Evaluation of protein extraction methods to obtain protein concentrate from cassava leaf

Abstract

ABSTRACT:The cassava leaf, waste generated in the harvest of the roots, is characterized by high content of protein, vitamins and minerals; however, its use is limited due to the high fiber content and antinutritional substances, which can be removed by obtaining protein concentrates. In this context, the objective of this study was to evaluate protein extraction processes, aiming the use of cassava leaves (Manihot esculenta Crantz) as an alternative protein. Four methods were tested: 1) Coagulation of Proteins by Lowering the Temperature, 2) Extraction by Isoelectric Precipitation, 3) Solubilization of Proteins and 4) Fermentation of Filter Leaf Juice. To obtain the concentrates, the use of fresh or dried leaves and extraction in one or two steps were also evaluated. The solubilization of proteins (method 3) showed a higher extraction yield; however, with concentrate of low quality. The fermentation of the juice (method 4) produced concentrates with higher quality and lower costs and the isoelectric precipitation (method 2) promoted the obtention of concentrates in less time, both with good prospects for use. The use of two extraction steps was not advantageous to the process and there was no difference between the use of fresh or dried leaf, and the use of fresh leaves is presented as a good option for the simplicity of the method.KEYWORDS: exploitation, agricultural waste, protein extraction. AVALIAÇÃO DE MÉTODOS DE EXTRAÇÃO DE PROTEÍNAS PARA OBTENÇÃO DE CONCENTRADO PROTÉICO DE FOLHAS DE MANDIOCARESUMO: A folha de mandioca, resíduo gerado na colheita das raízes, caracteriza-se pelo alto teor de proteínas, vitaminas e minerais, no entanto sua utilização é reduzida devido ao alto teor de fibras e substâncias antinutricionais que podem ser removidas durante obtenção de concentrados proteicos. Neste contexto, o objetivo do presente trabalho foi avaliar processos de extração de proteínas, visando ao aproveitamento das folhas de mandioca (Manihot esculenta Crantz) como alternativa proteica. Quatro métodos foram testados: 1) Coagulação de Proteínas por Abaixamento da Temperatura; 2) Extração por Precipitação Isoelétrica; 3) Solubilização das Proteínas; 4) Fermentação do Suco de Folhas Filtrado. Para a obtenção dos concentrados, avaliaram-se também a utilização de folhas frescas ou secas e a extração em uma ou duas etapas. A solubilização das proteínas (método 3) apresentou maior rendimento de extração, no entanto com concentrado de baixa qualidade. A fermentação do suco (método 4) produziu concentrados com mais qualidade e menores custos, e a precipitação isoelétrica (método 2) promoveu a obtenção de concentrados em menor tempo, sendo ambos com boas perspectivas de utilização. A utilização de duas etapas de extração não foi vantajosa ao processo e não houve diferença entre a utilização de folha seca ou fresca, sendo que a utilização de folhas frescas se apresenta como boa opção pela simplicidade do método. PALAVRAS-CHAVE:aproveitamento, resíduo agrícola, extração de proteínas.

Identification of the Active Principle Conferring Anti-Inflammatory and Antinociceptive Properties in Bamboo Plant

“…Dialysis processes were maintained at 4 • C for 48 h under slow agitation and periodic changes of distilled H 2 O, always in a proportion of 1/200 H 2 O. The two fractions obtained by this process (internal dialysate molecules >3.5 kDa and external dialysate molecules <3.5 kDa) were lyophilized and then subjected to biological evaluation of anti-inflammatory action by neutrophil migration [56].…”

Comparison of amino acid and chemical composition of jackfruit seed flour treatment

“…The process of extracting protein from plants basically consists of an extraction step and precipitation of proteins which can be obtained by thermocoagulation (temperature action), autocoagulation (fermentation), flocculation, ultrafiltration and extraction with organic solvents (Coldebella et al, 2013). However, germination treatment has no effect in protein content compared to raw jackfruit seed flour.…”

Sugar beet leaves for functional ingredients

“…Similar results were observed with cassava leaves. Additional processing of the fibrous residue did not increase the protein yield (Coldebella et al, 2013 For this study, the total protein content was determined from total nitrogen values, while the amount of solubilised protein was determined by a spectrophotometric method. The difference between these values was assumed to be the green (insoluble) protein content; a similar approach was used by Teixeira et al with Kjeldahl and Lowry methods (2014).…”

“…The juicing step needs to be fast to prevent protein losses (Barbeau & Kinsella, 1988) or the fibre-rich portions of the plant (e.g. stems, petioles) have to be left out of the process (Coldebella et al, 2013;. Finally, small crystal-like structures were observed using polarised light (Figure 2.…”

“…Leaf protein extraction involves three major steps: tissue disruption by mechanical treatments, protein precipitation by one or more heat and/or pH treatments and protein concentration (Coldebella et al, 2013;Merodio & Sabater, 1988). For instance, rubisco purification from soluble leaf concentrate often combines different methods such as heat precipitation at 80 -82°C, pH precipitation, flocculation and organic solvent precipitation (Barbeau & Kinsella, 1983, 1988Martin et al, 2014;Van de Velde et al, 2011).…”