200 assays (manual) / 2000 assays (microplate) / 1960 assays (auto-analyser)
Content: | 200 assays (manual) / 2000 assays (microplate) / 1960 assays (auto-analyser) |
Shipping Temperature: | Ambient |
Storage Temperature: |
Short term stability: 2-8oC, Long term stability: See individual component labels |
Stability: | > 2 years under recommended storage conditions |
Analyte: | Glucose Oxidase |
Assay Format: | Spectrophotometer, Microplate, Auto-analyser |
Detection Method: | Absorbance |
Wavelength (nm): | 510 |
Signal Response: | Increase |
Linear Range: | 0.01 to 0.08 U/mL of glucose oxidase per assay |
Limit of Detection: | 10 U/L |
Reaction Time (min): | ~ 20 min |
Application examples: | Enzyme preparations, and other materials (e.g. biological cultures, samples, etc.). |
Method recognition: | Novel method |
The Glucose Oxidase assay kit is a simple procedure for the rapid and reliable measurement and analysis of glucose oxidase activity in industrial enzyme preparations and bread improver mixtures.
View more of our assay kits for enzyme activities.
- Very competitive price (cost per test)
- All reagents stable for > 12 months after preparation
- Simple format
- Mega-Calc™ software tool is available from our website for hassle-free raw data processing
- Standard included
- Suitable for manual, microplate and auto-analyser formats
The Antibacterial Properties of Polish Honey against Streptococcus mutans—A Causative Agent of Dental Caries.
Grabek-Lejko, D. & Hyrchel, T. (2023). Antibiotics, 12(11), 1640.
Streptococcus mutans is considered the main pathogen responsible for dental caries, one of the major infectious diseases, affecting more than 4 billion people worldwide. Honey is a natural product with well-known antibacterial potential against several human pathogens. The aim of the study was to evaluate the antibacterial efficacy of Polish honey against S. mutans and analyze the role of some bioactive substances on its antibacterial action. The antibacterial potential of different honey varieties (goldenrod, buckwheat, honeydew, and lime) was analyzed using a microdilution assay. Manuka and artificial honey were used as controls. The content of GOX, hydrogen peroxide, total polyphenols, and antioxidant potential was assayed in honey. The influence of catalase and proteinase K on antibacterial activity as well as antibiofilm action was also determined. The strongest antibacterial activity was observed for buckwheat, honeydew, and manuka honey, which were also characterized by the highest antioxidant activity and polyphenols content. Catalase treatment decreases the antibacterial activity of honey, while proteinase K treatment influences the antibacterial potential of honey slightly less. Obtained results suggest that honey can be a good natural product against S. mutans, and hydrogen peroxide was identified as a crucial contributor to its antimicrobial action.
Hide AbstractCharacterisation of physicochemical parameters and antibacterial properties of New Caledonian honeys.
Bucekova, M., Godocikova, J., Gueyte, R., Chambrey, C. & Majtan, J. (2023). Plos one, 18(10), e0293730.
Honey is an attractive natural product with various health benefits. A few honey-based commercial products have successfully been adopted in clinics to improve wound healing. However, screening of other potential sources of medical-grade honey, in particular, honeys from territories with high floral species diversity and high endemicity, is highly needed. The goal of this study was to characterise the physicochemical and antibacterial properties of New Caledonian honey samples (n = 33) and to elucidate the major mechanism of their antibacterial action. Inhibitory antibacterial activity of honeys against Staphylococcus aureus and Pseudomonas aeruginosa was determined with a minimum inhibitory concentration (MIC) assay. Enzymatic activity of glucose oxidase and the content of hydrogen peroxide (H2O2) in honey samples were analysed. Furthermore, total protein content of honeys together with their electrophoretic protein profiles were also determined in the study. The antibacterial efficacy of 24% of the tested honey samples was slightly superior to that of manuka honey with unique manuka factor 15+. The antibacterial activity of catalase-treated honey sample solutions was significantly reduced, suggesting that H2O2 is a key antibacterial compound of diluted honeys. However, the kinetic profiles of H2O2 production in most potent honeys at a MIC value of 6% was not uniform. Under the experimental conditions, we found that a H2O2 concentration of 150 μM in diluted honeys is a critical concentration for inhibiting the growth of S. aureus. In contrast, 150 μM H2O2 in artificial honey solution was not able to inhibit bacterial growth, suggesting a role of phytochemicals in the antibacterial activity of natural honey. In addition, the continuous generation of H2O2 in diluted honey demonstrated an ability to counteract additional bacteria in re-inoculation experiments. In conclusion, the tested New Caledonian honey samples showed strong antibacterial activity, primarily based on H2O2 action, and therefore represent a suitable source for medical-grade honey.
