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关键词： Vegetables  

摘要： This review, summarizes the physicochemical and rheological properties (RP) of beetroot (Beta vulgaris L.), carrot (Daucus carota L.), celery (Apium graveolens L.), coriander (Coriandrum sativum L.), fenugreek (Trigonella foenum-graecum L.), kale (Brassica oleracea L.), spinach (Spinacia oleracea L.), and tomato (Solanum lycopersicum L.) juices, and their concentrates. Carbohydrates, crude fiber, organic acids (ascorbic, citric, malic, and oxalic acids), vitamins (A, B, C, and E), minerals (calcium, potassium, and magnesium), amino acids, and phenolic compounds (PC) are major constituents of vegetable juice (VJ). If consumed in sufficient amount, VJs contribute to nutritional requirements for good health in humans. Vegetable concentrates are typically non-Newtonian fluids in which the apparent viscosity decreases with increasing shear rate. The apparent viscosity of VJs decreases at higher temperatures. Several equations are employed to describe flow behavior, but most are difficult to use and none give good overall agreement with experimental data from Power-law and Herschel-Bulkley models. The effect of temperature on apparent viscosity of VJ is generally expressed by the Arrhenius relationship and the activation energy (E-a) for the fluid flow increases with concentration. The E-a values reported for the vegetable products were between 3.6 and 39.7 kJ center dot mol(-1)center dot K-1. Higher E-a indicates apparent viscosity is more prone to temperature change. Practical applications Juice can be extracted from fresh vegetables to be used without further change or as concentrates in value added products. Rheological study of vegetable juice, in part how it flows, is important to handling and processing, quality control, and sensory evaluation of derived products. In this study, properties of vegetable juices and concentrates were reviewed. Vegetable concentrates are typically non-Newtonian fluids. The Power-law and Herschel-Bulkley models were successfully applied

关键词： Moisture  

摘要： The study aimed to evaluate the effect of drying on the functional quality of stingless bee (Heterotrigona itama) honey. The honey was subjected to vacuum drying (40-60 degrees C), vacuum evaporation (40-60 degrees C), and freeze drying, respectively, to achieve a standardized moisture content. The dehydrated honey seemed to have a significant (p < .05) darker color (lower L* and higher b* values) as compared to the raw honey. Results suggested that the dryness of the dehydrated honey has significantly affected its antioxidant capacity except oxygen radical absorbance capacity (ORAC) assay. It seems vacuum drying at 60 degrees C for 2.2 hr produced honey with higher total phenolic (300.24 +/- 6.81 mg GAE/kg) and flavonoid contents (273.83 +/- 2.52 mg QE/kg), which were also characterized by the highest 2,2-azinobis-(3-ethylbenzothiazoline-6-sulphonate) (ABTS) (371.34 +/- 2.57 mu mol TE/100 g) and ferric reducing antioxidant power (FRAP) (344.20 +/- 6.81 mu mol Fe2+/100 g). Rosmarinic acid and quercetin are the most dominant phenolic compounds found in the dehydrated honey. In conclusion, vacuum drying could be an efficient way to improve honey physicochemical and functional stability. Practical applications Stingless bee honey production is a new emerging industry in tropical and subtropical countries. The keeping quality of stingless bee honey is limited due to its nature of high moisture content. Thus, removal of excessive moisture from the honey is necessary to maintain the product quality and stability particularly during handling and storage. The application of low-pressure dehydration processes can aid the evaporation process of water from stingless bee honey. The findings of the present work provide a better insight toward the effect of low-pressure dehydration on the physicochemical quality and functional properties of stingless bee honey in addition to extend its shelf life.

关键词： nitrogen rate   physicochemical property   rice starch   controlled irrigation  

摘要： BACKGROUND In this study, we investigated the effects of water-nitrogen interaction on the grain quality of two varieties ofjaponicarice grown on the North China Plain, based on evaluations of grain biochemical components, starch X-ray diffraction properties, thermal and pasting characteristics, and particle size distribution. RESULTS We found that, under controlled irrigation, increasing levels of nitrogen resulted in a reduction in grain starch content and an increase in protein content. Nitrogen fertilization, irrigation, and their interaction had significant effects on the particle size and size distribution of rice flour. Under both controlled and flooding irrigation, the lowest values of pasting parameters for cultivars Xindao22 and Xindao10 were observed in response to moderate and high nitrogen application, respectively. Under flooding irrigation, Xindao22 exhibited lower mean value of gelatinization onset, peak, and conclusion temperatures and enthalpy in response to control irrigation, whereas in Xindao10 these parameters were relatively stable with respect to nitrogen and irrigation treatments. However, we observed no significant effects of either nitrogen or irrigation on amylopectin chain length distribution or starch relative crystallinity. CONCLUSION Nitrogen application rate and irrigation methods had distinct effects on the physicochemical properties of flour derived from treated rice plants. The findings will provide support for scientific irrigation and fertilization in order to improve rice grain quality. (c) 2020 Society of Chemical Industry

