本篇研究之目的在利用傳統的三明治型酵素連結免疫吸附分析法(Sandwich enzymelinked immunosorbent assay)分析及觀察在生、鮮乳中免疫球蛋白濃度及量上的差異性,以探討此蛋白的濃度可否作為牛奶品質的一個指標。 在之前的預實驗,利用SDS-polyacrylamide gel electrophoresis電泳分析經不同濃度硫酸銨劃分所得到的生、鮮乳蛋白質成份的差異,發現其中的免疫球蛋白G (immunoglobulin G)的色帶顏色差異相當大。由東海大學牛乳加工廠所取得的生乳經單離純化得到均一純度免疫球蛋白,由兔子免疫後所製得具有單一特異性(mono-specific)的抗血清,應用三明治型酵素連結免疫吸附分析法追蹤生、乳鮮中免疫球蛋白含量的變化。 生乳中的濃度為140.73±16.99 μg/ml,在市售鮮乳濃度的變化在0.16±0.017μg/ml至0.28±0.04μ/ml,此現象可能是因為牛奶會隨著加熱、加工過程所造成的差異。
In addition to analysis of the immunoglobulin concentration in milk by traditional sandwich enzyme-linked immunosorbent assay methods, we have further observed the difference of the immunoglobulin concentration between the raw and fresh milk. Protein of untreated raw milk, provided by the milk plant of Tunghai University, and commercial fresh milks were separated by ammonium sulfate precipitation. The variances of proteins between raw and fresh milk were compared by using SDS-polyacrylamide electrophoresis. The results showed by comparing the bands that there was a difference in immunoglobulin G between the raw and the fresh milk. The bovine immunoglobulin G of the raw milk was further isolated and purified. A mono- specific antiserum was prepared. The technology of sandwich ELISA was conducted to analyze and observe the difference of immunoglobulin concentrations between raw and fresh milk. Raw milk contained 140.73±l6.99μg/ml and that varied from 0.l6±0.017μg/ml to 0.28±0.04μg/ml in fresh milk. The content of immunoglobulins might be one of the indicators to evaluate heat treatment of milks.