Agriculture and Horticulture

Biography

Biography: Fhatuwani N Mudau

Abstract

Baby spinach is normally harvested during a fairly early stage of the normal spinach, usually between 30 and 45 days after planting. Several studies have shown that concentration of nutrients in spinach may vary owing to a combination of factors. In addition, harvest date/stage after a specific planting date may also play a decisive role in the spinach content as well as postharvest shelf life. Thus, the aim of this work was to investigate the effect of growth harvest stage on the quality and postharvest storage of baby spinach. Seeds were sown on 3 different occasions, and in each set of occasion, the harvest was performed at 3 growth stages at 7 days intervals. The middle stage was corresponded with the period commonly used for baby spinach by commercial farmers. Throughout the study, when spinach leaves are harvested, they were exposed to 4°C, 10°C and 20°C for 12 days. The first stage, which refers to spinach leaves harvested after 28 days of planting have shown the highest level of antioxidant activity and flavonoid contents during harvest. Thus, the level of antioxidants during harvest was 0.65 mg.g-1 at 4°C, 10°C and 20°C and postharvest (0.43 mg.g-1, 0.35 mg.g-1 and 0.20 mg.g-1 at 4°C, 10°C and 20°C for 12 days, respectively). It was then followed by stage II with 0.29 mg.g-1, 0.23 mg.g-1, and 0.17 mg.g-1 at 4°C, 10°C and 20°C for 12 days, respectively. The least levels of antioxidant activity was observed in the stage III, where spinach leaves were stored at 10°C and 20°C with the value of 0.10 mg.g-1 and 0.02 mg.g-1, respectively. Flavonoids showed similar trend, since highest content of flavonoids was observed in stage I (12 mg.g-1) and II (9.30 mg.g-1) at 4°C for 12 days. Whereas, the lowest flavonoid contents were yielded in stage III, particularly in samples stored at 20°C with 3.56 mg.g-1 for 12 days. However, the level of antioxidants and flavonoids was well maintained at 4°C in all 3 treatments compared to 10°C and 20°C. The study findings suggest that harvesting baby spinach a few days earlier than the commercial timing of harvest may influence the most retain of antioxidant activity and flavonoid contents when stored at 4°C.