Solid-state fermentation in cereal grains on chemical properties, gas and methane production in vitro

Abstract

Objective: To evaluate the effect of solid-state fermentation on the pro-duction of in vitro gas and methane and chemical propierties of cereal grains.
Design/methodology/approach: Corn and sorghum grains were fer-mented with Aspergillus oryzae for 5 days and oats and barley for 7 days. Neutral detergent fiber (NDF), acid detergent fiber (ADF), acid detergent lignin (ADL), flavonoids content, and in vitro gas production were deter-mined at 0, 3, 6, 9, 12, 24, 48, 72 y 96 and methane at 24 h.
Results: In general, solid-state fermentation (SSF) decreased NDF and increased flavonoid content in the grains. It also decreased methane pro-duction in sorghum grains after 5 days of fermentation. Regarding to gas production, SSF improved fermentation parameters by reducing lag time (A) and increasing gas production rate (k); apparently SSF reduced gas pro-duction due to the partial consumption of soluble carbohydrates during SSF.
Limitations on study/implications: These results were obtained under in vitro conditions. Therefore, they are not yet applicable to in vivo systems; however, these results may suggest an approach of the rumen metabolism using SSF in cereal grains for animal feeding to reduce methane production. 
Findings/conclusions: Solid- state fermentation improves the grain structure and allows for greater degradation of its components and lower methane production.