Hide AbstractPlant immunity suppression by an exo-β-1, 3-glucanase and an elongation factor 1α of the rice blast fungus.
Liu, H., Lu, X., Li, M., Lun, Z., Yan, X., Yin, C., .et al. (2023). Nature Communications, 14(1), 5491.
Fungal cell walls undergo continual remodeling that generates β-1,3-glucan fragments as products of endo-glycosyl hydrolases (GHs), which can be recognized as pathogen-associated molecular patterns (PAMPs) and trigger plant immune responses. How fungal pathogens suppress those responses is often poorly understood. Here, we study mechanisms underlying the suppression of β-1,3-glucan-triggered plant immunity by the blast fungus Magnaporthe oryzae. We show that an exo-β-1,3-glucanase of the GH17 family, named Ebg1, is important for fungal cell wall integrity and virulence of M. oryzae. Ebg1 can hydrolyze β-1,3-glucan and laminarin into glucose, thus suppressing β-1,3-glucan-triggered plant immunity. However, in addition, Ebg1 seems to act as a PAMP, independent of its hydrolase activity. This Ebg1-induced immunity appears to be dampened by the secretion of an elongation factor 1 alpha protein (EF1α), which interacts and co-localizes with Ebg1 in the apoplast. Future work is needed to understand the mechanisms behind Ebg1-induced immunity and its suppression by EF1α.
Hide AbstractEffects of glucose release kinetics of extruded-maize diet on energy utilization of growing pigs.
Zhu, H., Zhao, Y., Mi, M., Zhang, Q., Fu, X., Zheng, Y., Qin, G., Pan, L. & Bao, N. (2023). Animal Feed Science and Technology, 304, 115747.
The precise energy requirement of swine should not only meet the static parameters of net energy but also consider the dynamic supply of glucose release. The effects of glucose release characteristics on nitrogen and energy utilization of growing pigs were conducted by the energy metabolism in vivo using open-circuit respiratory calorimetry and the hydrolysis in vitro of glucose release. Sixteen castrated boars were randomly divided into two groups (Raw maize group and Extruded maize group, RAW and EXT). Maize in the RAW diet was completely replaced by extruded-maize in the EXT diet. In vitro studies showed that extrusion treatment had a rapid and huge glucose release of maize (P < 0.05). The metabolizable energy (ME) in EXT was higher than that in RAW (P = 0.002), but no difference in net energy (NE) was observed (P = 0.864). EXT had higher crude protein (CP) apparent digestibility (P = 0.035) but lower nitrogen deposition (P < 0.001) due to higher urinary nitrogen (UN) excretion (P < 0.001). Extrusion treatment changed the proportion of heat production of carbohydrates, fat, and protein. EXT presented higher oxidation of protein (OXP, P < 0.001) and fat (OXF, P = 0.025) and lower oxidation of carbohydrates (OXCHO, P = 0.003). There was no difference in retained energy (RE) between the two groups (P = 0.803). Extrusion treatment can accelerate the glucose release of maize, and the extruded maize fully replacing raw maize in the diet can enhance ME of growing pigs, and the ratio of nutrient oxidation to energy supply was altered, resulting in lower protein deposition and energy utilization.
Hide AbstractAntibacterial and enzyme inhibitory activities of flavan-3-ol monomers and procyanidin-rich grape seed fractions.
Ares, P. S., Gaur, G., Willing, B. P., Weber, F., Schieber, A. & Gänzle, M. G. (2023). Journal of Functional Foods, 107, 105643.
