低酯果胶的凝胶质构性能研究

以X-T21型质构仪为主要研究设备,重点研究了低酯果胶凝胶性能和相关影响因素。研究结果表明,提高低酯果胶浓度和体系pH、适当降低凝胶形成温度是增强凝胶质构性能的有效手段;在几种金属离子中,铜离子促进凝胶形成的能力最强,但其离子浓度必需适中,否则过量的离子会对凝胶性能产生负面影响;低分子糖类成分并非低酯果胶凝胶形成的必备成分,但适量糖类的添加有助于凝胶性能的提高;加热及高速搅拌处理对已经形成的凝胶结构椲产生一定破坏作用。     

低甲氧基果胶凝胶特性的研究

以桥联作用为基础，研究了低甲氧基果胶与多价金属离子形成桥联时的数量关系，以及不同金属离子，ＰＨ值对ＬＭＰ凝胶速度，质地，稳定性的影响，为解决ＬＭＰ在应用中存在的脱水，凝胶不匀等现象提供了科学依据。     

低酯果胶的提取与制备技术研究进展

低酯果胶因为其独特的凝胶、增稠特性和风味被广泛应用于传统食品工业中,最近低酯果胶在医药保健中的作用也被大量报道,然而由于生产技术和设备的限制,我国实现工业化生产厂家分布零星,规模也较小,国民日益增长的需求依然需要进口满足,成本昂贵。该文综述近20年国内外低酯果胶的酸法提取、酸法脱酯、碱法脱酯,酶法脱酯、酰胺化技术和其他新兴提取制备方法,同时对目前低酯果胶的研究和应用趋势进行展望,以期能为我国低酯果胶生产应用提供有价值的信息。     

果胶酯酶制备低酯果胶的研究进展

随着对低糖、低热量食品的需求日益增大,低酯果胶已供不应求。果胶酯酶脱酯制备低酯果胶是一种生产效率极高的方法,对解决国内低酯果胶供不应求的难题将有极大帮助。本文综述了国内外果胶酯酶制备低酯果胶的研究进展。      

果胶酯酶制备低酯果胶的研究进展

随着对低糖、低热量食品的需求日益增大,低酯果胶已供不应求。果胶酯酶脱酯制备低酯果胶是一种生产效率极高的方法,对解决国内低酯果胶供不应求的难题将有极大帮助。本文综述了国内外果胶酯酶制备低酯果胶的研究进展。     

低酯果胶协同NaCl对全蛋液凝胶性质的影响

通过添加低酯果胶(low ester pectin,LEP),与NaCl协同使用改善全蛋液凝胶性质.以鲜蛋为原料,研究NaCl添加量(0.10％、0.15％)和LEP添加量(0.10％、0.20％、0.30％)对全蛋液凝胶性质及微观结构的影响,并结合理化性质的变化对其原因进行分析.研究表明,在NaCl添加量为0.10％...     

碱化法制备低酯果胶工艺研究

果胶是苹果渣中最为主要的功能性成分.以从苹果渣中提取的高酯果胶为原料,研究碱化法制备低酯果胶的工艺技术条件.通过单因素试验分别探讨pH值、温度和反应时间对低酯果胶得率的影响,并在此基础上设计出三因素三水平的正交试验,得出碱化法制备低酯果胶的最优工艺条件为:pH=9.0,反应温度36℃,反应时间1.5 h.     

