不同盐离子对豌豆淀粉/低酯果胶复配体系理化特性的影响

以豌豆淀粉(pea starch, PS)和低酯果胶(low methoxyl pectin, LMP)为原料,将二者按质量比8.5∶1.5混合后形成豌豆淀粉/低酯果胶(PS/LMP)复配体系,考察在不同浓度(0.1、0.5、1.0 mol/L)及不同种类(NaCl、CaCl_2、KCl)的盐离子作用下,复配体系流变、质构、糊化等理化特性的变化情况。结果表明,3种盐离子均提高了复配体系的抗剪切性能,但未改变复配体系的非牛顿流体特征,复配体系的稠度系数K随盐浓度增大而增大,流体指数n变化较小。盐离子能降低复配体系的弹性性能,提高体系的黏性比例。K~+能显著增强复配体系的硬度,而Ca~(2+)对复配体系的黏着性与咀嚼性的影响较大。盐离子会影响复配体系的糊化特性,其中Ca~(2+)的影响最为显著,复配体系的峰值黏度和糊化温度在Ca~(2+)存在时大幅增加,崩解值也随之增加,而回生值则呈下降趋势。观察淀粉颗粒结构发现,盐离子抑制淀粉吸水膨胀,对淀粉起到一定的保护作用,而这种作用以二价离子更为显著。说明盐离子对PS/LMP复配体系的流变、质构、糊化等理化特性有较大影响,其影响程度总体表现为Ca~(2+)K~+Na~+。     

不同盐离子对κ-卡拉胶凝胶质构及流变学性质的影响

研究了盐离子的种类和浓度对κ-卡拉胶凝胶质构及流变学性质的影响。试验结果表明,在2~10g/L浓度范围内,K~+、Na~+、Mg~(2+)、Ca~(2+)四类盐离子均可增加κ-卡拉胶凝胶强度和弹性,降低κ-卡拉胶的黏度和内聚性,胶黏性和咀嚼性呈先增大后减小的趋势,其中钾盐对凝胶强度的提高幅度最大,K+含量1%时,凝胶硬度为14.12N。流变学研究表明,κ-卡拉胶的凝胶温度与盐离子浓度呈正相关关系。25℃条件下0.2%的各类盐离子添加量时,κ-卡拉胶凝胶复合黏度明显增加,以添加Ca~(2+)的凝胶的复合黏度变化最为显著,复合黏度为58.81×105m Pa·s。     

刺云实胶与黄原胶复配体系质构及流变性研究

将总浓度为1%的刺云实胶(TG)与黄原胶(XTG)按照不同的质量比复配,采用质构仪和流变仪对复配体系的凝胶特性和流变学特性进行测定,通过Carreau模型对流动曲线进行拟合分析,并利用电子扫描显微镜分析复配体系网络形成机理。结果表明:在质构分析中TG与XTG质量比为64时有最大的凝胶强度;在流变分析中TG与XTG质量比为64时呈现最大表观黏度并且在频率扫描和温度扫描中表现出最大的储能模量(G′)。因此,TG与XTG的最佳复配比例为质量比64。在pH为5～10时,最佳复配比例体系的黏度保持相对稳定;当添加盐离子(Na+、Ca2+)后,体系黏度降低,Ca2+降低的趋势更为显著。通过电子扫描显微镜(SEM)分析,表明在TG与XTG之间存在明显的协同增效作用,可形成良好的凝胶网络结构。     

银耳多糖与结冷胶复配体系的流变及凝胶特性

对不同质量浓度的银耳多糖溶液、结冷胶溶液（均为0.4、0.8、1.2、1.6、2.0 g/100 mL）及不同质量比（1.6∶0.4、1.2∶0.8、0.8∶1.2、0.4∶1.6）的银耳多糖/结冷胶复配体系的流变和凝胶特性进行研究,初步探讨其相互作用机理。结果表明,随着银耳多糖质量比的提高,复配体系的表观黏度和动态黏弹性增加,储能模量（G’）和损耗模量（G”）增加。复配体系的触变环随银耳多糖质量比例的增加而减小,说明银耳多糖可以改善复配体系的触变性。质构分析和持水性测试结果表明,结冷胶是银耳多糖/结冷胶复配凝胶强度和硬度的决定性因素,银耳多糖可以明显提高复配体系的弹性、黏性和持水性。基于傅里叶变换红外光谱和低温扫描电子显微镜分析,初步判断在复配体系中银耳多糖与结冷胶之间存在相互作用,形成了凝胶网络结构。     

