CAJ | 학술논문

为了进一步了解卵磷脂在果胶凝胶中的作用，该文考察卵磷脂对果胶凝胶流变性的影响，以低酯苹果果胶为原料，在钙离子浓度为12 mmol/L条件下，加入质量分数0.2%～1.2%的卵磷脂，考察凝胶过程中储能模量（G′）与损耗模量（G″）变化。通过凝胶结构形成速度（structure developing rate，SDR）流变学分析方法探讨在果胶凝胶过程中卵磷脂对凝胶体系的影响，结果显示：卵磷脂的添加对果胶钙凝胶的形成速度（SDR）和储能模量（G′）有影响，在整个温度变化范围内，卵磷脂添加量小于0.4%时对SDR曲线和G′曲线的影响不明显；卵磷脂添加量为0.4%时SDR曲线和G′曲线明显上升，显示出较快的凝胶速度和较强的凝胶强度；当卵磷脂添加量大于0.4%时，SDR曲线和G′曲线下降。凝胶形成动力学研究显示，加入0.4%的卵磷脂，使果胶的凝胶过程在高温区和低温区的差别更大，活化能差别也较大（P<0.05）：高温区活化能为290.6 kJ/mol，低温区活化能为67.1 kJ/mol。电镜扫描显示添加0.4%卵磷脂的果胶钙凝胶结构更为均匀紧密。研究结果为卵磷脂/果胶体系的应用提供理论参考数据。
위료진일보료해란린지재과효응효중적작용，해문고찰란린지대과효응효류변성적영향，이저지평과과효위원료，재개리자농도위12 mmol/L조건하，가입질량분수0.2%～1.2%적란린지，고찰응효과정중저능모량（G′）여손모모량（G″）변화。통과응효결구형성속도（structure developing rate，SDR）류변학분석방법탐토재과효응효과정중란린지대응효체계적영향，결과현시：란린지적첨가대과효개응효적형성속도（SDR）화저능모량（G′）유영향，재정개온도변화범위내，란린지첨가량소우0.4%시대SDR곡선화G′곡선적영향불명현；란린지첨가량위0.4%시SDR곡선화G′곡선명현상승，현시출교쾌적응효속도화교강적응효강도；당란린지첨가량대우0.4%시，SDR곡선화G′곡선하강。응효형성동역학연구현시，가입0.4%적란린지，사과효적응효과정재고온구화저온구적차별경대，활화능차별야교대（P<0.05）：고온구활화능위290.6 kJ/mol，저온구활화능위67.1 kJ/mol。전경소묘현시첨가0.4%란린지적과효개응효결구경위균균긴밀。연구결과위란린지/과효체계적응용제공이론삼고수거。
Pectins were traditionally applied in food industry as well as other industries such as pharmaceutical industry as typical gelling, emulsifying, thickening and stabilizing agents. Lecithin, a highly compatible lipid and an important constituent of biological membranes, is applied to the pectin gel as a colon-specific carrier in recent years. In order to investigate the gel properties of pectin, the effects of soybean lecithin on the rheological properties of low-methoxyl apple pectin gels were studied in this paper. The weight average molecular weight of pectin obtained by the size exclusion chromatograph method was 1.27×105, the number average molecular weight was 3.77×104, and thus the molecular weight distribution index was 3.36. In the presence of calcium ion, adding different proportions of lecithin to low-methoxyl apple pectin, the storage modulus (G') and loss modulus (G") were recorded through the observation during the gelation process of the pectin, when the plate was cooled from 80 to 26℃ at a certain rate with the rheological technology. Then the structure development rate (SDR) analysis method was adopted to explore the effects that the presence of lecithin brought to the gelation system in the gelation process of pectin. The results showed that the addition of lecithin had significant effects on SDR andG'. With a low amount of lecithin (<0.4%) added into the pectin gel, both SDR andG’ had no considerable changes in comparison with the low-methoxyl pectin calcium gel without lecithin; with a higher amount (0.4%), a significant increase inSDR andG' suggested a faster gel development rate and a stronger strength of gel than the sample without lecithin, which indicated that adding lecithin could promote the formation of the pectin gel. However, with a much higher amount (>0.4%), SDRandG' tended to decrease. The average structure developing rate and the end storage modulus showed the same tendency as above; when adding 0.4% lecithin, the average structure developing rate increased to 4.2 Pa/s and the end storage modulus increased to2950 Pa; both of them were significantly higher than the sample without lecithin (P<0.05). Loss tangent curves of all gel samples showed the same trend that the loss tangent began to decrease while the temperature dropped. But when adding 0.4% lecithin, the loss tangent of pectin calcium gel was the lowest, which indicated the best elasticity. Then a non-isothermal kinetic model, which described the storage modulus change during the gelation induced by cooling dispersions, was adopted for analysis. Pectin gelation could be described by a two-step process corresponding to 2 different temperature ranges. Adding suitable amount of lecithin (0.4%) resulted in more obvious difference between the pectin gelation processes of the 2 temperature districts as well as the values of activation energy, which were 290.6 kJ/mol for high temperature district and 67.1 kJ/mol for low temperature district. Finally, after the vacuum freeze drying treatment, the scanning electron microscopy showed that the three-dimensional network structure of pectin calcium gels added with 0.4% lecithin was characterized by greater uniformity and compactness. The research results will provide a theoretical basis and reference for the application of the system of lecithin pectin gel.