Mixture Of Sucrose Research Articles

Raspberry as a Source for the Development of Drosophila suzukii Attractants: Laboratory and Commercial Polytunnel Trials.

Several commercial products and home-made attractants have been developed for monitoring and mass-trapping of the spotted wing drosophila, Drosophila suzukii. Growers in Mexico have adopted an attractant based on a fermenting mixture of raspberry pulp and sucrose, with anecdotally promising results. We compared the capture rates of traps baited with raspberry pulp + sucrose with captures from a range of alternative attractants. Raspberry pulp alone or with sucrose was more attractive than apple cider vinegar (ACV) or SuzukiiTrap and similar to baker’s yeast + sucrose in laboratory cage studies. Synthetic raspberry aroma (0.1–10% concentration), in water or mixed with ACV, did not improve capture rates in the laboratory. Traps baited with raspberry + sucrose or ACV had similar captures of D. suzukii in raspberry or blackberry polytunnels in Michoacán, Mexico. Raspberry + sucrose baited traps captured significantly higher numbers of other drosophilid species, leading to higher total numbers of captured flies (all species), which may explain why Mexican growers favor the raspberry-based attractant. The commercial products SuzukiiTrap and Z-Kinol had lower captures than ACV in polytunnels, although SuzukiiTrap had the highest selectivity in captures of D. suzukii (81% of flies captured). A two-component trap (2C trap) baited with ACV + ethanol as the drowning solution and raspberry pulp + sucrose or baker’s yeast + sucrose in a ventilated tube device was markedly more effective than the trap currently used by growers. We conclude that raspberry pulp + sucrose is as effective for the attraction of D. suzukii as ACV under commercial polytunnel conditions. The 2C trap performed better than the transparent cup trap currently used by berry producers in Mexico.

Solid–Liquid Equilibria and Characterization of the Reaction Mixture To Produce Sucrose Palmitate in Solvent-Free Media

This work deals with the characterization of the reactive mixtures involved in the production of sucrose palmitate from methyl palmitate and sucrose, through a solvent-free process. The solid–liquid equilibrium in mixtures of sucrose–methyl palmitate–sucrose palmitate (SE) at temperatures between 363 and 403 K and sucrose ester concentrations between 0 and 15 g SE/100 g methyl palmitate was measured. Solid and liquid heat capacities of sucrose palmitate and thermal properties useful in the equilibrium modeling were measured through differential scanning calorimetry and thermogravimetric analysis. The viscosity and surface tension of the reaction product were also measured. According to results sucrose palmitate melts at 315.82 K and decomposes at 510.67 K. The average solid and liquid heat capacities of sucrose ester in the evaluated ranges were 2010 J/kg·K and 2475 J/kg·K, respectively. The predictive modified UNIFAC method for sugars (mS-UNIFAC) and the nonrandom two-liquid equation were used to model t...

KAJIAN PENGGUNAAN VAKTOR (VAKUM EVAPORATOR) DALAM MEMPERTAHANKAN KANDUNGAN VITAMIN DAN ANTIOKSIDAN PADA MINUMAN SERBUK

Instant Beverages are a food requirement that is difficult to separate from human life in this millennium. However, because human needs for fluids are far more than food, it is very important to pay attention to every food and beverage product consumed. Based on data from the Ministry of Health of the Republic of Indonesia, more than 5% of Indonesia's population consumes various types of ready-to-drink drinks (instant). The still high debate about the negative impact of instant drinks, it is very important to standardize the quality of instant drinks on the market today. Related to this, the process of making tomato instant powder drinks has been optimized using the vacuum evaporator method with variations in temperature, time and filler in the evaporation process. Each product produced is analyzed for the content of vitamins C and antioxidants. The vacuum evaporator is used to maintain the quality of the vitamins and antioxidants in powder drinks. The quality of instant powder drinks is improved by varying the drying temperature (50 - 70 °C), and variations in the drying time of products (3 - 7 hours). To obtain a granule formation, a mixture of sucrose, dextrin and tween 80 with a specific composition was used as a filler. The results showed that the vitamin C content can be maintained high on drying for 7 hours with a low temperature, which is 50 °C, with a value of 65,17 mg/100 g. In contrast, the highest total IC50 antioxidant activity (24.10 mg/ml) was obtained in the drying process for 3 hours using a temperature of 700C. The results of this study are expected to be a reference for determining parameters in vacuum evaporator designs equipped with packaging, so that it becomes a reference for home industries to produce healthy and nutritious instant drinks, namely instant powder drinks rich in vitamins and antioxidants, in accordance with SNI Standards and BPOM.

