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Luz Del Carmen Huescaespitia - One of the best experts on this subject based on the ideXlab platform.
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effects of steam autoclave treatment on geobacillus stearothermophilus spores
Journal of Applied Microbiology, 2016Co-Authors: Luz Del Carmen Huescaespitia, Milomir Suvira, Kayla Rosenbeck, George Korza, Barbara Setlow, William Li, Yongqing Li, Shiwei Wang, Peter SetlowAbstract:Aims To determine the mechanism of autoclave killing of Geobacillus stearothermophilus spores used in biological indicators (BIs) for steam autoclave sterilization, and rates of loss of spore viability and a spore enzyme used in BIs. Methods and Results Spore viability, dipicolinic acid release, nucleic acid staining, α-glucosidase activity, protein structure and mutagenesis were measured during Autoclaving of G. stearothermophilus spores. Loss of dipicolinic acid and increases in spore core nucleic acid staining were slower than loss of spore viability. Spore core α-glucosidase was also lost more slowly than spore viability, although soluble α-glucosidase in spore preparations was lost more rapidly. However, spores exposed to an effective autoclave sterilization lost all viability and α-glucosidase activity. Apparently killed autoclaved spores were not recovered by artificial germination in supportive media, much spore protein was denatured during Autoclaving, and partially killed autoclave-treated spore preparations did not acquire mutations. Conclusions These results indicate that autoclave-killed spores cannot be revived, spore killing by Autoclaving is likely by protein damage, and spore core α-glucosidase activity is lost more slowly than spore viability. Significance and Impact of Study This work provides insight into the mechanism of autoclave killing of spores of an organism used in BIs, and that a spore enzyme in a BI is more stable to Autoclaving than spore viability. This article is protected by copyright. All rights reserved.
Duygu Gocmen - One of the best experts on this subject based on the ideXlab platform.
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effects of Autoclaving temperature and storing time on resistant starch formation and its functional and physicochemical properties
Carbohydrate Polymers, 2013Co-Authors: Ayse Neslihan Dundar, Duygu GocmenAbstract:Abstract In this study effects of Autoclaving temperature (140–145 °C) and storing time (24, 48 and 72 h) on resistant starch (RS) formation from high amylose corn starch were investigated and functional and pasting properties of RS preparations were determined. High Autoclaving temperature (145 °C) and long storing time (72 h) showed beneficial impacts on RS formation. Significant decreases were observed in all RVA viscosities of RS preparations as the Autoclaving temperature increased. There was significant effect of storage time on all RVA parameters of RS preparations within each Autoclaving temperature. The water binding values of RS preparations autoclaved at 145 °C were higher than those of the samples autoclaved at 140 °C. RS preparations had approximately 2-fold higher emulsion capacity values than the native starch. Thermal enthalpy (Δ H ) values of RS preparations were lower than those of native starch. Autoclaving temperature and storing time had no effects on T O and T P .
Robert G Gilbert - One of the best experts on this subject based on the ideXlab platform.
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autoclaved rice the textural property and its relation to starch leaching and the molecular structure of leached starch
Food Chemistry, 2019Co-Authors: Hongyan Li, Wenwen Yu, Haiteng Li, Robert G Gilbert, Lu YuAbstract:Abstract Autoclave cooking is used to produce “convenience” rice. In this study, Autoclaving effects on sensory properties are investigated, and mechanistic explanations in terms of the underlying molecular structure are explored by analyzing this structure by size-exclusion chromatography and fitting the results with models based on biosynthetic processes. Compared to steam cooking, Autoclaving produces stickier texture, and slightly affects hardness. It is found that molecular sizes of leached starch of both autoclaved and steam cooked rice are similar, but significantly smaller than that of the parent grain starch; model fitting parameters of leached amylopectin and amylose structures between autoclaved rice and steam cooked rice display no large variations. The amount of leached amylopectin (an important texture-controlling parameter) of autoclaved rice is higher than that of steam cooked rice. Correlation analysis indicates that, compared to steam-cooked rice, the stickier texture of autoclaved rice is caused by more amylopectin leaching during Autoclaving.
Ivan Kreft - One of the best experts on this subject based on the ideXlab platform.
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resistant starch formation following Autoclaving of buckwheat fagopyrum esculentum moench groats an in vitro study
Journal of Agricultural and Food Chemistry, 1998Co-Authors: Vida Skrabanja, Ivan KreftAbstract:Buckwheat groats (cv. Darja) were autoclaved at 120 °C for 1 h and cooled to room temperature (the temperature decreased to 25 °C in 150 min). A portion was treated further with two additional Autoclaving/cooling cycles. A higher number of Autoclaving/cooling cycles did not affect the proportion of slowly digested starch (SDS) or resistant starch (RS) fraction found in treated buckwheat but gave a significant (P < 0.001) rise in the retrograded starch (RS3) amount. In native groat starch, 24.6% of apparent amylose and 28.3% of true amylose was determined. In samples treated with three Autoclaving/cooling cycles there was significantly (P < 0.001) more apparent and true amylose in the starch in comparison to the native sample or to samples autoclaved once. This may be due to gradual cleavage of some glycosidic bonds of starch, resulting in shorter linear chains, which could be then more predisposed to forming both amylose-like helices and more complex aggregates. Keywords: Fagopyrum esculentum; Autoclaving...
Peter Setlow - One of the best experts on this subject based on the ideXlab platform.
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effects of steam autoclave treatment on geobacillus stearothermophilus spores
Journal of Applied Microbiology, 2016Co-Authors: Luz Del Carmen Huescaespitia, Milomir Suvira, Kayla Rosenbeck, George Korza, Barbara Setlow, William Li, Yongqing Li, Shiwei Wang, Peter SetlowAbstract:Aims To determine the mechanism of autoclave killing of Geobacillus stearothermophilus spores used in biological indicators (BIs) for steam autoclave sterilization, and rates of loss of spore viability and a spore enzyme used in BIs. Methods and Results Spore viability, dipicolinic acid release, nucleic acid staining, α-glucosidase activity, protein structure and mutagenesis were measured during Autoclaving of G. stearothermophilus spores. Loss of dipicolinic acid and increases in spore core nucleic acid staining were slower than loss of spore viability. Spore core α-glucosidase was also lost more slowly than spore viability, although soluble α-glucosidase in spore preparations was lost more rapidly. However, spores exposed to an effective autoclave sterilization lost all viability and α-glucosidase activity. Apparently killed autoclaved spores were not recovered by artificial germination in supportive media, much spore protein was denatured during Autoclaving, and partially killed autoclave-treated spore preparations did not acquire mutations. Conclusions These results indicate that autoclave-killed spores cannot be revived, spore killing by Autoclaving is likely by protein damage, and spore core α-glucosidase activity is lost more slowly than spore viability. Significance and Impact of Study This work provides insight into the mechanism of autoclave killing of spores of an organism used in BIs, and that a spore enzyme in a BI is more stable to Autoclaving than spore viability. This article is protected by copyright. All rights reserved.
