The Effect of Fridge Storing, Cooking and Freezing on the Nitrate and Nitrite Contents of Spinach (Turkish with English Abstract)

Öz

The aim of this study was to determine the nitrite and nitrate content of spinach samples (n=24). Spinach samples were washed, either stored in refrigerator (aerobic and anaerobic condition), cooked (without water, with water or pre-boiling) or stored in freezer (18 °C, 6 months). The nitrite and nitrate content of spinach was measured by spectrophotometer. Results showed that a low amount of nitrate reduced after washing since nitrate is water soluble (P>0.05). Cooked without water increased the nitrate levels (P>0.05) whereas cooking in water reduced (P<0.05). Storing in refrigerator did not alter the nitrate levels significantly in both aerobic and anaerobic conditions (P>0.05). Both cooked without water (P>0.05) and cooking in water (P<0.05) reduced the nitrite levels. Nitrite levels decreased when spinach was stored in aerobic condition (P<0.05) and increased in anaerobic condition (P>0.05). There was no change in the amounts of nitrate and nitrite in vegetables during freeze storing.

Anahtar Kelimeler

• Spinach, nitrate, nitrite, storing, cooking, freezing

Ispanakta Buzdolabında Bekletme, Pişirme ve Dondurmanın Nitrat ve Nitrit İçeriğine Etkisi

Öz

Bu araştırma, Ankara toptancı halinde satışa sunulan ıspanaklara (n: 24) uygulanan farklı işlemlerin; yıkama, buzdolabında bekletme (açık ve kapalı ortamda), pişirme (susuz, suda ve ön haşlama) ve dondurarak depolamanın (-18 oC’de 6 ay depolama) nitrat ve nitrit içeriklerine etkisini belirlemek amacıyla yapılmıştır. Ispanakların nitrat ve nitrit değerleri spektrofotometrik yöntemle analiz edilmiştir. Araştırma sonucunda; nitrat suda çözünen bir bileşik olduğu için yıkama ile miktarının bir miktar azaldığı tespit edilmiştir (P>0.05). Susuz pişirme ile nitrat miktarı artmış (P>0.05), suda pişirme ile azalmıştır (P<0.05). Nitrit miktarları ise, susuz pişirme (P>0.05) ve suda pişirme ile azalmıştır (P<0.05). Buzdolabında açık ve kapalı ortamlarda bekletme ile kuru ağırlıktaki nitrat miktarları arasında önemli bir farklılık bulunmamıştır (P>0.05). Açık ortamda bekletilen ıspanakların nitrit içeriği azalmış (P<0.05), kapalı ortamda bekletilenlerde ise artmıştır (P>0.05). Dondurarak depolama süresince, sebzelerin nitrat ve nitrit içeriğinin değişmediği belirlenmiştir.

Anahtar Kelimeler

• Ispanak, nitrat, nitrit, bekletme, pişirme, dondurma

Kaynakça

1. Santamaria P, Elia A, Serio F, Todaro E. 1999. A survey of nitrate and oxalate content in fresh vegetables. J Sci Food Agr, 79:1882-1888.
2. Prasad S, Chetty AA. 2008. Nitrate-N determination in leafy vegetables, study of the effects of cooking and freezing. Food Chem, 106:772-780.
3. Schuster BE, Lee K. 1987. Nitrate and nitrite methods of analysis and levels in raw carrots, processed carrots and in selected vegetables and grain products. J Food Sci, 52 (6):1632-1636.
4. Chung JC, Chou SS, Hwang DF.2004. Changes in nitrate and nitrite content of four vegetables during storage and refrigerated and ambient temperatures. Food Addit Contam, 20(4):317-322.
5. Artık N, Poyrazo¤lu ES, fiimflek A, Kadakal Ç, Karkaçıer M. 2002. Enzimatik yöntemle bazı sebze ve meyvelerde nitrat düzeyinin belirlenmesi. GI- DA, 27(1):5-13.
6. Concon JM (ed). 1988. Food Toxicology, Principles and Concepts. Part A, Marcel Dekker INC, USA, 628-675p.
7. Mendicoa JC, Astiasaran I, Bello J. 1997. Nitrate and nitrite levels in fresh and frozen broccoli. Effect of freezing and cooking. Food Chem, 58(1-2):39-42.
8. WHO. 2003. Nitrate and nitrite – intake assessment. In: Safety evaluation of certain food additives (Food additives Series 50). Geneva www.inchem. org/documents/jecfa/jecmono/v50je07.htm (Accessed 10 May 2012)

