effect of gamma irradiation and chemical process on gas production parameters of some agricultural by-products in in vitro

the aim of this study was investigating the effect of gamma irradiation and naoh treatment of some agricultural by products (tomato pulp, orange pulp, pistachio hull and wheat straw) on fermentation parameters and gas production test. treatments of gamma irradiation (50, 100 and 200 kgy) and %5 naoh was done on each source of by products. the results showed that gamma irradiation at the dose of 200 kgy numerically and %5 naoh increased (p<0.05) cumulative gas production of wheat straw and tomato pomace. there was no effect of treatments on cumulative gas volume of pistachio hull. in orange pulps highest gas volume observed in 200 kgy gamma irradiation treatment. gamma irradiation at the dose of 200 kgy and %5 naoh increased fermentable fraction (b) and rate (c) of gas production in wheat straw (p<0.05). fraction of c and b in tomato pomace, pistachio hull and orange pulp increased by irradiation at 200 kgy and %5 naoh treating orange pulp resulted in lower b fraction compared to control and other treatments. in conclusion in the samples with lower level of cellulose and hemicelluloses, gamma irradiating can be effective in increasing the fermentation potential in in vitro condition.