Determination of Chemical composition and Gas Production Parameters of Raisin By-Product

The objective of this study was to determine nutritive value and phenolic contents in raisin by-product. The samples were obtained from four factories in Malayer (i. e.، treatments 1، 2، 3 and 4). The amount of DM، OM، ether extract، CP، NDF، ADF، lignin، ash، total phenolics (TP)، total tannin (TT)، condensed tannin (CT) and protein precipitable phenolics (PPP) were measured. The effect of polyethylene glycol (PEG) inclusion on the gas production and related parameters were also determined using the exponential equation of Y = A (1 − e−ct) by measurement of gas production at 0، 2، 4، 8، 24، 36، 48، 72، 96، 120 and 144 h after incubation. The data were analyzed using completely randomized design. The amounts of NDF، ADF، lignin and ash in treatment 2 were higher than the others. The amount of TP and TT were significantly influenced in all treatments (P<0. 05). There were no difference between treatment in terms of CT and PPP. The type of raisin by-product had a significant effect on gas production، rate of gas production، organic matter digestibility and metabolizable energy (P<0. 05). Adding PEG led to an increase in gas production and related parameters (e. g.، metabolizable energy and organic matter digestibility) in all treatments. This increment illustrates that detanification of raisin byproducts can partly improve their nutritive value.