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关键词： Liquid egg white   Phospholipase A(2)   Meringue   Creep-recovery rheology   Storage stability   Sensorial and textural characterization  

摘要： This research aimed to investigate the effects of various concentrations (0.1;0.2 and 0.3 v/v %) of phospholipase A(2)(PLA) enzyme-modified liquid egg albumen (LEA) on color, water activity, specific volume, textural profile analysis, and sensorial characteristics of cooked meringues for 90 days storage period at room temperature. Also, the rheological creep-recovery changes, specific density, color, and physico-functional properties of meringue batters were evaluated. The meringue batter density in the control group (0.47 +/- 0.01) decreased significantly (p < 0.05) after PLA hydrolysis, while better specific gravity values were obtained in 0.3% enzyme concentration (0.36 +/- 0.01). The use of the enzyme-hydrolyzed LEA also significantly (p < 0.05) decreased water activity with control, 0.1, 0.2 and 0.3% of PLA (0.447 +/- 0.01;0.429 +/- 0.01;0.429 +/- 0.01, and 0.420 +/- 0.01), respectively. The batter densities of meringues prepared by PLA enzyme decreased with increasing the enzyme concentration, while as enzyme concentration increased, the meringues lost its elasticity. The increase in enzyme concentration leads to a significant increase in meringue's specific volume values. Sensory analysis of meringues showed that the lowest scores obtained by the control group, and the enzyme hydrolyzed with 0.2% were acceptable. The PLA modification provided the storage stability of meringues in hardness values. This study highlights the use of the PLA enzyme-modified LEA in meringue production results in the development of functional properties and storage stability.

关键词： pit lakes   Muskau Arch   water chemistry   temporal changes  

摘要： Thirteen pit lakes of the Muskau Arch (Western Poland) were studied in the summer season of 2016. The lakes display great geomorphological and hydrochemical diversity. The aim of the study was to characterize temporal changes in the physicochemical conditions of the pit lakes over the last 30 years (1986-2016) and to determine the main factors influencing their evolution. All the lakes were characterized in terms of the same set of physicochemical parameters measured and used for comparative analysis with literature data from the years 1986 and 1992. The results showed significant temporal differentiation in terms of morphometric features and most of the physicochemical characteristics. pH, EC, Ca2+, Mg2+ and total Fe were among the most significantly differentiating parameters. A similar pattern of changes was found for most of the lakes, suggesting natural fluctuations. Despite the differences in values of thermal and oxygen profiles, there were also similarities in lake stratification. Additionally, meromictic conditions were found in 4 lakes. In some of the lakes a negative effect of neutralization and fertilization of the water was observed. Our results showed that the Muskau Arch lakes are subject to dynamic hydrogeological and hydrochemical changes. In addition to natural changes, human-caused transformations were among the key factors responsible for the differentiation of the physicochemical conditions.

关键词： biosignature   digitate sinter   hot springs   microbial communities   silicification   stromatolite  

摘要： Digitate siliceous hot spring deposits are a form of biomediated sinter that is relatively common in the Taupo Volcanic Zone (TVZ), New Zealand, and elsewhere on Earth. Such deposits have gained prominence recently because of their morphological similarity to opaline silica rocks of likely hot spring origin found by the Spirit rover on Mars and the consequent implications for potential biosignatures there. Here, we investigate the possible relationship between microbial community composition and morphological diversity among digitate structures from actively forming siliceous hot spring sinters depositing subaerially in shallow discharge channels and around pool rims at several physicochemically distinct geothermal fields in the TVZ. The TVZ digitate sinters range in morphologic subtype from knobby to spicular, and are shown to be microstromatolites that grow under varied pH ranges, temperatures, and water chemistries. Scanning electron microscopy and molecular analyses revealed that TVZ digitate sinters are intimately associated with a diverse array of bacterial, archaeal and eukaryotic micro-organisms, and for most digitate structures the diversity and quantity of prokaryotes was higher than that of eukaryotes. However, microbial community composition was not correlated with morphologic subtypes of digitate sinter, and observations provided limited evidence that pH (acidic versus alkali) affects morphology. Instead, results suggest hydrodynamics may be an important factor influencing variations in morphology, while water chemistry, pH, and temperature are strong drivers of microbial composition and diversity.

