3,4-二羟基噻吩交联壳聚糖的合成及其对白桃的抑菌保鲜性能

以氯乙酸乙酯、硫化钠、草酸二乙酯和壳聚糖为原料合成了3,4-二羟基噻吩交联壳聚糖(DTCC),测定了该交联聚合物对一系列菌种的抑菌能力;测定了以该交联聚合物为涂膜剂处理白桃后的失重率、腐烂率、叶绿素含量、膜透率和总糖含量随贮存时间的变化关系。结果表明,部分交联的DTCC对革兰氏阳性、阴性菌有较强的抑菌效能,作用20min后对铜绿假单胞菌、荧光假单胞菌、蜡样芽孢杆菌、枯草芽孢杆菌的抑菌率分别可达96.7%、95.8%、97.9%和98.2%,最小抑菌浓度分别为25.0、25.0、3.1和3.1g/L;DTCC对黑曲霉菌和柑橘青霉菌亦有较强的抑菌效果,作用20min后的抑菌率分别达到99.0%和28.4%,最小抑菌浓度分别为25.0和12.5g/L。以质量浓度为1.0g/L的DTCC涂液处理白桃并在(27±0.5)℃贮存12d后,失重率仅有8.1%,腐烂率为40%,膜透率为34.1%,总糖含量可达75.1mg/g。

Synthesis of 3,4-Diolthiophene-2,5-bis Carbonyl Cross-linked Chitosan and Its Application as Antibacterial Reagent for Preserving White Peach

Chitosan cross-linked with 2,5-bis(formic acid)-3,4-diolthiophene(DTCC) was prepared with ethyl chloroacetate, sodium sulfide, diethyl oxalate and chitosan(CTS) as raw materials. The antibacterial effect of cross-linked polymer was studied against a series of test bacterial cultures by quantitative suspension method. Relation between storage time and variation of white peach mass-loss ratio, decomposition ratio, chlorophyll content, film penetration ratio and total saccharine content was examined thoroughly after fresh-keeping process with synthesized cross-linked polymer as over-coat film. Results obtained from experiments indicated that partially cross-linked DTCC had a relatively strong antibacterial effect against Gram-positive and Gram-negative bacteria. The mean anti-bacterial ratios of DTCC for pseudomonas aeruginosa(MSH), pseudomonas fluorescens(ATCC13525), bacillus cereus(CIP6624), bacillus subtilis(ATCC6633) are 96.7％,95.8％,97.9％and 98.2％, respectively, after 20 min treatment. The minimal inhibited concentrations(MIC) for 4 bacteia are 25.0, 25.0, 3.1 and 3.1 g/L, respectively. DTCC also demonstrates strong antibacterial effect on aspergillus niger and penicillium italium: mean antibacterial ratios for above bacteria are 99.0％ and 28.4％, respectively, with corresponding MIC of 25.0 and 12.5 g/L after 20 min treatment. DTCC with concentration of 1.0 g/L coated on the outer skin of white peaches shows a good preservation effect after 12 d storage under (27±0.5) ℃. The mass-loss, decomposition and film penetration ratios are 8.1%, 40% and 34.1％, respectively. The total saccharine content is around 75.1 mg/g.