Stability of freeze-dried pH-responsive dextrin nanogels containing doxorubicin

Induction of non-specific toxicities by doxorubicin(DOX) has restricted conventional DOXbased chemotherapy. p H-responsive dextrin nanogels(DNGs) have been fabricated in order to incorporate and deliver DOX to specific(targeted) sites. However, adequate stability studies of DOX-loaded DNGs are required for selection of storage conditions. The aim of this study was therefore to evaluate the accelerated(25 °C/60% RH) and long-term(5 °C) stability of DNGs prepared with formaldehyde(FDNGs) and glyoxal(GDNGs) as cross-linker by determining the change in their physicochemical properties. The mean diameter decreased with time during long-term storage. The drug content between freshly prepared(initial day) and after storage at 5 °C for 180 days of DOX-loaded FDNGs and DOX-loaded GDNGs was not significantly different(p > 0.05), but decreased after storage under the accelerated condition. The release of DOX from all DNGs was pH-dependent. However, DNGs kept under the accelerated condition showed higher amount of DOX release than those stored at 5 °C and the freshly prepared ones. The results indicate that the stability of DNGs could be improved by their storage at 5 °C.

Self-Assembled Dextrin Nanogel as Curcumin Delivery System

Curcumin is a natural polyphenol with anti-oxidative, anti-inflammatory and anti-cancer properties. Its therapeutic potential is substantially hindered by the rather low water solubility and bioavailability, hence the need for suitable carriers. In this study, we show that self-assembled nanogels obtained from hydrophobically modified dextrin are effective curcumin nanocarriers. The stability and loading efficiency of curcumin-loaded nanogel depends on the nanogel/curcumin ratio. Higher stability of the formulation is achieved in water than in PBS buffer, as evaluated by dynamic light scattering and fluorescence measurements. The in vitro release profile, using sink conditions, indicates that dextrin nanogel may perform as a suitable carrier for the controlled release of curcumin. Biological activity of curcumin-loaded nanogel in HeLa cell cultures was assessed using the MTS assay.

SYNERGISTIC EFFECT OF MINERAL SURFACE CONSTITUENTS IN DEXTRIN ADSORPTION

As part of a systematic research on the interaction mechanism between polysaccharides and mineral surfaces, ive extend the studies on dextrin adsorption to real minerals such as oxides and salt-type minerals, based on previous studies of model systems {surface-modified quartz ). The minerals tested include hematite, rutile, fluorite, calcite, apatite, etc. It is observed that dextrin adsorption on these minerals is strongly pH-depen-dent, with adsorption maxima appearing at pH values around the isoelec-tric points of the minerals, indicating interactions zvith surface metal hy-droxide species. X-ray photoelectron spectroscopy (XPS) measurements re-veal electronic binding energy shifts or Auger parameter changes of miner-al surface elements after dextrin adsorption , pointing to a chemical mecha-nism of interaction. Furthermore, it is observed that the reaction of miner-als with moderate amounts of fatty acids prior to dextrin addition results in an increase in dextrin adsorption, whereas excessive fatty acids do the opposite. Combined with our previous studies, it is concluded from the ex-perimental observations that although surface hydrophobic species alone do not have any effect on dextrin adsorption, they synergistically enhance the adsorption when present together with surface metallic sites.

Safety assessment of dextrin hydrogel adhesion barrier (AdSpray®) for elective laparoscopic cholecystectomy

Objective:Adhesion barriers have not traditionally been used during laparoscopic cholecystectomy(lapchole),and so there are no data confirming the safety of the dextrin hydrogel adhesion barrier(AdSpray®)for the use during lap-chole.The aim of this prospective study is to investigate the safety of AdSpray®for elective lap-chole.Methods:Between July 2019 and March 2021,we conducted a prospective study at Saiseikai Kumamoto Hospital to assess the safety of applying AdSpray®around the hepatoduodenal ligament,liver surface,and port area after extraction of the gallbladder during elective lap-chole.We assessed patient morbidity,mortality,and laboratory data on postoperative day 1 and at the outpatient follow-up visit.Results:A total of 100 patients(43 men,57 women)received AdSpray®application during elective lapchole at our institution.The mean patient age was 56.5±14.8 y,and the mean body mass index was 25.1±4.8 kg/m2.Preoperative gallbladder drainage was performed in 3(3.0%)patients as conservative treatment for acute cholecystitis.The mean operative time was 91.7±35.1 min,and the median blood loss was 5 mL(range,5e120 mL).Intraoperative gallbladder perforation was observed in 4.0%of patients(n=4).There was no intraoperative bile duct injury.One(1.0%)patient had a postoperative subhepatic fluid collection without bacterial infection.The mean white blood cell count and C-reactive protein level was significantly elevated on postoperative day 1 but returned to preoperative levels by the time of the follow-up visit.All patients were successfully discharged after surgery,and the median postoperative hospital stay was 2 d(range,2e9 d).Conclusion:Applying AdSpray®during elective lap-chole is safe,with an acceptable rate of postoperative complications.

