Comparative study of protein pattern changes and mineral composition in cultivated and newly domesticated wild Flammulina velutipes

Abstract: A wild strain of Flammulina velutipes indigenous to Iran has been recently adapted for artificial cultivation, requiring nutritional information in order to improve its utilization as a medicinal-culinary mushroom. Thus, the current study aimed to evaluate protein profile of this domesticated wild F. velutipes strain over six different developmental stages, in comparison with a commercially cultivated strain of F. velutipes. Various macro- and microelements were also investigated in the mature sporomes cultivated in a lignocellulosic substrate composed of 40% wheat straw +40% sawdust +18% wheat bran +1% lime +1% gypsum. The lowest and highest amounts of protein were observed in primordia (33% of dry matter) and sporomes picked at the third or fifth day of harvesting (57% of dry matter), respectively (p ≤ 0.05), followed by an obvious decrease in protein content at the late stages of harvesting (p ≤ 0.05). Further SDS-PAGE analyses revealed that the protein molecular mass increased from less than 30 kDa in primordia to 235 kDa in mature sporomes. However, no significant difference in protein profiling was noticed between the wild and the reference strains of any given stage (p ≥ 0.05). While nutritional elements such as K, P and Mg were found at 886.9, 745.2, and 142.7 mg/100 g of dry weight, respectively, no heavy metals was found at levels higher than the provisional maximum tolerable intake in the sporomes. This study may be considered an initial step towards recognition of the wild F. velutipes as a nontoxic functional food, warranting further proteomics studies.

Key words: 
• Developmental stages /
• Nutritional elements /
• PAGE /
• Protein content /
• SDS /
• Wild mushrooms