Concentrated Sugar Solutions Research Articles

Calculation of the partial specific volumes of proteins in concentrated salt, sugar, and amino acid solutions.

A method for calculating the isopotential partial specific volumes of proteins in concentrated salt, sugar, and amino acid solutions has been developed. It is based on the finding that the preferential hydration of the protein in these solutions is relatively independent of the concentration of the additive and is proportional to the specific surface area of the proteins, i.e., to the ratio of the total accessible surface area to molecular weight. Agreement between the calculated and experimental values was satisfactory, indicating the reliability of the proposed method. These calculations show that the isopotential partial specific volume increases greatly with the concentration of the additive, in particular in the case of Na2SO4, (NH4)2SO4 and sucrose, and for smaller proteins.

Sorbic acid diffusivity in relation to the composition of high and intermediate moisture model gels and foods

The diffusivity at infinite diffusant dilution (D0) of sorbic acid in high and intermediate moisture gels (with various substrates and water contents) and in three foods was evaluated. The determination of D0(25°C) was achieved by tridimensional diffusion in gels cubes or by monodimensional diffusion in infinite food columns. For the same substrate concentration by weight, D0 values of sorbic acid in concentrated sugar solutions decreased slightly when the molecular weight of the sugar was increased. When a liquid substrate such as glycerol was used, D0 values referred to equal concentrations by weight, were higher than in sugar solutions. The diffusion of sorbic acid is related, as a first approximation, to the water content rather than to the water activity of the diffusion medium.

Stability of Sorbic Acid in Model Food Systems of Reduced Water Activity: Sugar Solutions

ABSTRACTThe behavior of sorbic acid in model systems comprised of concentrated sugar solutions (water activity 0.94) at pH 3.5 and 4.5 was studied. Sorbic acid degraded appreciably as a function of time and temperature during storage and its destruction could be described by first‐order kinetics. The rate constants of sorbic acid destruction were found to be related to composition of the sugar model system. Non‐enzymatic browning reactions which occur in systems containing lysine greatly influenced the kinetics of sorbic acid destruction.

A kinetic study of Saccharomyces strains: Performance at high sugar concentrations

Alcoholic fermentation represents a significant example of production of compounds utilizable as alternative energy sources. High ethanol concentration in the fermented wort is needed in order to reduce the energy consumption in the process of alcohol recovery. A particular Saccharomyces strain, of the oviformis species, obtained from fermented worts exhibiting high ethanol concentrations is studied and compared with a common S. cerevisiae strain in order to show its skill in fermenting very concentrated sugar solutions with an energy saving of ca. 10%.

Contact chemoreception by the propodium of the sandy beach whelk Bullia digitalis (Gastropoda: Nassariidae)

1. 1. The leading edge (propodium) of the foot of Bullia is shown to be active in contact chemoreception, food extracts applied directly to the epithelial surface stimulating eversion of the proboscis. 2. 2. A number of amino acids are also effective in evoking this response, while trimethylamine, to which the osphradium is sensitive, is not. Concentrated sugar solutions evoke some response but are probably unimportant under field conditions. 3. 3. None of the above solutions applied to the metapodium, anal cirri or cephalic shield produces a positive response.

In vitro study of bacterial growth inhibition in concentrated sugar solutions: microbiological basis for the use of sugar in treating infected wounds.

The use of sugar for the treatment of infected wounds was investigated in in vitro experiments with bacteria pathogenic to humans, such as Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, and Staphylococcus aureus. Studies showed that solutions of appropriate sugar concentration incubated at pH 7.0 and 35 degrees C were lethal to the bacterial species studied. On the basis of these results, it is proposed that an important function of sugar in the treatment of infected wounds is to create an environment of low water activity (aw), which inhibits or stresses bacterial growth.

Aspects of the Water, Electrolyte and Carbohydrate Physiology of the Silvereye, Zosterops Lateralis (Aves).

