The effect of heat on the vitamin B6 of milk: II. A comparison of biological and microbiological tests of evaporated milk

1959 ◽  
Vol 26 (2) ◽  
pp. 215-220 ◽  
Author(s):  
Mary K. Davies ◽  
Margaret E. Gregory ◽  
Kathleen M. Henry
Keyword(s):  
Vitamin B6 ◽  
Experimental Error ◽  
Freeze Drying ◽  
Room Temperature ◽  
Raw Milk ◽  
Vitamin B ◽  
Experimental Conditions ◽  
Freeze Dried ◽  
Microbiological Research ◽  
Chick Diet

1. For chicks and rats pyridoxine, pyridoxal and pyridoxamine were equally active in terms of the free bases when given separately from the diet.2. Under our experimental conditions pyridoxine mixed with the chick diet was stable, but 20% of pyridoxamine, and a variable amount of pyridoxal was lost.3. The vitamin B6 activities measured with Saccharomyces carlsbergensis, chicks and rats respectively and expressed as μg. pyridoxine/g. freeze-dried milk were: raw milk 3·4, 3·2 and 4·9; evaporated milk 1·0, 2·1 and 2·7; stored evaporated milk 0·6, 1·4 and 2·0. For the chicks the milks were mixed with the diets; they were given separately to the rats.4. The microbiological and biological results for raw milk agreed within the limits of experimental error. For the processed milks the differences between biological and microbiological tests were statistically significant.5. All three methods of assay showed a 45–70% loss of vitamin B6 activity on processing and a further loss of 30% of the remainder after storage for 6 months at room temperature.We are indebted to Mr J. Rothwell, Department of Dairying, University of Reading, for preparing the evaporated milk and to Dr B. Record, Ministry of Supply, Microbiological Research Establishment, Porton, for freeze-drying the milk. We should like to thank Dr S. K. Kon for his interest in this work.

Scanning Electron Microscopy-cuticular Lesions on the Roundworm Ascaris Suum

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.

scholarly journals Protective Effects of Tropical Fruit Processing Coproducts on Probiotic Lactobacillus Strains during Freeze-Drying and Storage

2020 ◽  
Vol 8 (1) ◽  
pp. 96 ◽  
Author(s):  
Caroliny Mesquita Araújo ◽  
Karoliny Brito Sampaio ◽  
Francisca Nayara Dantas Duarte Menezes ◽  
Erika Tayse da Cruz Almeida ◽  
Marcos dos Santos Lima ◽  
...  
Keyword(s):  
Membrane Potential ◽  
Freeze Drying ◽  
Room Temperature ◽  
Membrane Integrity ◽  
Added Value ◽  
Protective Effects ◽  
Tropical Fruit ◽  
Freeze Dried ◽  
Fruit Processing ◽  
And Storage

This study evaluated the protective effects of coproducts from agroindustrial processing of the tropical fruits acerola (Malpighia glabra L., ACE), cashew (Anacardium occidentale L., CAS), and guava (Psidium guayaba L., GUA) on the probiotics Lactobacillus paracasei L-10, Lactobacillus casei L-26, and Lactobacillus acidophilus LA-05 during freeze-drying and storage. The occurrence of damage to membrane integrity, membrane potential, and efflux activity of Lactobacillus cells after freeze-drying was evaluated by flow cytometry, and viable counts were measured immediately after freeze-drying and during 90 days of storage under refrigerated or room temperature conditions. Probiotic strains freeze-dried without substrate had the overall highest count reductions (0.5 ± 0.1 to 2.9 ± 0.3 log cycles) after freeze-drying. Probiotics freeze-dried with fruit processing coproducts had small cell subpopulations with damaged efflux activity and membrane potential. Average counts of probiotics freeze-dried with ACE, CAS, or GUA after 90 days of storage under refrigerated or room temperature were in the range of 4.2 ± 0.1 to 5.3 ± 0.2 and 2.6 ± 0.3 to 4.9 ± 0.2 log CFU/g, respectively, which were higher than those observed for strains freeze-dried without substrate. The greatest protective effects on freeze-dried probiotics were overall presented by ACE. These results revealed that ACE, CAS, and GUA can exert protective effects and increase the stability of probiotic lactobacilli during freeze-drying and storage, in addition to supporting a possible added-value destination for these agroindustrial coproducts as vehicles for probiotics and for the development of novel functional foods.

