Effect of storage temperature on physicochemical properties of dried black jelly (Auricularia polytricha) and grey oyster (Pleurotus ostreatus) mushrooms
摘要
This study investigates the impact of storage temperatures (4 °C and 25 °C) on the physicochemical properties of dried black jelly, BJM (Auricularia polytricha) and grey oyster, GOM (Pleurotus ostreatus) mushrooms over a 28-day period with 7 days interval. The samples were dried using cabinet dryer at 60 °C for 24 h. Then, dried mushrooms were packed in a polypropylene zip-lock bags for 28 days and stored at two different temperatures, 4 °C (chiller) and 25 °C (room temperature). The O-H stretching were found in both mushrooms, where at BJM the broad peak was found at 3269.18 cm− 1 (fresh) and 3399.55 cm− 1 (dried) while for GOM at 3253.30 cm− 1 (fresh) and 3348.20 cm− 1 (dried). Protein availability reflected by the peaks at 1546.61 cm− 1 and 1453.25 cm− 1, which linked to N-H bending vibrations. The hardness for BJM significantly higher on Day 28 (2412.92 g) compared to 1114.26 g on Day 0 at 4 °C. GOM also resulted in reduced texture after Day 28 when kept at 4 °C (3616.55 g) compared to 4687.25 g at Day 0. For dried BJM kept at 4 °C, L* value was significantly higher at day 28 (49.50) compared to day 0 (44.47). Similarly, when kept at 25 °C, L* value was significantly higher at day 28 (48.07) compared to day 0 (44.47). BJM stored at both temperatures had significantly lower moisture content at day 0 compared to other storage days. BJM stored at 25 °C contained significantly higher water activity (day 28, 0.40) compared to day 0 (0.28). After 28 days, BJM stored at 4 °C indicated significantly lower gallic acid (3.87 mg/ml) compared to day 0 (62.57 mg/ml). Similarly, GOM stored at 25 °C showed significantly lower gallic acid (69.6 mg/ml) compared to day 0 (1050.91 mg/ml). These findings are important for mushroom growers and food industrialists as understanding optimal storage conditions for mushroom are critical in postharvest aspect.