Total body water content (TBW) and TBW turnover were measured by means of tritiated water (HTO) in free-ranging populations of silvereyes, Zosterops lateralis, near Margaret River, W.A. Birds were studied in their natural habitats during spring and summer, and compared with a vineyard population in summer. In the natural habitat TBW content was found to be 77.6% in spring, which was not significantly different from that measured in summer (78.3%). Birds in vineyards in summer, however, were dehydrated, with a TBW content of 69.4%. Calculated rates of water influx for spring, summer and summer vineyards birds were 1.44,2.20 and 0.65 ml g.day-' respectively. These water turnover rates are much higher than those of any other bird yet studied. Dehydration was marked in the vineyard birds, with a significantly lower TBW content and an average net water loss of 0.63 ml day-'. Laboratory studies showed that silvereyes have a low tolerance to sodium loading. Their tolerance is, however, quite adequate for them to drink the most concentrated free water available to them in the field. Ingestion of concentrated sugar solutions of up to 25% did not provoke an osmotic diuresis and thus cannot account for the dehydration and negative water balance of vineyard birds.

Volumetric interpretation of viscosity for concentrated and dilute sugar solutions

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTVolumetric interpretation of viscosity for concentrated and dilute sugar solutionsTonny Soesanto and Michael C. WilliamsCite this: J. Phys. Chem. 1981, 85, 22, 3338–3341Publication Date (Print):October 1, 1981Publication History Published online1 May 2002Published inissue 1 October 1981https://doi.org/10.1021/j150622a026RIGHTS & PERMISSIONSArticle Views952Altmetric-Citations129LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (530 KB) Get e-Alerts

Species Composition and Diversity of Macroinvertebrates in Two Playa Lakes on the Southern High Plains, Texas

Species Composition and Diversity of Macroinvertebrates in Two Playa Lakes on the Southern High Plains, Texas

Release of Feeding by the Sweet Taste in Rats: The Influence of Body Weight

Rats that are not deprived of water, or that are overhydrated artificially, drink sweet solutions with avidity. We show that intake of sweet solutions is sensitive to nutritional status, suggesting that the rats are treating the solutions as liquid diets and “eating” rather than drinking them. First, when rats are force-fed to mild obesity, intake of dilute and concentrated saccharin and carbohydrate solutions is progressively reduced. Secondly, when weight loss is forced by restricted feeding, intake of saccharin and dilute carbohydrate is elevated, but intake of concentrated carbohydrate solutions is not. Perhaps the postingestive effects of concentrated sugar solutions set a limit on ingestion, so that intake can be driven below that limit as weight is gained, but cannot rise above it as weight is lost.

Use Of Honey-Sac Load and Dance Characteristics of Worker Honeybees to Determine Their Sugar Preferences

SummaryFrequency of dancing by returning honeybees (Apis mellifera) was shown to be positively correlated with concentration of sugar solution they had collected. Also, sucrose resulted in more dances than fructose, which in turn led to more dances than glucose.Amounts of these three sugars collected, when offered alone and in various combinations, showed sucrose to be the most acceptable sugar and glucose to be generally the least acceptable. However, at concentrations of 40% and 50% bees collected larger loads of glucose than of fructose. Mixtures of equal parts sucrose, glucose and fructose were collected in loads not significantly different in volume from other mixtures of these sugars.

Plasma corticosterone elevations in rats in response to consumption of concentrated sugar solutions.

The results of three experiments indicated that male hooded rats exhibit marked corticosterone elevations when they freely consume .740 mol/l (23.2% w/w) sucrose in tap water while nondeprived or .298 mol/l (9.8% w/w) sucrose when deprived of water for 36 hr. The magnitude of the corticosterone elevation was increased by lengthening the duration of prior water deprivation (2, 24, or 48 hr) and by raising the sucrose solution concentration (.189, .298, or .470 mol/l). Free ingestion of tap water following sucrose consumption accelerated the decline from peak level of corticosterone during the period 60-120 min following the onset of sucrose consumption. Glucose (.470 or 1.166 mol/l) consumption by 36-hr water-deprived rats also elevated corticosterone levels, but less effectively than equimolar sucrose. These data suggest strongly that the pituitary-adrenal system is activated by rapid, acute dehydration. The effect is surprising, considering the minimal effects of water deprivation per se on corticosterone levels and the interpretation of increased pituitary-adrenal activity as a sign of psychological stress.

