Kanya T C Sindhu, Sankar K Udaya, Sastry M C Shamnathaka
Department of Protein Chemistry and Technology, Central Food Technological Research Institute, Mysore, India.
Plant Foods Hum Nutr. 2003 Spring;58(2):179-96. doi: 10.1023/a:1024419914808.
The sunflower seed waxes obtained from two sources (i) seed hull as a standard and (ii) crude wax from oil refineries were studied for their crystallization, melting characteristics and morphology of crystals. The results of differential scanning calorimetry of wax obtained from seed hulls showed the melting temperature range of 13.18 degrees C with the onset at 62.32 degrees C, for purified wax, compared to the melting range of 24.73 degrees C with the onset at 42.3 degrees C. for crude wax. The enthalpy of fusion for both waxes were 57.55 mcal/mg and 7.63 mcal/mg, respectively. The DSC melt crystallization temperature range was 15.79 degrees C with the onset of 64.58 degrees C for purified wax and temperature range of 31.45 degrees C with an onset of 57.76 degrees C for crude wax. A similar pattern was observed of wax obtained from the crude wax of oil refineries. The enthalpy of crystallization was -64.27 mcal/mg and -7.67 mcal/mg, respectively. The purified wax obtained from the two sources (i) and (ii) were comparable with completion temperatures of 75.5 degrees C and 75.1 degrees C, respectively. The effect of inhibitor (lecithin) on crystallization of purified wax under light microscope and surface structure by scanning electron microscope were observed. Lecithin at 0.2% inhibited the crystallization but nucleation was unaltered. The wax crystal was inhibited to around 60% of the original size with 0.2% lecithin. It is concluded that the sunflower waxes studied were not comparable in their crystal properties of crude and purified states. Lecithin inhibited the crystallization of sunflower seed wax.
对从两个来源获得的向日葵籽蜡进行了研究，这两个来源分别是：（i）作为标准的种皮，以及（ii）炼油厂的粗蜡，研究内容包括它们的结晶、熔化特性以及晶体形态。从种皮获得的蜡的差示扫描量热法结果显示，纯化蜡的熔化温度范围为13.18℃，起始温度为62.32℃，而粗蜡的熔化范围为24.73℃，起始温度为42.3℃。两种蜡的熔化焓分别为57.55 mcal/mg和7.63 mcal/mg。纯化蜡的DSC熔体结晶温度范围为15.79℃，起始温度为64.58℃，粗蜡的温度范围为31.45℃，起始温度为57.76℃。从炼油厂粗蜡中获得的蜡也观察到了类似的模式。结晶焓分别为-64.27 mcal/mg和-7.67 mcal/mg。从（i）和（ii）两个来源获得的纯化蜡的完成温度分别为75.5℃和75.1℃，具有可比性。通过光学显微镜观察了抑制剂（卵磷脂）对纯化蜡结晶的影响，并通过扫描电子显微镜观察了其表面结构。0.2%的卵磷脂抑制了结晶，但成核未受影响。0.2%的卵磷脂使蜡晶体尺寸抑制到原始尺寸的约60%。得出的结论是，所研究的向日葵蜡在粗态和纯化态的晶体性质方面不具有可比性。卵磷脂抑制了向日葵籽蜡的结晶。
