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关键词： Bond angle   Bronsted site   Zeolite   Si   Al ratio   NH3-TPD  

摘要： The aluminosilicate structure of zeolites plays a decisive role in catalytic activity of HZSM-5 scaffolds leading to form exclusive features in the simultaneous reactions of xylene isomerization and ethylbenzene conversion. The aim of this work is to elucidate the effect of Si/Al ratio (150, 50 and 32) on the Si-O(H)-Al angle of Bronsted sites, which impresses the bond-length, activation energy, acidity strength of O-H Bronsted acid sites, specific surface area and porosity. To achieve these goals, BET test and the ammonia-TPD profiles of HZSM-5 zeolites possessing different Si/Al ratios were obtained and interpreted. The results of BET test show that the Si/Al ratio of 50 in comparing with the other ratios assessed in this work has the most specific surface area and porosity. Moreover, the results of NH3-TPD experiment revealed that a temperature shift of H-peak signals to higher temperatures occurs with decreasing the Si/Al ratio because of raising the enthalpy of Bronsted sites and increasing the acidity strength. The ammonia-TPD profiles in accordance with the deprotonation enthalpy theory highlighted the effect of Si/Al ratio on the angle of Bronsted sites resulting in increasing the length of O-H moiety or the acidity strength of Bronsted sites.

关键词： Vaccinium bracteatum Thunb   leaves (VBTL)   extrusion   antioxidant capacity   physicochemical properties   in vitro starch digestibility  

摘要： Vaccinium bracteatum *** (VBTL) are a traditional Chinese herbal medicine with potential natural pigments and antioxidants. Its application information on extrusion is limited. In this study, to increase the usage of foods containing VBTL, rice-based extrudates with VBTL were investigated. The extrusion was performed at a wide temperature range (60-140 degrees C) and with different VBTL supplementations (3%-10%). The extrudates with 10% VBTL showed a significant decrease in total phenolic content (TPC), total flavonoid content (TFC), and antioxidant activity upon extrusion. TPC and TFC increased with the rise of barrel temperature. The VBTL color was stable during the wide-temperature extrusion process. The bioactivities of the extrudates were positively correlated with the VBTLsupplement (R = 0.943-0.989). In addition, different addition levels of VBTL significantly changed the water absorption index (WAI), water solubility index (WSI), pasting properties, and in vitro starch digestibility of the extrudates. Moreover, extrudates with 3% VBTL showed the highest WAI and peak viscosity but the lowest in vitro starch digestibility. These results may suggest that rice extrudates with a low supplement of VBTL have an acceptable color and may be used as functional additives for high antioxidant and low glycemic response diets. Practical Application The results showed that the Vaccinium bracteatum Thunb. leaves (VBTL) color and antioxidation were stable during the wide-temperature extrusion process. Extrusion processing can be used to enlarge the usage of VBTL and simplify its traditional processing method. Applying VBTL to the process of extrusion appears to be a suitable method of producing value-added and low glycemic response extrudates.

关键词： Rice   Protein denaturation   Lipid removal   Pasting properties   Gelatinization properties  

摘要： The physicochemical properties of rice are influenced by their chemical components and their interactions. It has been demonstrated that the interactions among rice chemical components are enhanced by protein denaturation (PD) via heat treatment and by lipid removal (LR) via solvent extraction. The objective of this study was to investigate the impacts of PD, LR, and their combined treatments on the gelatinization and pasting properties, swelling power, and water solubility of four brown rice flours. Rice protein was denatured under a vacuum at 100 degrees C, and rice lipid was removed via hexane for varying times. The combined treatments were done in two ways, PD followed by LR (PD-LR), and LR followed by PD (LR-PD). The results showed that PD increased gelatinization temperatures, while LR decreased gelatinization temperatures. Both PD and LR reduced pasting and swelling properties;however, PD resulted in a greater decrease than LR. Polar lipids are proposed to serve as bridges to link denatured proteins and starch granules in the combined treatments, resulting in greater decreases in the pasting and swelling properties than the individual treatments. The results obtained in this study demonstrate the importance of starch-lipid-protein interactions on the physicochemical properties of brown rice flour.

