【作者】 孙昌波；

【导师】 李忠海； 钟海雁；

【作者基本信息】 中南林业科技大学 ， 林产化学加工工程， 2010， 博士

【摘要】 本文研究了蕨根淀粉高效提取工艺及过氧化氢漂白技术,研究了蕨根淀粉的糊化特性、流变特性、老化特性及膨化特性,为蕨根淀粉的深加工提供理论参考。蕨根淀粉提取的最佳工艺条件为石灰水的pH8.0,料液比1：4,浸泡时间3h,沉降时间7h,在此工艺条件下,淀粉的提取率为82.61%。蕨根淀粉中含有丰富的果胶、灰分、粗脂肪和蛋白质,直支比0.21-0.25。蕨根淀粉的溶解度和膨胀度较高。蕨根淀粉颗粒形状复杂,有球形、椭球形、肾形及多边形,颗粒表面光滑,不整齐,脐点位于一侧。蕨根淀粉颗粒长轴长度为4.6-24.3(平均11.9)u m,偏光十字清晰可见,偏光十字呈黑十字或“X”形。蕨根淀粉在20为5.8°、14.3°、15.6°、23.2°处出现明显的衍射峰,蕨根淀粉颗粒的结晶结构属于C型,结晶度为38%左右,其中微晶点14%,亚晶点24%。蕨根淀粉白度较低,过氧化氢漂洗能显著增加蕨根淀粉的白度。最佳漂白条件下,淀粉白度增加45.3%-132.4%。漂白之后,极少数淀粉颗粒表面出现凹陷和裂纹,绝大多数淀粉颗粒无变化。漂白对淀粉的偏光十字结构、X-射线衍射图谱基本没有影响,漂白前后化学成分的含量差异较小。经过漂白之后,淀粉的溶解度有所增加,抗冻能力明显增强。蕨根淀粉的糊化温度介于55-76℃之间,糊化焓AH为9.65 J／g。通过RVA分析可知：蕨根淀粉的峰值粘度高于玉米淀粉,低于马铃薯淀粉,但蕨根淀粉的谷值粘度、最终粘度、消减值比玉米淀粉、马铃薯淀粉都高,蕨根淀粉的崩解值小于马铃薯淀粉,大于玉米淀粉,表明蕨根淀粉抗剪切能力优于马铃薯淀粉。蕨根淀粉的峰值粘度时间随着盐用量的增加而推迟,盐能增强蕨根淀粉的热稳定性和抗剪切能力,盐对马铃薯淀粉、玉米淀粉的糊化温度影响不大,但盐明显提高了蕨根淀粉的峰值糊化温度,且蕨根淀粉和玉米淀粉的峰值粘度时间随着盐用量的增加而推迟；马铃薯淀粉的峰值粘度明显降低,而盐对蕨根淀粉、玉米淀粉的峰值粘度影响不大,在含盐条件下,蕨根淀粉的粘度明显高于马铃薯淀粉和玉米淀粉。pH值对蕨根淀粉的糊化温度没有影响,但对蕨根淀粉糊的粘度有明显影响,酸性环境中,峰值粘度、谷值粘度和最终粘度均较低,三种淀粉均在偏中性条件下呈现最低崩解值,表明极端pH条件可能会破坏淀粉的热稳定性,在强酸强碱性条件下,蕨根淀粉的崩解值小于马铃薯淀粉,所以蕨根淀粉的酸碱稳定性优于马铃薯淀粉。蔗糖使蕨根淀粉的峰值粘度、谷值粘度、最终粘度及崩解值均有所上升,表明蔗糖增强了淀粉的糊化和抗老化性能,并且破坏淀粉的热稳定性。蕨根淀粉糊的冻融稳定性较差,只经冻融一次就有水分析出。蕨根淀粉糊具有明显的触变性,存在“剪切稀化”现象。蕨根淀粉糊的粘度随着淀粉浓度、蔗糖浓度的增加而增加,随着转速、温度、氯化钠浓度的增加而下降。pH=10.0左右时,淀粉糊的粘度最大。蕨根淀粉凝胶稠度明显高于马铃薯淀粉和玉米淀粉,达120.75,为软胶凝度。蕨根淀粉糊在老化过程中,粘度先上升后下降,淀粉糊透光率降低。蕨根淀粉比玉米淀粉老化速度慢。老化过程中,淀粉糊的网络结构发生凝聚,体系的非均相性变大,特征衍射峰的强度不断增大,衍射曲线的总面积不断变大,结晶度也逐渐增加,无定形区域逐渐减小。老化主要发生在糊化后24h内。蕨根淀粉在强酸、强碱时凝沉稳定性较好。氯化钠使凝沉稳定性下降。葡萄糖和蔗糖都能使淀粉糊凝沉稳定性提高,且随着浓度的提高,其效果越明显。采用微波膨化时,膨化蕨根淀粉硬度与葛根淀粉相当而远小于马铃薯淀粉,孔隙率明显大于葛根和马铃薯淀粉；采用油炸膨化时,蕨根淀粉的膨胀率大于葛根和马铃薯淀粉,硬度与葛根淀粉相当而远小于马铃薯淀粉,孔隙率明显小于葛根和马铃薯淀粉。在微波膨化加工过程中,食盐、碳酸氢钠、蔗糖及油脂的添加均降低了淀粉的膨化倍数；食盐使膨化产品孔隙变大,糖及油则使其变小；食盐、碳酸氢钠、油脂的添加量越大产品的硬度越大,食盐的添加尤为明显,而蔗糖在低浓度时降低产品硬度,高浓度时则提高产品硬度。在油炸膨化加工过程中,食盐、碳酸氢钠、蔗糖及油脂的添加降低淀粉的膨化倍数；食盐、碳酸氢钠及糖的添加使膨化产品孔隙变大,而油则使其变小；食盐、碳酸氢钠、油脂的添加量越大,产品的硬度越大,碳酸氢钠的添加尤为明显,而蔗糖在低浓度时降低产品硬度,高浓度时则提高产品硬度。更多还原