634. The determination of the coagulating power of commercial rennet extracts using an automatic tester

1956 ◽  
Vol 23 (2) ◽  
pp. 269-276 ◽  
Author(s):  
F. C. Storrs
Keyword(s):  
Experimental Error ◽  
Freeze Drying ◽  
Milk Powder ◽  
Automatic Apparatus ◽  
Instrument Error ◽  
Single Observation ◽  
Rennet Coagulation ◽  
Freeze Dried ◽  
Two Samples

1. A method for preparing rennet reference standards by freeze-drying is described.2. A substrate has also been developed using ordinary spray dried separated milk powder which will give reproducible results under specified conditions. These include:(i) A constant temperature (37° C.) for the duration of the test.(ii) The exclusion of added calcium ions until actual testing begins.(iii) The equilibration of the milk at 37° C. for 2 hr. before use.3. The construction and use of an automatic apparatus for recording rennet coagulation time is also described.4. The instrument error of a single observation is about 1·0%.5. With liquid rennet extracts, the total experimental error, based on one sample of three replicates, is 2% or less: with two samples, it is 1% or less.6. With freeze-dried rennet preparations, the experimental error with two ampoules, sampled thrice with three replicates per sample, was ±2·.0%. With three ampoules it was ±1% or less.

scholarly journals Minimizing experimental artefacts in synchrotron-based X-ray analyses of Fe speciation in tissues of rice plants

2019 ◽  
Vol 26 (4) ◽  
pp. 1272-1279 ◽  
Author(s):  
Peng Wang ◽  
Brigid A. McKenna ◽  
Neal W. Menzies ◽  
Cui Li ◽  
Chris J. Glover ◽  
...  
Keyword(s):  
Freeze Drying ◽  
Plant Root ◽  
Experimental Conditions ◽  
X Ray ◽  
Freeze Dried ◽  
Fe Speciation ◽  
Root Tissues ◽  
X Ray Absorption ◽  
Beam Damage

Iron (Fe) plays an important role within environmental systems. Synchrotron-based X-ray approaches, including X-ray absorption spectroscopy (XAS), provide powerful tools for in situ analyses of Fe speciation, but beam damage during analysis may alter Fe speciation during its measurement. XAS was used to examine whether experimental conditions affect the analysis of Fe speciation in plant tissues. Even when analyzed in a cryostat at 12 K, it was found that FeIII can rapidly (within 0.5–1 min) photoreduce to FeII, although the magnitude of photoreduction varied depending upon the hydration of the sample, the coordination chemistry of the Fe, as well as other properties. For example, photoreduction of FeIII was considerably higher for aqueous standard compounds than for hydrated plant-root tissues. The use of freeze-dried samples in the cryostat (12 K) markedly reduced the magnitude of this FeIII photoreduction, and there was no evidence that the freeze-drying process itself resulted in experimental artefacts under the current experimental conditions, such as through the oxidation of FeII, although some comparatively small differences were observed when comparing spectra of hydrated and freeze-dried FeII compounds. The results of this study have demonstrated that FeIII photoreduction can occur during X-ray analysis, and provides suitable conditions to preserve Fe speciation to minimize the extent of beam damage when analyzing environmental samples. All studies utilizing XAS are encouraged to include a preliminary experiment to determine if beam damage is occurring, and, where appropriate, to take the necessary steps (such as freeze drying) to overcome these issues.

scholarly journals Freeze-dried plasma proteins are stable at room temperature for at least 1 year

2021 ◽  
Author(s):  
Jaimie Dufresne ◽  
Trung Hoang ◽  
Juliet Ajambo ◽  
Angelique Florentinus-Mefailoski ◽  
Peter Bowden ◽  
...  
Keyword(s):  
Liquid Nitrogen ◽  
Random Sampling ◽  
Freeze Drying ◽  
Room Temperature ◽  
Complement Component ◽  
Separate Experiment ◽  
Plasma Samples ◽  
Esi Ms ◽  
Freeze Dried ◽  
Edta Plasma