Quantitative capabilities of STXM to measure spatially resolved organic volume fractions of mixed organic ∕ inorganic particles

Abstract. Scanning transmission X-ray microscopy coupled with near-edge X-ray absorption and fine structure (STXM-NEXAFS) spectroscopy can be used to characterize the morphology and composition of aerosol particles. Here, two inorganic ∕ organic systems are used to validate the calculation of organic volume fraction (OVF) and determine the level of associated error by using carbon K-edge STXM data at 278, 285.4, 288.6, and 320 eV. Using the mixture of sodium chloride and sucrose as one system and ammonium sulfate and sucrose as another, three solutions were made with 10:1, 1:1, and 1:10 mass ratios (inorganic to organic). The OVFs of the organic-rich aerosols of both systems deviated from the bulk OVF by less than 1%, while the inorganic-rich aerosols deviated by approximately 1 %. Aerosols from the equal mass mixture deviated more (about 4 %) due to thick inorganic regions exceeding the linear range of Beer's law. These calculations were performed after checking the data for poor image alignment, defocusing issues, and particles too thick to be analyzed. The potential for systematic error in the OVF calculation was also tested by assuming the incorrect composition. There is a small (about 0.5 %) OVF difference if the organic is erroneously assumed to be adipic acid rather than the known organic, sucrose. A much larger difference (up to 25 %) is seen if sodium chloride is assumed instead of ammonium sulfate. These results show that the OVF calculations are fairly insensitive to the organic while being much more sensitive to the choice of inorganic.

The effect of a new mixture of sugar and sugar-alcohols compared to sucrose and glucose on blood glucose increase and the possible adverse reactions: A phase I double-blind, three-way randomized cross-over clinical trial

IntroductionSeveral sweeteners are introduced to replace sucrose in the human diet. However, they had their own limitations and concerns, particularly in terms of their taste and their long-term health consequences. This study examined the effect of a new mixture of sugars and sugar alcohol on the postprandial blood glucose levels and its possible gastrointestinal (GI) adverse reactions in human adults. MethodsIn this double-blind three-way randomized clinical trial, adults (21 with type 2 diabetes and 20 healthy) received 300ml of three beverages containing 50g glucose, sucrose, and lacritose (a mixture of lactose, fructose, sucrose, and erythritol) when they were in the fasted state in a random order. Postprandial serum glucose was checked every 30min up to 2h and the gastrointestinal reactions were collected. ResultsThe mean serum glucose was significantly lower in all time points after ingestion of the lacritose for participants with type 2 diabetes compared to glucose and sucrose (P<0.05). The blood glucose levels were significantly lower in the 30th and 60th min for healthy subjects (P<0.05). Adverse GI reactions were not significant between the test beverages. ConclusionsThe ingestion of a 50g dose of lacritose containing lactose, fructose, sucrose, and erythritol, led to an improved blood glucose levels without any significant adverse effect compared to the same amount of glucose and sucrose. Studying the long-term effects of lacritose on appetite, metabolic markers and adverse reactions is recommended. The trial was registered in Iranian registry of clinical trials: IRCT2015050912571N2.

Sickly Sweet: Insecticidal Polyols Induce Lethal Regurgitation in Dipteran Pests.