Osmotic Stress and the Hatching of Globodera Rostochiensis

When hatched juveniles are transferred from distilled water to 0.4 M sucrose or trehalose solutions their water content falls from 72% to 67%, the value observed for unhatched juveniles in eggs equilibrated with water. Juveniles move little after 6 hr immersion in 0.4 M or more concentrated sugar solutions, but dilution with water to give a sugar concentration 0.1 M restores many to active movement. Few juveniles emerge from cysts in solutions of potato-root diffusate or of an artificial hatching agent (0.4 mM picrolonic acid) which contain sucrose at concentrations 0.4 M. The evidence suggests that loss of solutes from the egg fluid permits hatching and supports the belief that changes in permeability of the egg shell precede other steps in the hatching process. Prolonged storage of second-stage juveniles is possible in 0.4 M solutions of sugars.

Rapid ethanol fermentations using vacuum and cell recycle

AbstractCell recycle and vacuum fermentation systems were developed for continuous ethanol production. Cell recycle was employed in both atmospheric pressure and vacuum fermentations to achieve high cell densities and rapid ethanol fermentation rates. Studies were conducted with Saccharomyces cerevisiae (ATCC No. 4126) at a fermentation temperature of 35°C. Employing a 10% glucose feed, a cell density of 50 g dry wt/liter was obtained in atmospheric‐cell recycle fermentations which produced a fermentor ethanol productivity of 29.0 g/liter‐hr. The vacuum fermentor eliminated ethanol inhibition by boiling away ethanol from the fermenting beer as it was formed. This permitted the rapid and complete fermentation of concentrated sugar solutions. At a total pressure of 50 mmHg and using a 33.4% glucose feed, ethanol productivities of 82 and 40 g/liter‐hr were achieved with the vacuum system with and without cell recycle, respectively. Fermentor ethanol productivities were thus increased as much as twelvefold over conventional continuous fermentations. In order to maintain a viable yeast culture in the vacuum fermentor, a bleed of fermented broth had to be continuously withdrawn to remove nonvolatile compounds. It was also necessary to sparge the vacuum fermentor with pure oxygen to satisfy the trace oxygen requirement of the fermenting yeast.

Incomplete taste adaptation to different concentrations of salt and sugar solutions

Two concentrations each of sodium chloride and sucrose solutions were used as stimuli in a study examining taste adaptation. Twenty subjects were presented a 3-min continuous flow of each taste stimulus over the anterior dorsal tongue surface, and periodically gave magnitude estimates of its intensity. The degree of adaptation was greater for the less concentrated solutions than for the more concentrated ones, but the majority of subjects did not adapt completely to any of the stimuli. This result, which is consistent with other reports from this laboratory, is discussed in terms of individual differences among subjects and in relation to recent taste research based on completely adapted subjects.

Membrane location of a deoxyribonuclease implicated in the genetic transformation of Diplococcus pneumoniae

The cellular localization of enzymes in Diplococcus pneumoniae was examined by fractionation of spheroplasts. A deoxyribonuclease implicated in the entry of deoxyribonucleic acid (DNA) into the cell during genetic transformation was located in the cell membrane. This enzyme, the major endonuclease of the cell (endonuclease I), which is necessary for the conversion of donor DNA to single strands inside the cell and oligonucleotides outside, thus could act at the cell surface. Another enzyme, the cell wall lysin (autolysin), was also found in the membrane fraction. Other enzymes, including amylomaltase, two exonucleases, and adenosine triphosphate-dependent deoxyribonuclease, and a restriction type endonuclease, were located in the cytosol within the cell. None of the enzymes examined were predominantly periplasmic in location. Spheroplasts were obtained spontaneously on incubation of pneumococcal cells in concentrated sugar solutions. The autolytic enzyme appears to be involved in this process. Cells that were physiologically competent to take up DNA formed osmotically sensitive spheroplasts two to three times faster than cells that were not in the competent state. Although some genetically incompetent mutants also formed spheroplasts more slowly, other such mutants formed them at the faster rate.

