不同接菌量和培养时间对叶酸检测结果的影响  

Effect of Different Inoculum Amount and Incubation Time on Folic Acid Test Results

作　　者：夏亚文 徐琼[1] 顾晟琳 XIA Yawen;XU Qiong;GU Shenglin(Key Laboratory of Milk and Dairy Products Detection and Monitoring Technology for State Market Regulation,Shanghai Institute of Quality Inspection and Technical Research,Shanghai 200233,China)

机构地区：[1]上海市质量监督检验技术研究院,国家市场监管重点实验室(乳及乳制品检测与监控技术),上海200233

出　　处：《食品科技》2023年第5期254-258,共5页Food Science and Technology

摘　　要：目的:研究乳粉中不同鼠李糖乳杆菌(Lactobacillus casei spp.rhamnosus ATCC 7469)的接菌量和培养时间对叶酸测定结果的影响。方法:通过1:200、1:100、1:20、1:10的接菌量和20 h、40 h培养时间,比较叶酸标准曲线的拟合程度,并根据标准曲线,分析20组叶酸质控样(Quality control products,QCs)叶酸含量结果差异性。结果:除接菌量1:200培养20 h外,其余处理的线性回归方程r~2都达到了0.99以上。通过对比标准曲线发现,4种不同接菌量培养40 h后,培养基中的叶酸被鼠李糖乳杆菌利用完全,微生物生长进入稳定期,标准曲线重合度较高,而高浓度接菌量(1:20和1:10)经过20 h的培养后也能够拟合成曲线,但是曲线走势低于相同接种浓度下培养40 h的生长曲线。20 h培养时间下,20组叶酸QCs结果离散性较大,而40 h培养时间各接菌量处理的结果离散性较小,其中接菌量1:100培养40 h处理的叶酸QCs结果为(151±3.96)μg/100 g。结论:通过对接菌量和培养时间的探讨,确定了接菌量和培养时间对叶酸结果的影响,为实验室微生物法检测叶酸的方法提供参考。Objective:To study the effect of different inoculation amount and incubation time of Lactobacillus casei spp.rhamnosus on the measurementof folic acid in milk powder.Method:By using different inoculation amount,1:200,1:100,1:20 and 1:10,and different incubation time,20 h and 40 h,the fitting degrees of the standard curve of folic acid were compared.And according to the standard curves,variability in folate content results for 20 groups of folic acid quality control products(QCs) were analysed.Results:The results showed that the r~2 of the linear regression equations of the other treatments reached more than 0.99 except that the inoculation amount was 1:200 after being cultured for 20 h.By comparing among the standard curves,it was found that after 40 h of incubation under four different quantities of inoculum amount,the folic acid in the medium was completely utilized by Lactobacillus casei spp.rhamnosus ATCC 7469,and the microbial growth entered a stable phase with a high overlap of the standard curves,while the high inoculum amount(1:20 and 1:10) were also able to fit the curves after 20 h of incubation,but the curve extent was lower than the growth curve after 40 h of incubation with the same inoculum concentration.The results of folic acid QCs were more discrete for the 20 groups at 20 h incubation time than that at 40 h incubation time,where in the results of folic acid QCs were(151±3.96)μg/100 g for the 40 h incubation treatment with 1:100 inoculum.Conclusion:Through the discussion on inoculum amount and culture time,the influence of inoculum amount and culture time on the results of folic acid was determined,which providing a reference for the method of laboratory microbial detection of folic acid.

关 键 词：叶酸 接菌量 培养时间 

分 类 号：TS207.3[轻工技术与工程—食品科学]