Polyols are commonly used in food and medicines as sweeteners and preservatives but may also have insecticidal properties against some species of Diptera. Here we compared the insecticidal activity and feeding response of glycerol and propylene glycol (PG) on two tephritids: Anastrepha ludens and Anastrepha obliqua, and the drosophilid Drosophila suzukii. First, flies were exposed to solutions of 50% sucrose and the two polyols at concentrations of 1.67 M, 2.78 M and 4.18 M for 24 h and then observed at 24 h intervals for a period of three days. Both polyols elicited strong regurgitation behavior in the three flies and killed them. Regurgitation apparently also reduced flies’ body weight, and this was particularly apparent in insects that fed on 4.18 M PG solutions. A high percentage of individuals exposed to PG solutions perished after 72 h. The number of proboscis extensions, which is associated with feeding preference, was lower in the 4.18 M polyols + sucrose mixtures than in the 50% sucrose solution. Glycerol had a lower insecticidal effect in Anastrepha spp. and very little insecticidal effect in D. suzukii. Finally, elevated regurgitation and mortality was confirmed in A. ludens treated with 1.0–2.78 M of erythritol plus sucrose. Our results demonstrate that PG, and to a lower extent glycerol, have the potential for being used as a safer method of insect pest control. The hyper-regurgitation response may contribute to the insecticidal properties of these polyols in Diptera.

Microstructure evolution and mechanical properties of in-situ bimodal TiC-Fe coatings prepared by reactive plasma spraying

An in-situ synthesis phenomenon of bimodal TiC-Fe coatings is discovered in the reactive thermal spraying of Fe-Ti-C composite powders. The Fe-Ti-C composite powders were prepared by a hybrid spray-drying/pyrolysis technology using a mixture of ferrotitanium (TiFe), graphite and sucrose. The microstructure evolution and mechanical properties of the coatings were investigated. The results showed that the TiC-Fe coatings exhibited an apparent bimodal particle size distribution of submicron and nano TiC particles in the α-Fe matrix. The formation of the bimodal distribution structure was revealed as following bi-precipitation mechanism: the first precipitation during the flight process to form submicron TiC particles and the second precipitation in the impact process with rapid cooling to form nano TiC particles. The bimodal TiC-Fe coatings showed high microhardness in various loads due to simultaneous hardening effect from submicron and nano TiC particles. The crack analysis showed that the in-situ bimodal TiC structure hindered the crack initiation and the crack propagation and thus improved the fracture toughness. The bimodal TiC-Fe coatings exhibited high abrasive wear resistance and the wear mechanism transformed from two-body abrasive wear to three-body abrasive wear with the increase of spray distances.

The Effect of an Encapsulated Nutrient Mixture on Food Intake and Satiety: A Double-Blind Randomized Cross-Over Proof of Concept Study.

Activation of the intestinal brake by infusing nutrients into the distal small intestine with catheters inhibits food intake and enhances satiety. Encapsulation of macronutrients, which protects against digestion in the proximal gastrointestinal tract, can be a non-invasive alternative to activate this brake. In this study, we investigate the effect of oral ingestion of an encapsulated casein and sucrose mixture (active) targeting the distal small intestine versus a control product designed to be released in the stomach on food intake, satiety, and plasma glucose concentrations. Fifty-nine volunteers received the active and control product on two separate test days. Food intake was determined during an ad libitum meal 90 min after ingestion of the test product. Visual analogue scale scores for satiety and blood samples for glucose analysis were collected at regular intervals. Ingestion of the active product decreased food intake compared to the control product (655 kcal compared with 699 kcal, respectively, p < 0.05). The area under the curve (AUC) for hunger was decreased (p < 0.05) and AUC for satiety was increased (p < 0.01) after ingestion of the active product compared to the control product. Ingestion of an encapsulated protein-carbohydrate mixture resulted in inhibition of food intake compared to a non-encapsulated control product.

