Succinyl pullulan-crosslinked carboxymethyl chitosan sponges for potential wound dressing

The crosslinked succinyl pullulan-carboxymethyl chitosan composite sponges (Pullulan-CMCS) were fabricated for potential wound dressing. The structure and micromorphology of Pullulan-CMCS sponges were investigated by FTIR spectroscopy and SEM. Pullulan-CMCS sponges had lots of porous structures, making it absorb much liquid and quickly reach swelling equilibrium. WVTR results showed that Pullulan-CMCS sponges can reduce the accumulation of wound exudates in a certain degree. Biocompatibility test showed these sponges had no cytotoxicity or hemolytic potential. In vivo experiments demonstrated that Pullulan-CMCS sponges can effectively heal full-layer wound of skin defects of male ICR mice with accelerated fibroblast proliferation and enhanced epithelial migration.     

Effects of Microbial Polysaccharides on the Oil Absorption and Quality Characteristics of a Deep-Fried Snack Namkeen

This study investigates the potential of microbial polysaccharides (MP) gellan gum and pullulan to reduce oil uptake in a deep-fried snack (Namkeen). The concentration of MP in refined wheat flour varied between 1–10% (w/w) and the frying time and temperature are optimized. The results reveal that MP added namkeens showed a maximum relative oil reduction of 33.87% with gellan gum and 26.93% with pullulan at 10% (w/w). Gellan gum and pullulan result in oil reduction of 23.19% and 15.97% with 5% (w/w). The results reveal that gellan gum added namkeens exhibited 1.45 times lower oil uptake than pullulan added namkeen indicating potential oil reduction capabilities. The hardness of namkeen is observed to increase with an increase in MP concentration. Sensorial and textural characteristics of control and MP incorporated fried samples are comparable up to 5% (w/w) with MP concentration. The results for the control samples and MP incorporated samples are statistically significant. Furthermore, overall sensorial acceptability of pullulan added namkeens (7.74 ± 0.53) is slightly higher than that of gellan gum added namkeens (7.64 ± 0.36). Practical Application: Low-fat diet and functional foods are expected to help in managing the conditions of hyperlipidaemia. This study focuses on the potential of MP in reducing the oil content of deep-fried snacks. The efficacy of MP gellan gum and pullulan as functional ingredients for oil reduction in fried snacks demonstrates its aid in formulating low-fat foods thereby retaining sensorial characteristics.     

Antimicrobial Activity of a Pullulan–Caraway Essential Oil Coating on Reduction of Food Microorganisms and Quality in Fresh Baby Carrot

This research evaluated the antimicrobial efficacy of pullulan films containing caraway essential oil (CEO). The films were prepared from a 10% of pullulan, containing from 0.12% to 10.0% of CEO. The composition of the CEO was analyzed with the use of gas chromatography. The antimicrobial activity of the CEO was evaluated with the method of serial microdilutions, and the films containing CEO—with the agar diffusion method against selected Gram‐negative, Gram‐positive bacteria, and fungi. The structure of the film surface and its cross‐section were analyzed using a scanning electron microscope (SEM). Analyses were also carried out to determine the efficacy of a pullulan coating with 10% CEO on baby carrots experimentally inoculated with Salmonella enteritidis, Staphylococcus aureus, Saccharomyces cerevisiae, or Aspergillus niger and stored at a room temperature for 7 d. At a concentration of 0.12%, CEO inhibited the growth of all the tested microorganisms. Pullulan films containing 8% to 10% of CEO were active against all tested microorganisms. Populations of S. aureus on carrot samples were reduced by approximately 3 log CFU/g, while those of A. niger and S. cerevisiae by, respectively, 5 and 4 log CFU/g, after 7 d of storage. S. enteritidis was the most resistant among the tested species, since it was not significantly reduced after 7 d of storage. At the end of storage, samples treated with pullulan–caraway oil coating maintained better visual acceptability than control samples. Results of this study suggest the feasibility of applying a pullulan film with incorporated CEO to extend the microbiological stability of minimally processed foods.     

茁霉多糖发酵和提取的研究

茁霉多糖是出芽短梗霉产生的细胞外多糖,一般都一蓝黑色素伴随着茁霉多糖一起产生,因此,出芽短梗霉俗称黑酵母。茁霉多糖一种无色无味的中性多糖,极易溶于水。具有安全性,无毒性,耐热性,耐酸碱性,耐盐性,粘性,可塑性,成膜性质等特性,具有广泛的应用前景。本实验选用出芽短梗霉3.933号菌种,进行复壮,发酵培养。并且采用醇提法提取茁霉多糖。     

基于明胶硬胶囊性能评价的明胶—普鲁兰复合膜研究

制备了明胶—普鲁兰复合膜,通过测定复合膜的性质来指导评价硬胶囊的性能、优化硬胶囊囊材配比及降低其脆碎性和水蒸气透过系数(WVP),并通过透光率、傅立叶红外光谱、扫描电镜来表征明胶与普鲁兰的相容性。结果表明:甘油添加量为10%(干基百分比),明胶/普鲁兰质量比为91时,可用于明胶硬胶囊的共混改性。相比明胶膜,上述条件下制备的复合膜的WVP降低了26%,低湿环境下的断裂延伸率提高了1.19倍,复合膜中明胶与普鲁兰分子间具有良好的相容性,因此机械性能稳定性增强,WVP降低。     

出芽短梗霉的发酵性能研究

就茁霉多糖和蓝色色素的产生,对出芽短梗霉的发酵性能进行了研究。通过对碳源、氮源、pH值、容氧量、发酵时间等影响因素的比较试验,得到了比较理想的发酵条件,为茁霉多糖和蓝色色素的生产与控制提供了参考数据。     

普鲁兰多糖对绿豆淀粉功能特性的影响

以资源丰富的绿豆淀粉为基材,按照不同比例与普鲁兰多糖共混,对混合物的功能特性进行了研究。结果表明:普鲁兰多糖可以降低绿豆淀粉的峰黏度、谷黏度、终黏度、稀懈值和回凝值,并且在一定范围内,这种变化随着普鲁兰多糖质量分数的增加而增大。另外,普鲁兰多糖的添加提高了绿豆淀粉的糊化温度,使其糊化受到抑制作用,且当普鲁兰多糖与绿豆淀粉的质量比达到2∶5时,这种抑制作用开始达到极显著水平。少量添加普鲁兰多糖后,绿豆淀粉老化的焓变值大大降低,但当普鲁兰多糖与绿豆淀粉的比例大于1∶6时这种抑制作用变缓。普鲁兰多糖可以增强绿豆淀粉的硬度、黏着性、弹性和胶凝性,而逐渐减小其黏聚性。     

响应面法优化短梗霉多糖培养条件

采用响应面方法对出芽短梗霉(Aureobasidium pullulans)生产短梗霉多糖的培养条件进行了优化。首先利用Plackett-Burman设计法研究了培养条件对响应值的影响程度,发现(NH_4)_2SO_4和K_2HPO_4的质量浓度对多糖产量的影响显著。然后利用最陡爬坡法逼近最大响应区域.最后在上升最高点处由中心组合试验和响应面分析确定其最优培养条件。并通过实验测得优化培养条件后的多糖产量为24.652 g/L,与预测值24.597 g/L非常接近,且比优化前多糖产量提高了28.4%。