Structure and functional properties of starches from Chinese ginkgo (Ginkgo biloba L.) nuts

Starch from the nuts of three cultivars (Dafozhi, Longyan and Qixingguo) of Chinese ginkgo (Ginkgo biloba L.) grown in Taixing, China was isolated and variability in composition, morphology, molecular structure and functional properties was evaluated. The starch granules of these ginkgo cultivars were oval or spherical in shape, with smooth surfaces and sizes in the range of 5-20 μm. Longyan starch had the lowest amylose content (28.51%), whereas Dafozhi starch had the highest (33.82%). Longyan starch had the highest average chain length (19.1) and the lowest proportion of short branch chains (DP 6-12, 19.6%). The order of crystallinities of the ginkgo starches was Longyan (34.63%) > Qixingguo (31.66%) > Dafozhi (30.74%). Longyan starch had the highest gelatinization temperature, melting enthalpy, and breakdown viscosity, whereas Dafozhi starch had the lowest gelatinization temperature, melting enthalpy, and breakdown viscosity. The ginkgo starches retained a large portion of slowly digestible starch and resistant starch (79.3%-82.4%). Results suggest that the starch from Longyan cultivars might have some advantages over the other two starches.

► The structural and functional properties of chinese ginkgo starches were studied. ► Physicochemical properties and digestibility varied from different ginkgo cultivars. ► Longyan has the highest ordered crystal structure compared to Dafozhi or Qixingguo. ► Molecular structure of starch is important for functional properties.