Utilization Starch of Avocado Seed （Persea Americana Mill.） as a Raw Material for Dextrin

Starch ofavocado seeds can be used as an alternative source of starch because it contains 80.1% starch. Natural starch can be made into a modified starch, for example dextrin. Dextrin can be made by using acid or enzyme hydrolysis. The purposes of this research were determine the concentration of hydrochloric acid （HCl）, the temperature and heating timein the optimum process of hydrolysis of starch into dextrin and to determine the quality of the resulting product dextrin terms of Indonesian National Standard 01-2593-1992. The methode was used in this research is hydrolisis with hydrochloric acid （HCl）. The results processing into starch avocado seed yield is 23.15%. HCl concentration, temperature and heating time significantly affect the value of dextrose equivalent （DE）, viscosity and part soluble in cold water. There is interaction between HCl concentration, temperature and heating time on the value of DE, viscosity and part soluble in cold water. Optimum conditions of process was obtained at a concentration of 0.15 N HCl, 30 minutes heating time and heating temperature of 90 ℃. Dextrose equivalent （DE） value is 19.61%. The value of solubility in cold water is 90.19%. Viscosity value is 1.61 ° E. Dextrin is not accordance with the standards of quality parameters Indonesian National Standard 01-2593-1992. Dextrin produced should be applied to non-food industry.

Aspergillus nidulans来源的α-葡萄糖苷酶分子改造及其在难消化糊精制备中的应用

难消化糊精是一类富含α-1,2、α-1,3、α-1,6糖苷键或环状糖链结构的可溶性糊精的总称,具有升糖指数低及促进肠道益生菌增殖的特点。难消化糊精的目前商业化主流制备工艺为酸热法,酶法制备相关研究仍然较少。难消化糊精制备的关键是增加难消化的α-1,2、α-1,3、α-1,6糖苷键含量或增加产物聚合度。对构巢曲霉(Aspergillus nidulans)来源的α-葡萄糖苷酶AgdB进行改造,以增加其产物α-1,3键型或提高其产物聚合度。通过理性设计,经定点突变后获得N466D、R450H、A445S、Y202A共4个突变体。以麦芽糖为底物反应时,突变体N466D、R450H产物α-1,3糖苷键含量增加,突变体R450H、A445S、Y202A生成更高聚合度的产物。随后将突变体与野生型分别与环糊精葡萄糖基转移酶进行复配,结果表明,突变体R450H、A445S、Y202A均能有效提高产物慢消化成分,突变体N466D虽然提高了α-1,3键含量,但同时提高了α-1,4键含量,因此产物慢消化成分反而有所降低。该研究为改造α-葡萄糖苷酶,提高难消化糊精的慢消化及抗消化组分提供了新的思路。

低升糖指数酥油茶粉的制备及品质评价

为了改善现有酥油茶粉中麦芽糊精添加导致产品升糖指数高的问题,并保证酥油茶粉的品质,该文采用抗性糊精代替麦芽糊精等改进措施,采取二次均质、喷雾干燥技术制备低升糖酥油茶粉。该文利用正交试验确定茶液、食盐和酥油配比后,考察抗性糊精和菊粉用量对喷雾干燥得到的酥油茶粉冲调性的影响,并通过测定粒径、冲调性、挥发性成分、热稳定性和预估升糖指数,对产品品质进行评价。结果表明,最佳配方为:茶液用量(干基计)14%、食盐用量10%、酥油用量20%、抗性糊精用量40%、D-甘露糖醇用量5%、菊粉用量10%、蔗糖酯用量1%。品质测定结果显示,低升糖酥油茶粉的平均粒径为500 nm,其分散性、结块率、休止角、稳定性与利用麦芽糊精制备的酥油茶粉差别不显著,但溶解时间更少(P<0.05)。此外,与利用麦芽糊精制备的酥油茶粉对比,低升糖酥油茶粉的热稳定性更高、挥发性成分更丰富、预估血糖指数大幅度降低,具有很好的市场开发前景。

