Molecular Structure and Gelatinization Properties of Turnip Starch (Brassica rapa L.)

  • Kim, Nam-Hee (Department of Food Science and Technology, Sejong University) ;
  • Yoo, Sang-Ho (Department of Food Science and Technology, Sejong University)
  • Published : 2005.08.30

Abstract

Starch was isolated from turnip (Brassica rapa L.), and to elucidate the structure-function relationship its structural and physical properties were characterized. Morphological structure of the starch was analyzed by SEM (Scanning Electron Microscopy). Most of the starch granules were spherical in shape with diameter ranging from 0.5-10mm. Apart from larger granules ($<10\;{\mu}m$) which dominated the population size of turnip starch, significant amount of small ($0.5-2\;{\mu}m$) and mid-size granules (${\sim}\;{\mu}m$) were also detected. It was revealed that presumably, erosion damages occurred due to the attack of amylase-type enzymes on the surface of some granules. Branch chain-length distribution was analyzed by HPAEC (High-Performance Anion-Exchange Chromatography). The chain-length distribution of turnip starch revealed a peak at DP12 with obvious shoulder at DP18-21. The weight-average chain length ($CL_{avg}$) was 16.6, and a large proportion (11.8%) of very short chains (DP6-9) was also observed. The melting properties of starch were determined by DSC (Differential Scanning Calorimetry). The onset temperature ($T_o$) and the enthalpy change (${\Delta}H$) of starch gelatinization were $50.5^{\circ}C$ and 12.5 J/g, respectively. The ${\Delta}H$ of the retrograded turnip starch was 3.5 J/g, which indicates 28.2% of recrystallization. Larger proportion of short chains as well as smaller average chain-length can very well explain relatively lower degree of retrogradation in turnip starch.

Keywords

References

  1. Starch: analytical aspects;Carbohydrates in food Hizukuri, S.
  2. Starch: Physicochemical and functional aspects;Carbohydrates in food Eliasson, A.C.;Gudmunsson, M.
  3. Carbohyd. Polym. v.45 Composition, molecular structure, and physicochemical properties of tubers and root starches: a review Hoover, R.
  4. Food Chem. v.81 Morphological, thermal and rheological properties of starches from different botanical sources Singh, N.;Singh, J.;Kaur, L.;Sodhi, N.S.;Gill, B.S.
  5. J. Cereal Sci. v.39 Starch-composition, fine structure and architecture Tester, R.F.;Karkalas, J.;Qi, X.
  6. Carbohyd. Polym. v.59 Banana starch: production, physicochemical properties, and digestibility-a review Zhang, P.;Whistler, R.L.;BeMiller, J.N.;Hamaker, B.R.
  7. Carbohyd. Polym. v.59 Structural and physicochemical characteristics of winter squash (Cucurbita maxima D.) fruit starches at harvest Stevenson, D.G.;Yoo, S.H.;Hurst, P.L.;Jane, J.
  8. Food Chem. v.88 Effects of drying temperatures on physico-chemical properties of dried and rehydrated chestnuts (Castanea sativa) Attanasio, G.;Cinquanta, L.;Albanese, D.;Di Matteo, M.
  9. Carbohyd. Polym. v.60 Characterization of some properties of starches isolated from Xanthosoma sagittifolium (tannia) and Colocassia esculenta (taro) Perez, E.;Schultz, F.S.;de Delahaye, E.P.
  10. Food Chem. v.87 Characterization of starch in apple juice and its degradation by amylases Carrin, M.E.;Ceci, L.N.;Lozano, J.E.
  11. Acta Physiol. Plant. v.23 Sink development, sucrose metabolizing enzymes and carbohydrate status in turnip (Brassica rapa L.) Gupta, A.K.;Singh, J.;Kaur, N.
  12. Methods Carbohyd. Chem. v.4 General method for starch isolation Badenhuizen, N.P.
  13. Cereal Chem. v.71 Characterization of the dominant mutant amylose-extender (Ael-5180) maize starch Kasemsuwan, T.;Jane, J.;Schnable, P.;Stinar, P.;Robertson, D.
  14. Starch/Staerke v.46 Anthology of starch granule morphology by scanning electron microscopy Jane, J.;Kasemsuwan, T.;Leas, S.;Zobel, H.;Robyt, J.F.
  15. Carbohyd. Polym. v.49 Structural and physical characteristics of waxy and other wheat starches Yoo, S.H.;Jane, J.
  16. Carbohyd. Res. v.300 Branch-structure difference in starches of A- and B-type X-ray patterns revealed by their Naegeli dextrins Jane, J.;Wong, K.;McPherson, A.E.
  17. Carbohyd. Res. v.227 The structure of four waxy starches related to gelatinization and retrogradation Dedicated to Professor David Manners Shi, Y.C.;Seib, P.A.
  18. Carbohyd. Res. v.283 A periodic distribution of the chain length of amylopectin as revealed by high-performance anion-exchange chromatography Hanashiro, I.;Abe, J.;Hizukuri, S.
  19. Cereal Chem. v.75 Effects of amylopectin branch chain length and amylose content on the gelatinization and pasting properties of starch Jane, J.;Chen, Y.Y.;Lee, L.F.;McPherson, A.E.;Wong, K.S.;Radosavljevic, M.;Kasemsuwan, T.
  20. Carbohyd. Res. v.227 Loss of crystalline and molecular order during starch gelatinization: Origin of the enthalpic transition Cooke, D.;Gidley, M.J.
  21. J. Food Sci. v.54 Low temperature sweetening in susceptible and resistant potatoes: Starch structure and composition Barichello, V.;Yada, R.Y.;Coffin, R.H.;Stanley, D.W.
  22. Cereal Chem. v.7 Characterization of phosphorus in starches using $^{31}P-NMR$ spectroscopy Lim, S.T.;Kasemsuwan, T.;Jane, J.