Abelmoschus esculentus (L.) Moench polysaccharide enhances the resistance of Bifidobacterium longum MYL16 to freeze-drying and artificially digestive processes

AbstractBifidobacterium longum, one of the main microorganisms in the human gut, is used as an adjunct to lactic acid starter cultures or sold as a probiotic product. Therefore, Bifidobacterium longum cell suspensions get freeze-dried with protective additives to prevent activity losses. To date, investigations covering growth and inactivation kinetics of Bifidobacterium longum during the whole process (cultivation, drying, and storage) have been lacking. In this study, the effect of cultivation conditions and shelf temperature as well as the influence of protectants (maltodextrin, glucitol, trehalose) at various concentrations on cell survival during freeze-drying was assessed. Drying was followed by a storage at + 4 °C and + 20 °C for 70 days to evaluate inactivation kinetics. The impact of the different factors was assessed by measuring surival rate and residual moisture content at various points of time over the whole process. In parallel cell membrane integrity and glass transition were determined to reveal inactivation effects. Cultivation strategy had a strong influence on survival with a huge potential for process improvement. A pH of 6.0 at the growth optimum of the strain provides better conditions regarding cell survival after drying than free acidification (non-regulated pH conditions). During the drying step, membrane leakage due to the removal of water is the main reason for the inactivation in this process step. In this study, the highest survival of 49% was obtained with cells dried at + 35 °C shelf temperature with an addition of maltodextrin (75% bacterial dry matter, w/w). The results show that Bifidobacterium longum cells are mostly inactivated during drying, whereas storage conditions at + 4 °C with an addition of 75% BDM maltodextrin relative to bacterial dry mass prevent cell loss completely.

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Effect of palmitoylated alginate microencapsulation on viability of Bifidobacterium longum during freeze-drying

LWT ◽

10.1016/j.lwt.2013.11.003 ◽

2014 ◽

Vol 56 (1) ◽

pp. 111-117 ◽

Cited By ~ 34

Author(s):

Khalie Mahamad Amine ◽

Claude P. Champagne ◽

Stéphane Salmieri ◽

Michel Britten ◽

Daniel St-Gelais ◽

...

Keyword(s):

Freeze Drying ◽

Bifidobacterium Longum

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Optimizing the Chemical Compositions of Protective Agents for Freeze-drying Bifidobacterium longum BIOMA 5920

Chinese Journal of Chemical Engineering ◽

10.1016/s1004-9541(12)60420-0 ◽

2012 ◽

Vol 20 (5) ◽

pp. 930-936 ◽

Cited By ~ 9

Author(s):

Chanyuan YANG ◽

Xiaoli ZHU ◽

Daidi FAN ◽

Yu MI ◽

Yan'e LUO ◽

...

Keyword(s):

Freeze Drying ◽

Bifidobacterium Longum ◽

Chemical Compositions ◽

Protective Agents

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Ca-Histochemistry in slime mold plasmodia

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100081516 ◽

1978 ◽

Vol 36 (2) ◽

pp. 130-131

Author(s):

Ulrich Dierkes

Keyword(s):

Physarum Polycephalum ◽

Carbon Coating ◽

Freeze Drying ◽

Freeze Fracture ◽

Freeze Substitution ◽

Uranyl Acetate ◽

Slime Mold ◽

Staining Procedure ◽

Protoplasmic Streaming ◽

Intracellular Ca

Calcium is supposed to play an important role in the control of protoplasmic streaming in slime mold plasmodia. The motive force for protoplasmic streaming is generated by the interaction of actin and myosin. This contraction is supposed to be controlled by intracellular Ca-fluxes similar to the triggering system in skeleton muscle. The histochemical localisation of calcium however is problematic because of the possible diffusion artifacts especially in aquous media.To evaluate this problem calcium localisation was studied in small pieces of shock frozen (liquid propane at -189°C) plasmodial strands of Physarum polycephalum, which were further processed with 3 different methods: 1) freeze substitution in ethanol at -75°C, staining in 100% ethanol with 1% uranyl acetate, and embedding in styrene-methacrylate. For comparison the staining procedure was omitted in some preparations. 2)Freeze drying at about -95°C, followed by immersion with 100% ethanol containing 1% uranyl acetate, and embedding. 3) Freeze fracture, carbon coating and SEM investigation at temperatures below -100° C.

