大豆分离蛋白流变学特性研究

研究了大豆分离蛋白在不同条件作用下黏度的变化情况。研究表明：随着温度升高,热处理时间的延长以及NaHCO3、VC、氧化剂H2O2用量的增加黏度都呈下降趋势,其中金属离子和温度对黏度影响较为明显,热处理到一定时间黏度趋于稳定,浓度增加黏度也随之增加,不同的pH值对黏度的影响不同,在等电点处黏度最低,远离等电点黏度又会增大,但在极端pH值环境下黏度又会很小。添加NaOH黏度呈先上升后下降的状态,而黏度会随pH值的增加先降低后上升。     

纤维素氨基甲酸酯溶液黏度与其结构及组成的关系

 探讨了纤维素氨基甲酸酯（CC）溶液黏度的影响因素。结果表明：含氮量大于2.0%的干态CC能很好地溶解在-7～-3℃的质量分数为9%～11%的氢氧化钠溶液中,形成质量分数小于8.5%的CC的氢氧化钠溶液。在研究范围内,CC溶液黏度随聚合度、含氮量、溶剂温度及溶液中CC的质量分数的提高而增加,随溶剂中碱量的增加及助溶剂-——尿素的添加而降低;另外,溶液存放温度及存放时间对CC溶液黏度也有显著影响;低温时,溶液黏度随温度升高而下降,高于15℃后,溶液黏度随温度升高而上升;起初的8 h内,溶液黏度随存放时间延长而下降,之后,溶液黏度又开始回升,出现凝胶化现象。     

硫酸酯化香豆胶的制备、表征及其性质

通过单因素和正交试验获得硫酸酯化香豆胶的优化工艺参数:香豆胶添加量为7 g,反应温度为0℃,浓硫酸添加量为3mL,正丁醇添加量为6mL.红外光谱分析表明,该条件下硫酸基已经与半乳甘露聚糖结合成酯.酯化后的香豆胶分子粒径减小,黏度降低,且随取代度的增大而下降,表现出较好的溶解性、透明度.冷水溶和热水溶硫酸酯化香豆胶溶液的表观黏度都随浓度的升高而呈指数规律的上升;酯化香豆胶溶液为非牛顿流体,随着温度的升高,表观黏度下降,具有耐热性;酯化香豆胶溶液在碱性条件下较为稳定;冻融处理可使酯化香豆胶溶液的表现黏度下降.     

氧化糯玉米淀粉的制备及性能研究

以糯玉米淀粉为原料,以次氯酸钠为氧化剂,氢氧化钠为催化剂,对氧化糯玉米淀粉的制备及性能进行了研究.考察了反应时间、反应温度、次氯酸钠用量、pH对氧化糯玉米淀粉羧基含量的影响,采用酸碱滴定法测定氧化糯玉米淀粉羧基含量.试验结果表明,随着次氯酸钠用量增加,氧化糯玉米淀粉的羧基含量也随之增大;在一定时间范围内,氧化糯玉米淀粉的羧基含量随反应时间的增加而增加;反应温度和pH对氧化糯玉米羧基含量的影响呈倒抛物线趋势,存在最大值.糯玉米淀粉经氧化后,其液透明度和黏度热稳定性提高,但其冻融稳定性和凝沉性下降.     

兔皮明胶功能特性及其影响因素

为研究兔皮明胶的功能特性,对兔皮明胶的流体特性、全质构特性等进行测定。结果表明兔皮明胶对剪切速率的敏感性较小,其硬度、胶着性、咀嚼性和弹性高于猪皮明胶,在耐咀嚼的糖果类食品、肉制品生产中具有应用优势。色差检测结果表明兔皮明胶对产品的外观颜色影响较小,在实际应用中可替代猪皮明胶。不同质量浓度和pH值条件下,兔皮明胶和猪皮明胶加工特性的测定结果表明,兔皮明胶的黏度、起泡性总体均高于猪皮明胶;兔皮明胶的黏度随质量浓度的增加而增大,当质量浓度为4 g/100 mL时达到最大,当pH值靠近等电点时,其黏度减小;兔皮明胶的起泡性随质量浓度增加呈上升趋势,在质量浓度为3 g/100 mL时达到最佳。兔皮明胶的乳化稳定性随质量浓度和pH值的增大呈现先升高后降低的趋势,当质量浓度和pH值分别为3 g/100 mL和4.0时乳化稳定性达到最佳,且均高于猪皮明胶。     

