NITRATE AND NITRITE CONTENTS AND POSTHARVEST QUALITY OF CHOY SUM (BRASSICA RAPA CHINENSIS GROUP) DURING STORAGE
Nitrates and nitrites are notorious as food preservatives. Nitrates are relatively non-toxic. However, nitrates can convert to nitrites exogenously and endogenously which are harmful to human health. Leafy vegetables as a major source of dietary nitrates can accumulate high level of nitrate when excessive nitrogen is the input during production. Prolonged storage of leafy vegetables may lead to conversion of nitrates to nitrites. Hence, the objectives of this study were to assess nitrate and nitrite contents, weight loss, firmness, titratable acidity and ascorbic acid content of organic and conventional choy sum. Choy sum were obtained from Zenxin Agri-Organic Food (KL) Sdn. Bhd and Selangor Wholesale Market. Choy sum were cleaned, packed in perforated PE bags and stored in a domestic refrigerator at 5±1°C for 9 days. The results showed that storage duration did not affect nitrate and nitrite contents of choy sum. The weight loss was significant during storage. Organic choy sum decreased in firmness while conventional choy sum decreased in titratable acidity during storage. Ascorbic acid content of organic choy sum was not affected by storage duration. It was reasonably safe to store fresh and clean choy sum in refrigerator up to 9 days. However, postharvest quality was affected during storage, particularly the weight and firmness. Wilted choy sum decreases in palatability. Hence, choy sum should be consumed as soon as possible after purchasing.
Chung, W.Q., Ahmad, S.H., Zamri, M.Z. and Rosenani, A.B. (2013). NITRATE AND NITRITE CONTENTS AND POSTHARVEST QUALITY OF CHOY SUM (BRASSICA RAPA CHINENSIS GROUP) DURING STORAGE. Acta Hortic. 1012, 315-320
organic choy sum, prolonged storage, perforated PE bags, domestic refrigerator, ascorbic acid