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Chemical and Physical Properties of Kiwifruit (Actinidia deliciosa) Starch
- Stevenson, David G., Johnson, Scott R., Jane, Jay-lin, Inglett, George E.
- Die Stärke = 2006 v.58 no.7 pp. 323
- kiwifruit, Actinidia deliciosa, starch, starch granules, amylose, physicochemical properties, X-ray diffraction, amylopectin, molecular weight, gelatinization, enthalpy, glass transition temperature, pasting properties, melting point, viscosity
- 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 µm or 7-9 µm. 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 (7.4x10⁷), and gyration radius (200 nm). Average amylopectin branch chain-length was long (DP 28.6). Onset and peak gelatinization temperatures were 68.9°C and 73.0°C, respectively, and gelatinization enthalpy was high (18.5 J/g). Amylose-lipid thermal transition was observed. Starch retrograded for 7 d at 4°C had a very high peak melting temperature (60.7°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°C) was marginally higher than onset gelatinization temperature. High paste viscosities and low pasting temperature could give kiwifruit starch some advantages over many cereal starches.