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关键词： brown seaweed   Padina pavonica   sodium alginate   structural analysis   M   G ratio  

摘要： This study focuses on the physico-chemical characterization of an alginate extracted from seaweed (Padina pavonica) collected on the Tunisian coast. Since alginates display a broad variety of applications, especially in the food and pharmaceutical fields, their quality requires a high certain standard of purity and an accurate knowledge of their composition and structure. With this aim, once extracted the Na-alginate was purified and then characterized for comparison with a commercially available alginate. Thermal analyses (TGA and DSC) were performed to evaluate the water content, i.e. the moisture loss and the thermal stability of this polysaccharide. Spectroscopic investigations demonstrated similarities but also significant differences between the two samples. NMR spectroscopy enabled determination of the mannuronic/guluronic (M/G) ratio, which happened to be lower for the alginate extracted fromP. pavonicaalgae. SEC, performed in water as eluent, was implemented for determination of the average molecular weight of these water-soluble polymers and revealed 6-fold higher molecular weights (M(n)andM(w)) than the commercial reference. (c) 2020 Society of Chemical Industry

关键词： Borophosphate glass   Mossbauer effect   Infrared spectra   Electron spin resonance  

摘要： A series of high iron content boro-phosphate glasses having composition of 30P(2)O(5)-70B(2)O(3)-xFe(2)O(3));0 <= x <= 80 wt% was prepared by conventional melt quench method. Mossbauer effect (ME), infrared (IR) and electron spin resonance (ESR) were used to study the behavior of iron brought into borophosphate glass and its effect on the structure of the glass. The results of the glasses containing from 10 to 80 wt% Fe2O3 indicated that iron is present in the glass in the form of Fe3+ and Fe2+, i.e. in tetrahedral and various octahedral symmetric sites. Electron paramagnetic resonance (EPR) spectra were utilized to investigate the glass structure. The analysis shows a well-defined signal at g = 2.04 characteristics for Fe3+ ions and the intensity increases with increasing Fe2O3 concentration before gamma irradiation. After exposing the samples to different doses of gamma irradiation up to 30 kGy;the EPR signal intensity decreases for the samples with a low Fe2O3 concentration (i.e. 10% and 40%), which can be used as radiation indicators. For glass with high iron concentrations above 40%, the intensity of the EPR signal remains approximately constant and therefore, high iron concentrations of this glass can be used for radiation protection purposes.

关键词： physicochemical methods   ICP–   AES   photosynthetic pigments   chlorophyll a   chlorophyll b   pheophytinization   total nitrogen   phenolic compounds   antioxidant activity   elemental composition   metals   macroelements   microelements   Hypogymnia physodes   natural phytocenoses   correlation analysis  

摘要： The physiological and biochemical parameters and elemental composition of Hypogymnia physodes lichen samples from various phytocenoses differing in lighting conditions and atmospheric humidity were studied. A significant increase in the chlorophyll a and nitrogen contents, the maximal pheophytinization coefficient, and the minimum content of phenolic compounds were observed in H. physodes thalli under severe shading conditions in a spruce forest. Most of these biochemical parameters reached their minimum values with high insolation in birch and pine forests except for the content of phenolic compounds, which reached the maximum value. ICP-AES analysis of H. physodes thalli detected 20 elements (Al, B, Ba, Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Mo, Na, Pb, Sn, Sr, Tl, V, W, Zn) that were found in lichen samples from all studied natural phytocenoses except for Mo, which was absent in samples from a black alder forest. The maximum concentrations for almost half of the elements (Al, B, Fe, K, Mo, Na, Sn, Ti, V) were determined in samples from the spruce forest where the thalli were more often and consistently hydrated because of the high and more stable humidity level. A complex system of correlation relationships was established based on an analysis of cross-correlations of the physiological and biochemical parameters and the metal concentrations in the samples. The results indicated a high coordination of various physiological processes. Chlorophyll a played a crucial role in maintaining their consistency with changing environmental conditions. Its content was associated with a more significant number of different parameters and elemental concentrations.