低甲氧基果胶凝胶条件的研究

本试验研究了在低糖条件下,低甲氧基果胶(LMP)使用浓度、钙试剂种类及添加量、溶液的pH值对低甲氧基果胶形成凝胶的影响。采用正交试验L9(4^3)得出最佳凝胶组合,旨在用于低糖食品的开发。     

酰胺化果胶的特性、应用及研究现状

本文将酰胺化果胶与普通低酯果胶以及高酯果胶进行了多方面的比较，重点介绍酰胺化果胶的特性。结合国内外对酰胺化果胶生产和研究的状况，及其在食品工业和医疗方面的应用现状，对酰胺化果胶生产的开发前景进行了分析。     

低酯大豆皮果胶球状凝胶水分吸附与解吸行为

本文主要研究不同钙离子质量分数对大豆皮低酯果胶球状凝胶吸附及解吸水分行为的影响,并通过热重分析及差热热重分析方法获得水分解吸动力学参数。结果表明,钙离子浓度对凝胶球体的水分吸附及解析均有较大影响,当钙离子浓度在80mmol/L以上时,吸附水分能力较强,且随钙离子浓度的增加而无显著变化。动力学研究表明,当钙离子浓度为120mmol/L时,指前因子及活化能均最大,表明此时果胶分子链结合位点均匀,形成的凝胶网络结构较致密,水分解吸的能量位垒高。     

Rheological behaviour of low-methoxyl pectin gels over an extended frequency window

The rheological behaviour of biopolymer gels is commonly investigated by means of small amplitude oscillatory measurements. This consolidated approach was used in the present paper to characterize the influence of ionic strength and temperature on the gelation of commercial low-methoxyl pectin (LMP) (DE = 22.5%). The main results showed that the sol/gel transition is very sensitive to the ionic strength of the medium, while the viscoelastic properties of the gel structure, developed over 8 h cure test, were retained up to 60 °C. The soft material under study displays the typical rheological behaviour of a solid-like material, in good agreement with results previously reported in the literature. It is known that the best time or frequency window useful to explore in dynamic mode the viscolelastic behaviour of complex materials such as a gel would range over several decades of frequency. The possibility to extend the frequency domain of the dynamic tests in the region of the lower frequencies (10⁻⁵–10² rad s⁻¹) was therefore investigated by matching information coming from dynamic and transient rheological tests and converting data from time domain into frequency domain throughout the discrete retardation spectrum of the material, as described by Kaschta [Kaschta, J., & Schwarzl, F. R. (1994). Calculation of discrete retardation spectra from creep data - I. Method. Rheologica Acta, 33, 517-529.].     

酰胺化果胶的特性、应用及生产和研究状况

对果胶类型做了概括介绍,将酰胺化果胶与普通低酯果胶以及高酯果胶进行多方面的比较,突出酰胺化果胶的特性。结合国内外对酰胺化果胶生产的研究现状,以及其在食品工业和医疗方面的应用现状,对酰胺化果胶生产的发展前景进行了分析。     

羧甲基纤维素钠对低酯果胶凝胶流变特性及凝胶形成的影响

为探究羧甲基纤维素钠(sodiuncarboxy methyl cellulose,CMC)在低酯果胶凝胶形成过程中的作用,以低酯果胶为原料,在pH 5.5下加入不同用量的CMC,考察复配后果胶凝胶的流变学性能,并对其凝胶形成进行了动力学分析。结果表明,CMC/低酯果胶复配体系是典型的假塑性流体,随着CMC添加量的增大,CMC/低酯果胶复配体系的黏度系数K增大,流体系数n减小。CMC的加入还能提高凝胶体系的黏性与弹性,当CMC的添加量为0.8%时,果胶凝胶体系的假塑性最强。同时,CMC还能提高凝胶形成速度,CMC添加量为0.8%时,SDR曲线和G'曲线明显上升,表现出较快的凝胶速度和较强的凝胶强度,当添加量大于0.8%时,凝胶形成速度下降。     

Textural properties of gelling system of low-methoxy pectins produced by demethoxylating reaction of pectin methyl esterase