This study aimed to determine structure–function relationships of monomeric and oligomeric flavan-3-ols (procyanidins) with respect to their antimicrobial activity and their inhibition of digestive enzymes. Monomeric flacan-3-ols were purchased as reference compounds; oligomeric procyanidins were extracted from grape seeds, separated by high-performance counter-current chromatography and characterized by LC-MS/MS. The antimicrobial activity against a broad range of intestinal microorganisms increased in the order catechin = epicatechin > epigallocatechin and oligomeric procyanidins > epigallocatechin gallate. Facultative anaerobes were highly resistant while strict anaerobes including Allobaculum sp. and Ruminococcus gnavus were 10 – 100 times more sensitive. The inhibition of digestive enzymes from the rat small intestine increased in the order catechin < epicatechin and oligomeric procyanidins < epigallocatechin < epigallocatechin gallate. Trimeric and polymeric procyanidins were more inhibitory than dimeric procyanidins. Both the antimicrobial and enzyme-inhibitory activities of procyanidins and flavan-3-ols likely relate to their microbiome-modulating and health beneficial properties.
Hide AbstractDevelopment of phytoglycogen-derived core–shell–corona nanoparticles complexed with conjugated linoleic acid.
Wang, Z., Hu, X., Hamaker, B. R., Zhang, T. & Miao, M. (2023). Food & Function, In Press.
Phytoglycogen-derived self-assembled nanoparticles (SMPG/CLA) and enzymatic-assembled nanoparticles (EMPG/CLA) were fabricated for delivery of conjugated linoleic acid (CLA). After measuring the loading rate and yield, the optimal ratio for both assembled host–guest complexes was 1 : 10, and the maximum loading rate and yield for EMPG/CLA were 1.6% and 88.1%, respectively, higher than those of SMPG/CLA. Structural characterization studies showed that the assembled inclusion complexes were successfully constructed, and had a specific spatial architecture with inner-core amorphous and external-shell crystalline parts. A higher protective effect against oxidation of EMPG/CLA was observed than that of SMPG/CLA, supporting efficient complexation for a higher order crystalline structure. After 1 h of gastrointestinal digestion under the simulated conditions, 58.7% of CLA was released from EMPG/CLA, which was lower than that released from SMPG/CLA (73.8%). These results indicated that in situ enzymatic-assembled phytoglycogen-derived nanoparticles might be a promising carrier platform for protection and targeted delivery of hydrophobic bioactive ingredients.
Hide AbstractPhysicochemical properties and in vitro digestibility of resistant starches obtained by autoclaving and lintnerization from native corn, apple and malanga starches.
Aguilar-Mendoza, V., Zamudio-Flores, P. B., Molina-Corral, F. J., Olivas-Orozco, G. I., Vela-Gutierrez, G., Hernandez-Gonzalez, M., et al. (2023). Biotecnia, 25(2), 12-22.
In this research, the effect of the application of successive autoclaving/cooling and lintnerization (acid hydrolysis) cycles in native starches of corn (NCS), apple (NAS), and malanga (NMS) on the formation of resistant starch (RS) was evaluated, and the physicochemical properties and in vitro digestibility of the obtained starches were studied. Autoclaved malanga starch (AMS) presented the highest RS content (14 %) compared to all analyzed starches. Enzymatic hydrolysis of native and modified starches indicated that autoclaving/ cooling decreased amylolysis (≈ 24 - 41 %), while with the lintnerization treatment, the reduction was lower (≈ 3 - 21 %), both results compared to their native counterparts. Autoclaving and lintnerization treatments reduced the apparent amylose content by ≈ 5 %, producing amylose with lower molecular weights (≈ 80 - 87 kDa) for autoclaved starches, and ≈ 92 - 101 kDa for lintnerized starches. The luminosity decreased due to the autoclaving treatment and not to the lintnerization process. These results suggest that malanga starch subjected to autoclaving/cooling cycles could be used in baking applications where an increase of the RS content without affecting the sensory color characteristics is desired.
Hide AbstractProduction of docosahexaenoic acid from spruce sugars using Aurantiochytrium limacinum.