Fabrication of a Magnet-Assembled Alignment Device for the Amperometric Detection of Carbohydrates in Combination with CE

The article describes the preparation of a magnet-assembled alignment device for the amperometric detection of carbohydrates in combination with capillary electrophoresis (CE). It consists of a self-positioning copper disc detection electrode plate, an NdFeB magnet, a painted iron screw nut as well as a cap bearing a grounding electrode, an auxiliary electrode and a reference electrode. Coaxially aligned copper wire and stainless steel tube were enclosed between two poly(methyl methacrylate) plates by far infrared-assisted encapsulation to fabricate the self-positioning electrode plate. The performance and advantages of the alignment device were demonstrated by the separation and detection of standard mixtures of mannitol, sucrose, glucose and fructose by CE. The four carbohydrates were well separated within 13 min in a 40-cm long capillary at a separation voltage of 9 kV using a 75 mM NaOH aqueous solution. Good linearity was observed between the peak current and concentration of carbohydrates over three orders of magnitude with detection limits (S/N = 3) ranging from 0.7 to 0.9 µM. The present system exhibited long-term stability and reproducibility with relative standard deviations of less than 5% for peak currents (n = 15). The advantages of the magnet-assembled alignment device include its simple design and construction, high alignment reproducibility, ease of operation, high degree of integration, portability and low cost. The method has been successfully applied in the determination of carbohydrates in Zingiber officinale Roscoe. Coaxially aligned copper wire and stainless steel guiding tube were enclosed between two PMMA plates by far infrared-assisted encapsulation to prepare self-positioning copper disc detection plate that was sandwiched between a magnet and a painted iron screw nut to form magnet-assembled alignment device for the amperometric detection of capillary electrophoresis.

Significant Drying Time Reduction Using Microwave-Assisted Freeze-Drying for a Monoclonal Antibody

Microwave-assisted freeze-drying (MFD) is a rapid drying process well known in food technology. However, little is known about its application to biologicals. In this study, we investigated the applicability and feasibility of this technology to different monoclonal antibody formulations and the influence on the resulting product properties. Moreover, one of our main objectives was to study if significant reductions in drying times could be achieved. In addition, the effect of the drying process on the accelerated stability of a sucrose-based antibody formulation at 40°C and 25°C over 12 weeks was investigated. MFD resulted in drying time reduction >75%. For all model formulations, cake appearance and solid state properties were found to be comparable to standard lyophilized products. These formulations covered a wider range of lyophilization excipients comprising sucrose and trehalose, semi-crystalline forming solids like mannitol:sucrose mixtures and others like arginine phosphate and a mixture of 2-hydroxypropyl-β-cyclodextrin with sucrose. Moreover, comparable low changes in relative monomer content, the relative amount of soluble aggregates and cumulative particles ≥1 μm per mL were observed over 12 weeks of storage, regardless of the drying technology. This makes MFD a promising innovative alternative for the rapid production of freeze-dried biologicals while maintaining product quality.

Microbiological Strategies for Sustainable Production of Bioactive Compounds Using Oil Produced Water Effluent with Sucrose and Crude Glycerine as Carbon Sources

Biopolymers and biosurfactants are bioactive compounds of great commercial interest. They are used for changing fluids viscosity and emulsifying properties of several types of solutions, characteristics necessary for the performance of enhanced oil recovery (EOR) strategies applied at distinct rock formations. The present work evaluated the production of Enterobacter amnigenus exopolysaccharide (EPS) of the strain grown alone or in consortium with Pseudomonas aeruginosa. Culturing was carried out using produced water amended with a mixture of crude glycerin and sucrose as carbon sources. E. amnigenus exopolysaccharide production was low when grown on pure culture, on the other hand, in the presence of P. aeruginosa, the amount of EPSwas of 14.74 gL-1. The produced biopolymer and biosurfactant exhibited excellent viscosity and emulsifyingactivity characteristics for the application in EOR strategies, and better pseudoplastic rheological behavior (was detected) than conventional chemicals used for this purpose. Statistical analysis showed that EPS production was influenced by the interaction between sucrose and glycerin amendments. Infrared absorption spectroscopy showed similar molecular structure to the E. amnigenus FucoPoL. This research shows that a recovering oil fluid can be prepared using produced water as main medium, contributing for reducing costs and increasing environmental gains.

