Trehalose Addition Research Articles

Characterization of the Rate of Thermally-Induced Aggregation of β-Lactoglobulin and Its Trehalose Mixtures in the Glass State

The thermally induced aggregation of bovine β-lactoglobulin in the glass state was studied both as the pure protein and in trehalose mixtures. Calorimetric measurements and size exclusion chromatography were used to characterize the glass state and aggregation, respectively. The initial aggregation rate was characterized by the initial rate of tetramer formation (β-lactoglobulin dimerizes under the elution conditions), which showed Arrhenius temperature dependence with an activation energy of 95 kJ mol(-1) in the temperature range 60-100 °C. The trehalose addition slowed the aggregation in a way that depended exponentially on volume fraction, exp(-φ/φ*). The volume fraction characterizing the retardation of the reaction, φ*, was 0.173 of the order required to fill the interstices between close-packed protein molecules. In this system, trehalose was acting as an inert glass-forming diluent. In a general way, this supports the water substitute hypothesis and the understanding of the mechanisms underlying anhydrobiosis and protein stabilization technologies.

Trehalose protects wine yeast against oxidation under thermal stress

Accumulation of trehalose in yeasts has been suggested to be an important mechanism of tolerance against adverse stress conditions, particularly in thermal stress. However, under thermal stress, it is not clear if the mechanism of protection is related to its antioxidant role. In this study, a newly isolated wine yeast Saccharomyces cerevisia was used to examine the protective effect of trehalose against oxidation during thermal stress treatment. Cells were treated either with a mild heat treatment at 37°C (which leads to trehalose accumulation) or with a 50 mM trehalose solution and then exposed to a high temperature of 53°C. According to our results, mild heat treatment at 37°C and trehalose addition which promote accumulation of trehalose significantly increased cell survival upon exposure to thermal stress at 53°C which seems to be correlated with decrease in reactive oxygen species levels and lipid peroxidation. Trehalose could protect yeast from oxidative injuries under thermal stress.

Photocatalytic Activity of Porous TiO<sub>2</sub> Film Prepared by Dip-Coating Technique Using Sol Containing Trehalose

To obtain porous and thick TiO2 film, the precursor sol was prepared by hydrolysis of Ti isopropoxide and then complexed with trehalose dihydrate. The porous TiO2 film was fabricated by dip-coating technique on quartz glass substrates using this sol. The TiO2 films were calcined at 500-700 °C. The photocatalytic activity of the films was evaluated by examining decomposition of methylene blue in aqueous solution under UV light irradiation. The TiO2 film prepared from the sol with trehalose was more active than TiO2 film prepared from the sol without trehalose. The trehalose addition to the dip-coating solution was effective in improving the photocatalytic activity of the TiO2 film.

Influence Of Trehalose Addition On Instrumental Textural Properties Of Strawberry Pastes

Objective of this study was investigation of influence of trehalose addition (3, 5 and 10%) on instrumental textural properties of evaporated and freeze-dried strawberry pastes. As a control, strawberry paste without addition of trehalose was used. Addition of trehalose had influence on both, hardness and stickiness of the samples, but it is very important to define the amount of trehalose in order to achieve desirable properties. With addition of trehalose hardness of both, evaporated and freeze-dried samples decreased, from 29.89 N to 14.72 N for evaporated samples and from 184.83 N to 44.95 N in freeze-dried samples. Also, from those results it could be seen that freeze-dried samples were much harder than evaporated ones, regardless of trehalose addition. While hardness of samples decreased with addition of trehalose, stickiness increased. Stickiness values were from 0.016 N to 0.0102 N for evaporated samples, and from 0.066 N to 0.018 N for freeze-dried samples. Since evaporated samples had lower values for stickiness they were stickier than freeze-dried ones.

