Main Article Content
rice bran, solubility, surface hydrophobicity, structure, heat aggregation
The effect of heat treatment on solubility, surface hydrophobicity and structure of rice bran albumin and globulin were characterised. The differential scanning calorimetry (DSC), FT-IR and Raman spectra were used to analyse the effect. The results of DSC analysis showed that albumin denatured after a thermal pre-treatment of 70 °C, while globulin denatured at 90 °C. The solubility of albumin sharply decreased after heat treatment, while the solubility of globulin decreased by up to 100 °C. The results of FT-IR demonstrated that heating globulin generally increased the content of ?-helix and ?-turn structure, but reduced ?-sheet and random coil structures, while heating albumin produced a pronounced increase in ?-helix and ?-sheet structures from random coil and ?-turn structures. Heating albumin decreased regions around 33 kDa but increased relative band intensity around 45-53 kDa in SDS-PAGE pattern, while heating globulin up to 90 °C caused losses in bands around 20 and 50 kDa. Raman spectrogram showed that heating albumin induced a slight decrease in intensity of the Trp band. However, the Trp band of heated globulin did not change.
Adebiyi, A.P., Adebiyi, A.O., Ogawa, T. and Muramoto K., 2007. Preparation and characterization of high-quality rice bran proteins. Journal of the Science of Food and Agriculture 87: 1219-1227.
Barth, A., 2007. Infrared spectroscopy of proteins. Biochimica et Biophysica Acta 1767: 1073-1101.
Boye, J.I., Mar, C.Y. and Harwalkar, V.R., 1997. Thermal denaturation and coagulation of protein. In: Damodaran S. and Paraf, A. (eds.) Food proteins and their applications. Marcel Dekker, New York, NY, USA, pp. 25-56.
Chandi, G.K., 2008. Effect of extraction temperature on functional properties of rice bran protein concentrates. International Journal of Food Engineering 4: 99-107.
Daussant, J., Mosse, J. and Vaughan, J., 1983. Seed proteins. Annual Proceedings of the Phytochemical Society of Europe. Academic Press, New York, NY, USA.
Ellepola, S.W., Choi, S.M., Phillips, D.L. and Ma, C.Y., 2006. Raman spectroscopic study of rice globulin. Journal of Cereal Science 43: 85-93.
El-Shafey, E.I., 2005. Behavior of reduction-sorption of Chromium (VI) from an aqueous solution on a modified sorbent from rice husk. Water Air and Soil Pollution 163(1-4): 81-102.
Goormaghtigh, E., Cabiaux, V. and Ruysschaert, J.M., 1994. Determination of soluble and membrane protein structure by Fourier transform infrared spectroscopy. II. Experimental aspects, side chain structure, and H/D exchange. Subcellular Biochemistry 23: 363-403.
Hamada, J.S., 1997. Characterization of protein fractions of rice bran to devise effective methods of protein solubilization. Cereal Chemistry 74: 662-668.
Helm, R.M. and Burks, A.W., 1996. Hypoallergenicity of rice bran protein. Cereal Foods World 41: 839-843.
Ju, Z.Y., Hettiarachchy, N.S. and Rath, N., 2001. Extraction, denaturation and hydrophobic properties of rice flour proteins. Journal of Food Science 66: 229-232.
Juliano, B.O., 1985. Polysaccharides, proteins, and lipids of rice. Rice: Chemistry and Technology. American Association of Cereal Chemists, Eagan, MN, USA, pp. 59-174.
Kennedy, G. and Burlingame, B., 2003. Analysis of food composition data on rice from a plant genetic resources perspective. Food Chemistry 80: 589-596.
Laemmli, U.K., 1970. Cleavage of structural proteins during the assembly of the head of bacteriophage T4. Nature 227: 680-685.
Lowry, O.H., Rosebrough, N.J., Farr, A.L. and Randall, R.J., 1951. Protein measurement with the Folin phenol reagent. Journal of Biological Chemistry 193: 265-275.
Marina, C., Paola, M., Paolo, D. and Alessandro, N., 2008. Application of Fourier transform infrared spectroscopy to legume seed flour analysis. Food Chemistry 108: 361-368.
Moon, S.Y. and Li-Chan, E.C.Y., 2007. Assessment of added ingredient effect on interaction of simulated beef flavour and soy protein isolate by gas chromatography, spectroscopy and descriptive sensory analysis. Food Research International 40: 1227-1238.
Murayama, K. and Tomida, M., 2004. Heat-induced secondary structure and conformation change of bovine serum albumin investigated by Fourier transform infrared spectroscopy. Biochemistry 43: 11526-1153.
Palazolo, G.G., Sorgentini, D.A. and Wagner, J.R., 2004. Emulsifying properties and surface behavior of native and denatured whey soy proteins in comparison with other proteins: creaming stability of oil-in-water emulsion. Journal of the American Oil Chemistry Society 81: 625-632.
Saunders, R.M., 1990. The properties of rice bran as a food stuff. Cereal Food World 35: 632-662.
Secundo, F. and Guerrieri, N., 2005. ATR-FT/IR study on the interactions between gliadins and dextrin and their effects on protein secondary structure. Journal of Agricultural and Food Chemistry 53: 1757-1764.
Shoji, Y., Mita, T., Isemaru, M., Mega, T., Hase, S., Isemura, S. and Aoyagi, Y., 2001. A Fibronectin-binding protein from rice bran wit cell adhesion activity for animal tumor cells. Bioscience Biotechnology and Biochemistry 65: 1181-1186.
Tang, S., Hettiarachchy, N.S., Horax, R. and Eswaranandam, S., 2003. Physicochemical properties and functionality of rice bran protein hydrolyzate prepared from heat-stabilized defatted rice bran with the aid of enzymes. Journal of Food Science 68: 152-157.