Production of mycosporine-like amino acid (MAA)-loaded emulsions as chemical barriers to control sunscald in fruits and vegetables

BACKGROUND: Sunscald is a physiological disorder that occurs in many horticultural products when exposed to excessive solar radiation and high temperatures. Traditionally, sunscald is controlled using physical barriers that reflect radiation, however this practice is not always efficient. A possible alternative would be the use of chemical barriers, such as mycosporine-like amino acids (MAAs), which protect aquatic organisms against ultraviolet (UV) radiation. Thus, this study aimed to develop a lipid-based emulsion containing MAAs for using in the preharvest of horticultural products. RESULTS: Emulsions were developed using 10% (w/v) of corn oil (CO) and soybean oil (SO), carnauba wax (CW), and beeswax (BW) as lipid bases (LBs). The emulsion containing CW and ammonium hydroxide was the most stable, resembling commercial wax. Therefore, this formulation was used as the basis for the incorporation of the commercial product Helioguard (TM) 365, a source of MAA, in concentrations of 0%, 1%, 2%, and 4% (v/v). The MAA incorporation resulted in little modifications in the stability of the emulsion, providing an increase in the absorbance with peaks in the UV-B ranging from 280 to 300 nm. CONCLUSION: The lipid-base emulsion containing MAAs could be used as a chemical barrier to control sunscald in horticultural products. (C) 2021 Society of Chemical Industry.

Automated summary

A lipid-based emulsion containing mycosporine-like amino acids (MAAs) was developed for preharvest treatment of horticultural products to control sunscald. Incorporation of MAAs resulted in increased absorbance in the UV-B range, while providing good stability for the emulsion formulation.