离子凝胶复合吸附剂的制备及空气取水性能

制备了一种LiCl复合可得然离子凝胶,并将其首次用于空气取水性能研究。在不同吸附温度、吸附湿度的开式环境中,完成了复合吸附剂的水蒸气吸附特性研究。探究了浸渍盐的质量浓度对复合吸附剂吸附性能的影响。根据目标工况,完成了复合吸附剂组分的优化配比。对优化后的离子凝胶进行了吸附动力学和等温吸附特性研究。结果表明,15% LiCl溶液复合而成的可得然吸附剂综合性能最佳。在35℃&75%RH下,该复合吸附剂的吸附量高达3.30g/g,是传统硅胶复合吸附剂的6.6倍;在55℃&40%RH工况下实现1.66 g/g的水量脱附,是硅胶复合吸附剂的3倍。在25℃&75%RH下,可得然复合凝胶吸附剂的吸附速率K高达3.48×10^-3s^-1;该离子凝胶复合吸附剂的研究,为吸附式空气取水技术提供了基础支持。     

可德兰多糖-阿魏酸接枝共聚物的制备工艺优化

采用自由基介导的接枝方法制备可德兰多糖-阿魏酸（FA）接枝共聚物,通过单因素试验考察FA添加量、维生素C（Vc）添加量、过氧化氢（H2O2）浓度和反应时间对接枝率和得率的影响,在此基础上,利用正交试验设计进一步优化接枝共聚物的制备工艺参数。研究表明,可德兰多糖-阿魏酸接枝共聚物制备的最佳工艺条件为：25 mL 5 mg/mL可德兰多糖溶液,FA和Vc添加量分别为250 mg和50 mg,H2O2浓度5 mol/L,反应时间12 h,此时,可德兰多糖-FA接枝共聚物的接枝率和得率均最大,分别为98.62 mg FA/g和40.84%,并通过紫外和红外光谱验证了接枝反应的发生。因此,该方法不仅改善了可德兰多糖的理化特性,而且能够提高可德兰多糖-FA接枝共聚物的接枝率,为其在食品工业中的应用奠定了理论基础。     

可得然胶对面团及面条品质的影响

可得然胶是一种发酵多糖类物质,具有良好的凝胶特性。通过在小麦粉中加入可得然胶,测定面团的粉质、拉伸特性、糊化特性及面条的质构、蒸煮损失等指标,研究可得然胶对面团与面条品质的影响。结果表明:可得然胶对于面团特性具有一定的改良作用,但由于它只有在加热时才能充分地形成凝胶,所以改良程度不是很明显;对小麦粉的糊化特性没有改良作用;对面条的品质具有较明显的改良作用,它可以明显地降低面条的蒸煮断条率与弯曲断条率,对面条的硬度、弹性、咀嚼性与剪切强度等质构指标有较明显的改良作用;可得然胶适合在面条生产中应用,最佳使用量应为小麦粉用量的0.2%。     

可得然胶功能特性及在肉及肉制品中的应用进展

可得然胶是一种微生物胞外多糖,因其良好的增稠、持水、凝胶以及成膜等性能,近些年在肉类加工及保鲜领域得到了广泛的应用。该文综述了可得然胶的功能特性,重点阐述了可得然胶对肉及肉制品品质特性的影响及其对肉品的品质提升机制,最后总结了由可得然胶制备的不同类型可食性复合膜在肉类保鲜中的应用效果,以期为可得然胶在肉类加工和保鲜领域的广泛应用提供理论参考。     

一种新型微生物胶凝剂──凝结多糖

介绍了一种新型微生物多糖——凝结多糖生产、流变性质及其在食品加工中的应用。     

凝胶多糖发酵液流变学特性及提取条件的初步研究

初步研究了凝胶多糖发酵液的流变学特性并应用正交实验对其提取条件进行了研究,通过极差和方差分析可知,碱液浓度对多糖得率有显著影响(P<0.05),碱液浓度和pH对多糖含量有显著影响(P<0.05),在a=0.05的条件下,各因素对含氮量的影响在统计学意义上不是很显著。通过评价多糖得率、多糖含量及含氮量三个指标,确定了其提取的最佳工艺条件为0.6moL/LNaOH,碱溶时间2h,pH8.0,以及添加乙醇倍数为1.5倍。     

Characterization of water distribution in xanthan-curdlan hydrogel complex using magnetic resonance imaging, nuclear magnetic resonance relaxometry, rheology, and scanning electron microscopy

