Effect of different durations of root area Chilling on the Nutritional quality of Spinach

Abstract

It has been proposed that cold acclimatization of the plant body enhances the nutritional value of leaf vegetables; however, little is known about the optimal duration of cooling required to enhance the quality of factory-processed vegetables. The ideal low temperature acclimatization period increases ascorbic acid and sugar content without increasing the nitrate ion concentration for a given root area. Here, we investigated the ascorbic acid and sugar contents in spinach with a given root area subject to chilling for different durations; 2, 4, 5, 6, and 7 days. Ascorbic acid and sugar content levels remained stable at the beginning of chilling; however, after 6 days, the levels of both parameters doubled compared to those in the control (no chilling). In comparison, nitrate ion concentration gradually decreased with increasing acclimatization period. Spinach plants acclimatized for 7 days showed similar results as those acclimatized for 6 days. Our results show that the optimal duration for root area chilling to produce high quality spinach is 6 days, when controlling the temperature of the nutrient solution under plant factory conditions.