FOOD SCIENCE ›› 2017, Vol. 38 ›› Issue (20): 83-89.doi: 10.7506/spkx1002-6630-201720012

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Nutritional Characteristics and Protein Composition of Fruiting Bodies of Boletus griseus

BAO Changjun, CHANG Weidan, ZHUANG Yongliang, SUN Liping   

  1. (Yunnan Institute of Food Safety, Kunming University of Science and Technology, Kunming 650500, China)
  • Online:2017-10-25 Published:2017-09-29

Abstract: The proximate composition, monosaccharide composition, fatty acid and amino acid compositions, and mineral contents of the fruiting bodies of Boletus griseus were detected and the protein composition of the mushroom was evaluated by successive extraction. Besides, the nutritional value of proteins of the mushroom was also assessed systematically. Results showed that the crude protein content in the mushroom was 28.22% and the glucose content was 258.04 mg/g. A total of 17 fatty acids were detected, with linoleic acid, oleic acid and palmitic acid accounting for 35.91%, 28.46% and 24.50% of the total fatty acids, respectively. A total of 29 free amino acids were detected, among which, Tyr and Ala showed the highest contents. Sweet amino acids and umami amino acids accounted for 23.37% and 12.69% of the total free amino acids, respectively. The amino acid score (AAS), essential amino acid index (EAAI), biological value (BV), nutritional index (NI) and score of ratio coefficient of amino acid (SRCAA) of essential amino acids in the protein hydrolysate of Boletus griseus, which accounted for 38% of the total amino acids, were 71.88, 69.93, 64.52, 19.73 and 50.05, respectively. B. griseus contained high levels of Mg, Fe, Zn, and Cu. Meanwhile, the toxic element Cd was also at a relatively high level. Furthermore, albumin was the most prominent protein in the mushroom, accounting for 65.62% of the crude protein, but the content of Cd in albumin accounted for 38.79% of total Cd. The molecular masses (mw) of albumin and globulin in Boletus griseus were identified by SDS-PAGE to be around 40 kD. Differential scanning calorimetry (DSC) results showed the thermal denaturation temperatures of the two proteins were 125.04 and 75.04 ℃, respectively. In conclusion, the results indicated that B. griseus showed high nutritional quality, but its consumption could pose considerable health risk due to the high content of Cd.

Key words: Boletus griseus, amino acid composition, nutritional value assessment, Cd, thermal denaturation temperature

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