Influence of trehalose addition and storage conditions on the quality of strawberry cream filling

Strawberry cream fillings are usually produced commercially by evaporation. This process can cause degradation of colour and loss of some aroma compounds in the final product. In the present study, freeze-drying was used as an alternative to evaporation and the quality of the products obtained by the two processes were compared. In addition, the influence of trehalose, used at concentrations of 3%, 5% and 10% as a partial replacement of sucrose, on the quality of strawberry cream filling stored at room temperature over a period of 6 months was investigated. The control sample was taken to be a strawberry cream filling prepared by evaporation and without the addition of trehalose. Both, colour and aroma of samples were significantly influenced by trehalose addition. The anthocyanin content of the cream fillings increased proportionally with trehalose addition, but this was not the case with fruity esters. Freeze-dried samples exhibited better colour and higher anthocyanin content, as well as higher content of fruity esters in comparison with the samples produced by evaporation. In addition, strawberry cream fillings were packed in air and nitrogen atmosphere, and stored for 5 months at room temperature. Trehalose addition and packaging atmosphere also influenced colour, aroma and texture.

Influence of Calcination Temperature on the Microstructure of Porous TiO2 Film

To obtain porous TiO2 film, the precursor sol was prepared by hydrolysis of Ti isopropoxide and then complexed with trehalose dihydrate. The porous TiO2 film was fabricated by dip-coating technique on glass substrates using this solution. The TiO2 film was calcined at 500 °C. The maximum thickness of the film by one–run dip-coating was ca. 740 nm. The film was composed of nanosized particle and pore. The porosity of the TiO2 film was increased by the addition of trehalose dihydrate to the sol. The porous TiO2 films were calcined at various temperatures. The effects of the calcination temperature on the microstructure of the porous TiO2 film were investigated. The porous film prepared from sol containing trehalose still kept the porous structure for calcination at 950 °C. The phase transition temperature from anatase to rutile of the film was shifted from 650 to 700 °C by trehalose addition to the sol.

Aroma of dehydrated pear products

Pear purees and cubes were dehydrated with sugars (sucrose and trehalose) addition. Freeze drying and foam-mat drying were used. Manual solid-phase microextraction (SPME) coupled with gas chromatography (GC–flame ionization detector (FID) and GC–MS) was applied to determine the changes in retention of aroma compounds in dehydrated pear purees and cubes. The best retention of aroma compounds in dehydrated pear purees was noticed in the case when freeze drying and trehalose addition were combined. In dehydrated pear cubes, previously dipped in trehalose solution, the highest aroma retention was also determined. This study showed possible application of trehalose as potentially beneficial food ingredient, with the aim to improve the quality of dehydrated fruit products, especially their aroma, and to produce superior dried fruit products or ingredients, which are widely used in food formulation.

Effects of sugars and sugar alcohols on thermal transition and cold stability of corn starch gel

Various sugars and sugar alcohols (ribose, xylose, glucose, fructose, mannose, sucrose, maltose, isomaltose, trehalose, xylitol, mannitol, and sorbitol) were compared in their effects on thermal transitions and cold-storage stability of a corn starch–sugar gel (40% starch, starch:sugar=10:1 or 10:3 dry solids basis) using a differential scanning calorimetry. As the molar concentration of sugar increased, the onset temperature and enthalpy for starch melting were increased. Among the sugars, the samples with disaccharides exhibited higher onset temperature and enthalpy than those with monosaccharides at the same molar concentration. Under cold storage (4 or −20 °C), the sugars facilitated amylopectin recrystallization. Fructose and isomaltose produced higher degrees of amylopectin recrystallization than did other sugars. Sugar alcohols produced slightly greater recrystallization than did the corresponding sugars. Ice melting temperature and glass transition temperature ( T′ g) of the freeze-concentrated phase were decreased as the molar concentration of sugars increased, and there was no or little dependence on the chemical structure of sugars. Ice melting enthalpy for the gels showed no clear dependence on sugar concentration or structure. Sucrose addition lowered the ice melting enthalpy (ice formation by rapid freezing), whereas isomaltose or trehalose addition raised it. By cold storage, the T′ g of the starch gels was increased, whereas the ice melting enthalpy was decreased, as a result of water consumption for starch recrystallization. In the gel system (40% starch), sugar addition (10 or 30% based on starch) enhanced starch recrystallization, but decreased the ice melting and glass transition temperatures.