Ethylene Oligomerization by 8-Aminoquinoline Nickel Dichloride Complex Supported on β-Cyclodextrin

Cyclodextrin was pretreated by methylaluminoxane (MAO) and subsequently reacted with 8 aminoquinoline nickel dichloride complex to yield the supported catalyst, which was characterized by ICP, IR and XPS methods. Using MAO as cocatalyst, the catalytic activity of this supported catalyst was investigated at various reaction temperature and Al/Ni molecular ratio. The results showed that, despite possessing a number of polar groups, the supported catalyst displayed relatively high activity over 1×10 5 g ethylene/(mol Ni·h) under mild conditions.

A networked swellable dextrin nanogels loading Bcl2 siRNA for melanoma tumor therapy

In this study, a networked swellable dextrin nanogel （DNG） was developed to achieve stimulated responsive small interfering RNA （siRNA） release for melanoma tumor therapy, siRNA was loaded into multidimensional dextrin nanogels by charge condensation with positive arginine residues modified in the dextrin backbone. Moreover, the networked nanogel was destroyed and loosened based on its bioreducible responsive property to control accelerated siRNA release in a bioreducible intracellular environment, while it remained stable under normal physiological conditions. We demonstrated that DNGs had swellable and disassembly properties under reduced buffer condition by transmission electron microscopy evaluation. The DNGs achieved an endosomal escape followed by selective release of the cargo into the cytosol by glutathione- triggered disassembly according to confocal microscopy observation. Thus, this smart nanogel achieved outstanding luciferase gene silencing efficiency and decreased Bcl2 protein expression in vitro and in vivo based on western blot analysis. Moreover, this nanogel exhibited superior anti-tumor activity for B16F10 xenograft tumors in C57BL/6 mice. These results demonstrate that the networked DNGs are effective for gene condensation and controlled intracellular release for tumor therapy. Overall, these findings suggest that this multidimensional swellable stimuli-responsive dextrin nanogel is an innovative strategy with great promise for gene and drug delivery.

Preparation of high-quality resistant dextrin through pyrodextrin by a multienzyme complex

As a soluble food raw material with a low calorie content,resistant dextrin (RD) has broad application prospects in the food industry.Branching enzymes (BEs),as a key enzyme for RD preparation,can break the α-1,4 glycosidic bonds of donor chains and reconstruct the cleaved chains to acceptor chains through the α-1,6 glycosidic bonds.BEs with high transglucosidic activity toward amylopectin and short-chain substrates are urgently needed to increase the quality of RD.Herein,BE derived from Thermuobifida fusca (TfBE) was mined and characterized.The optimal temperature and pH of the TfBE were 40 ℃ and 6.5,respectively.A total of 1500 U/g substrate TfBE reacted with 20% (w/v) pyrodextrin for 12 h,the ratio of α-1,4 to α-1,6 glycosidic bonds was changed from 3.52:1 to 2.33:1,and the content of enzyme-resistant components notably increased from 44.0% to 53.8%.Furthermore,to make full use of receptor chains and small molecular sugars in the reaction system,a multienzyme complex of TfBE with T.fusca α-cyclodextrin glucosyltransferase (TfCGTase),TfBE with TfCGTase and Aspergillus nidulans α-glucosidase (AnGS) was used to further increase the enzyme resistance of RD from 44.0% to 65.3% and 70.6%,respectively.The developed multienzyme complex method could effectively contribute to improving the production quality and efficiency of RD preparation.

