Abstract:

Soybean ingredients adulterated in milk powder was firstly determined by real-time Fluorescent PCR in our study using lectin, the endogenous gene of soy-bean as a reference gene. This method provided a quick and precise way for the detection of adulteration of milk powder and also presented new insights for the market supervision and administration. After respective removal of fat and protein in milk powder with hexane and tris-balanced phenol, a high-quality DNA template was obtained using Promega Wizard genomic DNA purification kit. The experimental results indicated that the sensitivity of detecting soybean ingredients adulterated in milk powder was highly improved by using real-time fluorescent PCR method, and the PCR amplification curve and cycle numbers remained corresponding relationship with adulteration amounts of soybean ingredients in milk powder. This method can provide a rapid and accurate way for detection and analysis of the adulteration of milk powder, which can be used as a new evidence for market supervision and administration.

Key words: milk powder, real-time fluorescent PCR, plant protein ingredients, DNA extraction and purification