RESUMO
ABSTRACT: Response surface methodology was used to determine optimum conditions for extraction of protein from pumpkin seed meal. A central composite rotational design (CCRD) including independent variables such, pH and sodium trimetaphosphate (STMP) content was used. Maximum yield was obtained at a central point of CCRD, with STMP content and pH of 4% and 4.5, respectively. These conditions resulted in protein yield of 50.04 g of soluble protein from extract/100 g pumpkin seed. The optimization of pH and STMP content allowed obtaining a product with a high protein concentration (62.56 g 100 g-1), digestibility (62.03 g 100 g-1) and concentration of essential amino acids (27.26 g 100 g-1). Regarding the polyphenols concentration, phosphorylated protein concentrate from pumpkin seed and the pumpkin seed meal presented 13.11 g 100 g-1 and 23.19 g 100 g-1, respectively. The adequacy of the model was confirmed by extracting the protein under optimum values. These results help in designing the process of optimal protein extraction from pumpkin seeds.
RESUMO: A metodologia de superfície resposta foi utilizada para determinar condições ideais para a extração de proteína da farinha de semente de abóbora. Foi utilizado um delineamento composto central rotacional (DCCR), incluindo vários níveis independentes, tais como pH e trimetafosfato de sódio (TMPS). O rendimento máximo foi obtido em um ponto central de DCCR, com conteúdo de TMPS e pH de 4% e 4,5, respectivamente. Essas condições resultaram em rendimento proteico de 50,04 g de proteína solúvel no extrato/100 g de semente de abóbora. A otimização de pH e conteúdo de TMS permitiu a obtenção de um produto com alta concentração de proteína (62,56 g 100 g-1), digestibilidade proteica (62,03 g 100 g-1) e concentração de aminoácidos essenciais (27,26 g 100 g-1). Em relação à concentração de polifenois, o concentrado proteico fosforilado de semente de abóbora e a farinha de semente de abóbora apresentaram 13,11 g 100 g-1 e 23,19 g 100 g-1, respectivamente. A adequação do modelo foi confirmada pela extração da proteína sobvalores ótimos. Estes resultados auxiliam na concepção do processo de extração ótimo da proteína de semente de abóbora.
RESUMO
An 8-week feeding trial was conducted to evaluate the effect of replacing fish meal with pumpkin seed meal (PSM) or phosphorylated protein concentrate of pumpkin seed meal (PPCPS) on growth and metabolic responses of silver catfish. Five isonitrogenous and isocaloric diets were formulated. Control diet contained fish meal as the main protein source. The treatment groups contained 25 and 50% of either PSM or PPCPS protein replaced the fishmeal protein. A total of 400 silver catfish, with initial mean weight of 24 ± 0.46 g, were distributed into 20 tanks. For data four orthogonal contrasts were applied: control diet versus PSM diets; control diets versus PPCPS diets; control versus other diets; PSM diets versus PPCPS diets. The results indicated that the fish fed PSM diets had lower weight gain when compared to either control diet or PPCPS. The PPCPS do not affect growth and protein efficiency ratio. Lower albumin contents were found for the control diet fish for the contrasts control diet versus PPCPS diet and control diet versus other diets. The hepatic ALAT enzyme activity was higher in the fish fed the control diet (P < 0.05). The hepatic ALP was most active in fish that received the PPCPS diets, when comparing control diet versus PPCPS diets and control diet versus other diets. The hepatosomatic index was higher for fish fed the PPCPS. Our results indicated that PPCPS presents relevant nutritional quality for fish and can replace the fish meal protein up to 50% without affecting growth, PER and intermediate metabolites in silver catfish.