低碱条件下糊精与钙离子协同作用对闪锌矿与黄铁矿浮选分离的影响

闪锌矿与黄铁矿的浮选分离大多在高碱条件下进行,但这会导致药剂用量大、设备腐蚀严重等问题,为此,采用清洁高效的有机抑制剂糊精作为黄铁矿的抑制剂,通过矿物表面润湿性检测、吸附量测试以及红外光谱检测阐明糊精与矿物之间的作用机理,并利用浮选溶液化学理论分析钙离子、糊精与黄铁矿三者之间的吸附方式。研究结果表明:在弱碱性条件下,糊精单独作用时,对黄铁矿的抑制效果不佳,但加入钙离子后,糊精对黄铁矿的抑制作用显著增强;在弱碱性条件下,钙离子会以Ca(OH)^(+)的形式强烈地吸附在黄铁矿表面,同时,Ca(OH)^(+)与糊精之间也具有很强的吸附力,促进糊精在黄铁矿表面的吸附,从而加强了糊精对黄铁矿的抑制,实现闪锌矿与黄铁矿的浮选分离。

糊精添加量对西瓜喷雾干燥粉品质的影响

为了开发及实现西瓜粉的生产,本研究以糊精作为助干剂,探究了糊精不同添加量对喷雾干燥西瓜粉品质的影响。结果表明,糊精添加量为西瓜汁的0.4和0.6倍时难以喷雾成粉。添加量为0.8-1.4倍时制得的西瓜粉的集粉率高于54%,含水量低于10%,休止角小于23°,分散性高于45s。糊精添加量越高,西瓜粉的集粉率越高,流动性越好,溶解性越弱,但香气和滋味减弱。添加量高于1.2倍后,糊精含量的增加对粉质的提升效果不显著。研究表明,糊精可作为单一助干剂用于西瓜粉的喷雾干燥,其最佳添加量为1.2倍,适用于工业生产。

膜分离法提高麦芽四糖糖浆纯度的研究

该研究拟采用膜分离法将麦芽四糖糖浆中麦芽四糖的纯度提高到80%以上。研究结果表明,麦芽四糖糖浆经截留分子质量为1000 Da的膜超滤后,大部分糊精被去除,但小分子糖含量几乎没有损失;以渗透通量、各糖截留率、分离系数为评价指标,筛选出最适合用于提高麦芽四糖纯度的纳滤膜的截留分子质量为150~300 Da;实验确定的纳滤膜最优工艺参数为跨膜压差1.0 MPa,操作温度35℃,进料质量浓度15 g/L,纳滤后麦芽四糖纯度由73.40%提升至78.20%;进一步采用浓缩因子为2的五阶段间歇渗滤,截留液中麦芽四糖的纯度达到87.14%。膜分离工艺不能完成相近分子质量低聚糖的绝对分离,但利用各糖截留率的差异,可以提高产品中麦芽四糖的纯度。

脱支和重结晶法制备抗性糊精的结构和功能特性分析

为探究脱支和重结晶法制备抗性糊精的结构和功能特性。以蜡质玉米和普通玉米淀粉为原料,采用脱支和重结晶法制备抗性糊精,对其形貌特征、结晶结构、热力学特性、官能团、糖苷键等变化进行表征,并探究其抗消化特性。结果表明:与原淀粉相比,两种抗性糊精热稳定性和溶解度显著增加(P<0.05),具有良好的色泽。两种抗性糊精形貌粗糙、呈不规则形状的小碎片聚集体。蜡质玉米抗性糊精呈典型的A型结晶结构,普通玉米抗性糊精呈典型的B型结晶结构。由核磁共振波谱和红外结果可知,抗性糊精在制备过程中糖苷键断裂重新聚合形成新的抗消化糖苷键,无新的官能团产生。两种抗性糊精的抗消化性能力增加,且普通玉米淀粉制备的抗性糊精的慢消化和抗消化性能力最强。综上所述,脱支和重结晶法能提高抗性糊精的抗消化能力,将为抗性糊精的绿色制备工艺进而实现产业化生产提供新的思路和理论指导。

超声协同微波法制备抗性糊精及其结构和体外消化特性

以小麦淀粉为原料,采用单因素及正交试验优化抗性糊精制备工艺,并表征其结构和体外模拟消化。结果表明,超声协同微波法的最佳制备工艺条件为盐酸浓度0.3mol/L、超声时间30min、微波功率700 W、微波时间10min,此工艺条件下抗性糊精含量为63.71%,白度为70.51%。与酸热法相比,抗性糊精含量提高了9.32%,白度升高了7.76%;与微波法相比,抗性糊精含量提高了3.57%,白度升高了11.11%。在精制工艺中,将酶解液按3∶1(体积比)进行浓缩,用78%乙醇溶液沉淀4次,再用3%活性炭在40℃、pH3的条件下脱色30min,此时抗性糊精的纯度为91.28%,得率为50.73%。制得的抗性糊精相较于小麦淀粉结晶度降低,但没有产生新的官能团,在热转化过程中因其有序的结晶结构被破坏而没有出现吸热峰。模拟体外消化的结果显示,超声协同微波法制备的抗性糊精抗消化成分含量高达97.66%,显著高于酸热法、微波法制备的抗性糊精,表明相较于原有方法超声协同微波法能制备出品质更高的抗性糊精。

