This paper examined the growth and yield performance of Lentinus citrinus on cupuaçu exocarp (Theobroma grandiflorum) mixed with litter (CE + LI) or rice bran (Oryza sativa) (CE + RB) in the ratio of 2:1 (800 g:200 g) to investigate the nutritional composition and proteolytic potential of the fruiting body produced. Significance values of yield were determined on substrate combinations. In CE + LI the biological efficiency of the mushrooms was 93.5% and the content of fat (4.5%), fiber (11.0%), protein (27.0%) and amino acids were higher when compared with CE + RB. Among the amino acids, the amount of glutamic acid, aspartic acid, alanine, arginine and leucine was high. The biological efficiency on CE + RB reduced to 84.2% and based on the nutritional value, carbohydrates (53.59%), energy (324.33 kcal) and minerals such as zinc, iron, copper, potassium and phosphorus were higher in this substrate combination. Protease activity from fruiting body was significant in CE + LI (463.55 U/mL). This protease showed an optimal activity at 50 °C in neutral and alkaline pH with maximum stability at 30 °C at alkaline pH. This is the first report of L. citrinus fruiting body nutritional composition with potential for human food and application in industrial processes.
Summary Six strains of Aspergillus flavo furcatis were screened to investigate milk‐clotting enzyme production by fermentation in natural liquid medium. The growth media comprised extracts of cupuaçu exocarp+rice bran [10% or 20% (v/v) CE+RB] and açai waste+rice bran [10% or 20% (v/v) AW+RB] with or without supplementation of 0.1% (w/v) yeast extract and 0.5% (w/v) gelatin. Significant values of milk‐clotting activity were determined by A. flavo furcatis DPUA 1461 and DPUA 1608, in the standard and natural media, respectively. According to criteria of clot and whey formations, 8.3% of the samples tested were classified as strong coagulation, 41.70% showed weak coagulation and in 50% was not observed milk coagulation. The enzyme optimal action of DPUA 1608, the selected strain, was at 40 °C and pH 7.0. Milk‐clotting proteases were inhibited by pepstatin (94.72%) and moderately inhibited by the others metal ions tested.
Researches have been done to discover new sources of microbial proteases with milk-clotting activity to replace the traditional rennet from calves. The aim of this study was to select a species of edible mushroom as milk-clotting enzymes producer using the submerged fermentation technology. From the six species evaluated, Pleurotus albidus was the one that expressed the highest value of coagulant ratio (21.60). The milk-clotting enzymes showed maximum activity at 60°C and pH 6.0. Iodoacetic acid presented the highest inhibition in proteolytic activity suggesting the presence of cysteine proteases in the crude extract from P. albidus. The enzymes did not present toxic action against human fibroblasts (MRC5) in the analyzed conditions and, for that reason, can be suitable to applications in food industry. This is the first report of milk-clotting enzymes production by the edible mushroom P. albidus
ResumoNo congelamento de polpas de frutas a atividade enzimática não é completamente cessada. Podem ocorrer mudanças sensoriais, nutricionais e de coloração devido à ação de enzimas oxidativas, como a peroxidase e a polifenoloxidase. Considerando que as polpas de cupuaçu congeladas, comercializadas no Brasil, têm um prazo de validade de um ano e tornam-se escurecidas ao longo deste período, objetivou-se neste estudo avaliar o efeito do tempo de congelamento nas características físico-químicas e nas atividades da polifenoloxidase e peroxidases solúvel e insolúvel presentes nas polpas de quatro novos genótipos de cupuaçu, durante doze meses. Os frutos dos genótipos de cupuaçu, desenvolvidos pela Embrapa Amazônia Ocidental, foram despolpados, congelados e armazenados à temperatura de -30 ºC. A polifenoloxidase das polpas dos quatro genótipos apresentou aumento na sua atividade com picos no sexto, nono e décimo mês e as peroxidases apresentaram oscilações na atividade enzimática. As