关键词： Prunus dulcis   Water stress   Regulated deficit irrigation   Quality parameters   Gas chromatography   Roasting  

摘要： Regulated deficit irrigation (RDI) is a useful strategy to reduce the water consumption maintaining the fruit quality. The almonds cultivated under RDI conditions are called hydroSOStainable because are produced under environmentally friendly conditions and present an improved quality. It was demonstrated that almond cultivar and agronomical practices, can affect the kernel chemical composition and consequently the parameters for the roasting process of almonds. The influence of three roasting temperatures (150 degrees C, 170 degrees C and 190 degrees C) on the quality of almonds belonging to 2 irrigation treatments (T1: control and T2: hydroSOStainable almonds) was evaluated. For this, moisture, water activity (aw), organic acids, sugars, antioxidant activity (AA), total phenolic content (TPC) and fatty acids content were measured. Results showed that moisture content, aw, AA (ABTS(center dot+) and DPPH center dot), and polyunsaturated fatty acids (PUFAs) were reduced with the most severe roasting treatment. While citric, isobutyric, maltoheptaose and maltotriose content was increased. HydroSOStainable almonds had significantly higher content of AA, TPC, organic acids, sugars, PUFAs and total fatty acids than control almonds;this tendency was present at 170 degrees C, but not at 190 degrees C. Consequently, 170 degrees C during 10 min was the recommended roasting conditions for the hydroSOStainable almonds.

关键词： Raisin   Drying   Texture   Phenolics   Sensory analyses   Composition  

摘要： Raisins are commonly found in the Mediterranean diet due to their delicious taste and their nutrient richness. This study evaluated the effect of drying at three temperatures (50 to 70 degrees C) on the physico-chemical, textural, phytochemical and sensory proprieties of Italia raisins subjected to different pre-treatments: control samples (not treated, C), dipping berries in sodium hydroxide (SH) and raisins obtained by a traditional method (Trad). According to physico-chemical analyses, drying at 60 degrees C allowed to obtain raisins with attractive color, high contents in protein, total soluble solids and titratable acidity, but lower pH values. The textural parameters of Italia raisins are assessed for the first time. Our findings demonstrated that the firmer raisins were obtained with Trad pre-treatment at 70 degrees C. Phytochemical results were dependent on each drying condition. It seems that Trad at 60 degrees C favored coutaric and fertaric acids, quercetin-3-O-glucoside and rutin, Trad at 70 degrees C gallic acid and total phenolic content and no pre-treatment (C) at 50 degrees C the flavanol monomers and procyanidin B2. Regarding sensory analysis, panelists scored Italia raisins as sweet, firm, sticky, a slight acid, with the abundance of dried plum/red berries, fig/hay/tobacco and caramel/vanilla aromas. The results revealed that from the same grape, it is possible to get raisins with different characteristics according to each drying condition, that suggests consequently to meet different consumer markets.

关键词： Acid-soluble collagen   large yellow croaker   physicochemical properties   thermal stability  

摘要： Acid-soluble collagens (ASCs) were extracted and characterised from different tissues of large yellow croaker (Larimichthys crocea). The yields of ASCs in bones, skins, scales and muscles were 3.22 +/- 0.47%, 42.30 +/- 1.15%, 2.82 +/- 0.31% and 0.89 +/- 0.12%, respectively. SDS-PAGE and ATR-FTIR analysis showed that all ASCs were type I collagen with intact triple helical structure and consisted of alpha 1,3-chain, alpha 2-chain, beta-chain and gamma-chain. Quantitative analysis of SDS-PAGE revealed that the ratio of beta-chains in ASC from scales was lower than other tissues. The imino acid contents of ASC from bones, skins, scales and muscles were 169, 167, 162 and 173 residues/1000 residues, respectively. The maximum transition temperature (T-m) of ASC from scales was 30.15 degrees C, lower than the other three ASCs, indicated that the thermal stability of collagen was affected by both the content of imino acid and beta-chains. The results also implied that thermal stability of ASC might exist the tissue specificity among different fish species.

