Nitrogen determination for rapid quality control of oilseed meals

The classic Kjeldahl procedure for determing protein (nitrogen) in oilseed meals is satisfactory but too time consuming for quality control in plants handling large amounts of meal. This paper describes attempts to decrease the time required for nitrogen analysis of safflower seed and meal using equipment available in the quality control feeds laboratory. A dye‐binding method on undigested proteins, digestion followed by colorimetric ammonium determination, digestion followed by distillation of ammonia, and several different digestion catalysts were tested. Digestion with the AOAC catalysts for 15 min and distillation of ammonia for 10–15 min for 90 ml of distillate followed by titration gave results on safflower meals in agreement with the AOAC method and is recommended for accelerated protein tests.