酚酸、苯甲酸改性魔芋葡甘聚糖化合物的制备及抗菌活性研究

Preparation and Antibacterial Activity of Konjak Glucan Compound Modified with Phenolic Acid and Benzoic Acid

以一羟基、二羟基、三羟基酚酸及苯甲酸通过湿法对魔芋葡甘聚糖(Konjak glucomannan,KGM)进行酯化改性。利用红外光谱验证所得改性物,研究改性化合物黏度随温度变化的规律和抗菌活性。结果表明,通过简单的湿法反应,将酚酸基团接入到KGM的分子链中,KGM酚酸改性物黏度有明显差异,改性化合物的黏度均低于KGM。对改性化合物进行猕猴桃溃疡病菌(Pseudomonas syringae pv.actinidiae,Psa)、柑橘溃疡病菌(Xanthomonas spp.,Xac)抗细菌测试和葡萄座腔菌、猕猴桃拟茎点菌抗真菌测试。结果显示,改性化合物的抗真菌活性较差,但对Psa和Xac则有较好抑制率。其中,100μg/m L时,3,4,5-三羟基苯甲酸改性物的活性最佳,对Psa的抑制率超过对照药噻菌酮的50%;同浓度下2-羟基苯甲酸改性物对Xac的抑制率达到对照药噻唑锌的50%。研究结果为KGM改性物在果蔬保鲜和防腐方面的应用提供理论依据。

Konjak glucomannan(KGM)was modified by wet esterification with mono-,di-,tri-hydroxy phenolic acids and benzoic acid.The modified compounds were verified by infrared spectroscopy,and the viscosity of the modified compounds with temperature and antibacterial activity were studied.The results indicated that the phenolic acid groups were incorporated into the molecular chain of KGM through a simple wet reaction.The viscosity of the KGM phenolic acid-modified compounds varied significantly,with all modified compounds showing lower viscosity compared to KGM.The antibacterial activity of the modified compounds was tested against Pseudomonas syringae pv.actinidiae(Psa)and Xanthomonas spp.(Xac),and their antifungal activity was tested against Cladosporium spp.and Pseudocystis spp.The results showed that the modified compounds had poor antifungal activity but exhibited good inhibition rates against Psa and Xac.Among them,at a concentration of 100μg/mL,the 3,4,5-trihydroxybenzoic acid modified compounds showed the best activity,with an inhibition rate against Psa exceeding 50%compared to the control drug thiophanate-methyl.At the same concentration,the 2-hydroxybenzoic acid modified compounds had an inhibition rate against Xac equivalent to 50%of the inhibition rate of the control drug thiazole zinc.These findings provide a theoretical basis for the application of KGM modified compounds in fruit and vegetable preservation and preservation.