Thirty human EDTA plasma samples from male and female subjects ranging in age from 24 to 74 years were collected on ice, processed ice cold and stored frozen at −80 °C, in liquid nitrogen (LN2), or freeze dried and stored at room temperature in a desiccator (FDRT) or freeze dried and stored at −20 °C for 1 year (FD-20). In a separate experiment, EDTA plasma samples were collected onto ice, processed ice cold and maintained on ice ± protease inhibitors versus incubated at room temperature for up to 96 h. Random and independent sampling by liquid chromatography and tandem mass spectrometry (LC–ESI–MS/MS), as correlated by the MASCOT, OMSSA, X!TANDEM and SEQUEST algorithms, showed that tryptic peptides from complement component 4B (C4B) were rapidly released in plasma at room temperature. Random sampling by LC–ESI–MS/MS showed that peptides from C4B were undetectable on ice, but peptides were cleaved from the mature C4B protein including NGFKSHALQLNNR within as little as 1 h at room temperature. The frequency and intensity of precursors within ± 3 m/z of the C4B peptide NGFKSHALQLNNR was confirmed by automated targeted analysis where the precursors from MS/MS spectra that correlated to the target sequence were analyzed in SQL/R. The C4B preproprotein was processed at the N terminus to release the mature chain that was cleaved on the carboxyl side of the isoprene C2 domain within a polar C terminal sequence of the mature C4B protein, to reveal the thioester reaction site, consistent with LC–ESI–MS/MS and Western blot. Random sampling showed that proteolytic peptides from complement component C4B were rarely observed with long term storage at − 80 °C in a freezer or in liquid nitrogen (LN2), freeze drying with storage at − 20 °C (FD-20 °C) or freeze drying and storage at room temperature (FDRT). Plasma samples maintained at room temperature (RT) showed at least 10-fold to 100-fold greater frequency of peptide correlation to C4B and measured peptide intensity compared to samples on ice for up to 72 h or stored at − 80 °C, LN2, FDRT or FD-20 °C for up to a year.

scholarly journals Trace-nutrient-binding proteins in milk and the growth of bacteria in the gut of infant rabbits

1983 ◽  
Vol 49 (2) ◽  
pp. 231-240 ◽  
Author(s):  
C. B. Cole ◽  
K. J. Scott ◽  
M. J. Henschel ◽  
M. E. Coates ◽  
J. E. Ford ◽  
...  
Keyword(s):  
Freeze Drying ◽  
Binding Proteins ◽  
Raw Milk ◽  
Viable Count ◽  
Vitamin B ◽  
Γ Irradiation ◽  
Germ Free ◽  
Sterilized Milk ◽  
Growth Of Bacteria ◽  
Milk Feeding

1. The influence of trace-nutrient-binding proteins on the growth of coliforms, streptococci and lactobacilli in the gastrointestinal tract was examined in neonatal rabbits delivered germ-free and dosed with an artificial flora (ESL), or born conventionally and dosed with ESL or rabbit faeces.2. In the stomach and small intestine of both gnotobiotic and conventional animals the counts of coliforms were usually atypically high and those of streptococci were always low. In the colon the counts of coliforms and streptococci were high. Lactobacilli usually became established in the gut of the gnotobiotic animals but were not found in the conventional rabbits.3. Sterilization (freeze-drying followed by γ-irradiation) of the milk decreased its capacity to bind added iron by 45% and vitamin B12by 30%. When compared with raw milk, feeding of radiation-sterilized milk did not affect the viable count of coliforms and streptococci in the gut of gnotobiotic animals.4. Saturating the nutrient-binding proteins in milk with Fe, folic acid and vitamin B12had no effect on the numbers of coliforms, streptococci and lactobacilli recovered from the intestine.

scholarly journals Role of Calcium Alginate and Mannitol in Protecting Bifidobacterium

2012 ◽  
Vol 78 (19) ◽  
pp. 6914-6921 ◽  
Author(s):  
Dianawati Dianawati ◽  
Vijay Mishra ◽  
Nagendra P. Shah
Keyword(s):  
Freeze Drying ◽  
Room Temperature ◽  
Cell Envelope ◽  
Aluminum Foil ◽  
Alginate Beads ◽  
Content Type ◽  
Bifidobacterium Animalis ◽  
Freeze Dried ◽  
Cell Envelopes ◽  
Ca Alginate

