Solubilization and Electrophoretic Characterization of Select Edible Nut Seed Proteins

• Published in: Journal of agricultural and food chemistry Vol. 57; no. 17; pp. 7846 - 7856
• Main Authors: Sathe, Shridhar K, Venkatachalam, Mahesh, Sharma, Girdhari M, Kshirsagar, Harshal H, Teuber, Suzanne S, Roux, Kenneth H
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 09.09.2009
• Subjects: Animals; Antibodies; Antibodies - immunology; Biological and medical sciences; Borates; buffers; Chemical Composition of Foods/Feeds; chemistry; Electrophoresis; Electrophoresis, Polyacrylamide Gel; extraction; food composition; Food industries; Fruit and vegetable industries; Fundamental and applied biological sciences. Psychology; Humans; Immunoglobulin E; Immunoglobulin E - immunology; immunology; interspecific variation; ionic strength; Isoelectric Focusing; molecular weight; Nut Hypersensitivity; Nut Hypersensitivity - immunology; Nuts; Nuts - chemistry; Osmolar Concentration; peanuts; plant proteins; Plant Proteins - chemistry; Plant Proteins - immunology; polypeptides; qualitative analysis; quantitative analysis; Rabbits; Seeds; Seeds - chemistry; Solubility; solubilization; solvents; species differences; SDS-PAGE; polypeptide; IgE; protein; immunoblot; Tree nut; solubility; Immunoglobulins; Nuts; Seeds; Solubility; Solubilization; Protein; Characterization; Polypeptide; Tree
• ISSN: 0021-8561; 1520-5118; 1520-5118
• DOI: 10.1021/jf9016338

The solubility of almond, Brazil nut, cashew nut, hazelnut, macadamia, pecan, pine nut, pistachio, walnut, and peanut proteins in several aqueous solvents was qualitatively and quantitatively assessed. In addition, the effects of extraction time and ionic strength on protein solubility were also investigated. Electrophoresis and protein determination (Lowry, Bradford, and micro-Kjeldahl) methods were used for qualitative and quantitative assessment of proteins, respectively. Depending on the seed, buffer type and ionic strength significantly affected protein solubility. The results suggest that buffered sodium borate (BSB; 0.1 M H3BO3, 0.025 M Na2B4O7, 0.075 M NaCl, pH 8.45) optimally solubilizes nut seed proteins. Qualitative differences in seed protein electrophoretic profiles were revealed. For a specific seed type, these differences were dependent on the solvent(s) used to solubilize the seed proteins. SDS-PAGE results suggest the polypeptide molecular mass range for the tree nut seed proteins to be 3−100 kDa. The results of native IEF suggested that the proteins were mainly acidic, with a pI range from >4.5 to <7.0. Western immunoblotting experiments indicated that rabbit polyclonal antibodies recognized substantially the same polypeptides as those recognized by the corresponding pooled patient sera IgE.