食品组分与天然抑菌剂对芽孢耐热性的影响

The effect of food constituents and natural preservatives on the thermal resistance of Bacillus stearothermophilus spores

研究了不同浓度的NaCl、乳清蛋白、蔗糖、表没食子儿茶素没食子酸酯(EGCG)、乳酸钠和乳酸链球菌素(Nisin)以及不同pH对于嗜热脂肪芽孢杆菌芽孢耐热性的影响。结果显示,pH对芽孢耐热性有显著影响,D值随着pH的降低而逐渐减低;乳清蛋白在115℃和118℃条件下对芽孢耐热性有保护作用,但在121℃时无显著保护性;在115℃条件下,8%以内NaCl对芽孢耐热性无显著影响,但在118℃和121℃条件下,NaCl浓度在4%～8%之间时,对芽孢耐热性有降低效应;蔗糖只在10%浓度时对芽孢的耐热性有保护作用外,其余浓度对芽孢耐热性无显著影响。在三种报道的具有抑菌物质中,0.4mg/mLEGCG和4%乳酸钠对芽孢耐热性无显著影响,而Nisin则可以显著降低芽孢D值,而且随着浓度提高,对芽孢耐热性的降低效果越明显。

The effects of NaCl,whey protein,sucrose,Epigallocatechin Gallate（EGCG）,sodium lactate,Nisin and pH on the thermal resistance of Bacillus stearothermophilus（ATCC7953） spores were investigated. The results showed that pH affected the thermal resistance of spores significantly and D values decreased as pH decreased. Whey protein could protect the spore when heated temperature were 115℃ and 118℃,while there was no obvious protective effect when heating temperature was 121℃. The D value of spore was not affected significantly by NaCl at 115℃ when concentration of NaCl lower than 8%. While D value was affected obviously by NaCl at 118℃ and 121℃ when concentration 4%～8%. 10% of sucrose could protect the spore,while other concentration of sucrose showed no obvious effects on the D value of spore. EGCG and sodium lactate could not affect the D value of spore,but Nisin could dramatically reduce the D values of spore,and the reducing effect was stronger following with the increasing of Nisin concentration.