ABSTRACTFourier transform infrared (FTIR) spectroscopy was carried out to ascertain the mechanism of Ca-alginate and mannitol protection of cell envelope components and secondary proteins ofBifidobacterium animalissubsp.lactisBb12 after freeze-drying and after 10 weeks of storage at room temperature (25°C) at low water activities (aw) of 0.07, 0.1, and 0.2. Preparation of Ca-alginate and Ca-alginate-mannitol as microencapsulants was carried out by dropping an alginate or alginate-mannitol emulsion containing bacteria using a burette into CaCl2solution to obtain Ca-alginate beads and Ca-alginate-mannitol beads, respectively. The wet beads were then freeze-dried. The awof freeze-dried beads was then adjusted to 0.07, 0.1, and 0.2 using saturated salt solutions; controls were prepared by keeping Ca-alginate and Ca-alginate-mannitol in aluminum foil without awadjustment. Mannitol in the Ca-alginate system interacted with cell envelopes during freeze-drying and during storage at low aws. In contrast, Ca-alginate protected cell envelopes after freeze-drying but not during 10-week storage. Unlike Ca-alginate, Ca-alginate-mannitol was effective in retarding the changes in secondary proteins during freeze-drying and during 10 weeks of storage at low aws. It appears that Ca-alginate-mannitol is more effective than Ca-alginate in preserving cell envelopes and proteins after freeze-drying and after 10 weeks of storage at room temperature (25°C).

scholarly journals Pengaruh Proses Freeze-Drying dan Penyimpanan pada Suhu Kamar terhadap Viabilitas dan Patogenisitas Plasma Nutfah Mikroba Pasteurella Multocida

2016 ◽  
Vol 12 (1) ◽  
pp. 40
Author(s):  
Siti Chotiah
Keyword(s):  
Freeze Drying ◽  
Room Temperature ◽  
Pasteurella Multocida ◽  
Culture Collection ◽  
Pathogenicity Test ◽  
Drying Process ◽  
Colony Forming Unit ◽  
Freeze Dried ◽  
Conservation Method ◽  
Preservation Medium

<p>The effect of freeze-drying process and preserving in a vacuum at room temperature against viability and pathogenicity of veterinary microbe germ plasma of Pasteuerella multocida BCC 2331 was investigated at Balitvet. The aim of this study was to find out the most effective and efficient conservation method. As much as 5,2 x 1011 colony forming unit (CFU)/ml of bacteria suspension in 7.5% glucose serum as the preservation medium being pathogenic in mice with LD50 of 9,8 CFU/ml was freeze dried then stored at room temperature (&amp;plusmn;27oC) until the study was completed. Viability and pathogenicity test were done immediately after the process, 1 and 2 months after storage. The results showed that there were viability decreases amounted 1,3 x 101 CFU/ml, 102 CFU/ml and 8,2 x l02 CFU/m1 due to the effects of the process, one month and two-month storage respectively. The decreases of pathogenicity on mice were shown by the increases of LD50 amounting log 1, log 2, and log 3 a day after the process, one month and two-month storage respectively.</p><p> </p><p><strong>Abstrak</strong></p><p>Pengaruh proses kering beku dan penyimpanan hasil proses pada suhu kamar 27oC terhadap viabilitas dan patogenisitas plasma nutfah mikroba veteriner telah dipelajari di Balitvet untuk menentukan cara pelestarian yang efektif dan efisien. Dalam kegiatan ini dipakai bakteri Pasteurella multocida koleksi Balitvet Culture Collection nomor koleksi B2331. Suspensi bakteri sebanyak 5,2 x l011 coloni forming unit (CFU)/ml dalam medium preservan 7,5% glukosa, serum dan bersifat patogen pada mencit dengan LD50 9,8 CFU/ml diproses kering beku, kemudian disimpan pada suhu kamar (+27oC) sampai penelitian selesai. Uji viabilitas dan patogenisitas dilakukan langsung setelah proses dan pada 1 serta 2 bulan setelah penyimpanan. Hasil penelitian menunjukkan terjadi penurunan viabilitas sebanyak 1,3 x 101 CFU, dan 8,2 x 102 CFU/ml masingmasing karena pengaruh proses, pengaruh penyimpanan selama 1 dan 2 bulan. Patogenisitas pada mencit menurun yang ditandai oleh adanya peningkatan LD50 sebanyak log 1, log 2, dan log 3 masing-masing 1 hari setelah proses, 1 dan 2 bulan setelah penyimpanan.</p>

scholarly journals Freeze-dried plasma proteins are stable at room temperature for at least 1 year

