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关键词： Starch   Films   Active packaging   Biodegradable   Phenolic acids  

摘要： Plasticised cassava starch films with 1-2% ferulic or cinnamic acid were obtained by melt blending and compression moulding. Partial losses (about 40%) of the more thermo-sensitive ferulic acid occurred during processing. Incorporation of phenolic acids did not provoke remarkable changes in the oxygen and water vapour permeability of starch films, but these became less water soluble (13-25% reduction), more extensible and less resistant to break, especially with the highest concentration of ferulic acid. Films with 2% of either acid effectively inhibited the growth of E. coli and L. innocua in tests carried out in culture medium;being cinnamic acid more effective than ferulic and L. innocua more sensitive than E. coli;a Log CFU reduction, with respect to the control, higher than 6 was obtained for L. innocua with 2% of cinnamic acid in the films. The growth of both strains was also inhibited in chicken breast (log CFU reduction>2) with 2% of either acid. In fresh-cut melon, the L. innocua growth was significantly inhibited by films with 2% cinnamic acid, but lower growth inhibition of E. coli in fresh-cut melon was observed.

关键词： Temperature measurement   Temperature   Electric breakdown   HVDC transmission   Production   Aging   Space charge   insulation testing   EHVDC insulation   breakdown   space charge   conductivity  

摘要： This paper presents the influence of thermal ageing on the physico-chemical and electrical properties of 500 kV extra high voltage direct current (EHVDC) XLPE cable insulation. EHVDC XLPE cable sections are placed in a thermal oven and thermally aged at 106 degrees C (melting peak temperature) for 250, 500 and 1000 h. After ageing, the inner, middle and outer layers of the cable insulation are characterized by Fourier transform infrared (FTIR) spectroscopy, oxidation induction time, X-ray diffraction (XRD), space charge, DC conductivity and DC breakdown measurements. The physicochemical analysis results show that the cross-linking by-products in the cable insulation are difficult to be completely removed during the ageing process, whereas the thermal ageing cannot completely consume the antioxidants in the materials. The space charge measurement results show that the hetero charges are accumulated inside the unaged middle layer samples. However, the space charge accumulation and electrical conductivity of the samples are significantly reduced after 1000 h ageing. Moreover, the DC breakdown strength of the inner and middle layer samples is continually increased with the increase of the ageing time. It is elucidated that the thermal ageing leads to the re-crystallization and re-degassing of samples, improving the space charge behavior and the charge carrier trapping phenomenon. It is proposed that the temperature of 106 degrees C could be used as a suitable degassing temperature for the EHVDC XLPE cable production.

关键词： Carbon deposition   Cobalt-based catalyst   Dry reforming of methane   Physicochemical properties   Structural characterization   Catalyst stability  

摘要： This study deals with the development of alumina-supported cobalt (Co/Al2O3) catalysts with remarkable performance in dry reforming of methane (DRM) and least carbon deposition. The influence of Co content, calcination, and reduction temperatures on the physicochemical attributes and catalyst activity of the developed catalysts was extensively studied. For this purpose, several characterization techniques including ICP-MS, H-2 pulse chemisorption, HRTEM, H-2-TPR, N-2 adsorption desorption, and TGA were implemented, and the properties of the developed catalysts were carefully analyzed. The impact of reaction temperature, feed gas ratio, and gas hourly space velocity (GHSV) on the reactants conversion and products yield was investigated. Use of 10%Co/Al2O3 catalyst, calcined at 500 degrees C and reduced under H-2 at 900 degrees C in DRM reaction at 850 degrees C, CH4/CO2 ratio of 1:1, and GHSV of 6 L.g(-1).h(-1) resulted in a remarkable catalytic activity and sustainable performance in long-term operation where great CO2 (96%) and CH4 (98%) conversions and high H-2 (83%) and CO (91%) yields with a negligible carbon deposition (3 wt%) were attained in 100-h on-stream reaction. The good performance of the developed catalyst in DRM reaction was attributed to the small Co particle size with well-dispersion on the alumina support which increased the catalytic activity and also the strong metal-support interaction which inhibited any serious metal sintering and enhanced the catalyst stability.