辛烯基琥珀酸酐苦荞糊精酯对姜黄素增溶效果研究

以苦荞淀粉为主要原料制备辛烯基琥珀酸酐苦荞糊精酯。通过响应面法优化辛烯基琥珀酸化苦荞糊精胶束荷载姜黄素的过程,并研究不同工艺对姜黄素的增溶效果。结果表明:最佳工艺参数为搅拌功率4.5 W、糊精摩尔质量11.5×10^(4)g/mol、取代度0.0754,在此条件下,姜黄素的质量浓度为(5.25±0.07)μg/mL。傅里叶红外光谱、差示扫描量热法和X射线衍射分析表明,辛烯基琥珀酸化苦荞糊精胶束作为纳米载体对姜黄素具有良好的增溶效果。

二醛糊精对麦醇溶蛋白膜性能的影响

通过二醛糊精(DAD)交联麦醇溶蛋白(Gli)制备Gli膜,研究了不同质量浓度DAD对Gli膜微观结构、光学性能、耐水性能、阻隔性能、机械性能、热稳定性、抗菌性能等的影响,旨在改善Gli膜的相关性能,以期减少塑料制品的使用,保护环境。结果表明DAD的交联作用使得Gli膜的机械性能、耐水性能、热稳定性和抗菌性能均明显提高,当DAD质量浓度在3 g/100 mL时(3#组),相关膜的机械性能、热稳定性和耐水性能在各组中最优。经初步成膜机理研究发现席夫碱键是相关膜性能改善的主要作用力。

荷载β-胡萝卜素OSA马铃薯糊精的稳定性研究

以辛烯基琥珀酸马铃薯糊精(OSA-pd)为荷载载体,利用其自组装特性,针对脂溶性营养成分β-胡萝卜素构建纳米包埋体系。以β-胡萝卜素保留率和胶束粒径为指标,对荷载β-胡萝卜素OSA-pd的加工稳定性和体外胃肠液稳定性进行研究。结果表明:冻融处理会增大OSA-pd胶束的粒径和多分散性指数(PDI),降低β-胡萝卜素保留率;热处理OSA-pd胶束的粒径和PDI变化不明显,表现出良好的胶束热稳定性;随着储藏时间的延长和温度的升高,OSA-pd胶束的粒径和保留率总体降低,PDI总体增大,表明胶束储藏稳定性一般。体外模拟胃肠液稳定性试验显示,胶束颗粒在胃液中有较好的稳定性,但在肠液中稳定性较差。

谷朊粉添加量对面粉糊化和馒头品质的影响

研究了谷朊粉对小麦粉糊化特性的影响,并对添加谷朊粉的馒头进行了质构特性和感官评价分析,为制备高品质的面食制品提供理论依据。结果表明,谷朊粉添加量对小麦粉糊化峰值温度、终止温度及糊化焓的影响存在差异性,对馒头的弹性和黏聚性无显著性影响。添加适量谷朊粉可增大馒头的硬度、黏性和咀嚼度,且外观、色泽等感官指标也明显改善,当添加量为6%时,面粉的糊化温度最高,馒头综合品质最佳。

分支酶介入酸热法制备焦糊精的工艺优化

抗性糊精属于小分子、低热量的膳食纤维,被广泛应用于食品行业中,其中保健品应用市场最大,占比38.7%。但目前高温酸热生产抗性糊精普遍得率低、副产物多。研究以低水分玉米淀粉为原料利用高温酸热法制备焦糊精,通过单因素实验优化工艺,确定最佳工艺参数,细化操化手法,增加吸酸预反应过程,得率可达61.9%,在此基础上,引入淀粉分支酶作用焦糊精,催化α-1,4向α-1,6糖苷键转化,得率可达68.5%,葡萄糖聚合度有所增加,抗性含量提高1.2%。