关键词： Shear thinning  

摘要： The effects of superfine grinding on the properties of chrysanthemum powder (CP) and high pressure homogenization (HPH) on the rheological properties of CP suspensions were investigated. Superfine grinding reduced particle size to a D-50 of 28.45 mu m. Instantaneous flow function and wall friction tests demonstrated that superfine ground CP had poor flowability and was more cohesive than more coarsely ground samples. Superfine grinding increased thermal stability and reduced the crystallinity of CP. After HPH treatment, the apparent viscosity and consistency coefficient (k, from 0.027 +/- 0.005 to 1.847 +/- 0.472) of CP suspension was significantly improved (p <.05), indicating that HPH treatment increased the consistency and reduced the fluidity of CP suspensions. As the HPH pressure increased from 40 to 120 MPa, the storage modulus (G') and loss modulus (G") of the CP suspensions increased, which fitted well with the Power Law model (R-2 >.961). The CP suspension is a non-Newtonian fluid with shear thinning behavior. Flow and rheological characteristics are measured under different consolidation pressures and HPH pressures, respectively. These findings reveal the potential application of superfine grinding and high pressure homogenization in the development of CP. Practical application The use of superfine grinding and high pressure homogenization to process CP has broad application prospects, such as the preparation of micronized Chinese medicinal powders in the pharmaceutical industry and functional foods and beverages in the food industry.

关键词： Fucoidan   Surimi   Microstructure   Antioxidant effect   Bacteriostatic activity  

摘要： In this study, we evaluated the effects of crude fucoidan on the physicochemical properties and biological activities of surimi gels. The gel strength and water holding capacity of surimi products significantly increased by adding 0.125% of fucoidan, and reduced with the further addition of fucoidan. Crude fucoidan exhibited little effect on the textural properties and protein content of surimi products. Moreover, the whiteness of surimi gels was inversely proportional to fucoidan concentrations. The scanning electron microscopy analysis suggested fucoidan at low concentration promoted the cross-linking of protein and the densification of gel network structure to improve the gel properties of surimi products, while excessive fucoidan hindered the cross-linking of proteins resulting in the formation of loose and inhomogeneous microstructure. Interestingly, the biological activities analysis revealed the homogenates from surimi gels containing fucoidan exhibited potent DPPH, ABTS, hydroxyl radical scavenging capacity, and reducing capacity, also displaying significant bacteriostatic effects on both Escherichia coli and Staphylococcus aureus in concentration-dependent manners.

关键词： Edible film   Aquatic products   Chitosan   Lemon essential oil   Ethyl lauroyl arginate  

摘要： In this study, we aimed to determine the effects of lemon essential oil (LEO) and ethyl lauroyl arginate (LAE) on the physico-chemical, mechanical and morphological properties of chitosan (C) films (2%, w/w) for mackerel fillet coating application. The highest film solubility was found as 54.02% in chitosan films incorporated with LAE. Mechanical properties of films were found between 1.90 MPa and 3.32 MPa for tensile strength (TS) and between 16.75% and 32.30% for elongation at break (E). The highest total phenolic content and antioxidant activity was found as 1069.05 mu g/g and 39.89% in chitosan film incorporated with LEO, respectively. In general, the physico-chemical properties of the films formed by adding LEO and LAE to the chitosan film solution were improved compared to the films obtained only from chitosan. These film-forming solutions were applied to mackerel fillets as coating materials and their effects on the physico-chemical parameters including pH, color, total dry matter, antioxidant activity, total phenolic content were analyzed during storage at 2 degrees C for 9 days (0, 3, 6, and 9 days). The highest antioxidant activity was found as 8.59% in fish samples coated with chitosan. It is observed that the coatings applied provide a safer and better storage of the fish. The use of additive-added coatings has more protective effects on quality parameters. LEO was added at 1% (v/v), while LAE was added at 0.1% (w/v) in the chitosan solution and these additives exhibited similar effects on films and fish.

