Main Article Content
wheat germ, lipase, interfacial activity, interfacial tension, interfacial loss factor
Wheat germ lipase (LA), which is abundant in wheat germ, could result in the deterioration of wheat germ. To explore the method of stabilising wheat germ and understand the regulatory mechanism of the interfacial activity of wheat germ LA, the effects of the substrate and hydrolysis products of LA on its oil-water interfacial activity were studied via interfacial enzymatic analysis in the research. The results indicated that the interfacial tension and interfacial loss factor of wheat germ LA decreased as the concentration of wheat germ LA increased, and the interfacial tension was unstable when the concentration of wheat germ LA exceeded 1.70×10-6 mol/l. In addition, the results indicated that triglyceride (TAG) substrate and products like monoacylglycerol (MAG) and oleic acid of wheat germ LA played an important role in the inhibition of its interfacial activity, by occupying the interfacial layer of the oil-water interface, and the effects of TAG, MAG, and oleic acid on the interfacial activity of wheat germ LA followed the order: TAG>MAG>oleic acid. In addition, the TAG, MAG and oleic acid, which under the concentrations of 1.0×10-5, 1.0×10-5 and 5.0×10-6 mol/l respectively, had the most significant effect on the oil-water interface activity of LA. These findings regarding the interfacial activity of wheat germ LA provided a solid theoretical support for the exploitation of efficient methods for wheat germ stabilisation.
Brockman, H.L., Momsen, W.E. and Tsujita, T., 1988. Lipid-lipid complexes: properties and effects on lipase binding to surfaces. Journal of the American Oil Chemists’ Society 65: 891-896.
Carrasco-López, C., Godoy, C. and Las Rivas, B., 2009. Activation of bacterial thermoalkalophilic lipases isspurred by dramatic structural rearrangements. Journal of Biological Chemistry 284: 4365-4372.
De Vasconcelos, M., Bennett, R., Castro, C., Cardoso, P., Saavedra, M.J. and Rosa, E.A.,2013. Study of composition, stabilization and processing of wheat germ and maize industrial by-products. Industrial Crops and Products 42: 292-298.
Dunford, N.T. and Zhang, M., 2003. Pressurized solvent extraction of wheat germ oil. Food Research International 36: 905-909.
Hemmati-Sarapardeh, A., Ayatollahi, S., Ghazanfari, M.H. and Masihi, M., 2014. Experimental determination of interfacial tension and miscibility of the co2-crude oil system; temperature, pressure, and composition effects. Journal of Chemical & Engineering Data 59: 946-955
Li, H., Song, C., Zhou, H., Wang, N. and Cao, D., 2011. Optimization of the aqueous enzymatic extraction of wheat germ oil using response surface methodology. Journal of the American Oil Chemists Society 88: 809-817.
Liu, A.M. and Yu, G., 2003. The cost and benefit of wheat production in China and the United States. China Agricultural Information Bulletin 6: 7-9.
Muth, M., Rothkötter, S., Paprosch, S., Schmid, R.P. and Schnitzlein, K., 2016. Competition of thermomyces lanuginosus, lipase with its hydrolysis products at the oil-water interface. Colloids Surf B Biointerfaces 149: 280-287.
Rao, H.P., Kumar, G.V. and Ranga, R.G.,1980. Studies on stabilization of wheat germ. Food Science and Technology 13: 302-307.
Reis, P., Holmberg, K., Watzke, H., Leser, M.E. and Miller, R., 2009. Lipases at interfaces: a review. Advances in Colloid & Interface Science 147-148: 237-250.
Reis, P., Watzke, H. and Leser, M.E., 2010. Interfacial mechnism of lipolysis as self-regulated process. Biophysical Chemistry 147: 93-103.
Sarda, L. and Desnuelle, P., 1958. Action de la lipase pancréatique surles esters en émulsion. Biochimica Et Biophysica Acta 30: 513-521.
Shurpalekar, S.R. and Rao, P.H., 1977. Wheat germ. Advances in Food Research 23: 187-304.
Sullivan, B. and Howe, M.A., 1933. Lipases of wheat. Journal of the American Chemical Society 55(1): 320-324.
Torcello-Gómez, A., Jódarreyes, A.B., Maldonado-Valderrama, J. and Martín-Rodríguez, A., 2012. Effect of emulsifier type against the action of bile salts at oil-water interfaces. Food Research International 48: 140-147.
Verger, R., 1997. ‘Interfacial activation’ of lipases: facts and artifacts. Trends in Biotechnology 15: 32-38.
Wilde, P.J. and Chu, B.S., 2011. Interfacial and colloidal aspects of lipid digestion. Advances in Colloid & Interface Science 165: 14-22.
Xu, B., Miao, W.-J., Guo, K., Hu, Q.-S., Li, B. and Dong, Y., 2012. An improved method to characterize crude lipoxygenase extract from wheat germ. Quality Assurance & Safety of Crops & Foods 4: 26-32.
Xu, B., Miao, W.-J., Hu, Q.-S., Gao, C. and Dong, Y., 2013. A modified colorimetric method for determining the activity of wheat germ lipase in low-aqueous media. Quality Assurance And Safety Of Crops & Foods 5: 113-118.
Yang, B.H., Wu, K. and Liu, B., 2003. Rhizopus arrhizus lipasecatalyzed syntheses of three esters in nonaqueous solvents. Chinese Journal of Biochemistry and Molecular Biology 19: 572-575.
Zheng, D.S., Liu, X. and Li, Y., 2012. Cultivated plants originated in China. Journal of Plant Genetic Resources 13: 1-10.