低酰基结冷胶酸性凝胶的凝胶特性

以葡萄糖酸-δ-内酯(glucono-δ-lactone,GDL)作为酸诱导剂,制备低酰基结冷胶(low acyl gellan gum,LA)酸性凝胶,考察基体质量浓度、GDL/LA复配比例以及酸液浸泡对酸性凝胶凝胶特性的影响。研究结果表明,GDL酸化为缓慢酸化,GDL/LA复配比例越高、体系的pH值越低,酸化速率越快。基体质量浓度和GDL/LA复配比例对酸性凝胶结构影响显著,断裂应力和保水性随着GDL/LA复配比例的增大先升高后降低。基体质量浓度越高,断裂应力和不透明性越大。GDL/LA复配比例增大,断裂应变减小,不透明性增大。当酸液pH值为1时,酸液浸泡对GDL/LA复配比例为2∶1和4∶1的酸性凝胶强度无影响,但GDL/LA复配比例为1∶4、1∶2和1∶1时,凝胶强度随浸泡时间的增加而增强,酸液浸泡可以促使酸性凝胶进行结构重建。     

钙离子对小麦淀粉-低酯甜菜果胶复配体系糊化和流变特性的影响

以小麦淀粉(WS)和低酯甜菜果胶(LP)为原料组成复配物体系，研究钙离子添加(0.5，1.0，1.5 mmol/L)对WS/LP复配体系糊化和流变特性的影响。结果表明:随着钙离子添加量的提高，复配体系的峰值黏度、崩解值、终值黏度和回生值均显著增加(P<0.05)。添加钙离子后，复配体系屈服应力(σ0)提高，稠度系数(K)降低，仍表现出剪切变稀的特征，而复配体系的储能模量(G′)和损耗模量(G")均随添加量的增加呈逐渐增加的趋势。钙离子提高了复配体系的硬度、胶着性和咀嚼性，而体系的内聚性未发生显著变化(P>0.05)。红外光谱结果表明添加钙离子后复配体系未形成新的共价键。此外，微观结构结果显示，随钙离子浓度的增加，复配体系的孔径增大，孔壁厚度增加。钙离子可显著改善WS/LP复配体系的糊化和流变性质，研究结果可为WS/LP复配体系在食品中的应用提供参考。     

不同条件下锦橙皮渣果胶的黏度分析

以传统酸提取法从榨汁后锦橙皮渣中提取的果胶为研究对象,研究在不同果胶质量浓度、温度、pH值、蔗糖质量浓度、NaCl浓度和钙离子浓度条件下,果胶溶液的黏度随剪切速率的变化情况。结果表明:锦橙皮渣果胶溶液是典型的假塑性非牛顿流体,随着温度的上升,果胶溶液的黏度不断下降,在100℃条件下,果胶溶液表现出了牛顿流体的性质。在较高和较低pH值环境下都会导致果胶溶液黏度的下降。果胶溶液的黏度随着蔗糖质量浓度和钙离子浓度的增加而增大,而随NaCl浓度的增加先增大后减小。     

亚麻籽复配胶体系性质分析

分析亚麻籽复配胶体系性质,研究总胶浓度、钾、钠、钙离子浓度,以及柠檬酸浓度、温度和蔗糖浓度对亚麻籽复配胶体系性质的影响。以魔芋胶、卡拉胶、亚麻籽胶为原料制备亚麻籽复配胶,测定亚麻籽复配胶体系的质构、凝胶透明度、析水率,采用扫描电镜(SEM)、红外光谱检测魔芋胶、卡拉胶和亚麻籽胶复配前后的结构性质变化。实验表明:当总胶浓度增大,亚麻籽复配胶的凝胶透明度和析水率均降低。随着NaCl浓度的增大,亚麻籽复配胶的体系析水率先减小后增大,凝胶透明度增加。增大KCl的浓度,亚麻籽复配胶的凝胶透明度和析水率均增大。增加CaCl_2的添加量,亚麻籽复配胶的析水率先增大然后降低再增大,凝胶透明度增大。亚麻籽复配胶的析水率随着柠檬酸添加量的增加而先增大后降低再增加,凝胶透明度先降低再增大。升高水浴温度,凝胶析水率先降低后增加,凝胶透明度增大。蔗糖浓度增大,亚麻籽复配胶析水率降低,凝胶透明度增大;由此可见3种胶体之间存在相互作用力。     

