卡拉胶和黄原胶对酸性凝胶型再制干酪质构的影响

通过质构仪分析和感官评定,研究卡拉胶和黄原胶对酸性再制干酪质构的影响。结果表明:在pH4.25的酸性条件下,在添加0.2%刺槐豆胶的基础上,添加卡拉胶能增强再制干酪的硬度,形成的凝胶硬实且黏厚;添加黄原胶能增强再制干酪的弹性和咀嚼性,形成的凝胶柔滑且富有弹性。可按不同质构需求将两者复配起来运用于酸性凝胶型再制干酪的加工。     

Hydrocolloid/Milk Gel Formation and Properties

Three rheological measurements, as well as cryo-scanning electron microscopy, were used to study the mechanism of gel formation and structure of a hydrocolloid-based milk gel. Processing conditions included combinations of pH level and total solids concentration as well as fat content. The first two variables and their interaction influenced gel point, gel strength, viscoelasticity and syneresis; while fat served primarily as a filler of the gel matrix, it also influenced those properties. In model studies of carrageenan and kappa-casein, calcium ions promoted gelation. Gel microstructure was dictated by processing variables and governed physical properties. The cold-setting mechanism occurred in three stages, hypothesized to include increased viscosity and molecular alignment, molecular interaction, and aggregation.     

魔芋胶的交联化学改性研究

采用三氯氧磷、氯乙酸醚化和卡拉胶复配三种方法对魔芋葡甘聚糖(KGM)进行改性,采用AR500动态流变仪测定了魔芋胶的剪切弹性模量和粘性模量随温度和角频率的变化,并与改性后的样品作了比较。结果显示,不同的改性方法可以有效调控魔芋胶的流变性,使之适应更广泛的技术要求,拓展应用范围。     

高强度卡拉胶纤维的制备及性能测试

通过卡拉胶与环氧氯丙烷交联反应制得改性卡拉胶;并将改性卡拉胶溶于热水制得纺丝液,采用湿法纺丝制备高强度卡拉胶纤维。红外光谱测试及粘度提高证明交联反应的发生;用单因素实验法找到影响因素的最佳范围,通过正交实验法得到最佳合成条件为温度90℃、交联剂加入量为6.25%、反应时间2.0h、pH值为10.0;利用万能材料试验机测得纯卡拉胶纤维的断裂强度为2.17cN/tex,改性卡拉胶纤维的最大断裂强度为3.99cN/tex,交联后断裂强度提高85%。     

Modified carrageenan. 4. Synthesis and swelling behavior of crosslinked κC‐g‐AMPS superabsorbent hydrogel with antisalt and pH‐responsiveness properties

To synthesize a novel biopolymer‐based superabsorbent hydrogel, 2‐acrylamido‐2‐methylpropanesulfonic acid (AMPS) was grafted onto kappa‐carrageenan (κC) backbones. The graft copolymerization reaction was carried out in a homogeneous medium and in the presence of ammonium persulfate (APS) as an initiator, N,N,N′,N′‐tetramethyl ethylenediamine (TMEDA) as an accelerator, and N,N′‐methylene bisacrylamide (MBA) as a crosslinker. A proposed mechanism for κC‐g‐AMPS formation was suggested and the hydrogel structure was confirmed using FTIR spectroscopy. The affecting variables on swelling capacity, i.e., the initiator, the crosslinker, and the monomer concentration, as well as reaction temperature, were systematically optimized. The swelling measurements of the hydrogels were conducted in aqueous solutions of LiCl, NaCl, KCl, MgCl₂, CaCl₂, SrCl₂, BaCl₂, and AlCl₃. Due to the high swelling capacity in salt solutions, the hydrogels may be referred to as antisalt superabsorbents. The swelling of superabsorbing hydrogels was measured in solutions with pH ranging 1 to 13. The κC‐g‐AMPS hydrogel exhibited a pH‐responsiveness character so that a swelling–deswelling pulsatile behavior was recorded at pH 2 and 8. The overall activation energy for the graft copolymerization reaction was found to be 14.6 kJ/mol. The swelling kinetics of the hydrogels was preliminarily investigated as well. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 255–263, 2005     

