Process Optimization and Energy Analysis of Vacuum Freeze Drying for Button Mushroom Agaricus bisporus

Abstract

newlineButton mushroom (Agaricus bisporus) is the most widely cultivated and consumed newlinemushroom in the world. This research was conducted to optimize the process, analyze the newlineenergy used and to estimate the cost incurred on vacuum freeze-dried button mushroom. newlineWhole mushroom without pressure (T0), whole mushrooms were taken without blanching newline(T1), segment before blanching (T2), segment after blanching (T3) for vacuum freeze-drying newlineat 4 different pressure viz 0.25, 0.35, 0.50 and 0.75 Torr. Vacuum freeze drying parameters newlinelike moisture content (Initial and Final), moisture ratio, drying rate, moisture sorption newlineisotherm were determined. Quality attributes of vacuum freeze-dried buttom mushroom like newlinebulk density, shrinkage, colour, rehydration ratio were calculted. Energy analysis at the 4 newlinedifferent pressures and overall cost was estimated for 4 different pressures. newlineIn all the 4 treatments (T0, T1, T2, and T3) of vacuum freeze-drying there was a newlinereduction in moisture content. The max reduction was 89.89 % in T2 at 0.25 Torr. T2 newlinesample had highest moisture ratio at 0.25 Torr. The drying rate of T2 was 1.0 to 0.01, at newline0.25 Torr. The Halsey Model predicted R2 newlinevalue of 0.9947 indicating moisture sorption newlinevalue at 0.25 Torr. In vacuum freeze-drying button mushroom, the quality parameters newlineindicated as bulk density had lowest value of 0.701 g/cm-2 newlinefor T2 at 0.25 Torr and highest newlinebulk density was 0.1568 g cm-2 newlinefor T1 at 0.75 Torr. The lowest shrinkage was 1.8% for T3 at newline0.75 Torr and highest 5.28 % for T1 at 0.25 Torr. Colour value showed 71.13 for T2 at 0.75 newlineTorr and highest value of 74.67 for T1 at 0.25 Torr. Rehydration ratio found was minimum newlineof 6.91 for T2 at 0.25 Torr and maximum for 2.33 for T1 at 0.75 Torr. newlineEnergy consumption during vacuum freeze-drying on working pressure 0.25 Torr newlinefor product and residence time of 60 min (3600s) was found to be 17.94 kW. Total heat newlinetransfer area was 19.26 m2 newline, overall heat transfer coefficient was 11.268 (w/m2 newline°c), for 0.35 newlineTorr for product was found to b