鲶鱼皮明胶的功能性质分析

以鲶鱼皮明胶为研究对象,考察其持水性、起泡性和乳化性等功能性质。结果表明,随着离子强度的增大,明胶的持水性呈先增加后降低的趋势;因明胶大分子质量和亲水性使其泡沫性较吐温80差,但随浓度的增加而增加,且随时间的延长而降低。明胶的乳液呈水包油(O/W)型,其显微形态表明明胶的乳化性与吐温80相当。随着明胶浓度的增大,乳化活性由29.32上升至39.33 m~2/g,乳化稳定性却下降至19.27 min;盐溶效应有助于提升明胶的乳化活性,而盐析效应和静电作用导致乳化稳定性下降;等电点附近,乳化活性和稳定性均下降;随着温度的升高(30℃),解吸附和聚集使其乳化活性和稳定性逐渐降低。鲶鱼皮明胶的功能性质分析为其在食品工业中的应用提供了理论指导。     

马铃薯氧化羟丙基淀粉的制备及其性能研究

以马铃薯淀粉为原料,环氧丙烷为醚化剂,H2O2为氧化剂,采用先羟丙基醚化后氧化工艺制备了氧化羟丙基淀粉。首先研究了环氧丙烷用量、氢氧化钠用量、反应时间、反应温度对羟丙基醚化反应的影响,应用单因素和正交试验确定了羟丙基醚化反应的最佳工艺条件。在此基础上,对羟丙基淀粉进行氧化改性,研究氧化剂用量对产品羧基含量的影响。探讨了羟丙基和氧化改性对淀粉在颗粒结构、白度、糊化温度、峰值黏度、透明度、冻融稳定性的影响。结果表明:(1)影响羟丙基含量的因素依次为:环氧丙烷用量、反应温度、NaOH用量、反应时间,制备羟丙基淀粉的最优条件为:环氧丙烷18%、反应时间22 h、氢氧化钠1%、反应温度45℃,淀粉的羟丙基含量为5.77%;(2)随着H_2O_2用量的增加,氧化羟丙基淀粉的羧基含量升高;(3)羟丙基改性降低了淀粉的糊化温度,提高了冻融稳定性;氧化改性降低了淀粉的黏度,增加了淀粉的透明度。氧化羟丙基淀粉具有黏度低、透明度好、抗老化性能强等优点。     

蜡质玉米辛烯基琥珀酸麦芽糊精酯的制备及性能研究

采用蜡质玉米淀粉为原料,辛烯基琥珀酸酐(OSA)为酯化剂,应用湿法工艺制备了辛烯基琥珀酸淀粉钠(SSOS)。使用耐高温α-淀粉酶对SSOS进行酶解处理,制备了蜡质玉米辛烯基琥珀酸麦芽糊精酯(MSSOS)。研究了OSA用量对SSOS取代度(DS)的影响;探讨了耐高温α-淀粉酶用量、酶解时间、淀粉乳浓度、酯化程度对MSSOS产品葡萄糖值(DE)的影响;并对具有不同DE值MSSOS在表观黏度、透明度、乳化稳定性等性能的差异进行了比较分析。结果显示:(1)SSOS的DS值随OSA用量的增加呈升高趋势;(2)随DS值的升高,SSOS的HLB值增大,亲水性加强、淀粉的糊化温度降低、峰值黏度升高;(3)MSSOS的DE值随α-淀粉酶用量的增加和酶解时间的延长而升高,SSOS的酯化程度对DE值影响不大;(4)随DE值的升高,MSSOS表观黏度降低,透明度增大;DE值高于11.5%后,乳化稳定性降低。     

水合温度、胶用量和氯化钾用量对kappa-卡拉胶胶液黏度的影响

目的：实现kappa-卡拉胶在肉类制品、乳制品、甜点和果冻等食品工业领域以及药用无缝胶囊、烟用爆珠等领域的精准应用。方法：采用数显式黏度计对在不同水合温度、不同卡拉胶用量以及不同氯化钾用量下制备的kappa-卡拉胶胶液的黏度进行测定。结果：① 水合温度对kappa-卡拉胶胶液的黏度具有较大的影响。随着水合温度的升高(固定水合时间1 h),kappa-卡拉胶胶液黏度下降。总体而言,kappa-卡拉胶用量越高,其黏度下降幅度越大。② kappa-卡拉胶胶液黏度随胶用量的增大而呈指数规律增加。③ 在低kappa-卡拉胶用量下,在试验所选用的KCl用量范围内,KCl用量对样品黏度的影响不大,但在高kappa-卡拉胶用量下,随着氯化钾用量的增大,样品的黏度有所增大。结论：水合温度、胶用量对kappa-卡拉胶的胶液黏度具有重要影响,氯化钾用量对黏度的影响相对较小。     

