Preparation and characterization of rice protein isolates

Abstract

Various enzymes were used to treat a protein-enriched rice flour for the production of rice protein isolates. The rice flour containing 49% protein was a by-product from the processing of brown rice for syrup production. The treatment sequence of α-amylase followed by glucoamylase was most effective, resulting in a product with 85% protein content. The product was then treated with a mixture of cellulase and xylanase, which raised the protein content in the insoluble fraction to 91%. Inorganic impurities, such as the metal manganese in the starting rice flour, were effectively removed. The recovered rice proteins, practically intact according to electrophoretic analysis, had relatively poor solubility and emulsification properties; however, these functional properties were improved substantially by adding xanthan gum as a functionalityenhancing agent.

An update on the processing of high‐protein rice products

“…After removing the hydrolyzed starch as syrup, the insoluble residue contains up to 50% protein and is a low-cost industrial co-product [30,33]. Shih and Daigle [34] reported that treatment of this co-product with a-amylase and glucoamylase resulted in a product containing 85% protein. Follow-up treatment with a mixture of cellulase and xylanase raised the protein content to 92%.…”

Comparison the effect of three commercial enzymes for enzymatic hydrolysis of two substrates (rice bran protein concentrate and soy-been protein) with SDS-PAGE

“…This large amount of rice production has led to accumulation of rice byproducts. One of the major by-products is rice bran which is accounted for 8 % of milled rice (Shih and Daigle 2000). Rice bran is a source of proteins, oil,…”

Extração enzimática das proteínas da farinha de arroz

“…Diversas enzimas têm sido utilizadas, entre estas, encontram-se a pancreatina, as proteases alcalinas, fúngicas ou bacterianas, em conjunto ou não com a ação de amilases e carboidrases ( AGBOOLA; NG; MILLS, 2005; ANSHARULLAH; CHESTERMAN, 1997;EUBER;PUSKI;HARTMAN JR., 1991;FISCHER et al, 2001;SHAW;SHEU, 1992;SHIH et al, 1999;DAIGLE, 1997;DAIGLE, 2000;TANG;SHELLHAMMER, 2002;WANG et al, 1999).…”

“…Grande parte do arroz polido é consumida diretamente após cozido, mas uma parte significativamente crescente tem sido usada industrialmente na produção de farinha de arroz que é, posteriormente, utilizada como aditivo em gel, pudins, sorvetes e outros produtos similares devido às suas propriedades nutricionais, sua hipoalergenicidade, por possuir sabor agradável e por não interferir na cor do produto final (BRASIL, 1978;CHRASTIL, 1992;JU;RATH, 2001;DAIGLE, 2000).…”

“…Entretanto, dentre os componentes do arroz, as proteínas têm sido consideradas de grande valor, pois são hipoalergênicas, particularmente saudáveis para o consumo humano e altamente nutritivas em relação aos outros cereais. O conteúdo de lisina é de 3 a 4%, aproximadamente 50% maior que o do trigo, por exemplo (JU; HETTIARACHCHY; RATH, 2001;DAIGLE, 2000).…”