Autoclave‐Assisted Acidic Extraction of Water‐Soluble Carbohydrates in Forage Grasses

Abstract

Methods for extracting water‐soluble carbohydrates (WSC) in plants are often time‐consuming and limited to few samples per run. Aiming at resolving such restraints, the utilization of an autoclave in replacement of the traditional reflux‐based protocol was studied in completely randomized design experiments with five replicates. WSC contents were determined in stocks of 11 standards and samples of 14 grass species, following autoclave‐ or reflux‐assisted hydrolyzation. Results revealed that both methods were equally effective in recovering most standards, and plant WSC levels were similar or only narrowly lower with autoclave. Autoclave was operationally advantageous, allowing for 15‐min concurrent processing of 90 samples against a 150‐min extraction of 4 samples with reflux, and energy savings of more than 87% on a per sample basis. It is concluded that the utilization of autoclave for acidic WSC extraction is feasible and even preferable compared with reflux for the studied standards and grasses.

Keywords:

• Analytical method
• autoclave
• forage grasses
• reflux
• water‐soluble carbohydrates

Acknowledgments

Authors are grateful to Sebastião de Castro Evaristo and Rogério de Paiva Dias for their assistance in the laboratory. Frederico B. Sousa, Hernane S. Barud, and Ana Flávia C. Paiva are recipients of scholarships from Embrapa.