关键词： Municipal sludge   Vermicompost   Moisture content   Microfauna   Bioindicator  

摘要： The present study aimed to explore the effect of a range of moisture content levels, including 65%, 72%, and 78%, on physicochemical properties and microfauna communities during vermicomposting of municipal sludge. As a result, death of perishable microfauna together with the degradation of organic matter was the dominant response in all groups in the early period of vermicomposting, while the effects of moisture content levels on various physiochemical parameters did not appear until the mid-later period. After the treatment with 78% moisture content, the content of mineral nitrogen was 1.186 g/kg in the sludge, with a 9.36 x 10(3) ind./g of microfauna quantity and 663.01 g of earthworm biomass. The values of these three measurements in 78% group were significantly higher than other two groups (p < 0.05), indicating that the effects of 78% moisture content were more pronounced for promoting nitrogen mineralization as well as microfauna and earthworms growth during vermicomposting. Specifically, testate amoebae were strongly associated with nitrification process, while nematodes were related to ammonification and phosphorus mineralization, of which testate amoebae had great potential of being bioindicators during vermicomposting of municipal sludge.

摘要： Aflatoxin B1 is a mycotoxin that can be present in peanut-based products, such as fried peanut biscuits, if Good Agricultural Practices are not respected. Impact of plant powder presence on aflatoxin B1 levels was investigated in contaminated peanut biscuits. It was observed that adding 2% of Moringa oleifera powder led to a significant (p < .05) reduction of the toxin after 3 hr of contact time in the dough before the frying step. The toxin level reduction was estimated at 17%. The addition of moringa powder can also have some nutritional benefits. It doubled the content of iron and calcium in the biscuits, leading to products that could bear a claim "source of" for 100 g of biscuits. There was almost no loss of those minerals during the frying step. beta-carotene content is a nutrient present in moringa powder, unfortunately the losses during the frying step were estimated at 78%, probably due to the molecule migration from the biscuit to the frying bath. Adding 2% moringa powder in fried peanut biscuit could present safety and nutritional benefits, however, consumer acceptance should be studied as the color as well as the peanut smell and flavors were significantly impacted (p < .05). It is recommended to pursue the investigation of the role of moringa powder onto the toxin degradation to understand the mechanism behind and assess the toxicity of the secondary molecules generated.

关键词： Leaves   Amazon fruits   Soluble solid   Overall liking   Polyphenolic compounds   Ascorbic acid  

摘要： This study aimed to produce beverages using extract or infusion ofHibiscus sabdariffaleaves with cupuassu pulp. The blended drinks with cold or hot extraction were formulated using the response surface methodology. Moreover, the physico-chemical and sensory stability of these beverages was performed for 180 days. The conditions production for beverage leaf extract were: 28% leaf extract, 72% cupuassu pulp, and 14 degrees Brix. For beverage leaf infusion, were 37% leaf extract, 63% cupuassu pulp, and 13 degrees Brix. Comparing the two beverages, the polyphenolic compounds and the antioxidant activity (ABTS and DPPH) were higher in the blends produced with leaf extract. Thus, the cold extract provided better extraction of these components in the leaves. During storage, pH, reducing and total sugars and soluble solids of blends increased linearly (p < 0.05). Nevertheless, vitamin C, polyphenolic compounds, and the antioxidant activity reduced linearly (p < 0.05). The sensory acceptance of blends containing leaf extract, in the hedonic scale, all sensory attributes were positively scored up to 135 days. At 180 days, the acceptance reduced for rejection. The blended beverage containing leaf infusion had all sensory attributes positively scored up to 90 days, with a rating between 6.27 and 7.42. At 135 and 180 days, the values were in the indifference region of the hedonic scale or acceptance region. Therefore, the blend with leaf infusion maintained better acceptance during storage when compared to leaf extract beverage. Thus, the blended beverages had good nutritional value and sensory acceptance and were acceptable for up to 135 days.

