NITRATE AND NITRITE LEVELS OF SOME FRESH VEGETABLES IN EGYPT AND THE EFFECT OF PROCESSING ON THESE LEVELS | ||||
| Journal of Plant Production | ||||
| Article 20, Volume 27, Issue 10, October 2002, Page 6953-6960 PDF (2.38 MB) | ||||
| Document Type: Original Article | ||||
| DOI: 10.21608/jpp.2002.256556 | ||||
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| Author | ||||
| Zeinab K. EI-Awamry, | ||||
| Central Lab. For Food and Feed (CLFF) Agricultural Research Center, Giza, Egypt | ||||
| Abstract | ||||
| The present work is concerned with the determination of nitrate and nitrite levels in some fresh vegetables and follow the effect of cooking and freezing in order to decrease the content of nitrate and nitrite. Fresh vegetables were purshased from 3 governorates during 2000-2001 (cabbage, cauliflower ,carrot, spinach, squash, lettuce cucumber, green bean, tomato, peppers, parsely, mushroom and potatoes) and the nitrate and nitrite levels were determined. The results can be summarized as follow:- 1.The fresh vegetable samples (lettuce, spinach and cabbage) have higher nitrate level ranging (200-1100),(70-980) and (65-820) mg I Kg, respectively, whereas cauliflower, potatoes carrots and green bean have moderate nitrate level ranging(53-680), (53-590), (100-501) and (35-280) mg I Kg, respectively, while cucumber, mushroom, tomato, peppers and parsley have low nitrate level ranging (18-125), (6-32), (16-42), (8-25) and (35-79) mg I Kg, respectively. 2.The fresh vegetable samples (cauliflower, carrots and spinach) have high nitrite level ranging (0.0-30), (0.0-33) and (0.4-55) mg/Kg respectively, whereas cabbage, squash, lettuce, cucumber, green bean, parsely and mushroom have moderate nitrite level ranging (0.0-0.5), (0.0-0.7), (0.0-3),(0.0-0.5), (0.0-0.5), (0.0-0.7) and (0.0-0.2) mg/kg, respectively. While tomato and peppers have no nitrite level. 3.The cooking process reduced the nitrate level in vegetables. The reduction was found in cauliflower (86 - 90%), spinah (77 - 87%), carrots (66 - 81%), cabbage (60 - 78%) and green bean (58 - 71%). 4.Also, the cooking process reduced the nitrite level in vegetables. The reduction was found in cabbage (80 - 100%), cauliflower, carrots and spinach (90 - 100%) and green bean (87 -100%). 5.The nitrate and nitrite levels didn't change in case of cabbage and green bean during frozen storage for up to 5 weeks, then a trend toward decreased nitrate level and at the same time, an increase in nitrite level was observed from the nineth week to eleventh week, whereas, the nitrate and nitrite levels didn't change in case of cauliflower, carrot and spinach for up to 3 weeks then a trend toward decreased nitrate level and at the same time, an increase in nitrite level was observed from the fifth week to the eleventh week. So, the cooking process is important in order to decrease the nitrate and nitrite contents in vegetables, while it was found that the freezing process is related to the number of weeks, so it is recommended that the freezing process didn't exceed 3 weeks in case of cauliflower, carrot and spinach, and 5 weeks in case of cabbage and green bean due to the decrease in nitrate content followed by an increase in nitrite content after these periods of freezing. | ||||
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