Extraction of Bran Protein Using Enzymes and Polysaccharide Precipitation

Rice bran is normally used as a raw material for rice bran oil production or sold as feed with a low price. Conventionally, the protein in defatted rice bran was extracted using alkaline extraction and acid precipitation, which involves in chemical usage and lowering some nutritious component. This study was conducted in order to extract of rice bran protein concentrate (RBPC) from defatted rice bran using enzymes and employing polysaccharides in a precipitating step. The properties of RBPC obtained will be compared to those of a control sample extracted using a conventional method. The results showed that extraction of protein from rice bran using enzymes exhibited the higher protein recovery compared to that extraction with alkaline. The extraction conditions using alcalase 2% (v/w) at 50 C, pH 9.5 gave the highest protein (2.44%) and yield (32.09%) in extracted solution compared to other enzymes. Rice bran protein concentrate powder prepared by a precipitation step using alginate (protein in solution: alginate 1:0.016) exhibited the highest protein (27.55%) and yield (6.84%). Precipitation using alginate was better than that of acid. RBPC extracted with alkaline (ALK) or enzyme alcalase (ALC), then precipitated with alginate (AL) (samples RBP-ALK-AL and RBP-ALC-AL) yielded the precipitation rate of 75% and 91.30%, respectively. Therefore, protein precipitation using alginate was then selected. Amino acid profile of control sample, and sample precipitated with alginate, as compared to casein and soy protein isolated, showed that control sample showed the highest content among all sample. Functional property study of RBP showed that the highest nitrogen solubility occurred in pH 8-10. There was no statically significant between emulsion capacity and emulsion stability of control and sample precipitated by alginate. However, control sample showed a higher of foaming capacity and foaming stability compared to those of sample precipitated with alginate. The finding was successful in terms of minimizing chemicals used in extraction and precipitation steps in preparation of rice bran protein concentrate. This research involves in a production of value-added product in which the double amount of protein (28%) compared to original amount (14%) contained in rice bran could be beneficial in terms of adding to food products e.g. healthy drink with high protein and fiber. In addition, the basic knowledge of functional property of rice bran protein concentrate was obtained, which can be used to appropriately select the application of this value-added product from rice bran.

Authors:

• Sudarat Jiamyangyuen
• Tipawan Thongsook
• Riantong Singanusong
• Chanida Saengtubtim

Keywords:

• Alginate
• carrageenan
• rice bran
• rice bran protein.

References:

[1] R. Gnanasambandam, and N.S. Hettiarachchy, “Protein Concentrates
from Unstabilized and Stabilized Rice Bran: Preparation and
Properties,” J. Food Sci., vol. 60(5), pp. 1066-1069, 1995.
[2] L.D. Chen, and F. Houston, “Solubilization and recovery of proteins
from defatted rice bran,” Cereal Chem., vol. 47, pp. 72–79, 1970.
[3] A. K. Smith, A. M. Nash, A. C. Eldridge, and W. J. Wolf, “Recovery of
soybean whey protein with edible gums and detergents,” J. Agric. Food
Chem., vol. 10, pp. 302–304, 1962.
[4] C. B. Fabian, and Y. H. Ju, “Precipitation of rice bran protein using
carrageenan and alginate,” LWT- Food Sci. Tech., vol.43, pp. 375-379,
2010.
[5] M. B. Bera, R. K. Mukherjee, “Solubility, Emulsifying, and Foaming
Properties of Rice Bran Protein Concentrates,” J. Food Sci., vol. 54 (1),
pp. 142–145, 1989.
[6] L.S. Bernardi, A. M.R. Pilosof, G. B. Bartholomai, “Enzymatic
modification of soy protein concentrates by fungal and bacterial
proteases,” J. Am. Oil Chem. Soc., vol. 68 (2), pp. 102–105, 1991.
[7] N. S. Hettiarachchy, V. K. Griffin, and R. Gnanasambandam,
“Preparation and functional properties of protein isolate from defatted
wheat germ,” Cereal Chem., vol. 73(3), pp. 364-367, 1996.
[8] A. A. Betschart, R. Y. Fong, and R. M. Saunders, “Rice by-products:
Comparative extraction of nitrogen from U.S. and Spanish bran and
germ,” J. Food Sci., vol. 42, pp. 1088–1093, 1977.
[9] M. A. Connor, R. M. Saunders, and G. O. Kohler, “Rice bran protein
concentrates obtained by wet alkaline extraction,” Cereal Chem., vol.
53, pp. 488–496, 1976.
[10] A. Benichou, A. Aserin, and G. Nissim, “Protein-polysaccharide
interactions for stabilization of food emulsions,” J. Disp. Sci. Tech., vol.
23, pp. 93–123, 2002.
[11] M. Wang, N. S. Hettiarachchy, M. Qi, W. Burks, and T. Siebenmorgen,
“Preparation and Functional Properties of Rice Bran Protein Isolate” J.
Agric. Food Chem., vol. 47(2), pp. 411– 416, 1999.
[12] P. J. Halling, “Protein-stabilized foams and emulsions,” CRC Crit. Rev.
Food Sci. Nutr., vol. 21, pp. 155-203, 1981.
[13] L. G. Phillips, D. M. Whitehead, and J. E. Kinsella, Structure Function
Properties of Food Proteins. Academic Press: New York, 1994, pp. 207-
255.
[14] H. J. Zhang, H. Zhang, L. Wang, and X. N. Guo, “Preparation and
functional properties of rice bran proteins from heat-stabilized defatted
rice bran” Food Res. Int., vol. 47, pp. 359-363.
[15] E. Li-Chen, S. Nakai, and D. F. Wood, “Hydrophobicitiy and solubility
of meat proteins and their relations E. Li-Chen, S. Nakai, and D. F.
Wood, “Hydrophobicitiy and solubility of meat proteins and their
relationship to emulsifying properties,” J. Food Sci., vol. 49, pp. 345-
350, 1984.
[16] C. Schmitt, C. Sanchez, S. Desobry-Banon, and J. Hardy, “Structure and
techno-functional properties of protein-polysaccharide complexes CRC
Crit. Rev. Food Sci. Nutr., vol. 38, pp. 689–753, 1998.