Olsen, P. M., Kósa, G., Klüver, M., Kohler, A., Shapaval, V. & Horn, S. J. (2023). Bioresource Technology, 376, 128827.
In this study lignocellulosic sugars from Norway spruce were used for production of docosahexaenoic acid (DHA) by the marine thraustochytrid Aurantiochytrium limacinum SR21. Enzymatically prepared spruce hydrolysate was combined with a complex nitrogen source and different amounts of salts. Shake flask batch cultivations revealed that addition of extra salts was not needed for optimal growth. Upscaling to fed-batch bioreactors yielded up to 55 g/L cell dry mass and a total fatty acid content of 44% (w/w) out of which 1/3 was DHA. Fourier transform infrared spectroscopy was successfully applied as a rapid method for monitoring lipid accumulation in A. limacinum SR21. Thus, this proof-of-principle study clearly demonstrates that crude spruce hydrolysates can be directly used as a novel and sustainable resource for production of DHA.
Hide AbstractNewborns from Mothers Who Intensely Consumed Sucralose during Pregnancy Are Heavier and Exhibit Markers of Metabolic Alteration and Low-Grade Systemic Inflammation: A Cross-Sectional, Prospective Study.
Aguayo-Guerrero, J. A., Méndez-García, L. A., Manjarrez-Reyna, A. N., Esquivel-Velázquez, M., León-Cabrera, S., Meléndez, G., Zambrano, E., Martinez, E. R., Fragoso, J. M., Garduno, J. C. B. & Escobedo, G. (2023). Biomedicines, 11(3), 650.
Robust data in animals show that sucralose intake during gestation can predispose the offspring to weight gain, metabolic disturbances, and low-grade systemic inflammation; however, concluding information remains elusive in humans. In this cross-sectional, prospective study, we examined the birth weight, glucose and insulin cord blood levels, monocyte subsets, and inflammatory cytokine profile in 292 neonates at term from mothers with light sucralose ingestion (LSI) of less than 60 mg sucralose/week or heavy sucralose intake (HSI) of more than 36 mg sucralose/day during pregnancy. Mothers in the LSI (n = 205) or HSI (n = 87) groups showed no differences in age, pregestational body mass index, blood pressure, and glucose tolerance. Although there were no differences in glucose, infants from HSI mothers displayed significant increases in birth weight and insulin compared to newborns from LSI mothers. Newborns from HSI mothers showed a substantial increase in the percentage of inflammatory nonclassical monocytes compared to neonates from LSI mothers. Umbilical cord tissue of infants from HSI mothers exhibited higher IL-1 beta and TNF-alpha with lower IL-10 expression than that found in newborns from LSI mothers. Present results demonstrate that heavy sucralose ingestion during pregnancy affects neonates’ anthropometric, metabolic, and inflammatory features.
Hide AbstractGlucose oxidase as an important yet overlooked factor determining the antibacterial activity of bee pollen and bee bread.
Pełka, K., Bucekova, M., Godocikova, J., Szweda, P. & Majtan, J. (2022). European Food Research and Technology, 248(12), 2929-2939.
Bee pollen (BP) and bee bread (BB) have attracted great attention due to their biological activities including antibacterial activity. However, the mechanism of antibacterial activity is largely unknown. Therefore, we aimed to characterise the antibacterial effect of BP and BB aqueous extracts against bacterial pathogens (Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Proteus mirabilis and Enterococcus faecalis) and identify the key compound(s) responsible for this effect. Here, we demonstrate that BP and particularly BB extracts display antibacterial activity which is significantly increased in the presence of glucose. Immunoblot analysis of extracts revealed the presence of MRJP1 in all analysed BP and BB samples and the enzyme glucose oxidase (GOX) in the majority of BB samples. Treatment of extracts with catalase resulted in the restoration of bacterial growth but only in those samples where glucose supplementation caused the enhancement of antibacterial activity. Our findings provide a deeper understanding of antibacterial activity of BP/BB which is mediated by the enzymatic activity of bee-derived GOX.
Hide AbstractDevelopment of a novel pretreatment protocol for the efficient isolation and enrichment of honey proteome using pine honey and the hypopharyngeal glands of Apis mellifera L.
