•Cooking technique influences the chemical composition of soup.•Stewed soup had small particle size.•Stewed soup had low fat and total triglycerides levels.•Stewed soup had more flavor ...characteristics.•Stewed soup had more taste characteristics.
Meat soup is an important diet with desirable taste and abundant nutrients. Unveiling the chemical composition of soup will help to understand the health effects. In this work, pork ribs and Silkie chicken were used to prepare soups by boiling, steaming and four-stage stewing, respectively. The chemical composition and sensory qualities of these soups were obviously influenced by the cooking technique. Silkie chicken and pork rib soups prepared by four-stage stewing technique had particle size smaller than 850 nm, smaller chromatic aberration, higher stability, higher levels of free amino acids, lower levels of fat and total triglycerides than the other two techniques. More abundant flavor and taste characteristics were also detected. The high temperature boiling technique could promote the accumulation of the mineral elements in soup. According to healthy and sensory concerns, stewing was the best choice for preparing soups of pork rib and Silkie chicken.
Chinese yam has been widely used in food products. The growth stage significantly influences the qualities of Chinese yam. In this work, the physicochemical properties and microstructure of Chinese ...yam flours from expansion stage (ES-FF) and dormant stage (DS-FF) were investigated. The amylose content of DS-FF was lower than ES-FF, while the fat content of DS-FF was higher. The size and shape of Chinese yam flour granules at two growth stages remained consistently. ES-FF and DS-FF presented A- and C-type crystalline structure, respectively. DS-FF had a lower crystallinity and a higher short-range order than ES-FF. Dormant stage induced the formation of more amylose-lipid complex and ordered structure in granule. The values of To, Tp, Tc and enthalpy indicated that DS-FF had a higher thermal stability and a more compact structure than ES-FF. Moreover, Chinese yam flour showed a good elasticity and stickness with a high viscosity.
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•Growth stage influenced the crystalline structure of Chinese yam flour.•Chinese yam flour showed good rheological characteristics.•Chinese yam flour showed good paste properties.•Dormant stage promoted the formation of more amylose-lipid complex.
This study focused on the cloning, overexpression, and characterization of the gene encoding l-asparaginase (ansZ) from a nonpathogenic strain of Bacillus subtilis B11–06. The recombinant enzyme ...showed high thermostability and low affinity to l-glutamine. The ansZ gene, encoding a putative l-asparaginase II, was amplified by PCR and expressed in B. subtilis 168 using the shuttle vector pMA5. The activity of the recombinant enzyme was 9.98 U/mL, which was significantly higher than that of B. subtilis B11–06. The recombinant enzyme was purified by a two-step procedure including ammonium sulfate fractionation and hydrophobic interaction chromatography. The optimum pH and temperature of the recombinant enzyme were 7.5 and 40 °C, respectively. The enzyme was quite stable at a pH range of 6.0–9.0 and exhibited about 14.7 and 9.0% retention of activity following 2 h incubation at 50 or 60 °C, respectively. The K m for l-asparagine was 0.43 mM, and the V max was 77.51 μM/min. Results of this study also revealed the potential industrial application of this enzyme in reducing acrylamide formation during the potato frying process.
In recent years, with the development of the new energy industry, the demand for cobalt as a raw material for power batteries has been increasing. However, China itself has a shortage of cobalt ...resources. Therefore, overcoming poor resource conditions and enhancing the international competitiveness of the cobalt industry have become urgent issues. This paper is based on global trade data on cobalt resources from 2007 to 2020. A panel regression model is constructed from the perspective of trade networks, and Entropy-Topsis is used to construct a comprehensive evaluation index system for the international competitiveness of critical nonferrous metals. This study empirically examines the impact of the trade network characteristics of cobalt resources on international competitiveness, assigns practical significance to trade network characteristic indicators, and analyses the overall competitiveness changes in the global cobalt industry chain and its upstream, midstream, and downstream sectors. The research findings reveal the following key points: (1) In recent years, the competitive focus of the cobalt industry chain in various countries has shifted from upstream and midstream to midstream and downstream, with increasingly fierce trade competition downstream, gradually tilting toward countries such as South Korea, Japan, and China. (2) Cobalt trade competition, which was initially characterized by competition among multiple countries, has gradually become more centralized and stable, with differences in the competitiveness of various countries occurring at different stages of the cobalt industry chain. (3) Network centrality and network heterogeneity both have a significant promoting effect on the international competitiveness of the industry, while network connectivity has a significant inhibitory effect on the improvement of international competitiveness.On this basis, the study also suggests some policy implications. The purpose of the study is to enhance the international competitiveness of China's cobalt industry from a trade perspective and to investigate the developments of cobalt trade between China and the rest of the world.
