LAUSR

Ascorbic acid (1% w/w) and calcium lactate (1% w/w) were vacuum impregnated into mushrooms to improve their physicochemical quality. Experiments were carried out using central composite design under response surface methodology with four independent variables, viz., solution temperature (ST) (35-55°C), salt concentration (SC) (4-12%), vacuum pressure (VP) (50-170 mbar), and immersion time (IT) (30-90 min) with constant solution to sample ratio (4 : 1). The ascorbic acid content of mushroom increased with vacuum pressure with a maximum content of 30.68 mg/100 g. The results also suggested that calcium lactate allowed a better maintenance of texture during storage. The optimum conditions obtained for vacuum impregnation (VI) were 41°C, 10%, 140 mbar, and 75 min of solution temperature, salt concentration, vacuum pressure, and immersion time, respectively. Under these conditions, the corresponding responses were 22.14%, 2.31%, 28.74 mg/100 g, 0.28%, 4.61, 9.85 N, and 5.37 of water loss, solute gain, ascorbic acid, titratable acidity, colour change, texture, and pH, respectively. The vacuum impregnated mushrooms had more firmness, soluble solids, and ascorbic acid content than the control group. Therefore, the result suggested that vacuum impregnation could be used as an effective and simple technique to improve the quality of mushroom.