半干法快速合成羧甲基淀粉的研究

采用半干法高温快速合成羧甲基淀粉,以木薯淀粉为原料,研究了反应温度、时间、氯乙酸、氢氧化钠、酒精用量、室温搅拌时间对样品取代度(DS)和反应效率(RE)的影响。结果表明,反应温度120℃最佳,可以充分提高反应速度;随反应时间延长DS和RE先增加,而后趋于不变。DS和RE随氢氧化钠用量提高而增加,但用量过高导致糊化;DS随氯乙酸量增加而提高,高氯乙酸用量导致RE降低。过低的酒精用量不足以抑制淀粉糊化;过高则导致在工艺过程中损失部分氯乙酸钠而引起DS降低。DS和RE随室温搅拌时间延长而增加,然后趋于不变。半干法能够有效地降低生产中有机溶剂用量,工业生产上能达到环保效果,且方法简单效率有所提高。     

氢氧化钙对陕西传统饸饹品质及荞麦粉糊化特性的影响

向荞麦粉中添加0%～1.0%的氢氧化钙,探究其对荞麦饸饹品质和荞麦粉糊化特性的影响。随氢氧化钙添加量的增加,饸饹L*值下降,a*值增加,b*值先增加后减小,添加0.6%氢氧化钙的饸饹呈亮黄色,断条率最低（17.57%）,蒸煮损失最小（4.67%）,感官总分最高（80?分）,硬度适中,黏性和弹性较好;添加氢氧化钙可降低荞麦粉的透光率,增加溶解度,最终黏度和回生值先增后降,添加0.6%氢氧化钙的荞麦粉最终黏度和回生值适中。氢氧化钙可通过影响荞麦粉的糊化特性改善饸饹品质。     

从鸡骨中制取明胶的加工工艺

以鸡腿骨为原料 ,采用碱法 (浸灰法 )制备鸡骨明胶。探讨了浸灰过程Ca(OH) 2 浓度、温度、浸灰时间对明胶提取率、明胶粘度和胶凝性的影响 ,同时优化提取工艺条件。试验表明 :明胶最佳提取条件为温度 70℃ ,pH 5。采用方差和响应面分析优化浸灰工艺条件为 :Ca(OH) 2 质量分数 0 1 % ,温度 1 0℃ ,浸灰时间 6d。浸灰处理可以去除杂蛋白 ,使明胶纯度有所提高 ,粘度和冻力都有所上升     

Gelatin from cod skins as affected by chemical treatments

Concentrations of sodium hydroxide, sulfuric and citric acids used in processing gelatin from cod skins affected both yield and quality. The highest yield of gelatin was obtained when low concentrations [0.1–0.2% (w/v)] of sulfuric acid and sodium hydroxide were applied to the skins followed by treatment with 0.7% (w/v) citric acid. The effects on bloom value, viscosity, odor, clarity, color and pH of the gelatin varied. However, the use of 0.7% (w/v) citric acid in different combinations with sodium hydroxide and sulfuric acid usually gave best results. Freezedried gelatin had considerably higher bloom value than air-dried gelatin.     

多功能型明胶黏合剂的制备及应用研究进展

明胶是由胶原蛋白水解得到的一类聚合物,作为一种具有良好生物相容性和生物降解性等生物学性能的天然高分子材料,因其具有良好的发泡性、乳化性和成膜性等特点,在产品包装、增稠、充当递送载体等方面被广泛应用。本文就明胶凝胶强度、黏度、颜色、产量、等电点等理化性质及其影响因素,以及明胶不同类型的改性、交联方式和制备各种功能性明胶基水凝胶进行综述。通过设计使用不同材料,引入不同官能团来合成不同功能特性的明胶复合水凝胶黏合剂,以丰富其在日常生活中的应用,为明胶的提取及综合利用提供一些新的思路。     

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.     

