title: Simultaneous recovery and purification of rice protein and phosphorus compounds from full-fat and defatted rice bran with organic solvent-free process.
abstract: We studied a process that enables simultaneous recovery of protein and phosphorus compounds from rice bran. Phosphorus substances in full-fat and defatted rice bran such as phytic acid and inorganic ions were solubilized under acidic conditions in the first step. After that, inorganic and/or organic phosphate salts were recovered in insoluble form under weak alkaline conditions. Furthermore, protein fractions obtained after phosphorus compounds had been removed were solubilized under alkaline conditions. After solubilization, protein fractions with high content were recovered by isoelectric precipitation (IP) followed by electrolyzed water treatment (EWT). The highest protein content (52.3 w/w%) was attained when machine defatted rice bran was treated through the process. Energy-dispersive X-ray spectroscopy (EDX) and inductively coupled plasma atomic emission spectrometry (ICP-AES) analyses demonstrated efficient desalting from the protein fractions by EWT and higher phosphorus contents (15.1-16.4 w/w% P) in the phosphorus fractions compared with commercial phosphate rock. In addition, no heavy metal ions in either protein or phosphorus fractions were detected. These results suggest that the newly developed process is suitable for practical recovery of highly concentrated protein and phosphorus compounds from rice bran without enzymes or chemicals such as organic solvents, buffering agents, and surfactants.
authors.affiliation: Department of Food, Life and Environmental Science, Faculty of Agriculture, Yamagata University, 1-23 Wakaba-machi, Tsuruoka, Yamagata 997-8555, Japan. Electronic address: mwata@tds1.tr.yamagata-u.ac.jp.
authors.forename: Masanori
authors.initials: M
authors.lastname: Watanabe
authors.affiliation: Graduate School of Agricultural Science, Utsunomiya University, 350 Minemachi, Utsunomiya 321-8505, Japan.
authors.forename: Isamu
authors.initials: I
authors.lastname: Maeda
authors.affiliation: Department of Bioscience and Biotechnology, Graduate School of Agriculture, Shinshu University, Minamiminowamura, Nagano 399-4598, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Koyama
authors.affiliation: Department of Bioscience and Biotechnology, Graduate School of Agriculture, Shinshu University, Minamiminowamura, Nagano 399-4598, Japan.
authors.forename: Kozo
authors.initials: K
authors.lastname: Nakamura
authors.affiliation: Shokkyo Co., Ltd., 1-10-28 Fukawa, Asakita-Ku, Hiroshima 739-1751, Japan.
authors.forename: Kazuo
authors.initials: K
authors.lastname: Sasano
mesh_terms: D004572:Electrolysis; D009930:Organic Chemicals; D012275:Oryza / Q000737:chemistry*; D017553:Phosphorus Compounds / Q000302:isolation & purification*; D010940:Plant Proteins / Q000737:chemistry / Q000302:isolation & purification*; D012972:Sodium Hydroxide; D012995:Solubility; D012997:Solvents; D013997:Time Factors; D014867:Water / Q000737:chemistry
chemical_list: D009930:Organic Chemicals; D017553:Phosphorus Compounds; D010940:Plant Proteins; D012997:Solvents; D014867:Water; D012972:Sodium Hydroxide
keywords: Electrolyzed water; Full-fat rice bran; Isoelectric precipitation; Machine defatted rice bran; Phosphorus compounds; Rice protein