复配粉理化性质与米线质构性质关系的研究

将粳米粉与绿豆淀粉按照一定比例进行混合,得到粳米粉和绿豆淀粉的复配粉体系,并测定了复配粉体系的溶胀性质、糊化性质、凝胶质构性质和拉伸性质,研究了复配米粉体系的拉伸性质与米线质构性质的关系。结果表明:随着绿豆淀粉添加量比例的增加,复配米粉体系的总直链淀粉含量、可溶性直链淀粉含量和不溶性直链淀粉含量明显增加,峰值黏度、谷值黏度、末值黏度、硬度也显著性增加,咀嚼性、拉伸强度和表观弹性模量显著增加,85℃下的溶解度和膨润力显著上升;糊化温度显著降低;衰减值和回生值分别比粳米粉高了33.73 RVU和50.60 RVU;与单一体系相比,由复配粉体系制成的米线呈现较好的硬度、弹性、韧性、蒸煮性和物理性质。当绿豆淀粉∶粳米粉为1∶1时,其制得的米粉的质构性质最好。     

结冷胶-羧甲基纤维素复配胶性能的研究

利用全质构分析、离心分离和分光光度法研究了结冷胶-羧甲基纤维素（carboxyl methyl cellulose,CMC）的配比、离子种类和离子浓度对结冷胶-CMC复配胶质构、持水力以及透明度的影响。结果表明：复配胶硬度随结冷胶比例降低而降低;在离子浓度达到临界水平前随离子浓度增加而增加,临界水平之后随离子浓度增加而降低;添加钙离子比钠离子更容易得到高硬度的凝胶。总的来说,添加离子会降低凝胶的弹性和内聚性;适当的结冷胶和CMC比例可提高凝胶弹性和内聚性。降低结冷胶-CMC复配比例可提高复配胶的透明度。     

高酰基结冷胶/酪蛋白酸钠复合凝胶粘弹行为的研究

本文研究了酪蛋白酸钠浓度、结冷胶浓度、离子和测试条件对高酰基结冷胶/酪蛋白酸钠复合凝胶粘弹性的影响。结果表明:高酰基结冷胶/酪蛋白酸钠共混体系为典型的切力变稀流体,表观粘度随着酪蛋白酸钠浓度的升高而降低,而随着阳离子浓度的增大出现先增大后减小的变化趋势。压缩速度对复合凝胶硬度几乎无影响,而内聚性和弹性则随着压缩速度的增加而增大。内聚性随着压缩应变的增大出现先增大后减小的变化趋势。复合凝胶的硬度和弹性随着酪蛋白酸钠浓度的增加而下降,但复合凝胶的内聚性对酪蛋白酸钠浓度不敏感。高酰基结冷胶浓度越高,复合凝胶的硬度和弹性越大。相对于一价离子而言,二价离子形成的凝胶更强且用量更少。钾离子的添加对复合凝胶保水性影响较弱,而钙离子的添加则可以提高复合凝胶的保水性。     

Rheological characterization and activation energy values of binary mixtures of gellan

The present study determined the flow behavior and activation energy of high (HA) and low (LA) acyl gellan dispersions (0.2%) and their mixtures as a function of preparation temperature (25 and 90 °C) and of the presence or absence of Ca²⁺ (30 mM). Heated gellan mixtures containing calcium were acidified with δ-gluconolactone to obtain gels and determine linear viscoelasticity using the Kelvin–Voigt model. The studied dispersions showed non-Newtonian shear-thinning behavior. HA dispersions (with and without Ca²⁺) showed the highest activation energy values, 88.60 and 51.18 kJ/mol. Whereas, LA dispersions showed the lowest activation energy values, 3.73 and 9.19 kJ/mol. With respect to the rheological studies, it was observed that the relationships between HA and LA gellan did not affect the recovery percentages because similar values were obtained (86.90–90.00%), and this behavior along with the mean viscosity values obtained in the gel mixtures could indicate that the hydrogen bond formation between both gellan helix (HA, LA) is possible. These results can contribute to possible industrial applications of gellans in the development of new alimentary products.     

