Search

BACKGROUND To reflect and understand the real situation regarding immature honey, the quality parameters of 141 honey samples from different regions of China were evaluated. The possibility of classifying Chinese honey from different geographical origins was also considered. RESULTS: The results revealed that the values of diastase, sucrose, proline and 5‐hydroxymethylfurfural (HMF) met the international honey standard, although moisture, total glucose and fructose, and invertase content in most of the honey samples failed to meet the standards. In addition, honey from different geographical locations could be well separated based on the contents of maltose, sucrose, HMF and glucose oxidase. CONCLUSION: The maturity of honey has a great impact on its quality, and the geographical origin of immature honey could be classified according to the physicochemical parameters. © 2021 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Steamed bread is a traditional fermented pasta product in China, which plays an important role in the dietary structure. With the improvement of people's living standards and the acceleration of life pace in recent years, steamed bread has become a popular fast food product for consumer. However, the shelf life of steamed bread is short and easy to be aged, which greatly affects the industrialized production of steamed bread. Frozen dough technology can provide an economic and effective technical way. However, the relevant research reports pointed out that the water in the dough formed ice crystals in the process of frozen storage. Because of the temperature fluctuation, recrystallization will occur, which will destroy the network structure of the dough, make the dough appear cracks after freezing, reduce the gas holding capacity, as well as affect the quality of frozen dough and its cooked products. At the same time, ice crystal will also lead to the damage and rupture of yeast cells, such as the damage of its respiratory system, the reduction of yeast vitality and the lack of gas production, which will cause the decline of dough specific volume, texture and sensory quality. The use of dough quality improver can enhance the structure of gluten network, protect yeast activity, improve the quality of dough, and prolong the storage period of frozen dough. To study the effect of different improvers on the quality of frozen dough and its cooked products, and to select the compound improvers which can improve the quality of the products better, it has a certain practical significance in the actual production. In order to improve the quality of frozen dough and to clarify the effect of different food improvers on the quality of unwrapped frozen dough, this paper studied compound thickeners (carrageenan, guar gum, sodium alginate) and compound emulsifier (diacetyl tartrate monoglyceride, carboxymethyl cellulose), complex enzyme preparations (glutamine transaminase, glucose oxidase) and trehalose on the quality of unwrapped frozen dough steamed bread, through single factor and response surface experimental design, the effect of different compound quality improver on the specific volume, texture and sensory quality of frozen dough. Studies have shown that the effect of trehalose and enzyme preparation on the specific volume of frozen dough is extremely significant (P<0.01). Under the compounding process of adding 0.4 % emulsifier, 0.8 % thickener, 45 mg/kg enzyme preparation and 2 % trehalose, the specific volume of the frozen dough steamed bread reached the level of 3.15 mL/g, and its hardness and the springiness also reached a superior value of 926.832 g and 0.912 8, respectively. At the same time, the frozen dough which was not added and added with the compound quality improver for 0-2.5 month was observed by scanning electron microscopy. It was found that most of the small starch granules in the frozen dough without the addition of the modifier were exposed outside, the particles were distinct, and the internal structure was uneven. The frozen dough starch granules with the compound quality improver added in the gluten network, the protein network structure is clear and complete, the internal structure of the frozen dough is even and tight. [ABSTRACT FROM AUTHOR]

In China, potato starch wastewater causes serious environmental pollution. Therefore, in this study, we aimed to develop a method for the transformation of potato starch in potato starch wastewater into ammonium gluconate, where potato starch wastewater was enzymatically hydrolyzed by liquefaction and saccharification. The optimum parameters of the hydrolysis process were as follows: α-amylase concentration, 0.5% (v/v); reaction time, 35 min; temperature, 90 °C; glucoamylase concentration, 0.7% (v/v); reaction time, 25 h; temperature, 50 °C; and pH, 4.0. Subsequently, ammonium gluconate was produced using 4.6 U/g glucose oxidase and 75 U/g catalase at 50 °C. The pH of the solution was maintained in the range of 6.8 ± 0.2. In the final crude ammonium gluconate-containing liquid, the protein, total nitrogen, total carbon, organic carbon, and ammonium salt content was 3.5 g/L, 8.47 g/L, 53.62 g/L, 13.79 g/ L, and 60 g/L, respectively. The environmental pollution was solved by using potato starch to produce value-added products. [ABSTRACT FROM AUTHOR]