Kinetics of ice crystallization in sugar solutions and fruit juices

AbstractIce‐crystal secondary nucleation kinetics are derived from thermal response experiments carried out with concentrated sugar solutions and fruit juices. Variables studied include the level of supersaturation, power input, sugar concentration, sugar type, and the presence of high‐molecular‐weight additives. The nucleation rate is indicated to have a low‐order dependence upon subcooling (about 1.25 power) for subcoolings in the range 0.25 to 1.00°C. Fruit juices are well modeled by the corresponding synthetic sugar solution. The selection and improvement of processing approaches for freeze concentration of food liquids are discussed in light of the experimental results.

Sugar-feeding behavior of Lutzomyia trapidoi (Diptera: Psychodidae) under experimental conditions.

Phlebotomine sandflies, like many other hematophagous Diptera, require a source of carbohydrate for sustenance. This paper is an attempt to establish useful criteria for sugar feeding of these flies. Utilizing the Panamanian Lutzomyia Trapidoi (Fairchild & Hertig), a number of parameters associated with experimental feeding were investigated. Of 11 sugars tested, 5 were preferred: sucrose, fructose, maltose, raffinose and glucose. These 5 sugars are primary constituents of nectar, probably the most important energy source in nature for hematophagous flies. Honey was less acceptable than fructose or corn syrup (Karo). Rate of sugar acceptance was unaffected by concentration, pH, NaCI content, color of the solution or temperature. Concentration of sugar solution had no appreciable effect on fly longevity. Higher feeding rates were obtained utilizing a new holding vessel (styrofoam cup).

Fermentation of Cane Molasses by Yeasts after Preservation under Conditions of High Sugar Concentration

Summary: Fermentations of cane molasses solutions by sugar‐tolerant flocculating strains of Saccharomyces cerevisiae Sa. 28 and Sacch. carlsbergensis Sa. 23, produced compact sediments from which supernatant liquid could be decanted easily. Immediate treatment of the residual yeast with molasses containing 70·2% w/v total sugars (64° Brix) at 20°, engendered viabilities of 21·9–58% and 0·043–0·25% after 3 and 100 days, respectively. Dilution of the molasses caused culture recovery with fermentation, the initial rate of which could be correlated with the % viability of the yeast culture. The technique of preserving yeast cultures by use of concentrated sugar solutions warrants further investigation and could perhaps find application in distillery practice.

Some factors contributing to the survival of rapidly cooled plant cells

The stability of innocuous intracellularly frozen cells was found to be influenced remarkably by the surrounding solutions and the degree of prefreezing. In the cells suspended in isotonic or slightly hypertonic glucose solution, innocuous intracellular freezing readily occurred and these rapidly frozen cells remained stable even at −30 °C for 20 min, while cells prefrozen to −10 °C after suspending in water survived standing at −30 °C only for 5 sec at most. These facts suggest that when the innocuous intracellularly frozen cells are surrounded with concentrated sugar solutions, these cells remain far more stable than those surrounded with ice. When winter hardy cortical cells suspended in water were rapidly cooled, they were killed as a result of prompt formation of intracellular ice crystals immediately after the beginning of freezing of suspending medium. In less hardy cells which resisted freezing to only −10 °C, the innocuous intracellular freezing seldom occurred, even when cooled and rewarmed ultrarapidly without suspending with water, since these less hardy cells were quite apt to cause fatal intracellular freezing during rapid cooling. However, in less hardy cells and winter hardy cortical cells suspended with water, innocuous intracellular freezing by rapid cooling could be readily induced, provided that they were prefrozen to the temperatures below −5 °C or suspended in isotonic or slightly hypertonic solutions of glucose and the related compounds, DMSO, etc., individually or in combinations depending upon the degree of freezing resistance of the samples.