Quality of dried Pleurotus eryngii as affected by pretreatments andmethods of drying

Abstract

Fruit bodies of Pleurotus eryngii were sliced and pretreated by blanching (100˚C), steeping in different concentrations of KMS (500 ppm, 1000 ppm and 1500 ppm) and citric acid (500 ppm, 1000 ppm and 1500 ppm) at room temperature. Pretreated and control samples were dried in cabinet tray dryer, solar dryer and in open sun drying until constant weight was gained. The dried products were ascertained in many respects upto three months of storage. Solar dried and cabinet dried P. eryngii samples gave better color when treated with citric acid as compared to sun dried samples. The P. eryngii samples dried in open sun showed maximum rehydration ratio when pretreated with 500 ppm citric acid and 500 ppm KMS i.e. 6.55 and 6.5 respectively. Maximum hardness (97.65 N) was observed in blanched mushroom samples when dried in cabinet tray dryer. Scanning electron micrographs of solar dried King oyster mushroom showed the more porosity. In blanched King oyster mushrooms, poor rehydration ratio (1.77–2.96), maximum hardness (97.65 N), minimum whiteness (L-values ranged between 35–55) and minimum bacterial count (upto 430 CFU/gram) was observed. Maximum protein content i.e. 25.68 g/100g in the first month of storage was found in the sun-dried mushrooms when 500 ppm KMS was used for pretreatment. Maximum value of carbohydrate content was observed in sun dried and solar dried samples when treated with KMS (500 ppm) i.e. 44.74 and 44.64 g/100g respectively.