【Abstract】 Fernery is roots of pteris fern plants, rich in starch, which is edible after prepared and applied to the food and pharmaceutical industries. The process of washing method and hydrogen peroxide bleaching of four samples was optimized. The pasting properties, rheological property, aging properties and puffing characteristics of fernery starch were studied and analyzed as well as the affects of the factors of processing on properties of fernery starch.The optimum conditions for extracting fernery were Limewater pH8.0, ratio of sample and water 1:4, extracting time 3 hours, subsiding time 7 hours. On these conditions, the starch extraction ratios were above 82.61%.The visible black polarization was observed by the polarizing microscopy, showing a black cross or "X"-shaped. The crystalline pattern of fern starch was C type. The shape of fern starch granule was various, irregularly, and its starch content was over 6.0%. Meanwhile, the content of fat and pectin in fernery starch were more than others, and bleaching technics had less effection to granule characteristic. With temperature rising, both solubility and turgidity values of fernery starch were inclined to increase.The bleaching with H2O2 improved the color effectively; the whitness increased 45.3%-132.4% in the optimazed conditions. And the effect of blaching on the micro-structure of starch was less. The solubility was improved a little during bleaching, and freezing stability was improved great during bleaching.Gelatinization temperature of four fernery starchs is between 55℃and 76℃. Freeze-thaw stability of starch paste was worse than potato starch, but better than corn starch. The transmittance value of fernery starch’s starch paste was lower. And it got higher as the pH value and the sugar concentration value increasing, and got lower as 1% and 3% NaCl or CaCl2 added.The analysis by RVA shows:with the increasing of concentration of starch, peak viscosity, final viscosity and breakdown value improved remarkably; with the salt concentration increasing, the peak viscosity and final viscosity inproved while breakdown value droped; the lowest value of peak viscosity, final viscosity appear in strong acid condition while the peak viscosity, final viscosity were higher in neutral and alkaline condition; as the concentration of sucrose increasing, the peak viscosity, final viscosity and breakdown value improved, too.Four samples all have thixotropy, which was increase in sample 1 and the others decreased. Viscosity of four samples was increased with the increased starch concentration, sugar concentration, decreased with the increasedspeed, temperature, concentration of NaCl; The viscosity decreased in strong acid and strong alkaline conditions. The stinffess of gel was 120.75, which was degree of soft condensed.The study shows that the retrogradation was occurred during the paste storage by optical microscope and X-diffraction analysis. Starch paste viscosity was increased and then decreased during 72 hour’s storage; the euphotic ratio was decreased, too.The retrogradation stability of paste was stable both in strong acid and in strong alkali. It decrease in 1-3% NaCl, glucose and sucrose can make starch retrogradation increased, sucrose was better than glucose.Fernery starch showed stability both in microwave puffing and fried puffing, which was hindered by the existence of salt, sodium bicarbonate, sucrose and fat; the more the concentration of salt, sodium bicarbonate and fat are, the more the hardness of the production will be. Salt has a great effect on microwave puffing of starch while so do sodium bicarbonate on fried puffing. The hardness of production was improved in low concentration of sucrose while was decreased in high. Salt make the pore of puffing production bigger, and fat make it small. Sodium bicarbonate enlarge pore of fried puffing production, but has almost no effect on microwave puffing production; Sugar enlarge the pore ofthe fried puffing production, but reduce which of the microwave puffing production.更多还原