Akyıldız, İ. E., Yetimoğlu, E. K., Raday, S., Erdem, Ö., Acar, S., Yilmaz, Ö., Uzunoner, D., Duz, G. & Damarli, E. (2022). Journal of Food Measurement and Characterization, 16, 2616-2629.
A versatile sample pretreatment method for the honey matrix is still needed for any proteomic-based investigations. Invertase and diastase are the most important enzymes in the maturation of pine honey and the origin of these enzymes are attributed to the bee's hypopharyngeal glands (HPG). In our study, we aimed to isolate and enrich these enzymes as model proteins representing the honey proteome in an efficient and practical way. As authenticity comparison, isolating the same enzymes from HPG samples was also accomplished. For yielding pine honey crude protein isolate, as a tandem two-step approach, stirred cell ultrafiltration followed by centrifugal ultrafiltration (CUF) protocol was determined after experimental optimization. HPGs were dissected from the Apis mellifera L. and proteins were extracted by using a bead beater followed by concentration using CUF. Protein profiles of pine honey and HPG were compared by SDS-PAGE. The resulting protein concentrations, enzyme activities, and the cleaning efficiencies of the applied techniques were evaluated and optimized using the Bradford assay, modified enzyme activity assays, and sugar profiling method developed at HPLC-RID. The novel pretreatment method provided invertase at 1055.1 U/kg activity and diastase at 693.3 Shade U/g activity with yields of 900.9% and 2432.6%, respectively. The final crude protein isolate can be interpreted as reference material at any authenticity and quality assays of honey. The obtained crude protein extract will pave the way for high throughput proteomic investigations at the honey matrix. Furthermore, this template methodology could be scaled up in the industry for natural enzyme production.
Hide AbstractPhysicochemical Characterization and Biological Properties of Pine Honey Produced across Greece.
Tsavea, E., Vardaka, F. P., Savvidaki, E., Kellil, A., Kanelis, D., Bucekova, M., et al. (2022). Foods, 11(7), 943.
Pine honey is a honeydew honey produced in the East Mediterranean region (Greece and Turkey) from the secretions of the plant sucking insect Marchalina hellenica (Gennadius) (Coccoidea: Marchalini-dae) feeding on living parts of Pinus species. Nowadays, honeydew honey has attracted great attention due to its biological activities. The aim of this study was to study unifloral pine honey samples produced in Greece regarding their physicochemical parameters and antioxidant and antibacterial activity against five nosocomial and foodborne pathogens. These honeys showed physicochemical and microscopic characteristics within the legal limits, except for diastase activity, a parameter known to be highly variable, depending on various factors. Substantially higher levels of H2O2 were estimated compared to other types of honeydew honey, whereas protein content was similar. The total phenolic content was 451.38 ± 120.38 mg GAE/kg and antiradical activity ranged from 42.43 to 79.33%, while FRAP values (1.87 to 9.43 mmol Fe+2/kg) were in general higher than those reported in the literature. Various correlations could be identified among these parameters. This is the first attempt to investigate in depth the antibacterial activity of pine honey from Greece and correlate it with honey quality parameters. All tested honeys exerted variable but significant antibacterial activity, expressed as MIC and MBC values, comparable or even superior to manuka honey for some tested samples. Although honey antibacterial activity is mainly attributed to hydrogen peroxide and proteins in some cases (demonstrated by elevated MICs after catalase and Proteinase K treatment, respectively), no strong correlation between the antibacterial activity and hydrogen peroxide concentration or total protein content was demonstrated in this study. However, there was a statistically significant correlation of moisture, antioxidant and antibacterial activity against Klebsiella pneuomoniae, as well as antioxidant and antibacterial activity against Salmonella ser. Typhimurium. Interestingly, a statistically significant negative correlation has been observed between diastase activity and Staphylococcus aureus antibacterial activity. Overall, our data indicate multiple mechanisms of antibacterial activity exerted by pine honey.
Hide AbstractIncreasing the pH value during thermal processing suppresses the starch digestion of the resulting starch-protein-lipid complexes.