Acetoin and 2,3-butanediol (2,3-BD) have a large number of industrial applications. The production of acetoin and 2,3-BD has traditionally relied on oil supplies. Microbial production of acetoin and ...2,3-BD will alleviate the dependence on oil. Acetoin and 2,3-BD are neighboring metabolites in the 2,3-BD metabolic pathway of bacteria. This review summarizes metabolic engineering strategies for improvement of microbial acetoin and 2,3-BD production. We also propose enhancements to current acetoin and 2,3-BD production strategies, by offering a metabolic engineering approach that is guided by systems biology and synthetic biology.
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, GIS, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Soft soils are widely distributed in the Guangdong-Hong Kong-Macao Greater Bay Area of China. The soft soils are featured with large water content, high compressibility and low permeability, posing ...great challenges in dealing with bearing capacity and foundation settlements. Extensive laboratory tests have to be conducted to determine parameters for shear strength and compressibility properties of soft soils. This is really time consuming and costly. In addition, sample disturbance and lab testing error are also unavoidable. The aim of this study is to develop a simple, efficient while satisfactorily accurate tool for prompt assessments of parameters for shear strength and compressibility of soft soils. The artificial neural network (ANN) technique is employed to reach this goal. A large database is first presented for measured physical and mechanical parameters of soft soils sampled from a core city in the Greater Bay Area. The data are obtained from six types of geotechnical laboratory tests, including direct shear test, consolidation test, unconsolidated undrained test, total stress consolidated undrained test, effective stress consolidated undrained test and compression test. Then, the ANN is applied to map the shear strength and compressibility properties of the soft soil from its physical parameters. The analytical forms of the ANN models are derived and presented to enhance their practical value. Next, the accuracies of the six ANN models are evaluated using model bias statistics where model bias is the ratio of measured to predicted value. The evaluation results showed that the ANN models are practically unbiased on average and the dispersions in prediction accuracy are low. Furthermore, the probability distributions of the model biases are characterized. This study helps saving time and cost of geotechnical investigation for soft soils in the area.
•A database containing over 1000 physical and mechanical properties for soft soils•Analytical ANNs for mechanical features of soft soils from physical properties•Evaluation of the model accuracy of the developed ANN models using bias statistics•Characterization of the bias distributions for the ANNs
Native potato starch was suspended in distilled water at starch: water ratio of 1:3 (w/v). The starch-water suspensions were then subjected to repeated annealing treatments (RANN) at 55 °C for 12 h, ...repeated for 8 cycles or continuous annealing treatments (CANN) at 55 °C for 24, 48, 72 and 96 h. The structural, physiochemical and digestive properties of the annealed starch samples were studied and compared with those of the native starch. The scanning electron microscopy and light microscopy analysis showed that the repeated and continuous annealing treatments could keep the integrity and surface perfection of the starch granules. The growth rings of the annealed starch granules were more distinct than those of the native starch granules as revealed by confocal laser scanning microscopy. The crystallinity degree increased and the crystalline retained the B-type pattern after the annealing treatments. There were no chemical bonds and functional groups produced or disappeared during the applied annealing treatments. Infrared absorption peak intensity of starch decreased and short-range ordered structures increased after treatments. The swelling power and solubility decreased at low temperature (50 to 60 °C) and increased at relatively high temperature (70 to 90 °C). The rapid visco-analyzer and differential scanning calorimeter analysis revealed an increase in the setback, final viscosity, pasting temperature and gelatinization transition temperature, and a decrease in breakdown value of the starch after the annealing treatments. On the other hand, the repeated and continuous annealing treatments resulted in starch with low in vitro digestibility degree, indicating formation of resistant starch. Generally, the repeated annealing treatment resulted in starch with high improved properties compared with the starch resulted from the continuous annealing treatments. Therefore, the repeated annealing treatments can be suggested as an effective method for producing of modified starch for food industrial applications.
