Hot air–assisted radio frequency hybrid technology for inactivating lipase in pearl millet
Srinivas Yarrakula, Gopinath Mummaleti, Akash Pare, Vincent Hema, S. Shanmugasundaram
Abstract
Nutricereal utilization is untapped due to its rapid rancidity by lipolytic hydrolysis of triglycerides during and after milling of grains. The synergistic effect of hot air–assisted radio frequency (HARF) was evaluated on enzyme inactivation by treating pearl millet grains at different processing parameters (10.50 ± 0.50, 12, and 15% moisture levels and 5, 10, 15, 20, and 25 min exposure periods) with 180 mm electrode position. HARF (10 kW, 40.68 MHz ± 0.5%) significantly (p < .05) lowered the lipase activity with the increase of HARF exposure time (up to 15 min) for different moisture levels and the maximum lipase inactivation (97.30%) was achieved at 15% moisturized sample processed for 15 min. Based on lipase inactivation and pasting properties, 15 min of exposure period with 5.2 ℃/min heating rate at 15% moisture was identified as optimum condition to obtain maximum reduction (97.3%) of lipase activity with better quality characteristic retention. Novelty impact statement Rapid off flavors and bitterness development due to hydrolytic rancidity in the pearl millet flour and its products has been the bane of huge postharvest losses. This study revealed that hot air–assisted radio frequency technology can be used as an effective lipase inactivation technique with better quality characteristic retention for commercial application in food industry. No chemical residues are also deliberated to be a significant assistance by this approach.