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Title: PHYSICOCHEMICAL PROPERTIES OF PIN OAK (QUERCUS PALUSTRIS MUENCHH.) ACORN STARCH

Author
item Stevenson, David
item JANE, JAY-LIN - IOWA STATE UNIVERSITY
item Inglett, George

Submitted to: Starch/Starke
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/11/2006
Publication Date: 11/3/2006
Citation: Stevenson, D.G., Jane, J., Inglett, G.E. 2006. Physicochemical properties of pin oak (Quercus palustris muenchh.) acorn starch. Starch/Starke. 58(11):553-560.

Interpretive Summary: Acorn starch, from oak trees in Peoria, had structure and functional properties characterized. Acorn starch granules were small to medium in size, had 26% amylose, and amylopectin molecular weight and branch chain-length distribution were similar to cereal starches. Acorn starch had distinctive characteristic of a large temperature difference between the temperature that starch molecules initially melted and the temperature that most starch molecules melted, as well as starch paste with high final and setback viscosity. This study assists the starch industry in modifying industrial starches to broaden commercial starch applications.

Technical Abstract: Physicochemical properties of acorn (Quercus palustris) starch were studied. Acorn starch granules were spherical or ovoid, with diameters ranging from 3-17 micrometers. Acorn starch exhibited A-type X-ray diffraction pattern, an apparent amylose content of 43.4% and absolute amylose content of 25.9%. Relative to other A-type starches, acorn amylopectin had comparable weight-average molecular weight (3.9 x 108), gyration radius (288 nm), and density (16.3 g/mol/nm3). Average amylopectin branch chain-length was DP 25.5. Onset gelatinization temperature was 65.0 deg C, and peak gelatinization temperature was considerably higher (73.7 deg C). Enthalpy change of gelatinization was very high compared to non-mutant starches (20.8 J/g). Amylose-lipid thermal transition was not observed. Starch retrograded for 7 d at 4 deg C had very high peak melting temperature (54.2 deg C) relative to other A-type starches. Final (260 RVU) and setback (138 RVU) viscosity of 8% acorn starch paste was high relative to other starches, and the pasting temperature was 71.5 deg C.