Wheat Germ: An Overview on Nutritional Value, Antioxidant Potential and Antibacterial Characteristics

Awad A. Mahmoud¹, Adel A. A. Mohdaly^1,2, Nady A. A. Elneairy^1*

¹Food Science and Technology, Faculty of Agriculture, Fayoum University, Al Fayoum, Egypt.
²Plant Production and Processing Department, Food Management Course, Agricultural Faculty, University of Applied Sciences Weihenstephan-Triesdorf, Triesdorf, Germany.

DOI: 10.4236/fns.2015.62027                

Abstract

Wheat germ is a by-product derived from the wheat milling industry. Defatted wheat germ is the main by-product of the wheat germ in the oil extraction process. This study aims at development of efficient and low cost processing methods to transform these residues in added value co-product. In this study, wheat germ was analysed for its proximate composition, fatty acid composition, physical and chemical characteristics of wheat germ oil. The basic chemical composition analyses revealed high values of dry matter (87.37 g/100g FW), significant amounts of total protein and fat (27.69 and 8.99 g/100g FW, respectively) content and low ash content (3.08 g/100g FW). The quality of the extracted oils was assessed in terms of acid value, iodine value, saponification value, peroxide value, refractive index, and unsaponifiable matter. The fatty acid profile was found to be made up of linoleic followed by palmitic and oleic as the major fatty acids. Antioxidant properties and in vitro antibacterial activity of defatted wheat germ (DWG) extract were also determined. DWG, as a source of natural antioxidants and antibacterial, could be used to formulate nutraceuticals with potential applications to reduce the level of oxidative stress. The antioxidant potency of the DWG extracts could be the basis for its health promoting potential. The results showed that these by-products could be used as a source of bioactive compounds beneficial for health.

Keywords

Antibacterial Activity, Antioxidant Properties, Defatted Wheat Germ, Fatty Acid, Wheat Germ Oil

Conflicts of Interest

The authors declare no conflicts of interest.