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•Potato starch prepared by repeated and continuous annealing.•The effect of repeated annealing on potato starch was more significant.•The redistribution of water during the intermission laid a foundation for rearrangement of starch molecules.•The increase/decrease of temperature was essential to consolidation of the reconstructed starch structure.
Mung bean starch slurries (75% moisture) were respectively treated by repeated annealing (RANN) at 50°C for eight repetitions (every repetition was treated for 12 h) and continuous annealing (CANN) ...at the same temperature for 24, 48, 72 and 96 h. After RANN and CANN modifications, variations in the physicochemical properties, structures as well as digestive characteristics of mung bean starch were investigated. Scanning electron microscopy observed the grooves on the surfaces of starch granules became deeper after RANN and CANN modifications, and the cracks in the granule centers were monitored by light microscopy. However, there was no distinct change detected by confocal laser scanning microscopy. RANN and CANN modifications increased the crystallinity and degree of crystalline order, but the crystalline patterns were not changed. Under the same annealing time, RANN samples presented higher crystallinity, gelatinization temperature, enthalpy, peak time, pasting temperature, resistant starch (RS), slowly digestible starch (SDS) and SDS+RS values, but lower solubility, swelling power, peak viscosity, breakdown and rapidly digestible starch (RDS) values than CANN samples. Therefore, RANN could exert conspicuous impacts compared to CANN, which illustrates the annealing impact on starch modification and it could be applied in food processing as an innovative approach.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
To standardize the specification of negative externality management of mining resources development and promote the process of marketization and diversification of ecological compensation, the ...article reviews the perspective and method of quantitative evaluation of negative externalities based on summarizing the mineralization principle, characteristics, and three-generation leaching process of weathered crust elution-deposited rare earth ore. Then, the principle of external loss in the process of mining and separation of weathered crust elution-deposited rare earth ore is analyzed and an external loss evaluation system is constructed. In this system, the market value method, shadow engineering method, and labor cost method are mainly used to measure and calculate the industrial “three-waste” pollution control expenses, ecological environment repair cost, and negative external derivative management cost of weathered crust elution-deposited rare earth ore development. Finally, based on the evaluation system, the data of the Longshe rare earth mining area in Jiading Town, Xinfeng County, was evaluated by the empirical study and it is obtained that the negative externality cost of the Longshe rare earth mining area in Xinfeng County is 102,900 RMB/t. National and local governments may refer to this model and data to strengthen the prevention and control of air, water, and soil pollution; scientifically control the ecological environment of weathered crust elution-deposited rare earth waste mines; and safeguard the livelihood and well-being of the residents of mining areas.
l-arginine, a semi essential amino acid, is an important amino acid in food flavoring and pharmaceutical industries. Its production by microbial fermentation is gaining more and more attention. In ...previous work, we obtained a new l-arginine producing Corynebacterium crenatum (subspecies of Corynebacterium glutamicum) through mutation breeding. In this work, we enhanced l-arginine production through improvement of the intracellular environment. First, two NAD(P)H-dependent H2O2-forming flavin reductases Frd181 (encoded by frd1 gene) and Frd188 (encoded by frd2) in C. glutamicum were identified for the first time. Next, the roles of Frd181 and Frd188 in C. glutamicum were studied by overexpression and deletion of the encoding genes, and the results showed that the inactivation of Frd181 and Frd188 was beneficial for cell growth and l-arginine production, owing to the decreased H2O2 synthesis and intracellular reactive oxygen species (ROS) level, and increased intracellular NADH and ATP levels. Then, the ATP level was further increased by deletion of noxA (encoding NADH oxidase) and amn (encoding AMP nucleosidase), and overexpression of pgk (encoding 3-phosphoglycerate kinase) and pyk (encoding pyruvate kinase), and the l-arginine production and yield from glucose were significantly increased. In fed-batch fermentation, the l-arginine production and yield from glucose of the final strain reached 57.3g/L and 0.326g/g, respectively, which were 49.2% and 34.2% higher than those of the parent strain, respectively. ROS and ATP are important elements of the intracellular environment, and l-arginine biosynthesis requires a large amount of ATP. For the first time, we enhanced l-arginine production and yield from glucose through reducing the H2O2 synthesis and increasing the ATP supply.
•Two new H2O2-forming flavin reductases from C. glutamicum are identified.•Inactivation of the flavin reductases facilitates L-arginine production.•Increasing the ATP supply facilitates L-arginine production.
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