9. US EPA. 2007. Nitrates and nitrites–Teach Chemical Summary. www.epa.gov/teach/ chem_summ/Nitrates_summary.pdf (Accessed 20 May 2012)
10. EFSA. 2008. Opinion of the scientific panel on contaminants in food chain on a request from the European Commission to perform a scientific risk assessment on nitrate in vegetables. EFSA Journal. 69: 1-79.
11. WHO. 1996. Nitrate. In: Safety evaluation of certain food additives (Food additives Series 35). Geneva. www.inchem.org/documents/jecfa/ jecmono/v35je14.htm (Accessed 30 May 2012)
12. Bednar CM, Kıes C, Carlson M. 1991. Nitrate –nitrite levels in commercially processed and home processed beets and spinach. J Agr Food Chem, 41:261-268.
13. Jaworska G. 2005. Nitrates, nitrites and oxalates in products of spinach and New Zealand spinach, effect of technological measures and storage time on the level of nitrates, nitrites, and oxalates in frozen and canned products of spinach and New Zealand spinach. Food Chem, 93:395-401.
14. Yurdagel Ü, Ural A, Pazır F. 1988. Ispana¤ın dondurulmaya uygunlu¤u ve donmufl depolanması üzerine arafltırma. EÜ Mühendislik Fakültesi Dergisi, 6(1):75-83.
15. Eichholzer M, Gutzwiller F. 1998. Dietary nitrates, nitrites and N-nitroso compounds and cancer risk: a review of the epidemiologic evidence. Nutr Rev, 56(4):95-105.
16. Pennington J. 1998. Dietary exposure models for nitrates and nitrites. Food Control, 9(6):385-395.
17. Sen NP, Donaldson B. 1978. Improved colorimetric method for determining nitrate and nitrite in foods. J Assoc Off Ana Chem, 61(6): 1389-1394.
18. ISO 1984. Fruits, vegetables and derived products. Determination of nitrite and nitrate content. Moleculer absorption spectrometric method. First edition, Ref. No. ISO 6635.
19. TSE 1988. Meyve, sebze ve mamulleri- nitrit ve nitrat tayini-moleküler absorpsiyon spektrometrik method. Birinci Baskı, TS 6183.
20. IDF 1984. Cheese: determination of nitrate and nitrite contents-method by cadmium reduction and photometry, 84 A.
21. AOAC. 1984. Official Methods of Analysis. 14thEdition, Association of Official Analytical Chemists INC, Virginia.
22. Siegel S.(ed). 1988. Non Parametric Statistics for the Behavioral Sciences. Second edition, Mc Graw-Hii, Ins, 399p.
23. Zengin M. 1997. Nitratın ıspanak bitkisinde birikimi ve topraktan yıkanması üzerine bazı azotlu gübrelerin etkileri. Selçuk Üniversitesi Fen Bilimleri Enstitüsü, Toprak ABD, Doktora Tezi, Konya, Türkiye.
24. Watson SW. 1974. Gram–negative chemolitrophic bacteria. Bergey's Manuel of Determinative Bacteriology, Gibbons NE and Buchanan RE (chief eds), 8th Edition, The Williams&Wilkins Company, Baltimore, pp.450-464.
25. Pelczar MJ (ed), Chan ECS, Krieg NK. 1986. The world of bacteria III: bacteria with unusual properties. Microbiology, 5thEdition, Mcgraw-Hill Book Company, Singopore, pp. 313-314.
26. Yang YJ. 1992. Effect of storage treatment on NO3and NO2contents in vegetables. J Korean Society for Horticultural Sciences, 33(2):125-130. 27. Phillips WEJ. 1968a. Changes in the nitrate and nitrite contents of fresh and processed spinach during storage. J Agric Food Chem, 16:88-91.
27. Heisler EG, Siciliano J, Krulick S and etal. 1974. Changes in nitrate and nitrite content and search for nitrosamines in storage-abused spinach and beets. J Agr Food Chem, 22 (6):1029-1032.
28. Minotti PL. 1978. Potential nitrate levels in edible plant parts. Nitrogen in the Environment Soil-Plant-Nitrogen Relationships. Donald RN and Macdonald JG (chief eds), Vol:2, Academic press, London, pp. 235-252.
29. Zhou ZY, Wang MH, Wang JS. 2000. Nitrate and nitrite contamination in vegetables in China. Food Rev Int, 16(1):61-76.
30. Ezeagu IE. 1995. Effect of wilting and processing on the nitrate and nitrite contents some Nigerian leaf vegetables. Nutr Health, 10:269-275.
31. Fletcher JR, Law SJ, Walters AH. 1987. Effect of cooking on the nitrate levels in vegetables. Nutr Health, 5 (1/2):53-60.
32. Leszczynska T, Filipiak-Florkiewicz A, Cieslik E, Sikora E, Pisulewski PM. 2009. Effects of some processing methods on nitrate and nitrite changes in cruciferous vegetables. J Food Composition and Analysis, 22:315–321.
33. Abo Bakr TM, El-Iraqui SM, Huissen MH. 1986. Nitrate and nitrite contents of some fresh and Processed Egyptian Vegetables, Food Chem, 19:265-275.
34. Aktafl N, Çakıro¤lu P, Günefl A. 1993. De¤iflik hazırlama ve piflirme yöntemlerinin ıspanak bitkisinin nitrat ve nitrit kapsamına etkisi. Beslenme ve Diyet Dergisi, 22 (1):59-68.
35. Gaiser M, Rathjen A, Spiess WEL.1996. Nitrate extraction during blanching of spinach. Lebensm -Wiss-Technol., 30:432-435.
36. Anon 2011. Türk Gıda Kodeksi, Bulaflanlar Yönetmeli¤i, Gıda Tarım ve Hayvancılık Bakanlı¤ı, 29 Aralık 2011 tarih ve 28157 sayılı Resmi Gazete, Ankara.
37. Murato M,Sugiyama S,Ueda A,Ishınaga M. 2010.Contents of nitrate and nitrite in menus containing more than 350 g of vegetables per day. Food Hygiene and Safety Science, 51 (1): 10-18.
38. Speijers GJA.1996. Toxicological evaulation of certain food additives and contaminants in food. The forty-fourth meeting of the joint FAO/WHO expert committee on Food Additives (JECFA), World Health Organization Series: 35, Geneva.