References

[1]	Mielke, T. (2011) Oil Word Annual 2011. ISTA Mielke Gmbh, Hamburg.
[2]	de Vasconcelos, M.C., 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. http://dx.doi.org/10.1016/j.indcrop.2012.06.007
[3]	Elliott, D.C., Orth, R.J., Gao, J., Werpy, T.A., Eakin, D.E., Schmidt, A.J., et al. (2002) Biorefinery Concept Development Based on Wheat Flour Milling. Fuel Chemistry Division Preprints, 47, 361-362.
[4]	Zhu, K.X., Zhou, H.M. and Qian, H.F. (2006) Proteins Extracted from Defatted Wheat Germ: Nutritional and Structural Properties. Cereal Chemistry, 83, 69-75. http://dx.doi.org/10.1094/CC-83-0069
[5]	Megahad, O.A. and El Kinawy, O.S. (2002) Studies on the Extraction of Wheat Germ Oil by Commercial Hexane. Grasas y Aceites, 53, 414-418. http://dx.doi.org/10.3989/gya.2002.v53.i4.339
[6]	AOAC (1990) Official Methods of Analysis. 15th Edition, Association of Official Analytical Chemists, Washington DC.
[7]	Lee, Y.C., Oh, S.W., Chang, J. and Kim, I.H. (2004) Chemical Composition and Oxidative Stability of Safflower Oil Prepared from Safflower Seed Roasted with Different Temperatures. Food Chemistry, 84, 1-6. http://dx.doi.org/10.1016/S0308-8146(03)00158-4
[8]	Dieffenbacher, A. and Pocklington, W.D. (1987) Standard Methods for the Analysis of Oils, Fats and Derivatives. In: International Union of Pure and Applied Chemistry, 7th Edition, Blackwell Scientific, Oxford.
[9]	Morrison, W.R. and Smith, L.M. (1964) Preparation of Fatty Acid Methyl Esters and Dimethylacetals from Lipids with Boron Fluoride—Methanol. Journal of Lipid Research, 5, 600-608.
[10]	Akowuah, G.A., Ismail, Z., Norhayati, I. and Sadikun, A. (2005) The Effects of Different Extraction Solvents of Varying Polarities of Polyphenols of Orthosiphon stamineus and Evaluation of the Free Radical-Scavenging Activity. Food Chemistry, 93, 311-317. http://dx.doi.org/10.1016/j.foodchem.2004.09.028
[11]	Re, R., Pellegrini, N., Proteggente, A., Pannala, A., Yang, M. and Rice-Evans, C.A. (1999) Antioxidant Activity Applying an Improved ABTS Radical Cation Decolorization Assay. Free Radical Biology Medicine, 26, 1231-1237. http://dx.doi.org/10.1016/S0891-5849(98)00315-3
[12]	Ranalli, L., Pollastri, S., Contento, E. and Iannucci, L. (2003) Effect of Olive Paste Kneading Process Time on the Overall Quality of Virgin Olive Oil. European Journal of Lipid Science and Technology, 105, 57-67. http://dx.doi.org/10.1002/ejlt.200390018
[13]	Cueva, C., Moreno-Arribas, M.V., Requena, T., Rodriguez, J.M., Vicente, F. and Basilio, A. (2010) Antimicrobial Activity of Phenolic Acids against Commensal, Probiotic and Pathogenic Bacteria. Research in Microbiology, 161, 372382. http://dx.doi.org/10.1016/j.resmic.2010.04.006
[14]	Ramadan, M.F., Showky, H.S. and Sulieman, A.M. (2008) Comparison between the Effect of γ-Irradiation and Roasting on the Profile and Antioxidant Activity of Wheat Germ Lipids. Grasas y Aceites, 59, 166-173. http://dx.doi.org/10.3989/gya.2008.v59.i2.506
[15]	Bockisch, M. (1998) Fats and Oils Handbook. American Oil Chemists Society, Champaign, 175-344.
[16]	Akubor, P.I. and Badifu, G.I.O. (2004) Chemical Composition, Functional Properties and Baking Potential of African Breadfruit Kernel and Wheat Flour Blends. International Journal of Food Science and Technology, 39, 223-229. http://dx.doi.org/10.1046/j.0950-5423.2003.00768.x
[17]	Mukprasirt, A. and Sajjaanantakul, K. (2004) Physico-Chemical Properties of Flour and Starch from Jackfruit Seeds (Artocarpus heterophyllus Lam.) Compared with Modified Starches. International Journal of Food Science and Technology, 39, 271-276. http://dx.doi.org/10.1111/j.1365-2621.2004.00781.x
[18]	Akbar, E., Yakoob, Z., Kamarudin, S.K., Ismail, M. and Salimon, J. (2009) Characteristic and Composition of Jatropha curcas Oil Seed from Malaysia and Its Potential as Biodiesel Feedstock. European Journal of Scientific Research, 29, 396-403.
[19]	Zhu, K.X., Lian, C.X., Guo, X.N., Peng, W. and Zhou, H.M. (2011) Antioxidant Activities and Total Phenolic Contents of Various Extracts from Defatted Wheat Germ. Food Chemistry, 126, 1122-1126. http://dx.doi.org/10.1016/j.foodchem.2010.11.144
[20]	Jamieson, S.G. and Baughman, F.W. (1992) Wheat Germ Oil. Oil and Soap.
[21]	Kahtani, H.A. (1989) Studies of Saudi Arabian Locally Produced Wheat Germ. Food Chemistry, 34, 121-130. http://dx.doi.org/10.1016/0308-8146(89)90080-0
[22]	Yoon, S.H. and Kim, E. (2003) Recent Progress in Enzymatic Production of Structured Lipids. Food Science and Biotechnology, 12, 721-726.
[23]	Canvin, D.T. (1965) The Effect of Temperature on the Oil Content and Fatty Acid Composition of the Oils from Several Oil-Seed Crops. Canadian Journal of Botany, 43, 63-65. http://dx.doi.org/10.1139/b65-008
[24]	Moreira, A.V.B. and Mancini-Filho, J. (2004) Influência dos compostos fenólicos de especiarias sobre a lipoperoxidacao e o perfil lipídico de tecidos de ratos. Revista de Nutricao, 17, 411-424. http://dx.doi.org/10.1590/S1415-52732004000400002
[25]	Ribarova, F., Zanev, R., Shishkov, S. and Rizov, N. (2003) α-Tocopherol, Fatty Acids and Their Correlations in Bulgarian Foodstuffs. Journal of Food Composition and Analysis, 16, 659-667. http://dx.doi.org/10.1016/S0889-1575(03)00079-6
[26]	Schram, L.B., Nielsen, C.J., Porsgaard, T., Nielsen, N.S., Holm, R. and Mu, H. (2007) Food Matrices Affect the Bioavailability of (n-3) Polyunsaturated Fatty Acids in a Single Meal Study in Humans. Food Research International, 40, 1062-1068. http://dx.doi.org/10.1016/j.foodres.2007.06.005
[27]	Dunford, N.T. and Zhang, M. (2003) Pressurized Solvent Extraction of Wheat Germ Oil. Food Research International, 36, 905-909. http://dx.doi.org/10.1016/S0963-9969(03)00099-1
[28]	Mohdaly, A.A., Sarhan, M.A., Smetanska, I. and Mahmoud, A. (2010) Antioxidant Properties of Various Solvent Extracts of Potato Peel, Sugar Beet Pulp and Sesame Cake. Journal of the Science of Food and Agriculture, 90, 218-226. http://dx.doi.org/10.1002/jsfa.3796
[29]	Yu, L., Haley, S., Perret, J., Harris, M., Wilson, J. and Qian, M. (2002) Free Radical Scavenging Properties of Wheat Extracts. Journal of Agriculture and Food Chemistry, 50, 1619-1624. http://dx.doi.org/10.1021/jf010964p
[30]	Wang, M., Li, J., Rangarajan, M., Shao, Y., La-Voie, E.J., Huang, T. and Ho, C. (1998) Antioxidative Phenolic Compounds from Sage (Salvia officinalis). Journal of Agriculture and Food Chemistry, 46, 4869-4873. http://dx.doi.org/10.1021/jf980614b
[31]	Huang, Y.C., Chou, Y.H., Su, L.H., Lien, R.I. and Lin, T.Y. (2006) Methicillin-Resistant Staphylococcus aureus Colonization and Its Association with Infection among Infants Hospitalized in Neonatal Intensive Care Units. Pediatrics, 118, 469-474. http://dx.doi.org/10.1542/peds.2006-0254