ABSTRACT:  After deesterification of commercial pectins with a pectin methyl esterase (PME), their gelling properties were characterized using instrumental texture analysis. The final degree of esterification (DE) of the high- and low-methoxy pectins reached approximately 6% after the PME treatment, while deesterification of low-methoxy amidated pectin stopped at 18% DE. Furthermore, DE of high-methoxy pectin was tailored to be 40%, which is equivalent to the DE of commercial low-methoxy pectin. As a result, significant changes in molecular weight (Mw) distribution were observed in the PME-treated pectins. The texture profile analysis showed that PME modification drastically increased hardness, gumminess, and chewiness, while decreasing cohesiveness and adhesiveness of the pectin gels ( P < 0.05). The pectin gel with relatively high peak molecular weight (Mp, 3.5 × 10⁵) and low DE (6), which was produced from high-methoxy pectin, exhibited the greatest hardness, gumminess, chewiness, and resilience. The hardness of low-methoxy amidated pectin increased over 300% after PME deesterification, suggesting that the effects of amide substitution could be reinforced when DE is even lower. The partial least square regression analysis indicated that the Mw and DE of the pectin molecule are the most crucial factors for hardness, chewiness, gumminess, and resilience of gel matrix.     

Comparison of full-fat and low-fat cheese analogues with or without pectin gel through microstructure, texture, rheology, thermal and sensory analysis

The effects of pectin gel and protein base on processed semi-solid cheese analogues were studied through microstructure, texture, rheology, thermal analysis and sensory evaluation. Scanning electron microscopy revealed differences in the microstructure of processed cheese analogues. Samples made with full-fat contained higher concentrations of fat globules and were denser compared with low-fat cheese analogues with or without pectin gel. The pectin gel in the products acted as a linkage with other ingredients and made the products more compact and had less cavity compared with the products without pectin gel added. On rheological analysis, the full-fat products manifested a more solid-like form. The storage modulus of pectin gel sample was higher than that without pectin gel. All the samples' rheological parameters were depending on the oscillatory frequency and temperature. In low-fat samples, pectin gel added or not affected the hardness, gumminess, chewiness and adhesiveness significantly. The pectin gel addition show positive effect to the texture profile of the low-fat cheese analogues. Through thermal analysis, the meltability and glass transition temperature of the processed cheese analogues were measured. The low-fat cheese analogue with pectin gel addition got the higher texture and mouthfeel scores through sensory evaluation.     

Improving pectin technology.

The effect of ultrasonic treatment on pectin stability in aqueous solution was studied to establish conditions which minimized degradation. Pectin was extracted under these conditions with an increased yield and without reducing the drainage properties of the extracted fruit mass. A pulsed ultrasonic method in aqueous acidic medium was developed, successfully tested with three different apple pomace samples, and its advantages demonstrated.     

柚皮果胶理化性质的研究

以柚皮干粉为原料提取果胶,采用正交实验优化柚皮果胶提取工艺,并对其理化性质进行检测。研究表明在提取温度100℃,pH2.0,时间60min,料液比1∶50(g/mL)的条件下柚皮果胶的得率最高,为27.06%,纯度达84.3%,酯化度为73.75%,所得果胶为淡黄色。常温下pH为4.86,属于酸性高酯果胶。柚皮果胶的溶解度随温度升高而增大、随着pH增大,溶解度有下降的趋势;柚皮果胶的热稳定性优于商品果胶,但随着时间增加迅速降低,15min后趋于稳定;柚皮果胶粘度与果胶浓度和蔗糖浓度的正相关,随pH的增大和温度的升高而下降;柚皮果胶理化性质与商品柑橘果胶相似,柚皮果胶的粘度和乳化性能优于商品柑橘果胶。实验结果表明柚皮果胶是一种优质的果胶。      

鸡胸肉肌原纤维蛋白的提取及凝胶特性的研究

研究从鸡胸肉中提取肌原纤维蛋白，探讨不同pH值对肌原纤维蛋白含量的影响。研究结果：在pH7．0时，蛋白含量最大为69．74％，通过SDS—PAGE凝胶电泳分析表明，其主要成分为肌球蛋白、肌动蛋白和肌动球蛋白及其他一些小分子肌原纤维蛋白碎片；在离子强度0．6、pH7．0时提取的肌原纤维蛋白所制备的凝胶的保水性、硬度、胶粘性最大。