Effect of Cultivar, Growth, and Environmental Factors on Lutein Content in Spinach (Spinacia oleracea) for Processing

Abstract

Lutein is an antioxidant with potential health benefits and is accumulated in spinach. However, little is known about the factors causing variations in the lutein content in spinach for processing. Thus, the effects of seasonal/cultivar variations, seedling thinning, and environmental conditions on lutein contents were investigated. The lutein content rose with increasing cultivation days, despite cultivation seasons. However, the lutein content interacted between cultivation days and cultivars in winter cultivation. A lower leaf water content under low temperatures may also enhance the lutein content. In addition, although plant growth, such as leaf/plant weight, was two-fold higher in thinning than in non-thinning plants, the lutein content was not affected by thinning. Furthermore, positive and negative interactions between environmental conditions and lutein contents were observed. The regression models between the lutein content and plant height/weight could be divided into two linear regressions according to plant development, such as whether the plant had started to bolt at harvest. Therefore, these results suggest the involvement of a decrease in the lutein content by flower bud differentiation/development. We conclude that the lutein content in spinach for processing is affected by cultivars, environmental conditions, and the developmental stage of the plant, such as flower bud differentiation.