest due to its phytochemicals specifically glucosinolates (GLS). Little is known about the impacts of cold storage and drying processing operations on the GLS composition of mashua-derived products. This work evaluated the changes in GLS content and profile, derived from GLS biotransformation and myrosinase activity content, during controlled postharvest cold storage (12 °C and 80% RH) and after drying (60 °C and 1.8 m s⁻¹). The GLS content reached its maximum value after 10 days of postharvest cold storage. The derivatives detected were 4-Methoxybenzyl isothiocyanate, 4-methoxy Benzeneacetonitrile, 4-Methoxybenzyl alcohol methyl ether, Benzyl isothiocyanate and Benzeneacetaldehyde. The processing of tubers into flour resulted in significant GLS losses of 38%–87% compared with the respective cold storage treatment. Myrosinase activity showed no correlation with the content and type of GLS and low correlation with isothiocyanates and nitriles present. Our results revealed that drying conditions must be controlled to maintain GLS concentration in the final product.