Effects of boiling and microwaving treatments on nutritional characteristics and antioxidant activities of Agaricus blazei Murril

Abstract

The effects of boiling and microwaving on nutritional compositions, antioxidant components and antioxidant activities of fresh and frozen A. blazei Murril (AbM) were evaluated and compared. The results showed that the contents of crude protein, ash, total soluble protein, total soluble sugar, vitamin C, and total phenolics decreased by both cooking treatments, but no significant changes were observed in lipids. Amino acid composition analysis showed that the ratio of total essential amino acids to total amino acids increased, and the ratio of total non-essential amino acids to total amino acids thus decreased by both cooking treatments. Boiling and microwaving significantly decreased the contents of glucose, galactose and mannose, and the effect of boiling was higher than that of microwaving. Furthermore, boiling and microwaving significantly decreased the DPPH-scavenging activity and reducing power of AbM. Analysis of the relations between the antioxidant activities and total phenolic concentrations testified that the cooking treatments not only decreased the total phenolic contents, but also changed the types and relative amounts of phenolic compounds of AbM.

Effects of thermal processing on nutritional characteristics and non-volatile flavor components from Tricholoma lobayense

“…However, the effect of microwaving on total soluble protein was significantly higher than that of boiling. Our study were in good agreement with the results Sun et al (2011), which suggested that heat treatment could significantly reduced the total sugars and proteins contents in Agaricus blazei Murril. It could be explained that some soluble sugars and proteins in FBTL were diffused from tissue to peripheral water.…”

“…Total soluble protein and sugar were extracted and analyzed as Sun et al with some modifications (Sun et al, 2011). Samples (100 mg) were polished, homogenized after adding 5 mL PBS (50 mM, pH 7.8), then were centrifuged at 10,000 rpm at 4ºC for 15 min.…”

Efeito da extração de compostos fenólicos sobre a atividade antioxidante e antibacteriana in vitro de cogumelo-do-sol

“…Foi encontrado valor de 2,55 mg de fenólicos totais/g de extrato de cogumelo-do-sol utilizando solvente metanol 50% com tempo de extração de 24 horas à temperatura ambiente (Sun et al, 2011), enquanto, com o solvente metanol 70% no mesmo tempo de extração (24 horas) à temperatura ambiente, foram achados valores de 0,83 a 42,21 mg de fenólicos totais/g de extrato para diferentes cogumelos comestíveis (Pleurotus porrigens, Hygrocybe conica, Xerula furfuracea, Schizophyllum commune, Polyporus tenuiculus e Pleurotus florida), representando oscilação bastante acentuada, conforme cada tipo de cogumelo avaliado (Wong;Chye, 2009).…”

“…Dessa forma, tendo em vista essa temperatura de extração, o valor mais baixo do IC 50 foi para o tempo de 60 min (15,80 mg mL -1 ). Nessas condições a atividade antioxidante aumentou com a elevação da temperatura de extração de 50º para 70ºC, diferindo de outros trabalhos, em que o tratamento térmico reduziu a quantidade de fenólicos totais, bem como alterou os tipos e a quantidade relativa desses compostos (Sun et al, 2011). Entretanto, esta pesquisa corrobora com resultados de outros estudos, que determinaram a temperatura de 70ºC como o limite máximo a ser empregado no processo extrativo para evitar a degradação, a polimerização e a oxidação de compostos fenólicos, fatores que resultariam na redução destes (Peixoto Sobrinho et al, 2010).…”

“…Quanto ao acúmulo desses compostos, o conteúdo de fenólicos totais e atividade antioxidante foram estimados e comparados em fases jovens e maduras de corpos de frutificação de AbM, não obtendo-se diferença entre elas (Soares et al, 2009). Por outro lado, a composição nutricional e os componentes antioxidantes do AbM, incluindo os fenólicos totais, podem diminuir quando submetidos a tratamentos térmicos (Sun et al, 2011).…”