Role of mono- and oligosaccharides from FOS as stabilizing agents during freeze-drying and storage of Lactobacillus delbrueckii subsp bulgaricus
Role of mono- and oligosaccharides from FOS as stabilizing agents during freeze-drying and storage of Lactobacillus delbrueckii subsp bulgaricus
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DOI：
10.1016/j.foodres.2016.11.003
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发表时间：
2016-12-01
影响因子：
8.1
通讯作者：
Gomez-Zavaglia, Andrea
中科院分区：
文献类型：
--
作者：
Romano, Nelson;Schebor, Carolina;Gomez-Zavaglia, Andrea
本工作的目的是评估的作用，单-和低聚糖存在于低聚果糖（FOS）的混合物作为保护剂，在冷冻干燥和储存的德氏乳杆菌亚种。保加利亚CIDCA 333.从蔗糖酶促获得不同的FOS混合物，并通过除去作为次级产物产生的单糖进一步纯化。在11%、22%和33%相对湿度（RH）下测定了它们的玻璃化转变温度（T-g）。将细菌培养物在所研究的FOS的20%w/v溶液的存在下冷冻干燥。通过细菌平板计数，并通过测定生长动力学和碘化丙啶（PI）摄取的滞后时间，评估它们在冷冻干燥过程中的保护作用。在4 ℃、11%RH、22%RH和33%RH条件下保存细菌80天，通过平板计数，对FOS的保护作用进行了合理的分析。在未纯化的FOS存在下冷冻干燥的微生物具有最短的滞后时间。用纯FOS或商业FOS（占总FOS的92%）冻干的细菌显示出较大的滞后时间（8.9-12.6 h）。用未纯化的FOS和蔗糖冷冻干燥的微生物的可培养性与冷冻干燥前的细菌的可培养性（8.74 +/- 0.14 log CFU/mL）没有显著差异。纯的或商业的FOS在冷冻干燥过程中保护细菌的效率较低。所有的保护剂防止膜损伤。FOS腐败菌冻干培养的可行性研究
The aim of this work was to assess the role of mono- and oligosaccharides present in fructo-oligosaccharides (FOS) mixtures as protective agents during freeze-drying and storage of Lactobacillus delbrueckii subsp. bulgaricus CIDCA 333.Different FOS mixtures were enzymatically obtained from sucrose and further purified by removing the monosaccharides produced as secondary products. Their glass transition temperatures (T-g) were determined at 11, 22 and 33% relative humidity (RH). Bacterial cultures were freeze-dried in the presence of 20% w/v solutions of the studied FOS. Their protective effect during freeze-drying was assessed by bacterial plate counting, and by determining the lag time from growth kinetics and the uptake of propidium iodide (PI). Plate counting during bacterial storage at 4 degrees C, and 11, 22 and 33% RH for 80 days completed this rational analysis of the protective effect of FOS.Purification of FOS led to an increase of T-g in all the conditions assayed. Microorganisms freeze-dried in the presence of non-purified FOS were those with the shortest lag times. Bacteria freeze-dried with pure or commercial FOS (92% of total FOS) showed larger lag times (8.9-12.6 h). The cultivability of microorganisms freeze-dried with non-purified FOS and with sucrose was not significantly different from that of bacteria before freeze-drying (8.74 +/- 0.14 log CFU/mL). Pure or commercial FOS were less efficient in protecting bacteria during freeze-drying. All the protectants prevented membrane damage. The cultivability of bacteria freeze-dried with FOS decayed