Evaluation of chemical, morphological, structural and thermal properties of white sorghum starch

Document Type : Research Article

Authors

• Ahmad Ehtiati ¹
• Fakhri Shahidi ¹
• Arash Koocheki ¹
• Seyed Mohammad Ali Razavi ¹
• Mahsa Majzoobi ²

¹ Department of Food Science, Ferdowsi University of Mashhad, Iran.

² Department of Food Processing Engineering, Shiraz University, Shiraz, Iran.

https://doi.org/10.22067/ifstrj.v1395i0.55234

Abstract

Introduction: Sorghum (Sorghum bicolor) is a tropical plant and has the fifth ranking of world cereals production. One of the important aspects of sorghum is drought tolerance and little input need during growth which has made that suitable for cultivation in semiarid regions. Due to the presence of tannin compounds in internal part of sorghum grains and low digestion of cooked protein, sorghum flour consumption is limited. Sorghum grain contains more than 70% starch which is an important tasteless ingredient in food formulas, as the main source of energy and thickening and gelling agent. Extraction of starch from sorghum in regarding to its nutritional problems is a good solution for extension of sorghum uses in food industry. Starch is a semi crystalline structure consisted on linear amylose and branched amylopectin molecules packed in granules. Ratio of these two molecules and their molecular short order and macrostructure and size and shape of granules determine functional properties of starch in the final product. Starch properties is depended on genetic residues so that starches from tubers have distinct differences with cereal starches even obvious differences exists between cereal starches and varieties. In this study we have investigated chemical, morphological, structural and thermal properties of starches four white sorghum line.

Material and methods: White sorghum grains were prepared from local farms with line numbers KDFGS1, KDFGS6, KDFGS9 and KDFGS20. Starches were extracted sorghum lines using alkaline steeping method and further purified using toluene-water-salt solution. Chemical parameters were determined including protein by Kjeldahl digestion method, lipid by soxhlet extractor, ash by burning in furnace, moisture by oven drying and amylose content by iodine binding colorimitry,. Light microscopy coupled with digital camera was used for granules shape and size determination moreover surface properties and morphology of granules was observed using scanning electron microscopy technique. Color of starches were determined with hunterlab colorimeter. To evaluate crystalline structure of sample i.e. type of crystals and degree of crystallinity, starches first were conditioned in desiccator containing saturated aqueous sodium chloride solution at 25°C for a week then X-ray diffraction of sample in diffraction angels from 4-40° was determined. Thermal properties of crystals melting or gelatinization were measured using differential scanning calorimetry of starch in deionized water in temperatures from 20-120°C with heating rate of 10°C/min .From heat flow changes over temperature, temperature of onset, peak and conclusion points of crystalline structure melting and its required enthalpy were calculated. Functional groups of starches were investigated using FTIR technique to observe.

Results & Discussion: Isolated starches had appropriate quality due to low amount of protein (

Keywords

• DSC
• FTIR
• SEM
• Sorghum
• Starch
• XRD

References

Adkins, G.K. & Greenwood, C.T., 1966, The Isolation of Cereal Starches in the Laboratory, Starch - Stärke, 18(7), 213-218.

Ali, T.M. & Hasnain, A., 2011, Functional and Morphological Characterization of Low-Substituted Acetylated White Sorghum (Sorghum bicolor) Starch, International Journal of Polymer Analysis and Characterization, 16(3), 187-198.

Andrade-Mahecha, M.M., Tapia-Blacido, D.R. & Menegalli, F.C., 2012, Physical–chemical, thermal, and functional properties of achira (Canna indica L.) flour and starch from different geographical origin, Starch - Stärke, 64(5), 348-358.

Awika, J.M., Rooney, L.W., Wu, X., Prior, R.L. & Cisneros-Zevallos, L., 2003, Screening Methods To Measure Antioxidant Activity of Sorghum (Sorghum bicolor) and Sorghum Products, Journal of Agricultural and Food Chemistry, 51(23), 6657-6662.

Boudries, N., Belhaneche, N., Nadjemi, B., Deroanne, C., Mathlouthi, M., Roger, B. & Sindic, M., 2009, Physicochemical and functional properties of starches from sorghum cultivated in the Sahara of Algeria, Carbohydrate Polymers, 78(3), 475-480.

Buleon, A., Gallant, D.J., Bouchet, B., Mouille, G., D'Hulst, C., Kossmann, J. & Ball, S., 1997, Starches from A to C (Chlamydomonas reinhardtii as a Model Microbial System to Investigate the Biosynthesis of the Plant Amylopectin Crystal), Plant Physiology, 115(3), 949-957.

Cai, C., Zhao, L., Huang, J., Chen, Y. & Wei, C., 2014, Morphology, structure and gelatinization properties of heterogeneous starch granules from high-amylose maize, Carbohydrate Polymers, 102, 606-614.

Chao, G., Gao, J., Liu, R., Wang, L., Li, C., Wang, Y., Qu, Y. & Feng, B., 2014, Starch physicochemical properties of waxy proso millet (Panicum Miliaceum L.), Starch - Stärke, 66(11-12), 1005-1012.

Du, S.-k., Jiang, H., Ai, Y. & Jane, J.-l., 2014, Physicochemical properties and digestibility of common bean (Phaseolus vulgaris L.) starches, Carbohydrate Polymers, 108, 200-205.

Fannon, J.E., Hauber, R.J. & BeMiller, J.N., 1992, Surface pores of starch granules, Cereal Chemistry, 69(3), 284-288.