关键词： modification   pasting properties   scanning electron microscopy   sweet potato starch   X-ray diffraction  

摘要： Three annealing (ANN) treatments on the physicochemical properties and structure of sweet potato starch are investigated in this work, including pure ANN (PA), enzymatical ANN (EA), and ultrasonically enzymatic ANN (UEA). Experimental results indicated the effects of different treatments on the starch are in the order: UEA > EA > PA, which are reflected by the decrease of the relative crystallinity, short-range molecular order, enthalpy (Delta H), and the increase of peak viscosity and swelling power. X-ray diffraction showed that the reduction of relative crystallinity of starch after UEA is up to 9.25%, however, this decrease after EA is 4.9%. Thermal analysis suggested that the Delta H of starch with UEA is reduced up to 8.27%, and after EA it is 6.34%. The oil absorption rate of starch after UEA increases by a maximum of 23.35%, whereas with EA treatment it increases by only a maximum of 21.75%. Ultrasound and enzyme make tiny holes on starch granules. ANN does not change the appearance of granules suspended in deionized water, however it brings out tiny holes on some starches in phosphate buffer solution. In conclusion, EA is more effective than PA for modifying starch, and ultrasound promotes the EA process.

关键词： Molecular weight distribution  

摘要： Polyamide 11 is an attractive material for additive manufacturing, however, in the selective laser sintering process it is subject to significant thermally induced stress. Suitable analytical methods are necessary to indicate any changes in the material properties. In this work, thermally stressed powder samples and printed tensile bars were analyzed by size exclusion chromatography-multi angle laser light scattering and differential scanning calorimetry. Based on the molecular weight distribution, crystallization and melting temperatures, ageing states of the investigated powders can be defined and transferred to the particles of the printed components. As a result, thermal stress led to an increase in molar mass and polydispersity. Moreover, calorimetric measurements indicated a delayed nucleation process as well as a decrease in polymorphism. Additionally, polymeric material with lower polydispersity values across the tensile bars could lead to decreasing elongation at break (epsilon(B)) values. For the crystallization onset temperature the opposite effect on epsilon(B) was observed.

关键词： Chemical composition   Color parameters   Frying   Grilling   Lipid oxidation   Microwaving   Roasting   Texture  

摘要： The effect of different cooking methods and the influence of the use of chestnuts (Castanea sativa Miller) rather than commercial feed in the pig diet on physicochemical characteristics, oxidative stability and volatile profile of cooked Longissimus thoracis et lumborum Celta pig muscle was investigated. Four treatments were used for cooking meat from both diets: roasting, grilling, frying and microwaving. Analysis of cooked meat included the proximate composition (moisture, protein, fat, and ash contents), colour parameters (L*, a*, b*), cooking loss, shear force, lipid oxidation and volatile compounds. Overall, the cooking technique significantly affected the proximal composition, colour parameters, cooking loss, TBARS and volatile profile of Longissimus thoracis et lumborum, whereas the shear force was not affected by the heat treatment. Frying was the technique that led to a greater presence of fat. Additionally, microwaved and fried samples presented the highest cooking losses. Regarding to the lipid oxidation, grilling and microwaving showed more negative effects on the samples, while frying involved a lower presence of TBARS and hexanal contents. The major volatile compounds were aldehydes for all cooking methods except for the frying technique, which besides presented the lowest amount of total volatiles compounds. With respect to the finishing diet, in general the use of chestnuts did not affect the chemical composition, colour parameters, cooking loss and shear force of cooked Longissimus thoracis et lumborum. Nevertheless, a significant decrease in the TBARS value was found with the inclusion of this fruit in the finishing diet. At the same time, the use of chestnuts also affects the content of some volatile compounds such as heptanal and furan, 2-pentyl.

关键词： food applications   inactivation mechanisms   influencing factors   microbial inactivation   physicochemical properties   plasma-activated water (PAW)  

摘要： Novel nonthermal inactivation technologies have been increasingly popular over the traditional thermal food processing methods due to their capacity in maintaining microbial safety and other quality parameters. Plasma-activated water (PAW) is a cutting-edge technology developed around a decade ago, and it has attracted considerable attention as a potential washing disinfectant. This review aims to offer an overview of the fundamentals and potential applications of PAW in the agri-food sector. A detailed description of the interactions between plasma and water can help to have a better understanding of PAW, hence the physicochemical properties of PAW are discussed. Further, this review elucidates the complex inactivation mechanisms of PAW, including oxidative stress and physical effect. In particular, the influencing factors on inactivation efficacy of PAW, including processing factors, characteristics of microorganisms, and background environment of water are extensively described. Finally, the potential applications of PAW in the food industry, such as surface decontamination for various food products, including fruits and vegetables, meat and seafood, and also the treatment on quality parameters are presented. Apart from decontamination, the applications of PAW for seed germination and plant growth, as well as meat curing are also summarized. In the end, the challenges and limitations of PAW for scale-up implementation, and future research efforts are also discussed. This review demonstrates that PAW has the potential to be successfully used in the food industry.

