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Physicochemical Properties of Rice Endosperm Proteins Extracted by Chemical and Enzymatic Methods
Author(s) -
Paraman Ilankovan,
Hettiarachchy N. S.,
Schaefer Christian,
Beck Markus I.
Publication year - 2006
Publication title -
cereal chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.558
H-Index - 100
eISSN - 1943-3638
pISSN - 0009-0352
DOI - 10.1094/cc-83-0663
Subject(s) - endosperm , chemistry , solubility , denaturation (fissile materials) , extraction (chemistry) , chromatography , enzyme , differential scanning calorimetry , salt (chemistry) , yield (engineering) , amylase , protein purification , rice protein , biochemistry , food science , organic chemistry , nuclear chemistry , physics , materials science , metallurgy , thermodynamics
Rice proteins are nutritional, hypoallergenic, and healthy for human consumption. Efficient extraction with approved food‐grade enzymes and chemicals are essential for commercial production and application of rice protein as a functional ingredient. Rice endosperm proteins were isolated by alkali, salt, and enzymatic methods and evaluated for extractability and physicochemical properties. Alkali (RP A ) and salt (RP S ) methods extracted 86.9 and 87.3% of proteins with 65.9 and 58.9% yield, respectively. The enzymatic methods with Termamyl (RP ET ) and amylase S (RP EA ) extracted 85.8 and 81.0% proteins with 85.2 and 86.2% yield, respectively. Enthalpy values of RP A (1.79 J/g), RP S (1.22 J/g), RP ET (nondetectable), and RP EA (0.17 J/g), determined by differential scanning calorimetry, demonstrated that the varying level of denaturation of proteins depends on the method of extraction. Surface hydrophobicity data supported this observation. Alkali‐ and salt‐extracted proteins had higher solubility and emulsifying properties than those of enzyme‐extracted proteins. Comparatively, more favorable protein composition, lower surface hydrophobicity, higher solubility, and a lower degree of thermal denaturation of alkali‐ and salt‐extracted proteins contributed to higher emulsifying and foaming properties than those of enzyme‐extracted proteins; therefore, alkali‐ and salt‐extracted proteins can have enhanced functional use and a potential starting material for preparing tailored rice protein isolates.