Analytical Aspects of Total Starch Polarimetric Determination in Some Cereals
Keywords:
polarimetry, starch, cerealsAbstract
Starch is the most important digestible polysaccharide present in foods and feeds. The starch concentration in cereals cannot be determined directly, because the starch is contained within a structurally and chemically complex matrix. Fine grinding and boiling in dilute HCl are preparative steps necessary for complete release of the starch granules from the protein matrix. Starch can be determined using simple and inexpensive physical methods, such as density, refractive index or optical rotation assessment. The polarimetric method allows the determination even of small starch contents due to its extremely high specific rotation. For more accurate results, the contribution of free sugars is eliminated by dissolution in 40% (V/V) ethanol. The influence of other optically active substances, which might interfere, is removed by filtration/clarification prior to the optical rotation measurement.
References
Belitz, H.-D., Grosch, W. and Schieberle, P., Cereals and cereal products. In: Food chemistry, 4th edn., Belitz H.-D., Grosch W., Schieberle P. (eds.) Springer, Berlin, 2009, pp. 670–675.
Caprita, R. and Caprita, A., Chemical methods for the determination of soluble and insoluble non-starch polysaccharides-review, Scientific Papers: Animal Science and Biotechnologies, 2011, 44 (2), 73-80.
Koehler, P. and Wieser, H., Chemistry of Cereal Grains. In: Handbook on Sourdough Biotechnology, Springer Science+Business Media, New York, 2013.
Rosell, C. M. and Dura, A., Enzymes in Bakeries: An Overview. In: Enzymes in Food and Beverage Processing, Muthusamy Chandrasekaran (ed.), CRC Press, 2015, pp. 171-204.
Eerlingen, R. C., and Delcour, J. A., Formation, analysis, structure and properties of type III enzyme resistant starch, Journal of Cereal Chemistry, 1995, 22, 129–138.
Bednar, G. E., Patil, A. R., Murray, S. M., Grieshop, C. M., Merchen, N. R. and George C. Fahey. Starch and fiber fractions in selected food and feed ingredients affect their small intestinal digestibility and fermentability and their large bowel fermentability in vitro in a canine model, The Journal of Nutrition, 2001, 131(2), 276-286.
Reddy, D. K., and Bhotmange, M. G., Isolation of Starch from Rice (Oryza Sativa L.) and its Morphological Study using Scanning Electron Microscopy, International Journal of Agriculture and Food Science Technology, 2013, 4(9), 859-866.
Bernetti, R., From corn syrup to fructose., Cereal Foods World, 1990, 35(4), 390-393.
Eliasson, A.-C., Starch in Food: Structure, Function and Applications, Eliasson A.-C. (ed.), CRC Press, 2004.
Tsuge, H., Hishida, M., Iwasaki, H., Watanabe, S., and Goshima, G., Enzymatic evaluation for the degree of starch retrogradation in foods and foodstuffs. Starch/Staerke, 1990, 42, 213-216.
Chow, P. S. and Landhäusser, S. M., A method for routine measurements of total sugar and starch content in woody plant tissues, Tree Physiology, 2004, 24, 1129 –1136.
Caprita, R., Caprita, A., Ilia, G., Cretescu, I. and Simulescu, V. O., Laboratory procedures for assessing quality of soybean meal, Proceedings of the World Congress on Engineering and Computer Science, San Francisco, 2010, 791-794.
ICC, Determination of starch content by hydrochloric acid dissolution. International Association for Cereal Science and Technology Method No.123/1, 1994.
USCL Method 11-02 Starch determination in cereal products using the modified Ewers' polarimetric method, 1997
AOAC, Official methods of analysis, Association of Official Analytical Chemists, Washington, DC, 1996.
ISO 10520:1997 Native starch – Determination of starch content – Ewers polarimetric method, 2013.
Asp, N.-G., Nutritional importance and classification of food carbohydrates. In: Plant Polymeric Carbohydrates. F.D. Meuser, J. Manners, and W. Seibel (eds.), Royal Society of Chemistry, Cambridge, United Kingdom, 1993.
Flood A., Refractive Index, Viscosity, and Solubility at 30°C, and Density at 25°C for the System Fructose + Glucose + Ethanol + Water, J. Chem. Eng. Data, 2000, 45, 902-907.