关键词： Electrowinning electrolytes   Physicochemical properties   Statistical models   Electrolyte composition  

摘要： Physicochemical properties of copper electrolytes are a strong fundamental consideration in electrodeposition processes during electro-purification and recovery of copper. Their influence extends to mass transfer as well as energy consumption during the electrodeposition process. In this study, the influence of electrolyte composition on electrolyte physicochemical properties was investigated to review the existing literature data. This review of data is considered necessary as more and more electrowinning models are being developed for process prediction and optimisation and a need of such data is required for accurate prediction of physicochemical properties. The major components of importance to the formation of smooth high-quality and high-purity copper cathodes at optimum current efficiency are considered the species in solution. These include Cu ions, Fe ions (major impurity), H2SO4, and a smoothing agent additive. A 5-factor, 2- and 3-level experimental design was employed to determine the effect of copper (35 and 45 g/l), sulphuric acid (160 and 180 g/l), iron (1, 3, and 6 g/l), polyacrylamide additive (2, 5, and 10 mg/l), and temperature (45 and 55 degrees C) on electrolyte density, conductivity, and the diffusion coefficient in synthetic copper electrowinning electrolytes. The major species in a copper electrowinning electrolyte are found to be the most relevant for prediction of physicochemical properties. These results indicate that relatively simple empirical models are sufficient for modelling of the electrolyte domain in electrowinning, without the need for the generation of vast amounts of complex experimental data.

关键词： Chlorophyll  

摘要： Mature kiwi after minimal processing were treated with 0.5-2.0 kGy gamma irradiation to monitor changes in quality parameters under refrigerated conditions (3 +/- 1 degrees C, RH 85%) for 16 days. The results revealed that treatment of 2.0 kGy proved helpful in delaying onset of surface browning, reducing the polyphenol oxidase activity and preserving the original color of samples till 16 days. Dose dependent decrease in polyphenol oxidase activity and surface browning was observed in kiwi samples. Control samples were almost devoid of chlorophyll after 12 days;whereas 2.0 kGy samples, showed decrease of 29.6% in chlorophyll after 16 days. Dose of 2.0 kGy significantly prevented the proliferation of microbial load and resulted in 5.7 log reduction in yeast and mold count and 6.0 log reductions in bacterial count of kiwi samples after the end of 16 days of storage;therefore, satisfying food safety concerns of ready to eat kiwi fruit. Practical applications Increasing demand for ready to eat, convenience chemical free and health promoting foods associated with limited shelf-life has forced the food scientists to search for new technologies. Extending shelf-life and maintaining both nutritional as well as microbial quality has beneficial implications on industry and consumers. Present investigation showed that radiation processing of minimally processed kiwi offers a promising alternative to chemicals to delay the onset of browning besides maintaining other quality attributes and thus ensuring consumer safety and satisfaction.

关键词： Cynara cardunculusrennet   Cheese   Brine   Yield   Rheology   Texture  

摘要： The main objective of this study was to test the efficiency of a wild cardoon (Cynara cardunculus L.) rennet, previously optimized by response surface methodology, in cheese making process;then to select the best brine concentration, leading to excellent cheese quality. Results showed that the optimizedC. cardunculusrennet and chymosin produced curds with similar properties (yield, colour, texture, viscoelasticity), suggesting that this coagulant could replace successfully calf rennet. After brining at different salt concentrations (5, 7, 10 and 15%), we concluded that the use of 15% of salt in brine was an efficient way to reduce considerably the proteolysis level inC. cardunculuscheeses, stored for 28 d at 4 degrees C. At this salt level, the highest hardness, gumminess, viscoelasticity and yield of soft cheeses were also recorded. In conclusion, the satisfactory findings could open new opportunities to produce industrially the optimizedC. cardunculusrennet and its cheeses in the Mediterranean area.

关键词： Graphene oxide   Benzofurazan derivatives   Fluorescence   Raman spectroscopy   Antimicrobial activity   Cytotoxicity  

摘要： Two novel graphene oxide-benzofuran derivatives composites were obtained through the covalent immobilization of [4-hydrazinyl-7nitrobenz-[2,1,3-d]-oxadiazole (NBDH) and respectively, N1-(7-nitrobenzo[c][1,2,5] oxadiazol-4-yl)benzene-1,2-diamine (NBD-PD), on graphene oxide. This covalent functionalization was achieved by activating the carboxylic groups on the surface of graphene oxide by the reaction with thionyl chloride followed by coupling with the amino group of benzofurazane derivatives to obtain the NBD derivatives grafted on graphene oxide. The formation of new materials was check by Raman spectroscopy, fluorescence, infrared spectroscopy and X-ray photoelectron spectroscopy, thermal analysis, scanning electron microscopy, and elemental mapping. The antimicrobial effect of the new composites was evaluated on Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa, both on planktonic and adherent biofilm populations. The cytotoxic effects of the materials on human colon cancer HCT-116 cell line and the normal human fibroblast BJ cell line were evaluated by investigating cell viability and membrane integrity. Apoptosis and colony forming ability of tumor cells were also investigated following exposure to new materials. The biological results of this study have shown that the new materials have potential in combating biofilm formation and also, the tested materials induced cytotoxicity in human colon cancer HCT-116 cell line with limited effects on normal BJ fibroblasts, suggesting their antitumor potential.