Effects of Refrigeration and Freezing on Nitrate, Nitrite, and Oxalate Levels in Green Beans and Peas..

This study investigates the effect of the blanching, refrigeration, and freezing on nitrate, nitrite, and oxalate levels in green beans and peas. Besides, the impact of these preservation methods on the nutritional and safety aspects of these vegetables was studied. The data revealed that the refrigeration significantly impacts nitrate levels in both green beans and peas, potentially due to biochemical and metabolic processes. Furthermore, there was a notable decrease in nitrate content from 2121.17 mg.kg-1 to 1371.74 mg.kg-1 in green beans after blanching and six months of freezing storage. This reduction in nitrate levels is attributed to both blanching and freezing storage, potentially influenced by enzymatic activities and chemical reactions. The study also observed a decline in oxalate levels, suggesting that blanching and freezing storage contribute to reduced oxalate content, likely influenced by enzymatic and chemical reactions. These findings align with previous research indicating significant reductions in nitrates, nitrites, and oxalates due to blanching, particularly for leafy vegetables, reinforcing the observed trends during freezing storage. In essence, the cold storage, blanching, and freezing processes led to reduced levels of nitrate, nitrite, and oxalates in green beans and peas.