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The Critical Point Drying Method Applied to Scanning Electron Microscopy of L-929 Cells

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100068382 ◽

1970 ◽

Vol 28 ◽

pp. 278-279

Author(s):

Charles TurnbiLL ◽

Delbert E. Philpott

Keyword(s):

Electron Microscopy ◽

Carbon Dioxide ◽

Surface Tension ◽

Critical Point ◽

Freeze Drying ◽

Attractive Alternative ◽

Crystal Formation ◽

Critical Point Drying ◽

Time Required ◽

Scanning Electron

The advent of the scanning electron microscope (SCEM) has renewed interest in preparing specimens by avoiding the forces of surface tension. The present method of freeze drying by Boyde and Barger (1969) and Small and Marszalek (1969) does prevent surface tension but ice crystal formation and time required for pumping out the specimen to dryness has discouraged us. We believe an attractive alternative to freeze drying is the critical point method originated by Anderson (1951; for electron microscopy. He avoided surface tension effects during drying by first exchanging the specimen water with alcohol, amy L acetate and then with carbon dioxide. He then selected a specific temperature (36.5°C) and pressure (72 Atm.) at which carbon dioxide would pass from the liquid to the gaseous phase without the effect of surface tension This combination of temperature and, pressure is known as the "critical point" of the Liquid.

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Preservation of Plant Cell Surfaces For Scanning Electron Microscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100072800 ◽

1973 ◽

Vol 31 ◽

pp. 472-473

Author(s):

Linda M. Sicko ◽

Thomas E. Jensen

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Critical Point ◽

Filter Paper ◽

Freeze Drying ◽

Cell Surfaces ◽

Air Drying ◽

Popular Method ◽

Critical Point Drying ◽

Scanning Electron

The use of critical point drying is rapidly becoming a popular method of preparing biological samples for scanning electron microscopy. The procedure is rapid, and produces consistent results with a variety of samples. The preservation of surface details is much greater than that of air drying, and the procedure is less complicated than that of freeze drying. This paper will present results comparing conventional air-drying of plant specimens to critical point drying, both of fixed and unfixed material. The preservation of delicate structures which are easily damaged in processing and the use of filter paper as a vehicle for drying will be discussed.

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Scanning Electron Microscopy-cuticular Lesions on the Roundworm Ascaris Suum

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010006756x ◽

1970 ◽

Vol 28 ◽

pp. 114-115

Author(s):

P. A. Madden ◽

W. R. Anderson

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Freeze Drying ◽

Room Temperature ◽

Secondary Electron ◽

Distilled Water ◽

Freeze Dried ◽

Silver Paint ◽

To Come ◽

Scanning Electron

The intestinal roundworm of swine is pinkish in color and about the diameter of a lead pencil. Adult worms, taken from parasitized swine, frequently were observed with macroscopic lesions on their cuticule. Those possessing such lesions were rinsed in distilled water, and cylindrical segments of the affected areas were removed. Some of the segments were fixed in buffered formalin before freeze-drying; others were freeze-dried immediately. Initially, specimens were quenched in liquid freon followed by immersion in liquid nitrogen. They were then placed in ampuoles in a freezer at −45C and sublimated by vacuum until dry. After the specimens appeared dry, the freezer was allowed to come to room temperature slowly while the vacuum was maintained. The dried specimens were attached to metal pegs with conductive silver paint and placed in a vacuum evaporator on a rotating tilting stage. They were then coated by evaporating an alloy of 20% palladium and 80% gold to a thickness of approximately 300 A°. The specimens were examined by secondary electron emmission in a scanning electron microscope.

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