Rehydration properties of hybrid method dried fruit enriched by natural components

Abstract The aim of the study was to determine the impact of osmotic pre-dehydration and drying of fruit on the rehydration properties of dried fruit. Herein, the effect of fruit juice, applied as a natural enriching substance was very important. In addition, the properties of dried fruits obtained through combined air-drying and subsequent microwave-vacuum drying with ‘puffing’ effect were similar to the freeze-dried fruits, but showed other rehydration properties. As raw material, frozen strawberry (Honeoye variety) and fresh apples (Idared variety) were used in the study. The apples and partially defrosted strawberries were prior dehydrated in solutions of sucrose and a mixture of sucrose with chokeberry juice concentrate at 50°C for 2 h. Next, the fruit samples were dried by one of two ways: air-drying (50°C, 5 h) and microwavevacuum drying for about 360 s; and freeze-drying (30°C, 63 Pa, 24 h). The rehydration was carried out in distilled water (20°C, 5 h). The osmotic pre-dehydration hindered fruit drying process. The impact of drying method became particularly evident while examining the kinetics of rehydration. During the rehydration of the pre-dehydrated dried fruit a slower hydration could be observed. Freeze-dried strawberries absorbed 2-3 times more water than those dried by the ‘puffing’ effect.

Conversion of Sugar Cane Molasses to 5-Hydroxymethylfurfural Using Molasses and Bagasse-Derived Catalysts

5-hydroxymethylfurfural (HMF) is a suitable platform chemical for the production of useful chemicals and fuels. This study examined the hydrolysis of mixtures of sucrose, glucose and fructose (synthetic sugar cane molasses) and industrial molasses using sulfonated carbon-based heterogeneous catalysts derived from sugar cane bagasse (B-SO3H) and sugar cane molasses (M-SO3H). Microwave heating at 150 °C for 4 h produced 39 mol % HMF yield with B-SO3H on the synthetic sugar solution. The addition of a molasses pretreatment step, as well as, increasing the microwave power was necessary to achieve similar HMF yields with the industrial molasses sample. The hydrolysis of molasses pretreated with formic acid or HCl resulted in a slightly higher HMF yield than the hydrolysis of molasses pretreated with H2SO4. The buffering capacity of the formic acid pretreated molasses was lowered through dilution with water; and subsequently HMF yield was increased to 64.3 mol % (170 °C, 3 h).

Preparation of a Small Acute-phase Cerebral Infarction Phantom for Diffusion-weighted Imaging

The present study aimed to prepare a small acute-phase cerebral infarction phantom made of gelatin and sucrose to simulate brain parenchymal cells, and a phantom made of collagen peptides and sucrose to simulate cerebral infarction for diffusion-weighted imaging (DWI). During the preparation of gelatin and sucrose mixture (17.0 wt% gelatin, 20.0 wt% sucrose), a cylindrical wooden bar was placed in the center of the phantom and covered with a heat-shrinkable film to ensure space remained after gelling. A mixed solution composed of collagen peptide and sucrose (16.0 wt% collagen peptide, 27.5 wt% sucrose) was then enclosed within the space. The T2 relaxation time and apparent diffusion coefficient (ADC) of the phantom were set equal to those observed in actual patients with acute-phase cerebral infarction. The mixture was selected based on the signal intensity of both the healthy brain tissue and that subjected to acute cerebral infarction, such that no contrast was observed during T2-weighted imaging (T2WI). T2WI and DWI were performed using a 1.5 T scanner. Although contrast between the mixed gel and mixed solution was obscure on T2WI, cerebral infarction was clearly visible on DWI. However, the phantom exhibited mono-exponential changes in the ADC value at b values of 0 and 1,000 (s/mm2), and was affected by the proton density and T1 value depending on the imaging condition.