关键词： Anthropization   Public green spaces (PGS)   Soil quality   Trace elements   Biological indicators   Health risk  

摘要： The public green space (PGS) in urban areas presents an image of nature and its animal and plant biodiversity in the city. Due to intense urbanization in the world, pollutants such as trace elements (FE) or pathogenic microorganisms are continually emitted into the environment and pose a threat to ecosystems. The aim of this work was to assess the soil quality of PGS in the cities of Marrakech (Morocco) and Torun (Poland) through physicochemical and microbiological approaches and to assess related health risks. Eighteen soils from the most visited historic parks in Marrakech and Torun were sampled and analyzed. The results showed that content of Total Organic Carbon (TOC) in Torun urban soils is about three times higher than that measured in Marrakech urban park soils. These differences are related to the naturally higher content of organic matter in the soils of temperate climate regions than in Mediterranean soils. The concentrations of trace element (FE) showed a similar trend in both cities, except for Pb in one Marrakech site, which exhibited a high concentration (400 mg Pb Kg(-1) in Bab Rab Park). Soil enzymes present a high sensitivity to anthropogenic disturbances and can be used as tool to evaluate early disturbance of urban soils. The alkaline phosphatase (APHa) and urease (URa) activities are less affected by anthropogenic pressure than dehydrogenase (DHa). Slight sensitivity to TE was observed in the microbial community in the order fungi < actinomycetes < bacteria. Total and fecal coliforms (TC, FC) were present in all soil samples, with higher concentrations in Marrakech sites. Based on estimated FC risk, the highest percentage did not exceed 11% of the guideline limit set by International Commission on Microbiological Specifications for Foods. Hazard index showed no health risk for adults caused by studied TE concentrations in the park soils of Marrakech and Torun, but potential adverse non-cancer health effects for children. Their safety depends on t

关键词： Soil physicochemical properties   Correlation   Ganoderma   Cell wall degrading enzyme   Defensive enzyme   Pathogenesis related protein  

摘要： Background and aims Ganoderma boninensecauses basal stem rot disease of oil palm, a serious problem in many countries producing crude palm *** host cells by producing cell wall degrading enzymes (CWDEs) and its mycelia trigger defense responses in the host plant. The soil physicochemical properties affect plant growth and soil microbes. Only limited knowledge is available on the relationship between soil characteristics and occurrence of plant diseases. Thus, this study aimed to determine soil physicochemical properties, CWDEs in rhizosphere soil, PR proteins, and defensive enzymes in plant roots, and to look for potential associations inGanoderma-infected oil palm plantations. Methods Roots and rhizosphere soil were sampled fromGanodermainfected and non- infected oil palms from the main oil palm plantation area in southern Thailand. Spectrophotometry was used to investigate enzyme activities. Results Fungal laccase, lignin peroxidase (LiP), and manganese peroxidase (MnP) were positively correlated to organic matter (OM) and organic carbon (OC) concentrations, but these enzymes were negatively correlated to soil pH. Cellulase was sensitive to soil physicochemical properties when compared with laccase, LiP, MnP and xylanase. Regarding plant defensive enzymes, high levels of OM, OC, calcium, potassium, manganese, magnesium, nitrogen and zinc in soil were related to chitinase, beta-1,3-glucanase, phenylalanine ammonia lyase (PAL), peroxidase (POD) and polyphenol oxidase (PPO) synthesis in oil palms. Moreover, POD, PPO and PAL were positively correlated to fungal laccase, LiP and MnP. Conclusions Our results indicate that the relationships between fungal enzymes, defense related enzymes in host plant, and soil physicochemical properties, are involved in determining basal stem rot disease occurrence in oil palm.

关键词： Chestnut   Air-drying   Starch   Physicochemical properties   In vitro digestibility  

摘要： Naturally air-dried chestnut is a traditional processed chestnut in North China and is eaten without being cooked. However, the processing is time-consuming and uncontrollable. To accelerate processing, two drying temperature of 40 degrees C and 50 degrees C (lower than the gelatinization temperature of starch) were selected. The optimum conditions for air-dried chestnut (ADC) and the physicochemical and digestive properties of ADC starch were investigated. Moisture and total starch contents decreased while amylose and total water-soluble sugar contents as well as the activity of endogenous amylase increased in ADC compared with fresh chestnut. The relative content of the high-molecular-weight fraction decreased as the low-molecular-weight fraction increased. The relative crystallinity and short-range molecular order of the starch decreased after air drying, and was positively correlated with onset temperature, peak temperature, conclusion temperature, and the enthalpy change. The ADC starch maintained the same proportion of resistant starch as observed in fresh chestnut starch. These results provide useful information for the industrial production of ADC in which the starch is of low digestibility.