Ability of whey protein isolate and/or fish gelatin to inhibit physical separation and lipid oxidation in fish oil-in-water beverage emulsion

The effect of pH on the capability of whey protein isolate (WPI) and fish gelatin (FG), alone and in conjugation, to form and stabilize fish oil-in-water emulsions was examined. Using layer-by-layer interfacial deposition technique for WPI–FG conjugate, a total of 1% protein was used to prepare 10% fish oil emulsions. The droplets size distributions and electrical charge, surface protein concentration, flow and dynamic rheological properties and physiochemical stability of emulsions were characterize at two different pH of 3.4 and 6.8 which were selected based on the ranges of citrus and milk beverages pHs, respectively. Emulsions prepared with WPI–FG conjugate had superior physiochemical stability compare to the emulsions prepared with individual proteins. Higher rate of coalescence was associated with reduction in net charge and consequent decrease of the repulsion between coated oil droplets due to the proximity of pH to the isoelectric point of proteins. The noteworthy shear thinning viscosity, as an indication of flocculation onset, was associated with whey protein stabilized fish oil emulsion prepared at pH of 3.4 and gelatin stabilized fish oil emulsion made at pH of 6.8. At pH 3.4, it appeared that lower surface charge and higher surface area of WPI stabilized emulsions promoted lipid oxidation and production of hexanal.     

Comparison of gelling properties and flow behaviors of microbial transglutaminase (MTGase) and pectin modified fish gelatin

The gelling and structural properties of microbial transglutaminase (MTGase) and pectin modified fish gelatin were compared to investigate their performances on altering fish gelatin properties. Our results showed that within a certain concentration, both MTGase and pectin had positive effects on the gelation point, melting point, gel strength, textural, and swelling properties of fish gelatin. Particularly, low pectin content (0.5%, w/v) could give fish gelatin gels the highest values of gel strength, melting temperature, and hardness. Meantime, flow behavior results showed that both MTGase and pectin could increase fish gelatin viscosity without changing its fluid characteristic, but the latter gave fish gelatin higher viscosity. Both MTGase and pectin could increase the lightness of fish gelatin gels but decreases its transparency. More importantly, fluorescence and UV absorbance spectra, particle size distribution, and confocal microscopy results indicated that MTGase and pectin could change the structure of fish gelatin with the formation of large aggregates. Compared with MTGae modified fish gelatin, pectin could endow fish gelatin had similar gel strength, thermal and textural properties to pig skin gelatin.     

慈菇淀粉糊特性研究

对慈菇淀粉糊与马蹄、绿豆、马铃薯、豌豆、玉米和木薯淀粉糊凝沉性和冻融稳定性进行比较,研究不同条件对慈菇淀粉糊黏度和透明度的影响。结果表明：慈菇淀粉糊凝沉速率较低,介于马蹄与木薯淀粉之间;冻融稳定性与木薯淀粉相似;在微酸和微碱条件下,慈菇淀粉糊的透明度下降,在强酸和强碱条件下,透明度上升;在低pH值时,淀粉糊黏度下降,pH＞7时,淀粉糊黏度上升;蔗糖和葡萄糖能增大淀粉糊的黏度,也能提高其透明度,而NaCl与CaCl2对其淀粉糊黏度和透明度的作用则相反;随剪切时间延长,其表观黏度减小,这表明慈菇淀粉糊属于典型的非牛顿假塑性流体。     

Characterization of tilapia (Oreochromis niloticus) skin gelatin extracted with alkaline and different acid pretreatments

Tilapia production is growing worldwide and to better utilize wastes from the processing industry, one important application is production of high quality fish gelatin to meet the needs of markets that are not amenable to beef or porcine gelatin. The extraction process from tilapia skin gelatin was optimized through the use of a combination of alkali (0.3 M NaOH) with different types and concentrations of acids before thermal hydrolysis. The effects of acid pretreatments on the protein yields and the physicochemical properties of tilapia gelatin were investigated. Acid concentrations (0.01–0.20 M) influenced gelatin protein recovery: 10.52%–22.40% for citric acid, 1.92%–21.55% for acetic acid, and 4.47%–24.35% for HCl. It was possible to increase gelatin yield for each of the tested acids by adjusting the acid concentration. Gelatin viscosity and the molecular weight distribution of gelatin proteins were related to the acid concentration used. Gelatin prepared using too low a concentration (e.g. 0.01 M acetic acid or HCl) or too high a concentration (e.g. >0.05 M HCl or citric acid) yielded an extract with a smaller ratio of large molecule components, such as β-chains, and exhibited lower viscosity. The film forming properties of gelatins extracted from three acid-optimized pretreatments showed no significant difference in transparency, tensile strength and elongation at break; though the gelatin film made from 0.03 M citric acid pretreated gelatin had somewhat better water barrier property than those made with HCl or acetic acid.