A simple and fast method for fixation of cultured cell lines that preserves cellular structures containing gamma-tubulin

When using fluorescence microscope techniques to study cells, it is essential that the cell structure and contents are preserved after preparation of the samples, and that the preparation method employed does not create artefacts that can be perceived as cellular structure/components. ?-Tubulin forms filaments that in some cases are immunostained with an anti-?-tubulin antibody, but this immunostaining is not reproducible [1]. In addition, the C terminal region of ?-tubulin (green fluorescence protein tagged [GFP]-?-tubulin334––449) forms cytosolic GFP-labeled structures, which can easily be imaged in live cells but are not preserved in fixed cells [1,2]. The purpose of this study was to identify a fixation technique that preserves cellular constituents containing ?-tubulin.•This protocol describes a method that preserves ?-tubulin-containing structures in fixed cells.•The technique entails two-step fixation. A pre-fixation step using paraformaldehyde is followed by a final fixation and permeabilization step performed at -80?°C.•In comparison with other methodology for fixation [3–5], the technique presented here uses a short pre-fixation step with a mixture of paraformaldehyde and sucrose followed by a short fixation/permeabilization step with a mixture of methanol and acetone at -80?°C.

42 Glycerol Dilution in the Straw by Mixing Methanol and Sucrose for Bovine Embryo Cryopreservation

This report focuses on post-thawing dilution of glycerol within the straws using a solution of methanol and sucrose. Dilution media contained 1.5 or 2.0 M methanol and 0 or 1.0 M sucrose (Suc). Straws of 0.25-mL were loaded as follows: (1) 15 mm of 10% glycerol (Gly) solution; (2) 7 mm of air layer; (3) 7 mm of Gly solution; (4) 7 mm of air layer; (5) 10 mm of Gly solution with an embryo; (6) 12 mm of air layer; and (7) 50 mm of dilution medium. Straws were then heat sealed. The ratio of Gly layer to dilution media layer was 1:6 after the solutions were properly loaded into the straw (post-thawing, 10% Gly then was diluted to 1.6%). For freezing, straws were held with cotton plug down and immersed in an alcohol bath to the column containing the embryo. The dilution media layer was not immersed in the bath immediately. When temperature reached –10°C or lower, the straw was taken out the alcohol bath and shaken towards a cotton plug, and the whole straw was immersed into the bath. By this operation, the air layer above the already frozen column containing the embryo was removed, and the dilution medium was directly mixed with Gly. For thawing, straws were kept in air for 5 to 8 s, and then immersed in a water bath at 25°C with cotton plug down for 3 or 10 min. All 18 fresh embryos exposed to 1.5 M methanol + 1.0 M Suc for 40 min at room temperature continued to develop for 48 h in TCM-199. Thawed embryos from diluting glycerol in the straw with methanol + Suc survived well regardless of sucrose concentration. All 28 embryos diluted in the straw with 1.5 M methanol + 1.0 M Suc, and all 14 from 2.0 M methanol without sucrose survived in culture. From 2009 to 2016, the direct transfer of in-straw glycerol diluted embryos using the 1.5 M methanol + 1.0 M Suc treatment led to 2,358/3,702 (63.7%) pregnancies. The mixtures of methanol and sucrose seemed to have no adverse effect on either fresh or frozen embryos. The hydrophilic methanol may absorb water from embryos at the same time that it antagonizes movement of glycerol into the embryo. This may allow gentle intracellular and extracellular glycerol equilibration.

NMR diffusometry data sampling optimization for mixture analysis

NMR diffusometry is a powerful but challenging method to analyze complex mixture. Each component diffuses differently, from the faster small species to the slower large species, corresponding to different signal attenuation. However, the method is highly sensitive to the quality of the acquired data and the performance of the processing used to resolve multiexponential signals influences. Adapting the signal decay sampling to the mixture composition is one way to improve the precision of the measure. In this work, we propose a prediction tool, based on the calculation of the Cramér-Rao lower bound to minimize the variance of diffusion coefficient estimation in order to determine the optimal number of diffusion gradient steps, the best diffusion gradient sampling (among linear, exponential, quadratic and sigmoidal ones) and the optimal maximum diffusion factor. The tool was validated experimentally on a unimer/micelle solution of sodium dodecyl sulfate and on Caelyx®, a commercial liposomal preparation containing a mixture of pegylated-liposomes and sucrose.

