Effects of microwave heating on the loss of vitamin B12 in foods
Effects of microwave heating on the loss of vitamin B12 in foods
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DOI：
10.1021/jf970670x
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发表时间：
1998-01-01
影响因子：
6.1
通讯作者：
Nakano, Y
中科院分区：
文献类型：
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作者：
Watanabe, F;Abe, K;Nakano, Y
为探讨微波加热对食品中维生素B-12损失的影响，对生牛肉、猪肉和牛奶进行微波加热处理，然后用含有猪内因子的化学发光法测定其维生素B-12的含量。在微波加热过程中，由于维生素B-12分子在微波加热过程中的降解，食物中的维生素B-12有相当程度的损失(约30-40%)。用微波加热处理食品中主要的羟基维生素B-12，然后用硅胶60薄层层析法分析，发现有两种维生素B-12的降解产物。对其中一种R-f为0.16的化合物进行了分离纯化和部分表征。该维生素B-12降解产物在需要维生素B-12的微生物Euglena gracilis Z的生长过程中没有显示任何生物活性，也不与哺乳动物维生素B-12结合蛋白HOG内在因子结合。给大鼠静脉注射该化合物(1 mg/d)7天，结果表明该化合物对哺乳动物无毒性，也不具有维生素B-12拮抗剂的作用。这些结果表明，在微波加热过程中，食物中发生了维生素B-12向非活性维生素B-12降解产物的转化。
To clarify the effects of microwave heating on the loss of vitamin B-12 in foods, raw beef, pork, and milk were treated by microwave heating and then their vitamin B-12 contents were determined according to a chemiluminescent vitamin B-12 assay with hog intrinsic factor. Appreciable loss (similar to 30-40%) of vitamin B-12 occurred in the foods during microwave heating due to the degradation of vitamin B-12 molecule by microwave heating. When hydroxo vitamin B-12, which predominates in foods, was treated by microwave heating and then analyzed by silica gel 60 thin layer chromatography, two vitamin B-12 degradation products were found. One of the compounds with a R-f of 0.16 was purified and partially characterized. The vitamin B-12 degradation product did not show any biological activity in the growth of a vitamin B-12 requiring microorganism, Euglena gracilis Z, and was not bound to hog intrinsic factor, a mammalian vitamin B-12 binding protein. Intravenous administration of the compound (1 mu g/day) for 7 days to rats showed that the compound neither has toxicity nor acts as a vitamin B-12 antagonist in mammals. These results indicate that the conversion of vitamin B-12 to the inactive vitamin B-12 degradation products occurs in foods during microwave heating.