Texture profile and turbidity of gellan/gelatin mixed gels

The effect of gellan (1.6–0.2%) to gelatin (0–1.4%) ratio and calcium ion concentration (0–30 mM) on the textural properties and turbidity of gellan/gelatin mixed gels was examined using instrumental Texture Profile Analysis (TPA) and spectrophotometry. Hardness of the mixed gels decreased as the proportion of gellan decreased. Hardness increased with increasing calcium ions until calcium concentration reached a critical level, after which further increases in calcium resulted in a reduction of hardness. Brittleness, springiness and cohesiveness were very sensitive to low levels of added calcium (0–10 mM), but less sensitive to higher calcium concentrations and gellan/gelatin ratio. In general, the addition of calcium ions caused gels to be more brittle and less cohesive and springy. Decreasing gellan to gelatin ratio caused an increase in gel turbidity at lower calcium ion levels (2–4 mM) and a decrease in turbidity at high calcium levels (20–30 mM). Maximum turbidity was observed in 0.6% gellan–1.0% gelatin gels without added calcium. The results of this study suggested a weak positive interaction between gellan and gelatin when no calcium was added, whereas at higher calcium levels gellan formed a continuous network and gelatin a discontinuous phase.     

Effect of polymer ratio and calcium concentration on gelation properties of gellan/gelatin mixed gels

Gelation properties of gellan/gelatin mixed solutions were studied using dynamic viscoelastic testing at eight different ratios of gellan (1.6–0.2% w/v) to gelatin (0–1.4% w/v) and seven different calcium levels (0–30 mM). The gelation temperature and gelation rate of the mixed gels were significantly affected by the ratio of gellan to gelatin as well as concentration of calcium. Addition of calcium at low levels resulted in an increase in gelation temperature and gelation rate compared to gels with no added calcium. Further increases in calcium increased the gelation temperature, but caused a decrease in gelation rate of the mixed gels. In addition, the presence of gelatin generally had a negative influence on gelation rate, especially at high proportions and when the solution had a high gelling temperature, probably by physically hindering the growth and development of gellan crosslinks. It appeared that in the presence of calcium, gellan formed the continuous gel matrix, with gelatin present as a discontinuous phase. Gellan/gelatin mixtures can form gels over a wide temperature range by varying the ratio of the two polymers as well as the calcium concentration.     

高酰基结冷胶的溶胶和凝胶特性研究及结构初步分析

采用黏度计和质构仪对高酰基结冷胶的溶胶和凝胶性质进行研究。结果表明：高酰基结冷胶在质量浓度为 0.05～0.1g/100mL 时,表观黏度随质量浓度增加而增加,并呈现假塑性流体特性;在质量浓度为0.2～0.5g/100mL时形成凝胶,凝胶强度受胶体及 Ca2+ 质量浓度的影响明显,同时高酰基结冷胶比例增加,高低复配胶体的凝胶强度减小。并利用红外光谱扫描和核磁共振技术对高酰基结冷胶结构进行初步分析。     

Effect of salts and sugars on the clarity of gellan gels

The effect of glucose, fructose and sucrose (0–15 wt%) on the clarity of low acyl gellan gels (0.5 wt%) in the presence of potassium chloride (40–100 mm ), calcium chloride (10–80 mm ) and their mixtures at a total molar concentration of 80 mm , was investigated by light absorbance experiments (490 nm). The effect on gel clarity (at 100 mm KCl) of all sugar combinations, at a final concentration of 15 wt%, was also investigated. All gels with potassium were less turbid than the ones with calcium. In the case of salt mixtures, increasing concentration of calcium in the mixtures resulted in decreased clarity. In addition, turbidity increased with increasing salt concentration. Moreover, and at the higher salt concentrations, the presence of sugars resulted in clearer gels. When mixtures of sugars were added, all combinations resulted in increased clarity compared to the individual sugars.     

The effect of salts on the retention of ethyl butyrate by gellan gels

The effect of gellan gels with different texture on the retention of ethyl butyrate was investigated by Static Headspace Gas Chromatography. Calcium induced gels enriched with 400 ppm of the volatile showed not significantly different aroma release for calcium concentrations up to 40 mM, whereas higher concentrations exhibited greater partition coefficient values not significantly different from each other. Aroma release was not controlled by the mechanical properties when 1000 ppm of ethyl butyrate was added. When mixtures of calcium and potassium chloride, at a total molar concentration of 80 mM, were used to induce gelation, aroma release became greater with increasing calcium concentration in the mixtures. Moreover, elevated concentrations of the aroma compound (400-1000 ppm) added to gellan matrices, gelled by 10 mM calcium chloride, resulted in increased aroma release. For all samples, the percentage of retention was also calculated and both positive and negative values were determined.