Background: In China, two common methods are used to detect serum glucose, glucose oxidase (GOD) and hexokinase (HK) methods. We evaluated five commercially available glucose reagent kits with the Center of Disease Control (CDC) HK reference method. Methods: Five routine methods were compared with the HK reference method according to Clinical and Laboratory Standards Institute (CLSI) guideline (EP9-A2). These five routine methods were performed on an “open channel” Olympus 5400 analyzer. Results: All five evaluated methods were closely correlated to the reference method (r>0.9998). Compared to the HK reference method, the Olympus-HK method and Roche-GOD method showed a very small positive bias (mean±SD: 0.08±0.09 mmol/L and 0.03±0.08 mmol/L); while the Biosino-HK method, Osborne-GOD method and Baiding-GOD method showed a very small negative bias (mean±SD: –0.07±0.06 mmol/L, –0.09±0.07 mmol/L and –0.01±0.04 mmol/L). Conclusions: All five reagents we evaluated using matching calibrators showed good correlation to the reference method and small bias. These five glucose reagents are acceptable for use in clinical laboratories. Clin Chem Lab Med 2010;48:361–4. [ABSTRACT FROM AUTHOR]

Rationale: Glucose oxidase (GOx)-based biocatalytic nanoreactors can cut off the energy supply of tumors for starvation therapy and deoxygenation-activated chemotherapy. However, these nanoreactors, including mesoporous silica, calcium phosphate, metal-organic framework, or polymer nanocarriers, cannot completely block the reaction of GOx with glucose in the blood, inducing systemic toxicity from hydrogen peroxide (H 2 O 2 ) and anoxia. The low enzyme loading capacity can reduce systemic toxicity but limits its therapeutic effect. Here, we describe a real 'ON/OFF' intelligent nanoreactor with a core-shell structure (GOx + tirazapamine (TPZ))/ZIF-8@ZIF-8 modified with the red cell membrane (GTZ@Z-RBM) for cargo delivery. Methods: GTZ@Z-RBM nanoparticles (NPs) were prepared by the co-precipitation and epitaxial growth process under mild conditions. The core-shell structure loaded with GOx and TPZ was characterized for hydrate particle size and surface charge. The GTZ@Z-RBM NPs morphology, drug, and GOx loading/releasing abilities, system toxicity, multimodal synergistic therapy, and tumor metastasis suppression were investigated. The in vitro and in vivo outcomes of GTZ@Z-RBM NPs were assessed in 4T1 breast cancer cells. Results: GTZ@Z-RBM NPs could spatially isolate the enzyme from glucose in a physiological environment, reducing systemic toxicity. The fabricated nanoreactor with high enzyme loading capacity and good biocompatibility could deliver GOx and TPZ to the tumors, thereby exhausting glucose, generating H 2 O 2 , and aggravating hypoxic microenvironment for starvation therapy, DNA damage, and deoxygenation-activated chemotherapy. Significantly, the synergistic therapy effectively suppressed the breast cancer metastasis in mice and prolonged life without systemic toxicity. The in vitro and in vivo results provided evidence that our biomimetic nanoreactor had a powerful synergistic cascade effect in treating breast cancer. Conclusion: GTZ@Z-RBM NPs can be used as an 'ON/OFF' intelligent nanoreactor to deliver GOx and TPZ for multimodal synergistic therapy and tumor metastasis suppression., Competing Interests: Competing Interests: The authors have declared that no competing interest exists., (© The author(s).)

The interfacial electron transfer of glucose oxidase (GOx) on a poly(glutamic acid)-modified glassy carbon electrode (PGA/GCE) was investigated. The redox peaks measured for GOx and flavin adenine dinucleotide (FAD) are similar, and the anodic peak of GOx does not increase in the presence of glucose in a mediator-free solution. These indicate that the electroactivity of GOx is not the direct electron transfer (DET) between GOx and PGA/GCE and that the observed electroactivity of GOx is ascribed to free FAD that is released from GOx. However, efficient electron transfer occurred if an appropriate mediator was placed in solution, suggesting that GOx is active. The PGA/GCE-based biosensor showed wide linear response in the range of 0.5-5.5 mM with a low detection limit of 0.12 mM and high sensitivity and selectivity for measuring glucose., (Copyright © 2015 Elsevier Inc. All rights reserved.)