Zhen, Y., Wang, K., Wang, J., Qiao, D., Zhao, S., Lin, Q. & Zhang, B. (2022). Carbohydrate Polymers, 278, 118931.
To date, how the pH conditions of thermal processing tailor the structure and digestibility of resulting starch-based complexes remains largely unclear. Here, indica rice starch (IRS), stearic acid (SA), and a whey protein isolate (WPI) were used as materials. Increasing the pH value from 4 to 8 during thermal processing (pasting) mainly suppressed the starch digestion of starch-WPI-SA complexes rather than starch-SA counterparts. The starch-SA complexes showed moderate structural changes as the pH value rose, and there was less rapidly digestible starch (RDS) only at pH 8. For the starch-WPI-SA complexes, an increased pH value allowed larger nonperiodic structures and more V-type starch crystallites, with almost unchanged short-range orders but apparently collapsed networks at pH 8. Such ternary complexes displayed more resistant starch (RS) as the pH value rose. The ternary sample at pH 8 contained ca. 29.87% of the RS fractions.
Hide AbstractResistant starch type 2 from lotus stem: Ultrasonic effect on physical and nutraceutical properties.
Noor, N., Gani, A., Jhan, F., Jenno, J. L. H. & Dar, M. A. (2021). Ultrasonics Sonochemistry, 76, 105655.
Resistant starch type 2 (RS) was isolated from lotus stem using enzymatic digestion method. The isolated RS was subjected to ultrasonication (US) at different sonication power (100–400 W). The US treated and untreated RS samples were characterized using dynamic light scattering (DLS), scanning electron microscopy (SEM), light microscopy and Fourier transform infrared spectroscopy (FT-IR). DLS revealed that particle size of RS decreased from 12.80 µm to 413.19 nm and zeta potential increased from −12.34 mV to −26.09 mV with the increase in sonication power. SEM revealed smaller, disintegrated and irregular shaped RS particles after ultrasonication. FT-IR showed the decreased the band intensity at 995 cm−1 and 1047 cm−1 signifying that US treatment decreased the crystallinity of RS and increased its amorphous character. The bile acid binding, anti-oxidant and pancreatic lipase inhibition activity of samples also increased significantly (p < 0.05) with the increase in sonication power. Increase in US power however increased the values of hydrolysis from 23.11 ± 1.09 to 36.06 ± 0.13% and gylcemic index from 52.39 ± 0.38 to 59.50 ± 0.11. Overall, the non-thermal process of ultrasonic treatment can be used to change the structural, morphological and nutraceutical profile of lotus stem resistant starch which can have great food and pharamaceutical applications.
Hide AbstractEffect of Rosa Roxburghii juice on starch digestibility: A focus on the binding of polyphenols to amylose and porcine pancreatic α-amylase by molecular modeling.
Zhu, J., Zhang, B., Tan, C. P., Ding, L., Shao, M., Chen, C., Fu, X. & Huang, Q. (2022). Food Hydrocolloids, 123, 106966.
Chestnut rose (Rosa Roxburghii) is an endemic fruit in China with many bioactivities. The present study investigated the effect of chestnut rose juice concentrate (CRJC) on the digestibility of normal wheat starch (NWS), with a focus on the interaction between polyphenols and amylose as well as that between polyphenols and porcine pancreatic α-amylase (PPA). NWS was mixed with CRJC and digestibility was determined using Englyst method. The composition of CRJC was analyzed by ultrahigh performance liquid chromatography-mass spectrometry. Molecular dynamics (MD) was used to study the binding between polyphenols and PPA and between polyphenols and amylose. The results showed that CRJC could significantly increase the resistant starch content. The MD results agreed with previous docking and experimental results regarding the inhibitory effects (IEs) of polyphenols (with galloyl and glycosyl group differences) against α-glucosidase. The MD results also showed that complex polyphenols with greater molecular weights or a high number of hydrogen bond donors (HBDs)/acceptors (HBAs) bind in a stronger and more lasting manner with amylose than simple polyphenols. CRJC has the potential to reduce the risk of developing type 2 diabetes and molecular simulation can be a supporting tool to study mechanisms in food system.
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