Abstract:The physicochemical characteristics of pumpkin starches from three cultivars (Miben, Dongshen and Cuili) were comparatively studied. The results showed that crude fat contents in three pumpkin starches varied between 0.15% and 0.25%, while crude protein varied between 0.09% and 0.57%. The amylose contents changed between 26.4% and 29.0%, and soluble amylose contents ranged between 4.48% and 7.40%. Dongshen pumpkin starch showed apparently higher contents of amylose and soluble amylose than the other two pumpkin starches. Scanning electron microscopy showed that pumpkin starches consisted of oval granules at the size of 5~15 μm with an average diameter around 10 μm. X-ray diffraction studies showed that all pumpkin starches exhibited a B-type diffraction pattern and the degrees of crystallinity were 30.9%, 42.7% and 43.3%, respectively. The ranges of initial and terminated gelatinization temperature of Dongsheng and Cuili pumpkin starches were 73.21~82.76 ℃ and 78.66~89.88 ℃, respectively. While MiBen pumpkin starch had a bimodal phenomena with two gelatinization temperature ranges being of 69.00~75.67℃ and 77.70~86.17 ℃. MiBen pumpkin starch had the lowest solubility, swellability and sediment stability, but the highest paste light transmittance. Dongsheng pumpkin starch had low solubility and paste light transmittance, but moderate to good sediment stability and freeze-thaw stability. CuiLi pumpkin starch had the highest solubility and swell-ability, but showed the lowest freeze-thaw stability.
