PSI-11 Moisture Content Throughout the Pelleting Process and Subsequent Effects on Pellet Quality

Abstract

Abstract This experiment was designed to evaluate the effects of steam addition to the conditioner on moisture content throughout the pelleting process and subsequent effects on pellet quality. Treatments consisted of diets pelleted with no steam and steam added to achieve conditioning temperatures of 62.8 and 87.8°C. Conditioner retention time was set at 30 sec and diets were pelleted with a 6.4×63.5 mm pellet die. Pellet samples were collected and immediately placed in an experimental counter-flow cooler for 15 min. All treatments were replicated at 3 separate time points to provide 3 replicates per treatment. Mash (M), conditioned mash (CM), hot pellets (HP), and cooled pellet (CP) samples were collected for moisture content analysis and CP for pellet durability index (PDI). Data were analyzed with pelleting run as the experimental unit and time period as the blocking factor. Moisture samples were analyzed as a 3×4 factorial of steam-conditioning and sample location. There was a steam-conditioning×sample interaction (P< 0.01) for moisture. Mash samples for all treatments were similar (13.3%; 36.2°C). For the no steam treatment, there was no difference in moisture content for the M, CM, and HP; however, moisture decreased in CP, with samples having 13.4, 13.1, 12.9, and 12.0% moisture, respectively. For the 62.7°C treatment, there was an increase in moisture from M to CM, followed by a decrease in both HP and CP, with samples having 13.2, 15.3, 14.9, and 12.7% moisture, respectively. For the 87.8°C treatment, moisture increased from M to CM, and decreased in HP and CP with samples having 13.3, 17.3, 16.3, and 13.4% moisture, respectively. Increasing conditioning temperature from no steam to 87.8°C increased (P< 0.01) PDI from 3.3, 59.1, to 91.1%, respectively. In conclusion, increasing feed temperature from 36.2 to 87.8°C via steam addition increased condition mash moisture content by 4.2% resulting in improved pellet quality.