Faostat. "Fao Statistics Database For The Year 2014" Food United And Agriculture Organization of The Nations Statistics Division. [On-Line]. http://faostat3.fao.org/download/Q/QC/E [27 Jun 2016].

Jiang, Q.-Q., Gao, W.-Y., Shi, Y.-P., Li, X. & Wang, H.-Y., 2015, Comparison of starches from five plants of Sect. Stenophora Uline and Sect. Lasiophyton Uline of Dioscorea grown in China, Journal of the Science of Food and Agriculture, 95(4), 836-842.

Li, W., Xiao, X., Zhang, W., Zheng, J., Luo, Q., Ouyang, S. & Zhang, G., 2014, Compositional, morphological, structural and physicochemical properties of starches from seven naked barley cultivars grown in China, Food Research International, 58(7-14.

Lopez-Rubio, A., Flanagan, B.M., Gilbert, E.P. & Gidley, M.J., 2008, A novel approach for calculating starch crystallinity and its correlation with double helix content: A combined XRD and NMR study, Biopolymers, 89(9), 761-768.

Maaran, S., Hoover, R., Donner, E. & Liu, Q., 2014, Composition, structure, morphology and physicochemical properties of lablab bean, navy bean, rice bean, tepary bean and velvet bean starches, Food Chemistry, 152(491-499.

McGrance, S.J., Cornell, H.J. & Rix, C.J., 1998, A Simple and Rapid Colorimetric Method for the Determination of Amylose in Starch Products, Starch - Stärke, 50(4), 158-163.

Olayinka, O.O., Adebowale, K.O. & Olu-Owolabi, I.B., 2011, Physicochemical properties, morphological and X-ray pattern of chemically modified white sorghum starch. (Bicolor-Moench), Journal of Food Science and Technology, 50(1), 70-77.

Pascoal, A.M., Di-Medeiros, M.C.B., Batista, K.A., Leles, M.I.G., Lião, L.M. & Fernandes, K.F., 2013, Extraction and chemical characterization of starch from S. lycocarpum fruits, Carbohydrate Polymers, 98(2), 1304-1310.

Pelissari, F.M., Andrade-Mahecha, M.M., Sobral, P.J.d.A. & Menegalli, F.C., 2012, Isolation and characterization of the flour and starch of plantain bananas (Musa paradisiaca), Starch - Stärke, 64(5), 382-391.

Perez-Pacheco, E., Moo-Huchin, V.M., Estrada-Leon, R.J., Ortiz-Fernandez, A., May-Hernandez, L.H., Rios-Soberanis, C.R. & Betancur-Ancona, D., 2014, Isolation and characterization of starch obtained from Brosimum alicastrum Swarts Seeds, Carbohydrate Polymers, 101. 920-927.

Sang, Y., Bean, S., Seib, P.A., Pedersen, J. & Shi, Y.-C., 2008, Structure and Functional Properties of Sorghum Starches Differing in Amylose Content, Journal of Agricultural and Food Chemistry, 56(15), 6680-6685.

Saravi, M.M., Shahbazi, R. & Malekian, A., 2015, Drought and water scarcity in Iran: How to cope with and prepare for it? In: Drought: Research and Science-Policy Interfacing, CRC Press, London, 481-484.

Schirmer, M., Höchstötter, A., Jekle, M., Arendt, E. & Becker, T., 2013, Physicochemical and morphological characterization of different starches with variable amylose/amylopectin ratio, Food Hydrocolloids, 32(1), 52-63.

Singh, H., Sodhi, N.S. & Singh, N., 2012, Structure and Functional Properties of Acetylated Sorghum Starch, International Journal of Food Properties, 15(2), 312-325.

Singh, S., Singh, N., Isono, N. & Noda, T., 2010a. Relationship of Granule Size Distribution and Amylopectin Structure with Pasting, Thermal, and Retrogradation Properties in Wheat Starch, Journal of Agricultural and Food Chemistry, 58(2), 1180-1188.

Singh, H., Sodhi, N. S. & Singh, N., 2010b. Characterisation of starches separated from sorghum cultivars grown in India, Food chemistry, 119(1), 95-100.

Sira, E.E.P. & Lares Amaiz, M., 2004, A laboratory scale method for isolation of starch from pigmented sorghum, Journal of Food Engineering, 64(4), 515-519.

Sun, Q., Han, Z., Wang, L. & Xiong, L., 2014a, Physicochemical differences between sorghum starch and sorghum flour modified by heat-moisture treatment, Food Chemistry, 145, 756-764.

Sun, Y., Wu, Z., Hu, B., Wang, W., Ye, H., Sun, Y., Wang, X. & Zeng, X., 2014b, A new method for determining the relative crystallinity of chickpea starch by Fourier-transform infrared spectroscopy, Carbohydrate Polymers, 108.153-158.

Tester, R.F., Karkalas, J. & Qi, X., 2004, Starch—composition, fine structure and architecture, Journal of Cereal Science, 39(2), 151-165.

Waterschoot, J., Gomand, S.V., Fierens, E. & Delcour, J.A., 2015, Production, structure, physicochemical and functional properties of maize, cassava, wheat, potato and rice starches, Starch - Stärke, 67(1-2), 14-29.

Wen, Y., Liu, J., Meng, X., Zhang, D. & Zhao, G., 2014, Characterization of proso millet starches from different geographical origins of China, Food Science and Biotechnology, 23(5), 1371-1377