2021 ◽  
Author(s):  
Jaimie Dufresne ◽  
Trung Hoang ◽  
Juliet Ajambo ◽  
Angelique Florentinus-Mefailoski ◽  
Peter Bowden ◽  
...  
Keyword(s):  
Liquid Nitrogen ◽  
Random Sampling ◽  
Freeze Drying ◽  
Room Temperature ◽  
Complement Component ◽  
Separate Experiment ◽  
Plasma Samples ◽  
Esi Ms ◽  
Freeze Dried ◽  
Edta Plasma

Thirty human EDTA plasma samples from male and female subjects ranging in age from 24 to 74 years were collected on ice, processed ice cold and stored frozen at −80 °C, in liquid nitrogen (LN2), or freeze dried and stored at room temperature in a desiccator (FDRT) or freeze dried and stored at −20 °C for 1 year (FD-20). In a separate experiment, EDTA plasma samples were collected onto ice, processed ice cold and maintained on ice ± protease inhibitors versus incubated at room temperature for up to 96 h. Random and independent sampling by liquid chromatography and tandem mass spectrometry (LC–ESI–MS/MS), as correlated by the MASCOT, OMSSA, X!TANDEM and SEQUEST algorithms, showed that tryptic peptides from complement component 4B (C4B) were rapidly released in plasma at room temperature. Random sampling by LC–ESI–MS/MS showed that peptides from C4B were undetectable on ice, but peptides were cleaved from the mature C4B protein including NGFKSHALQLNNR within as little as 1 h at room temperature. The frequency and intensity of precursors within ± 3 m/z of the C4B peptide NGFKSHALQLNNR was confirmed by automated targeted analysis where the precursors from MS/MS spectra that correlated to the target sequence were analyzed in SQL/R. The C4B preproprotein was processed at the N terminus to release the mature chain that was cleaved on the carboxyl side of the isoprene C2 domain within a polar C terminal sequence of the mature C4B protein, to reveal the thioester reaction site, consistent with LC–ESI–MS/MS and Western blot. Random sampling showed that proteolytic peptides from complement component C4B were rarely observed with long term storage at − 80 °C in a freezer or in liquid nitrogen (LN2), freeze drying with storage at − 20 °C (FD-20 °C) or freeze drying and storage at room temperature (FDRT). Plasma samples maintained at room temperature (RT) showed at least 10-fold to 100-fold greater frequency of peptide correlation to C4B and measured peptide intensity compared to samples on ice for up to 72 h or stored at − 80 °C, LN2, FDRT or FD-20 °C for up to a year.

The effect of heat on the vitamin B6 of milk: I. Microbiological tests

1959 ◽  
Vol 26 (2) ◽  
pp. 203-214 ◽  
Author(s):  
Margaret E. Gregory
Keyword(s):  
Vitamin B6 ◽  
Lactobacillus Casei ◽  
Residual Activity ◽  
Raw Milk ◽  
Test Material ◽  
Vitamin B ◽  
Optimum Conditions ◽  
Test Organisms ◽  
Liquid Milk ◽  
Assay Technique

1. Four test organisms were used for the microbiological assay of vitamin B6. The test organisms and the forms of vitamin B6 active for them were: Saccharomyces carlsbergensis 4228 (pyridoxine, pyridoxamine and pyridoxal), Streptococcus faecalis R ATCC8043 and Str. faecium Ø51 (pyridoxamine and pyridoxal), and Lactobacillus casei ATCC7469 (pyridoxal).2. By simultaneous assay of the test material with the four organisms the amounts of pyridoxine, pyridoxamine and pyridoxal present were determined. The differential assay technique has been improved by the use of Str. faecium, which is more specific for measuring total pyridoxamine plus pyridoxal, instead of Str. faecalis.3. The optimum conditions for measuring vitamin B6 in milk were studied and the differential assay technique was applied in an investigation of the effect of heat on the vitamin B6 activity of milk.4. It was found that pyridoxal accounted for about 80% of the vitamin B6 activity of raw milk, the other 20% being due to pyridoxamine.5. In the manufacture of evaporated milk there was a marked fall in the pyridoxal and a slight increase in the pyridoxamine content. The overall loss was some 60%.6. On storage of evaporated and of sterilized liquid milk at room temperature there was a further loss of vitamin B6 activity. Most of the residual activity in stored evaporated milk appeared to be due to a substance other than pyridoxal or pyridoxamine, possibly pyridoxine.

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