摘要
为了开发适宜的精油-发酵乳产品,该文以6株乳酸菌及2株致病菌为指示菌,采用滤纸片法和最小抑菌浓度(minimum inhibitory concentration,MIC)法研究8种精油的抑菌活性;用OD_(600)值分析精油浓度对指示菌生长曲线的影响;并监测了精油-发酵乳发酵及储藏过程活菌数、产酸及抗氧化能力等的变化。结果表明,牛至、肉桂、百里香、丁香精油对指示菌具有良好的选择抑制性,其抑制致病菌的能力显著强于抑制乳酸菌(P<0.05)。牛至精油效果最佳,对致病菌、乳酸菌的抑菌圈直径分别为35.03~43.89和17.88~19.86 mm;相同pH下,精油对乳酸菌MIC远大于对致病菌的MIC;精油对指示菌的MIC随pH降低而降低。牛至精油对致病菌、乳酸菌的MIC分别为0.156~0.313和0.625~2.500μL/mL。0.156、0.313μL/mL的牛至精油对乳酸菌影响较小,生长量可达空白的91.54%~104.57%,对金黄色葡萄球菌部分抑制,生长量为空白的0%~51.06%,对大肠杆菌完全抑制。0.156、0.313μL/mL的牛至精油在发酵乳发酵过程中,对凝乳时间及活菌数基本无影响,其促进凝乳期的产酸及抑制过度发酵导致的后酸化。在储藏过程中,显著提高了7 d内活菌数及酸度,并强化了清除DPPH自由基的能力,但造成感官评分的下降。综上,牛至、肉桂、百里香、丁香精油具有作为发酵产品抑菌剂的潜力,其中牛至精油效果最好。
In order to develop suitable essential oil-fermented milk products,six strains of lactic acid bacteria(LAB)and two pathogens were used as indicator bacteria,the filter paper method and the minimum inhibitory concentration(MIC)were used for the evaluation of eight kinds of essential oils.The effect of essential oil on the growth curve of indicator bacteria was analyzed by OD_(600) value.And the number of viable bacteria,acid production and antioxidant activity during fermentation and storage of essential oil-fermented milk were analyzed.The result showed that essential oils(oregano,cinnamon,thyme,clove)had mild selective inhibition on indicator bacteria,essential oils had better inhibition effect on pathogenic bacteria than that of LABs(P<0.05).Oregano essential oil(OEO)had the best inhibition effect,which was highly sensitive to inhibit pathogenic bacteria(35.03-43.89 mm),and it is moderately sensitive to inhibit LABs(17.88-19.86 mm).Under the same pH,the MIC of essential oil to LABs were better than that of pathogenic bacteria.The MIC of essential oil to indicator bacteria also decreased with the reduction of pH.The MIC of OEO against pathogenic bacteria and LABs were 0.156-0.313 and 0.625-2.500μL/mL,respectively.OEO with the concentration of 0.156 and 0.313μL/mL had little effect on LABs,and the growth rate reached 91.54%-104.57%(of the blank).It partly inhibited Staphylococcus aureus,and the growth rate was 0%-51.06%(of the blank),and it completely inhibited Escherichia coli.During the fermentation of milk,OEO with the concentration of 0.156 and 0.313μL/mL had little effect on rennet time and viable bacteria count,but promoted the acid production of the rennet period and inhibited the post-acidification due to over-fermentation.During storage,the number of viable bacteria and acidity within 7 d significantly increased,and DPPH free radical scavenging rate was strengthened,but the sensory score decreased.In conclusion,essential oils of oregano,cinnamon,thyme,and cloves,especially OEO,have more potential as bacteriostatic agents for fermented products.
作者
薛元泰
吴世芳
李义恒
石承瑞
杨晓丽
鲁迎瑞
王莹
张卫兵
文鹏程
XUE Yuantai;WU Shifang;LI Yiheng;SHI Chengrui;YANG Xiaoli;LU Yingrui;WANG Ying;ZHANG Weibing;WEN Pengcheng(Food Science and Engineering College,Gansu Agricultural University,Lanzhou 730070,China;Gansu Institute of Business and Technology,Lanzhou 730010,China;Wuwei Plateau Biological Products Co.Ltd.,Wuwei 733000,China)
出处
《食品与发酵工业》
CAS
CSCD
北大核心
2022年第23期124-131,共8页
Food and Fermentation Industries
基金
国家自然科学基金项目(32160583,31960486)
甘肃省民生科技专项(20CX9NA097)
甘肃省自然科学基金项目(20JR10RA532)
中小企业创新基金项目(21CX6NH280)
“伏羲青年英才培育计划”项目(Gaufx-02Y01)。
关键词
精油
乳酸菌
致病菌
pH
生长特性
抗氧化性
发酵乳
essential oils
lactic acid bacteria
pathogens
pH
growth characteristics
antioxidant
fermented milk