关键词： physiological development   maturity indices   maturation stages   Theobroma cacao L  

摘要： BACKGROUND Cacao is important for the economy of many countries in the humid tropics. Its quality is affected when fruits are not collected at the optimal harvest point. The aim of this study was to obtain maturity indices for producers to facilitate the timely harvest and improve the development of fermentation and the sensorial quality of cacao. The growth and respiration processes, and the physicochemical changes during the maturation of three cacao genotypes were determined. Physiological follow-ups measuring fruit length and diameter were performed from 30 days after anthesis to fruit deterioration in the tree. RESULTS Growth equations were obtained, establishing four maturity stages based on days after anthesis, and fruit length and diameter. Nineteen descriptors were used for the characterization, and through Pearson's correlation and principal component analysis (PCA), five descriptors were identified as representative of the maturity stages of the cacao fruit. PCA results and respiration measurements established that stage 3 presented the highest substrate availability for obtaining good fermentation and quality cacao. This stage showed values between 124 and 197 days after anthesis with lengths between 167.7 and 249.73 mm, and diameters between 64.4 and 95.8 mm, according to the locality. CONCLUSION Three growth phases of the cacao fruits were established considering days after anthesis. Both the edaphoclimatic conditions and the cacao genotype characteristics influenced this determination. Stage 3 of fruit maturation shows the best physicochemical conditions for good fermentation. (c) 2021 Society of Chemical Industry

关键词： Pulmonary surfactants   Surface tension       Mechanical behaviour   DPPC       Bubble tensiometry   Dilational rheology       Phospholipids monolayers  

摘要： The pulmonary surfactant (PS) is a complex mixture of lipids and proteins dispersed in the aqueous lining layer of the alveolar surface. Such a layer plays a key role in maintaining the proper lung functionality. It acts as a barrier against inhaled particles and pathogens, including viruses, and may represent an important entry point for drugs delivered via aerosols. Un-derstanding the physicochemical properties of PS is therefore of importance for the comprehension of pathophysiological mechanisms affecting the respiratory system. That can be of particular relevance for supporting the development of novel therapeutic interventions against COVID-19-induced acute respiratory distress syndrome. Owing to the complexity of the in vivo alveolar lining layer, several in vitro methodologies have been developed to investigate the functional and structural properties of PS films or interfacial films made by major con-stituents of the natural PS. As breathing is a highly dynamic interfacial process, most applied methodologies for studying PSs need to be capable of dynamic measurements, including the study of interfacial dilational rheology. We provide here a review of the most frequently and successfully applied meth-odologies that have proven to be excellent tools for under -standing the biophysics of the PS and of its role in the respiratory mechanics. This overview also discusses recent findings on the dynamics of PS layers and the impact of inhalable particles or pathogens, such as the novel coronavi-rus, on its functionality.

关键词： Tea polysaccharide conjugate   Emulsifier   Nanoemulsions   Lipid oxidation   Nutraceuticals  

摘要： With increasing consumer demand for label-friendly products, there is a push towards the identification and utilization of effective natural emulsifiers from botanical sources. In this study, we investigated the effect of controlled thermal treatments on the physicochemical and functional properties of tea polysaccharide conjugates (TPCs). Thermal treatment of the TPCs at 110 degrees C for 3 days (TPC-3d) markedly improved their emulsifying activity without negatively impacting their antioxidant activity. In comparison with animal-based (sodium caseinate) and synthetic (Tween 80) emulsifiers, TPC-3d stabilized emulsions were more effective at inhibiting the chemical degradation of encapsulated omega-3 oils and curcumin during storage at elevated temperatures. The improvement in the chemical stability of the bioactive lipids was mainly ascribed to the antioxidant activity of the conjugated phenolic groups in the TPC. Our results show that thermally-treated TPC has the potential to be used as a novel plant-based antioxidant emulsifier to encapsulate and protect chemically labile hydrophobic compounds.

关键词： Nanoparticles   Zeolites   Catalysts   Diffraction   Nuclear magnetic resonance spectroscopy