Compositional Changes in Spinach (Spinacia oleracea L.) Grown in the Summer and in the Fall

Abstract

Changes in carotenoid, ascorbic acid, reducing sugar, chlorophyll, nitrate, and soluble and insoluble oxalic acid contents in the leaf blade, petiole, and the edible portion of developing spinach plants were determined. The summer and fall cultivars studied were 'Magic' and 'Lead', respecitvely. In this summary, the chlorophyll content is expressed as mg/100 cm² of leaf area. The data for the remaining constituents are for the edible portion based on 100 g fresh wt.
1. Beta-carotene, the only carotene detectable, for 'Magic' and 'Lead' were 4, 450 and 7, 340 μg, respectively.
2. The total ascorbic acid contents which gradually decreased with time in 'Magic' and 'Lead' were 42 and 71 mg, respectively.
3. The reducing sugar content in 'Magic' decreased with leaf age, whereas that of 'Lead' increased. At harvest, the reducing sugar content in 'Lead' was 1.12 g ; that of 'Magic' was 0.07 g.
4. Chlorophyll content in 'Magic' remained nearly constant at 3.2 mg, whereas that of 'Lead' increased slightly from 3.8 to 4.1 mg by harvest. A positive correlation exists between chlorophyll and β-carotene contents.
5. Nitrate contents of 'Magic' and 'Lead' were 2, 500 and 2, 400 ppm, respectively.
6. Soluble oxalic acid contents at harvest for 'Magic' and 'Lead' were 740 and 560 mg, respectively. The ratio of the soluble to total oxalic acid was 0.871 in 'Magic' and 0.800 in 'Lead'.