D.H. Kleyn

Protein estimation in sesame seed and rapeseed flours and meals by a modified udy dye binding method

The Udy standard dye binding method (shaker mixing) employing Acid Orange 12 was improved through a series of single-factor experiments designed to approximate the optimum combination of sample size, mixing period, particle size, drying conditions, shaker speed, and number of glass beads added for uniform mixing. The modified procedure yielded a higher recovery of protein and had high correlations with the Kjeldahl method, i.e., 0.991, 0.995, and 0.977 for sesame flour, rapeseed meal, and rapeseed flour, respectively. Mean values obtained by the Kjeldahl and modified dye binding methods from 12–17 analyses each on single lots of sesame flour, rapeseed meal, and rapeseed flour were 58.9% vs. 59.4% 36.1% vs. 36.0%, and 60.0% vs. 59.4%, respectively. A composite analysis of cereals, legumes, and oilseeds by the modified method had a high correlation (0.995) with Kjeldahl results.