Formulation of aqueous concentrated alumina suspensions. Influence of a disaccharide: trehalose

AbstractTrehalose, a disaccharide, is very well known to protect living cells efficiently from dehydration and has been tested in the formulation of aqueous alumina suspensions. It has been added into slurries stabilized with Tiron®, (HO)2C6H2(SO3Na)2, which permits a high state of dispersion by creating repulsive potential between particles. Trehalose added into such suspensions acts as a lubricant and enhances flowing properties of suspensions because of its strong interaction with water which breaks the hydrogen‐bonded network of the solvent. Trehalose addition is beneficial for carrying out shaping methods of alumina components by coagulation as it increases solid concentration in the suspension, which facilitates pouring the suspension into a mould. Unfortunately this addition hinders coagulation of particles.© 2003 Society of Chemical Industry

Effect of Added Carbohydrates on Membrane Phase Behavior and Survival of DriedLactobacillus plantarum

The relation between the protective effect of externally added carbohydrates onLactobacillus plantarumcells during air-drying and the phase behavior of cell membranes was studied. The residual activity after drying could be improved from 44% in the control to 79 and 66% after the addition of sorbitol and maltose, respectively, whereas trehalose addition resulted in a residual activity of 30%. Membrane phase transition temperatures (Tm) were determined in intact hydrated and dry cells, using Fourier transform infrared spectroscopy. TheTmof hydrated cells was 4°C, increasing to only 20°C after drying. Because endogenous soluble sugars were absent, this phase behavior is attributed to the structure of the predominant phospholipids, PG and lysyl-PG. The restricted increase ofTmis held responsible for the survival of part of the cells. The added maltose, trehalose, and sorbitol did not influenceTmin vivo.We suggest that the effective carbohydrates act through their free radical scavenging activity and not by direct interaction with the polar lipid headgroups.

Transport protein synthesis in non-growing yeast cells

Addition of a metabolizable substrate (glucose, ethanol and, to a degree, trehalose) to non-growing baker's yeast cells causes a boost of protein synthesis, reaching maximum rate 20 min after addition of glucose and 40–50 min after ethanol or trehalose addition. The synthesis involves that of transport proteins for various solutes which appear in the following sequence: H +, l-proline, sulfate, l-leucine, phosphate, α-methyl- d-glucoside, 2-aminoisobutyrate. With the exception of the phosphate transport system, the K t of the synthesized systems is the same as before stimulation. Glucose is usually the best stimulant, but ethanol matches it in the case of sulfate and exceeds it in the case of proline. This may be connected with ethanol's stimulating the synthesis of transport proteins both in mitochondria and in the cytosol while glucose acts on cytosolic synthesis alone. The stimulation is often repressed by ammonium ions (leucine, proline, sulfate, H +), by antimycin (proline, trehalose, sulfate, H +), by iodoacetamide (all systems tested), and by anaerobic preincubation (leucine, proline, trehalose, sulfate). It is practically absent in a respiration-deficient petite mutant, only little depressed in the op 1 mutant lacking ADP/ATP exchange in mitochondria, but totally suppressed (with the exception of transport of phosphate) in a low-phosphorus strain. The addition of glucose causes a drop in intracellular inorganic monophosphate by 30%, diphosphate by 45%, ATP by 70%, in total amino acids by nearly 50%, in transmembrane potential (absolute value) by about 50%, an increase of high-molecular-weight polyphosphate by 65%, of total cAMP by more than 100%, in the endogenous respiration rate by more than 100%, and a change of intracellular pH from 6.80 to 7.05. Ethanol caused practically no change in ATP, total amino acids, endogenous respiration, intracellular pH or transmembrane potential; a slight decrease in inorganic monophosphate and diphosphate and a sizeable increase in high-molecular-weight polyphosphate. The synthesis of the various transport proteins thus appears to draw its energy from different sources and with different susceptibility to inhibitors. It is much more stimulated in facultatively aerobic species ( Saccharomyces cerevisiae, Endomyces magnusii) than in strictly aerobic ones ( Rhodotorula glutinis, Candida parapsilosis) where an inhibition of transport activity is often observed after preincubation with metabolizable substrates.