Rapid decolorization and mineralization of molasses by catalytic ozonation process with a nanocomposite from fermentation industry wastewater

Molasses is a byproduct of sugar and fermentation factories and a mixture of sucrose with other mono/poly saccharides and the conventional biological treatments are unable effectively to mineralize and decolorize them from the wastewater effluent. In this study, the efficacy of catalytic ozonation process (COP) with magnetic carbonaceous nanocomposite, as a novel catalyst, on dye degradation and mineralization of molasses were investigated and the results were compared with those obtained from single ozonation process (SOP) and granular activated carbon (GAC) catalyst. For this purpose, the nanocomposite synthesized with co-precipitation method and applied with ozonation in COP. Then the influential parameters such as pH, catalyst dosage and synergistic effect were all evaluated. The residual dye concentration, chemical oxygen demand (COD) and total organic carbon (TOC) were analyzed using american dye manufactures institute, acid digestion, and total organic carbon analyzing methods, respectively. The results showed that the degradation efficiency of dye, COD and TOC in COP was 95, 51 and 74%, respectively, and the highest efficiency of the nanocomposite was achieved at optimal pH of 8. However the results of dye removal in COP (95%) were higher than SOP (71%) and GAC/ozonation (86%). Furthermore, this catalyst has synergistic property on dye decomposition, so that the greatest synergistic effect on the dye removal efficiency is 15% which occurred in the first 15 min, and the catalytic role of magnetic carbon is not affected by dye adsorption. This finding revealed that the applied approach is technically suitable for the effective degradation and mineralization of dye contaminant form molasses industrial wastewaters.

Mass transfer kinetics and quality attributes of osmo-dehydrated candied pumpkins using nutritious sweeteners.

The aim of this study was to investigate the mass transfer and quality properties changes during the osmotic dehydration (OD) step of the candying process in pumpkins. The goal was to obtain nutritious, low calorie candied pumpkins improving the time-consuming and inconsistent traditional technique. The osmotic agents were sucrose, oligofructose and mixture of sucrose-oligofructose (1:1), while the concentration of each solution was constant (70° Brix). The process temperature varied in three levels (75, 85 and 95°C) and the duration was 180min for sucrose and 240min for the other osmotic agents. The determined parameters during OD include solid gain, water loss, water activity, chroma, hardness and compression work. An empirical model based on a first-order kinetic equation was developed to predict the products' properties, in which the rate constant is a function of the process temperature. The process temperature (Tosm ) had a significant effect on the water loss and solid gain as well as on the physiochemical characteristics of processed pumpkins. The chroma of osmo-dehydrated pumpkins was affected significantly by process parameters. Both hardness and compression work decreased until an equilibrium value was reached as time and temperature of the process increased, regardless the osmotic agent used.

Food selection and predation risk in the Andean white-eared opossum (Didelphis pernigra Allen, 1900) in a suburban area of Bogotá, Colombia

Urbanization is spreading throughout the Andes, and despite it there is still wildlife which survives in these novel environments throughout Colombia and elsewhere. The Andean white-eared opossum (Didelphis pernigra Allen, 1900) can tolerate moderate levels of urbanization in the Andes highlands, and we evaluated its food selection based on optimal patch use theory using foraging stations to measure giving-up densities in a suburban area in Bogotá (∼2600m a.s.l.). We offered the opossums equicaloric mixtures of protein-rich and sucrose-rich foods, and they preferred the sucrose mixture. However, the magnitude of this preference was influenced by temporal and spatial effects. We suggest that in environments such as the high Andes, where air temperature regularly drops below 10°C, the opossums prefer foods that provide energy easily. We also assessed the opossums’ perceived risk of predation when domestic dogs (Canis lupus familiaris) are present by sprinkling dog urine in cotton swabs next to foraging stations; we expected opossums to forage more when the predator’s signal was not present. Dog urine indicated a risk for opossum’s at only one of six foraging stations, suggesting a weak predator’s signal effect that depends on location. Both food preferences and perception of risk by the opossum were affected by the spatial heterogeneity of the urban environment. Thus, microhabitat management at the study site, which is part of a recently created reserve to preserve Bogotá’s natural capital, appears to be key to conserve the opossums and their ecological functions in highly disturbed areas of the Andes.