关键词： silsesquioxanes   sol-gel   carbon paste electrodes   rubeanic acid   determination of silveri  

摘要： Synthesis and study of the physicochemical properties of silsesquioxanes modified with 3-aminopropyl, 2-aminoethyl-3-aminopropyl, and dithiooxamide groups was carried out. The obtained sorbents were characterized by thermal stability, porosity, and a high degree of functionalization;the concentration of groups grafted to the particle surface reached 2.80 mmol g(-1). Modified silsesquioxanes were used as an electroactive substance for the development of indicator carbon paste electrodes (CPEs). When using a CPE with a 5% dithiooxamidated silsesquioxane content, the conditions selected for potentiometric titration of aqueous solutions containing silveri were pH 3-4, the titrant was potassium iodide. The designed sensor was successfully tested by analyzing a standard sample and a drug for silver ion content.

摘要： The tertiary structure of a native protein is dictated by the interplay of local secondary structure propensities, hydrogen bonding, and tertiary interactions. It is argued that the space of known protein topologies covers all single domain folds and results from the compactness of the native structure and excluded volume. Protein compactness combined with the chirality of the protein's side chains also yields native-like Ramachandran plots. It is the many-body, tertiary interactions among residues that collectively select for the global structure that a particular protein sequence adopts. This explains why the recent advances in deep-learning approaches that predict protein side-chain contacts, the distance matrix between residues, and sequence alignments are successful. They succeed because they implicitly learned the many-body interactions among protein residues.

关键词： Thawing  

摘要： The aim of this work was to study the effect of different air blast freezing conditions (temperature: −20 °C, air velocity: 1 m/s;−20 °C, 5 m/s;−50 °C, 1 m/s;−50 °C, 5 m/s) on the quality of high pressure processing (HPP) pretreated (200 MPa, 6 min) albacore steaks. After 2 and 9 months of frozen storage, HPP and control samples were thawed and analyzed (thawing loss, cooking loss, total weight loss, color, texture profile, salt-soluble protein content and lipid oxidation). The HPP pretreatment had more impact on the albacore quality than lowering the freezing temperature or increasing the air velocity. For instance, after 9 months of frozen storage, the HPP pretreated samples before freezing under the slowest (−20 °C and 1 m/s) and the fastest (−50 °C and 5 m/s) freezing conditions presented similar thawing loss reductions (37 and 40%, respectively) with respect to their corresponding controls. Considering the conditions and parameters tested, HPP pretreatment (200 MPa, 6 min) followed by a freezing at −50 °C (at 1 or 5 m/s) would achieve the best results in albacore after up to 9 months of frozen storage. © 2021 Elsevier Ltd

关键词： Euterpe oleracea   Biomass characterization   Acai seed   Acai fiber   Mannan   Hydrothermal treatment  

摘要： Acai residual biomass can be a potential source for a wide range of applications, especially biotechnological, such as solid-state fermentation processes and production of fermentable sugars (mannose), such as raw material for food, pharmaceutical, and other industries. Fiber and seed of acai fruit (Euterpe oleracea) were characterized, after pulp extraction, in samples collected at different maturation stages (seasonality). The seed contained a remarkable amount of mannose (75%) followed by glucose (6%) and galactose (2%), with mannan as the main polysaccharide. The fiber was a lignocellulosic biomass containing glucose (30%) and xylose (19%). Mannan and cellulose in the seed and fiber, respectively, were the polysaccharide responsible for the crystallinity of both materials, with the seed showing higher values. The period of fruit harvesting (winter or summer crops) influenced the maturity and chemical composition of the residues, which had higher crystallinity in the summer season. Hydrothermal treatment was very efficient for fiber but failed for seed, indicating a high recalcitrance of mannan in acai seed.