Pressurized system and microwave-assisted extraction for rapid analysis of fiber in animal feedstuffs

A pressurized system under microwave radiation and filter bags to contain the samples was proposed as an alternative to Neutral Detergent Fiber (NDF) determination in animal feed. After optimization by a 2 3 factorial design, the procedure was applied to nine forage and cereal bran with different amounts of starch (supplied by proficiency testing at various nutrition laboratories). Recoveries from 93 to 110% (0.7 to 7.4 RSD) were obtained. The proposed system allows the NDF simultaneous extraction from 18 samples, increasing the samples throughput from 6 or 40 day(-1) to approximately 280 day(-1), with low consumption of energy and reagents, producing low amounts of residue.