The effect of different methods of storage and chemical additives on total phenolic compounds and tannin of fresh pistachio residues.

Due to the adverse effects of phenolic compounds and tannins in ruminant rations and the importance of removing them, this study conducted with aim of survey on the effect of different methods of storage and chemical additives on total phenolic compounds and tannin of fresh Pistachio residues. Different processes included: oven drying (60 C), chopping followed by oven drying, oven drying with lime (2, 4& 6%), boiling in water for 10 to 60 minutes, soaking in water (12 to 48 h), soaking in lime water (12 to 48 h) and silage with 0, 2, 4 and 6% urea were used as 23 treatments in a completely randomized statistical design with 3 replicates for each one. The highest level of tannin (5.55%) observed follow by oven drying and was significantly (p0.0001) different from the others. The minimum tannin content (0.46%) obtained by drying with 6% lime and was significantly (p0.0001) different with all the other processes except soaking in lime water for 36 hours. Oven drying had resolted to the highest amount (13.92%) of phenolic compounds which was significantely different (p0.0001), compared to other treatments. The lowest amount (3.18%) of phenolic compounds observed followed by soaking in lime water for 36 hours and was significantly (p0.0001) different with all the others except different times of soaking in lime water. Chopping, water leaching and boiling in water didn t have any effect on tannin decrease but significantly decreased tannin (p0.0001) in comparison to only dryed group. Silage and dried with lime were similar and decreased more Tannin significantly (p0.0001) compared to other treatments. In total, drying with 6% lime leads to the best decrease of tannins (91.72%) and soaking in lime water for 36 hours was the best for phenolic compounds reduction. Key words: Pistachio residues, Tannin, phenolic compounds, Pistachio processing