Abstract: Xanthan‐curdlan hydrogel complex (XCHC) has been shown capable of retaining moisture up to 5 freeze‐thaw cycles (FTCs); however, moisture distribution in the complex in relation to the hydrogel composition and structure remains uncharacterized. In the present study, magnetic resonance imaging (MRI), nuclear magnetic resonance (NMR) relaxometry, rheology, and scanning electron microscopy (SEM) were used to examine the effect of water distribution and interaction with 2.0% aqueous solutions of xanthan, curdlan, and XCHC consisting of equal amounts of both polysaccharides. A gel structure with an indication of syneresis was clearly seen in the MR image of curdlan alone, whereas the distribution of protons throughout xanthan and XCHC samples remained homogeneous and showed no detectable syneresis. The three‐dimensional network, indicated by frequency sweeps, of curdlan was responsible for curdlan's gel structure. The frequency sweep and slope of the storage modulus (G′) of XCHC was significantly closer to curdlan with higher elasticity and less dependency upon angular frequency than xanthan alone. The reduction in XCHC dynamic moduli (G′ and G″) compared to curdlan could be attributed to the formation of wavy layers instead of a fully cured three‐dimensional structure. Addition of xanthan to curdlan restricted XCHC spin–spin relaxation time (T₂) to intermediate and slower exchange regimes, namely approximately 110 and 342 ms, respectively, promoting the polymer's interaction with water while inhibiting interpolymer interactions found in curdlan. A 3rd proton pool with the slowest T₂ seen in curdlan was not found in XCHC, correlating to the absence of syneresis. Practical Application: The combination of texture measurements and discrete noninvasive techniques was found capable of providing insightful understanding of water distribution in a gel system. These techniques may be applied to other hydrogel complexes. The XCHC system investigated has the potential to enhance freeze‐thaw stability in frozen food products by minimizing syneresis due to undesirable temperature fluctuations during distribution and consumer application.     

可得然胶功能性质及其在食品中的应用研究进展

可得然胶是一种微生物胞外多糖,具有良好的凝胶性、持水性、增稠性及冻融稳定等特性,在食品工业中得到广泛的应用。随着可得然胶应用研究的不断深入,近年来有关可得然胶的报道越来越多。本文综述了可得然胶的来源、化学结构及功能特性,重点阐述了可得然胶在各类食品加工领域应用的最新进展,以期为可得然胶进一步在食品加工中的应用提供理论参考。     

Influence of Xanthan–Curdlan Hydrogel Complex on Freeze‐Thaw Stability and Rheological Properties of Whey Protein Isolate Gel over Multiple Freeze‐Thaw Cycle

The effect of adding xanthan–curdlan hydrogel complex (XCHC) at 2 concentrations (0.25 and 0.5% w/w) on the freeze‐thaw stability of heat‐induced whey protein isolate (WPI) gel was investigated. Samples were stored at 4 °C for 24 h before subjected to 5 freeze‐thaw cycles alternating between ?16 °C (18 h) and 25 °C (6 h). Adding XCHC to the WPI solution resulted in the reduction of a significant amount of syneresis up to 5 repeated freeze‐thaw cycles. Addition of XCHC decreased the amount of syneresis from 45% in the control sample (pure WPI gel) to 31.82% and 5.44% in the samples containing 0.25% and 0.5% gum, respectively, after the 5th freeze‐thaw cycle. XCHC increased the storage modulus (G′) of the gels and minimized the changes of the G′ values over the 5 freeze‐thaw cycles, indicating improvement of the stability of the system. Furthermore, the minimum protein concentration for gel formation decreased in the presence of the XCHC. Scanning electron microscopy (SEM) images showed that addition of XCHC resulted in the formation of a well‐structured gel with numerous small pores in the network, which consequently improved the water retention ability during the temperature abuses up to 5 freeze‐thaw cycles. These results have important implications for using XCHC in the formulation of the frozen WPI‐based products with improved freeze‐thaw stability and rheological properties.     

Silver Loaded Nanofibrous Curdlan Mat for Diabetic Wound Healing: An In Vitro and In Vivo Study

A fibrous scaffold of curdlan/poly(vinyl alcohol) (PVA) blend is prepared by electrospinning technique and antimicrobial property is imparted to it by the addition of silver nitrate (1, 3, and 5 wt%). All the scaffolds except the PVA/curdlan with 5 wt% AgNO₃ show good viability of Swiss 3T3 fibroblast cells. Significant reductions in the growth of Staphylococcus aureus and Escherichia coli are also observed in all the scaffolds. In vitro scratch assay and cell adhesion studies indicate that the scaffold containing 1% AgNO₃ shows significant wound healing and better cell spreading. The in vivo results also show faster healing of excision wounds in diabetic rats treated with the same material when compared to the control and the commercial sample. Furthermore, downregulation of proinflammatory cytokines and upregulation of anti‐inflammatory cytokines on the skin of the treated animals confirm that PVA/curdlan/1% AgNO₃ electrospun mat could be a promising material for diabetic wound healing.