关键词： baked   imbibition   oat   viscosity   water absorption capacity  

摘要： Background and objectives Oat (Avena sativaL.) consumption has increased mainly due to the health benefits as this cereal is an excellent source of prebiotics and high-nutritional compounds. In this work, an imbibition treatment was applied to improve the physicochemical properties of baked oat (Avena sativaL.) grains. Findings Studied samples included flour from the grains imbibed, dried and baked at 120 degrees C for 30 min (IT120), flour from grains without imbibition and baked at 120 degrees C for 30 min (T120) and flour from raw grains (R). The protein and crude fiber content did not change with the treatments, but the lipids content decreased. The water absorption capacity (WAC) increased 1.14- and 2.6-folds for T120 and IT120, respectively, when compared to R. The rheological analysis demonstrated an important effect of the concentration and the imbibition processes as the viscosity values increased sixfold in IT120 at 30% solids content. Conclusions The imbibition and baking treatment of whole oat grains resulted in structural rearrangements changing the physicochemical properties which could be useful when using these flours as an ingredient. Significance and novelty The structural modification promoted by the imbibition and baking treatment could increase the potential applications of oat flour.

关键词： Physicochemical properties  

摘要： This study aimed to produce burgers using fructooligosaccharides (FOS) as a substitute for animal fat. Four treatments (T1-control;T2-with 50% fat reduction;T3-with 50% fat reduction + 5% FOS;T4-with 50% fat reduction + 10% FOS) were produced. For the proximate composition, T4 had the lowest moisture. For lipids, the fat reduced treatments (T2, T3, and T4) differed of T1. For lipid oxidation, T3 and T4 had highest (p < .05) values than T1. For the cooking characteristics, T4 had the highest yield and the lowest cooking loss. Before cooking, the redness of T3 differed from the other treatments. After cooking, the burgers of T4 had lower lightness than those of T1. Although flavor acceptance and overall liking reduced with the FOS, the scores remained within the acceptance region. Therefore, FOS is an alternative for the fat replacement in burgers. Practical applications Beef burgers are widely consumed by practicality. However, these products have high fat content. Thus, the reduction of this constituent is a challenge for meat industry because it is responsible for functional and palatability characteristics. Therefore, this study aimed to develop low-fat beef burgers containing fructooligosaccharides and to evaluate the effects on physicochemical characteristics, cooking quality, and sensory evaluation. Moreover, the present study used the Principal Component Analysis and the penalty analysis for better visualization and interpretation of sensory attributes.

关键词： sturgeon fillet   low temperature vacuum heating   physicochemical characteristics   protein oxidation   lipid oxidation  

摘要： BACKGROUND Sturgeon is popular for its nutritious value and its taste. However, sturgeon fillets are traditionally heated in 100 degrees C boiling water, resulting in unfavorable taste and with a negative effect on the quality. This study considered the effect of combinations of vacuum and low-temperature treatments (LTVH groups) on sturgeon fillets compared with the traditional heat treatment (TC groups). RESULTS The results show that the LTVH groups had lower cooking-loss rates. All LTVH fillets were changed to a white color, and appeared 'done', as did the TC fillets. The LTVH and TC methods gave rise to significant differences in texture: the springiness of the LTVH groups decreased with heating time, and decreased rapidly in the TC groups (P < 0.05);hardness and chewiness increased with time and temperature in the LTVH groups, but decreased in the TC groups. More compact and denser gaps were observed in LTVH70 groups and TC groups. Less protein and lipid oxidation was evident in LTVH groups, including more myofibril protein solubility;there was less protein aggregation, fewer thiobarbituric acid reactive substance, and Schiff base. CONCLUSION Vacuum and low-temperature treated sturgeon fillets can be served as a good alternative. This treatment caused slight tissue damage and less proteolysis and lipid oxidation, which is beneficial for the quality of aquatic products.

