茚三酮法测定蜂蜜及果葡糖浆中的氨基酸含量

Determination of Amino Acid in Honey and High Fructose Corn Syrup (HFCS) by the Method of Ninhydrin Colorization

蜂蜜是以葡萄糖和果糖为主要成分的天然保健品。果葡糖浆具有和蜂蜜相似的糖类成分,依据糖含量及感官指标很难区别蜂蜜和果葡糖浆。本文根据蜂蜜及果葡糖浆中的氨基酸含量差异,采用茚三酮显色法检测5种蜂蜜、13种果葡糖浆及蜂蜜与果葡糖浆混合物的氨基酸含量,建立快速评价蜂蜜品质的新方法。测定结果表明,茚三酮法测定氨基酸含量具有良好的线性(R2=0.9992),准确性(回收率96.3%～101.1%)和重复性(标准偏差0.8%～5.8%)。5种蜂蜜中氨基酸含量均高于200μg/g,而13种果葡糖浆中氨基酸的含量介于10.1～47.8μg/g之间;蜂蜜和果葡糖浆混合物中氨基酸含量随果葡糖浆掺入量的增加而线性减少,这说明可通过茚三酮法检测蜂蜜中的氨基酸含量,实现蜂蜜品质的快速评价。

Honey is a popular nature food having health-care benefits, and HPCS has similar carbohydrates composition to honey, bringing difficulties to differentiate them according the major constitution of carbohydrate and sensitive evaluation. Honey has amino acid content different from HPCS, which suggests a potential index for evaluation of honey. Ninhydrin colorization method was applied to determine the amino acid in five honey and 13 HFCS samples, and subsequently a new and simple method for monitoring the quality of honey was develop. The results indicated that the ninhydrin method had good linearity（R^2=0.992）, accuracy （recovery 96.3%-101.1%） and repeatability （relative standard deviation 0.8%-5.8% ） for analysis amino acid using glutamie acid as the standard. Amino acid contents of the five honey samples were all above 200 ~g/g. However, amino acid contents of the 13 HFCSs were within 10.1-47.8 μg/g. The con- centrations of amino acid in the mixtures of honey and HFCS showed good negative linearity to the percentages of HFCS. This result indicates ninhydrin colonization method is an effective approach to monitoring the quality of honey by distin- guishing the amino acid quantities of honey and HFCS.