Effect of Nitrogen Fertilization on the Quality of Swiss Chard at Harvest and during Storage as Minimally Processed Produce

The effects of different levels of nitrogen fertilization (0-50-100-150-200 kg ha-1), minimal processing and cold storage (14 days at 4°C) on yield and quality of fresh-cut Swiss Chard (Beta vulgaris L. var. cicla L.) were evaluated. Increasing the level of nitrogen fertilization over 100 kg N ha-1, plants had a higher fresh weight, reduced their dry matter content and resulted taller and leafier. Total and marketable yield increased linearly as increasing nitrogen level. Both nitrate and ascorbic acid content at harvest increased as increasing nitrogen supply. Nitrogen fertilization negatively affected the yield of minimal processing. No effect on appearance and quality loss during cold storage was detected. Reducing nitrogen fertilization could lead to a more environmentally friendly product with no significant loss in yield and quality both for raw plant and fresh-cut Swiss chard. Minimal processing can improve nutritional quality lowering nitrates and increasing ascorbic acid content in fresh-cut produce.