propriedades físico-químicas das polpas apresentaram variações durante os doze meses de armazenamento sob congelamento. O teor de vitamina C dos genótipos D 28-10 e P 3-10 diminuiu a partir do 4º e 10º mês, respectivamente. Por outro lado os genótipos B 28-7 e P 9-8 permaneceram estáveis. Em relação à acidez em ácido cítrico, as amostras B-28-7, D 28-10 e P 9-8 não diferiram, havendo redução no genótipo P 3-10. O valores de pH e sólidos solúveis totais de todos os genótipos diminuíram ao longo do período avaliado. Houve aumento na concentração de açúcares das polpas dos genótipos B 28-7, P 3-10 e P 9-8, com exceção da amostra D 28-10 que permaneceu inalterada. Todos os genótipos apresentaram-se dentro dos padrões físico-químicos exigidos pela legislação, com exceção do genótipo P 3-10 que apresentou acidez inferior. Em relação aos parâmetros enzimáticos, houve variações na atividade das peroxidases e polifenoloxidases de todos os genótipos avaliados. Palavras-chave: Theobroma grandiflorum, escurecimento enzimático, frutos amazônicos AbstractDuring the freezing of fruits pulps, the enzyme activity is not finished completely. Sensory, nutritional and coloring changes may occur on fruits due to the action of oxidative enzymes such as peroxidase and polyphenoloxidase. The frozen cupuaçu pulps, sold in Brazil, have a shelf life of one year and become browned during this period. The aim of this study was to evaluate the effect of frozen storage on the physicochemical characteristics, polyphenoloxidase activity and soluble and ionically bound peroxidases presented in the pulps of four new cupuaçu genotypes over twelve months. The cupuaçu 1 Discente de pós-graduação, Universidade Federal do Amazonas, UFAM, Manaus, AM.
As proteases constituem um grupo de enzimas que apresentam elevada aplicabilidade em diversos setores industriais, sendo obtidas de fontes animais, vegetais e microbianas. Entre os fungos, os cogumelos têm se destacado como fonte de proteases com potencial biotecnológico. O objetivo deste trabalho foi investigar a produção de proteases por cogumelos, utilizando a fermentação em meio líquido. A cultura matriz foi preparada em ágar batata dextrose, acrescida de extrato de levedura 0,5% (p/v), e o bioprocesso foi conduzido durante cinco dias, a 150 rpm e 25 °C. Azocaseína 1% (p/v) foi utilizada como substrato para avaliar a atividade proteolítica dos cogumelos. Entre as espécies avaliadas, Pleurotus albidus (Berk.) Pegler 1983 foi a produtora significativa de proteases (34,00 U/mL) e a síntese dessas enzimas foi estimulada pela idade e pelo volume do inóculo. Essas enzimas mostraram atividade ótima em pH 5 a 60 °C e estabilidade em pH 5-8, com temperaturas de 30 a 60 °C. As proteases foram classificadas como cisteíno e serinoproteases.
Bioassays under laboratory conditions aiming to determine the larvicidal activity of Bacillus sphaericus were carried out on Anopheles darlingi and Culex quinquefasciatus. In order to estimate the toxicity through median lethal concentration (LC50) and the relative potency of the strains to B. sphaericus standard strain 2362, probit analysis was performed utilizing the POLO-PC program. The findings of LC50 pointed out high effectiveness on strains IB15 (0.040 ppm), IB19 and S1116 (0.048 ppm), IB16 (0.052 ppm) and S265 (0.057 ppm). Strain IB15 presented nearly 50% more potency than strain 2362 in bioassays conducted on A. darlingi. It was observed that IB16 and S1116 strains were the most powerful against C. quinquefasciatus, showing to be about 300-400% stronger than 2362 strain. The results show that laboratory conditioned evaluation can be an important way to select promising bacteria with entomopathogenic action on biolarvicides production for use on mosquitoes breeding sites.
Modo de acesso: World Wide Web Inclui bibliografia 1. Tecnologia de Alimentos 2. Alimentos 3. Nutrição I. Título CDD-664.005 O conteúdo dos artigos e seus dados em sua forma correção e confiabilidade são de responsabilidade exclusiva dos seus respectivos autores.
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