Multivariate Analysis of Asparagus Antioxidant Properties in Relation to Environmental Factors

Asparagus officinalis L. widely distributed in most climates in Iran. The aim of the present study is to use multivariate analysis to understand the relationships between environmental conditions and phytochemical composition of asparagus. For this purpose, plant samples were collected from nine different habitats in Iran, and phytochemical compounds and antioxidant activities were measured. Their relationship with environmental factors was analyzed using canonical correlation and stepwise regression. Based on the results, first to fourth canonical variables were significant according to Wilks' lambda test (P>0.01). The first canonical variable showed an increase in catalase activity in relation to an increase in mean environment temperature. By decreasing the mean, minimum and maximum temperatures in the second canonical variable, total phenol and DPPH increased and flavonoids decreased. According to the results of stepwise regression, EC, relative humidity and altitude justified the highest changes related to the antioxidant parameters. According to the results of both tests, average temperature, relative humidity and total rainfall have the greatest effect on the antioxidant properties of asparagus. In general, in order to maintain the antioxidant properties of asparagus, cultivation in areas with a total annual rainfall of 500 to 900 mm, an average temperature of 11.5 to 17.5°C and an average relative humidity of 50 to 70% is recommended.