Optimization of steam treatment conditions of sugarcane bagasse and date frond.

In this study, effect of auto-hydrolysis and acid-hydrolysis of sugarcane bagasse and date frond on DM loss, chemical composition (CF, NDF, ADF, ADL, hemicellulose, water soluble sugars, total extractable phenolics and total phenolics) enzymic hydrolysis, two stage in vitro digestion, in vitro gas production, ruminal degradability and accessible pore volume was investigated. Samples were impregnated with water or 1% sulfuric acid solution to contain 50 percent moisture, then were steam treated under 3 levels of pressure (14, 17 and 20 atm) and 3 levels of reaction time (120, 180 and 240s) in 3 replications. Data were analyzed on the basis of CRD statistical design (3x3) with factorial arrangement and means were tested using Duncan's test. Maximum DML in sugarcane bagasse and date frond was 6.54% and 8.20% respectively. Among the three factores (acid, pressure and reaction time) acid was more effective in DML for both, date frond and Sugarcane bagasse. Among cell wall components, hemicellulose was more succeptible to hydrolysis. Results showed that maximum hydrolysis of hemicellulose in sugarcane bagasse and date frond was 74.9% and 72.7% respectively. Hydrolysis of hemicellulose was more affected by pressure than the two other factors. Steam treatment of date frond significantly (p0.05) increased ADL content from 8.13% in control to 16.23 % after treatment. Steam treatment did not affect quantity of ADL in sugarcane bagasse. Water soluble sugars in sugarcane bagasse and date frond significantly (p0.05) increased from 1.51% (in control) to 31.91% and from 1.40% (in control) to 9.48% after acid hydrolysis. Bioavailability of both sugarcane and date frond to rumen microbes was significantly (p0.05) changed after treatment. In vitro digestibility of sugarcane bagasse increased from 24.15 to 47.87 after treatment. In vitro digestibility of date frond also increased from 24.51 to 33.78 after treatment. In vitro gas production of untreated sugarcane bagasse and date frond was 44.77ml and 20.57ml which after treatemnt increased up to 38.88ml and 64.92ml respectively. Rumen potential degradation of untreated sugarcane bagasse and date frond were 46.16% and 23.87% which after treatment significantly (p0.05) increased up to 78.15 and 38.06% respectively. The maximum accessible pore volumes in sugarcane and date frond observed in acid hydrolysed sample treated at (20atm, 240s). The accessible pore volumes for 8, 12, 51, 110 and 270 Ao probe molecules were as: 1.80, 1.47, 1.24, 0.91 and 0.33 ml/g. The values for accessible pore volumes of date frond treated at the same conditions were as: 1.85, 1.37, 1.07, 0.95 and 0.34 ml/g.