Submitted to: Starch/Starke
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/12/2006
Publication Date: 7/1/2006
Citation: Stevenson, D.G., Johnson, S.R., Jane, J., Inglett, G.E. 2006. Chemical and physical properties of kiwifruit (Actinidia deliciosa) starch. Starch/Starke. 58(7):323-329. Interpretive Summary: Kiwifruit, grown in California, had starch structure and functional properties characterized. Kiwifruit starch granules were similar in size to rice and corn starch, and required high energy to melt starch. Kiwifruit starch had distinctive characteristics of low molecular weight amylopectins, high paste viscosity, and pasting temperature was marginally higher temperature than the onset of melting. This study assists the starch industry in modifying industrial starches to broaden starch commercial applications.
Technical Abstract: Chemical and physical properties of kiwifruit (Actinidia deliciosa var. ‘Hayward’) starch were studied. Kiwifruit starch granules were compound, irregular, or dome-shaped with diameters predominantly 4-5 micrometers or 7-9 micrometers. Kiwifruit starch exhibited B-type X-ray diffraction pattern, an apparent amylose content of 43.1%, and absolute amylose content of 18.8%. Kiwifruit amylopectins, relative to other starches, had low weight-average molecular weight (7.4 x 107), and gyration radius (200 nm). Average amylopectin branch chain-length was long (DP 28.6). Onset and peak gelatinization temperatures were 68.9 deg C and 73.0 deg C, respectively, and enthalpy change was high (18.5 J/g). Amylose-lipid thermal transition was observed. Starch retrograded for 7 d at 4 deg C had very high peak melting temperature (60.7 deg C). Peak (250 RVU), final (238 RVU), and setback (94 RVU) viscosity of 8% kiwifruit starch paste was high relative to other starches; and pasting temperature (69.7 deg C) was marginally higher than onset gelatinization temperature.