The Effect of Using Micro-Clustered Water as a Polymer Medium

The aim of the study was to investigate the changes within the physicochemical properties of gelatin, carrageenan, and sodium alginate hydrosols prepared on the basis of micro-clustered (MC) water. The rheological parameters, contact angle and antioxidant activity of hydrosols were investigated. Moreover, the pH, oxidation–reduction potential (ORP) and electrical conductivity (EC) were measured. The hydrosols with MC water were characterized by a lower pH, decreased viscosity, a lower contact angle, and only slightly lower antioxidant activity than control samples. The results showed that hydrosol’s properties are significantly changed by MC water, which can lead to enhancement of its applicability but requires further investigation.     

Flurbiprofen-loaded niosomes-in-gel system improves the ocular bioavailability of flurbiprofen in the aqueous humor

The present work aimed to prolong the contact time of flurbiprofen (FBP) in the ocular tissue to improve the drug anti-inflammatory activity. Different niosome systems were fabricated adopting thin-film hydration technique and using the nonionic surfactant Span 60. The morphology of the prepared niosomes was characterized by scanning electron microscopy (SEM). Physical characterization by differential scanning calorimetry, X-ray powder diffraction and Fourier transform infrared spectroscopy were conducted for the optimized formula (F5) that was selected on the basis of percent entrapment efficiency, vesicular size and total lipid content. F5 was formulated as 1% w/w Carpobol 934 gel. Pharmacokinetic parameters of FBP were investigated following ocular administration of F5-loaded gel system, F5 niosome dispersion or the corresponding FBP ocular drops to albino rabbits dispersion. Anti-inflamatory effect of F5-loaded carbopol gel was investigated by histopathological examination of the corneal tissue before and after the treatment of inflamed rabbit eye with the system. Results showed that cholesterol content, surfactant type. and total lipid contents had an apparent impact on the vesicle size of the formulated niosomes. Physical characterization revealed reduced drug crystallinity and incidence of interaction with other niosome contents. F5-loaded gel showed higher C_max, area under the curve (AUC_0–12), and thus higher ocular bioavailability than those of the corresponding FBP ocular solution. F5-loaded gel showed a promising rapid anti-inflammatory effect in the inflamed rabbit eye. These findings will eradicate the necessity for frequent ocular drug instillation and thus, improve patient compliance.     

The effect of carrageenan and gelatine hydrosols incorporated with acidic electrolysed water on surface microbiota and quality changes on pork meat

The aim of the study was to determine antimicrobial efficiency of carrageenan and gelatine hydrosols containing acidic electrolysed water (AEW) on surface microbiota of meat and evaluate possible quality changes in raw meat after treatment with experimental AEW‐containing hydrosols. Microbiological examination of meat samples covered with AEW‐containing hydrosols (total number of microorganisms, yeast and moulds, and psychrotrophs) was performed. To evaluate quality changes, haem pigments, colour, thiobarbituric acid‐reactive substances (TBARS), antioxidant capacity and preliminary sensory evaluations were performed. Treatment with AEW‐containing hydrosols causes improvement in microbiological quality of meat samples. The treatment with AEW‐containing hydrosols significantly influenced the variability of myoglobin forms of tested meat samples. Changes in L*a*b* colour parameters were found and favourably affected sensory evaluation of meat quality, especially for samples treated with AEW and gelatine‐containing hydrosols. The TBARS values of all AEW–sols‐treated samples were in the range of 0.30–0.39 mg malondialdehyde kg^?1. Radical scavenging (DPPH) and reducing ability (FRAP) assays confirmed that process of electrolysis significantly improved antioxidant activity of modified meat samples compared to treatment with hydrosols containing nonelectrolysed salt solutions. Obtained results suggest that hydrosols incorporated with AEW may be used for food preservation because of their antimicrobial activity and positive impact on quality factors of raw meat.