关键词： 物理化学   高等职业教育   教材  

ISBN: (纸本)9787564377038

摘要： 本书是高等职业教育“物理化学”课程教材，内容包括：气体、热力学第一定律、热力学第二定律、相平衡、电化学、化学动力学、表面现象、胶体与大分子溶液等。本书针对高职高专学生的实际情况，力求深入浅出，精简了公式的推导过程，着重强调公式的使用条件和应用范围。为了便于教学，本书在例题和习题的选编上也力求典型并注重启发性，在强调物理化学理论基础的同时，突出专业特点，注重物理化学原理在化工、医药方面的应用，书中例题多结合化工、医药知识，适合高职院校化工与制药等相关专业使用。

关键词： ChitosanBombyx mori   Hydroxyapatite   Composite   Nanostructure   Osteoporosis  

摘要： Composites of chitosanBombyx moriwith hydroxyapatite - (Ca-10(PO4)(6)(OH)(2)) were obtained and their interaction in aqueous solutions was studied. The composition and structure of composites obtained at various mass ratios were studied. The possibility of controlling the composition and morphology of composites by varying the ratios of the initial reagents was shown. FITR and UV spectroscopic methods were used to investigate the structure of composites. The results of XRDA studies have shown that depending on the CS/HA ratio, CS/HA crystals with sizes from 6.9 to 20.4 nm were formed in the system. Using the methods of potentiometry, conductometry and viscometric measurements the equivalent composition of the composite was determined, which is CS/HA-70:30 mass %. It was found that nanostructured composites with minimum sizes from 2 to 15 nm were obtained under the selected synthesis conditions. The obtained data are applied interest for the prevention and treatment of osteomolyosis, osteoporosis and bone replacement of living organisms.

关键词： bioactive compounds   food processing   food waste reduction   functional food   mango kernel oil   polyphenols  

摘要： Mango (Mangifera indicaL.) is a fruit plant of family Anacardiaceae, widely grown all over the world, and is a very popular fruit in the world market. Mango fruit is the second most traded tropical fruit and fifth in terms of production globally. Large quantities of mango processing coproducts are generated (peels and seeds), which usually are discarded as waste, yet are a potential source of fat, protein, carbohydrate, and certain bioactive compounds. Mango kernel is a remarkably rich source of macronutrients and micronutrients including calcium, potassium, magnesium, phosphorus, and vitamins A, E, K, and C. Phytochemicals with a notable therapeutic potential such as tocopherols, phytosterols, carotenoids, polyphenols (gallotannins, flavonols, benzophenone derivatives, mangiferin, homomangiferin, isomangiferin, anthocyanins, kaempferol, and quercetin), and phenolic acids (4-caffeoylquinic acids, caffeic, coumaric, ellagic, gallic, and ferulic acid) are reported. The phytochemicals have high antioxidant, antimicrobial, anticancer, and, antiproliferation activities and could be used for food, cosmetic, and pharmaceutical applications. The nutritional composition of mango kernel constitutes 32.34% to 76.81% carbohydrate, 6% to 15.2% fat, 6.36% to 10.02% protein, 0.26% to 4.69% crude fiber, and 1.46% to 3.71% ash on a dry weight basis. The nutritional profile of the kernel suggests its usability as a food ingredient in the development of value-added products such as mango kernel oil, mango kernel butter, mango kernel flour, and biofilms among other diverse products. This comprehensive systematic review explores mango kernel as a potential and novel food ingredient to meet the needs of a health-conscious population. The review also provides a remedy to waste management and environmental pollution.

关键词： Maple syrup   Physicochemical composition   Brix   Sugars   Phenolic compounds   Minerals   Seasonal changes   Nova Scotia  

摘要： Maple syrup is produced by concentrating the maple tree sap. The physicochemical profile of maple syrup can be varied depending on the processing method, microbial contamination, seasonal and geographical variations etc. Apart from being a better alternative to refined sugar, the minerals and phenolics in maple syrup may provide additional health benefits owing to their bioactivities. We studied the physicochemical profiles of maple syrup samples from North America and the seasonal compositional changes of the syrup from Nova Scotia (NS). Syrup pH, color, Brix were significantly differ depending on the location. Brix values ranged from 61.6 to 70.2 degrees. Thirteen different phenolics including protocatechuic acid, coniferyl alcohol, vanillin, and syringic aldehyde were identified and quantified. The total mineral content ranged from 2.6 to 4.8 g/L of syrup. Potassium was the most abundant, followed by calcium, magnesium, phosphorus, manganese, and zinc. Analyses of NS syrup during early, mid and late seasons revealed that, total phenolics and minerals increased and the syrup color became darker towards late season. Syrup pH, brix and sugars did not differ among the seasons. Interestingly, vanillin, syringic acid and syringic aldehyde were the main phenolics in early maple syrup samples while protecatechuic acid was the predominant in late season.