Search results for "sucrose"

Structure−Dynamics Coupling between Protein and External Matrix in Sucrose-Coated and in Trehalose-Coated MbCO:  An FTIR Study

2004

We performed FTIR measurements on carboxy-myoglobin (MbCO) embedded in a sucrose−water matrix to study the degrees of freedom coupling between protein and external matrix in such a system. The work was undertaken on the light of recent results by Giuffrida et al. (J. Phys. Chem. B 2003, 107, 13211−13217), who evidenced, in trehalose-coated MbCO, a structured water−sugar environment of the protein, tightly coupled to the heme pocket structure. Such information was obtained through a suitable analysis of the temperature dependence of the CO stretching and of the water association bands in samples of different content of residual water. We applied here the same analysis to sucrose-coated MbCO.…

Influence of the storage conditions on some physicochemical and mycological parameters of honey

1994

The authors studied the changes in yeast and mould counts, pH, free and lactone acidity, colour and sugar composition undergone by honeys with water contents of 169, 188 and 220 g kg-1 on storage at refrigeration temperature (4–7°C), room temperature and 28°C for two years. Of the solid culture media assayed, honey agar and osmophilic medium fostered yeast growth while malt-extract agar and yeast-extract-malt-extract agar allowed for better development of filamentous fungi. The yeasts isolated belonged to the genera Saccharomyces, Schizosaccharomyces and Zygosaccharomyces, while filamentous moulds were of the genera Aspergillus, Penicillium, Fusarium and Alternaria. The honeys studied under…

Cultivation ofZymomonas mobilis 113 S at Different Mixing Regimes and their Influence on the Levan Formation

2001

The Zymomonas mobilis I 13 S strain was cultivated in a bioreactor with a working volume of 1.4 I at different stirring regimes in a 15% initial sucrose medium The levan obtained in the fermentation process was analyzed by gel filtration. Because the sucrose/biomass ratio in the fermentation broth decreased to below 300 g/g, the insufficient concentration of sucrose might have decreased the concentration of levan. Besides the growth characteristics of the population, the mixing intensity and flow structure were also found to influence the molecular mass of levan. At 600 rpm, the microorganisms produced levan with a molecular mass lower than at 300 rpm. The stirring of a fermentation broth w…

Carbohydrate Metabolism and Source-Sink Relationships in Peach

2011

A growing plant can be viewed as a collection of carbohydrate sinks competing with each other for the available photosynthate supplied by the exporting leaves. Differences in sink strength often result in changes in the ability of various organs to compete for the available food determining final tree growth. A series of experiments have been conducted in peach to study changes and regulation of carbohydrate metabolism in growing organs and get a better understanding of the link between carbohydrate metabolism, sink strength, carbon partitioning and overall tree growth. Along with sucrose, sorbitol represents the major photosynthetic product and the main form of translocated carbon in peach…

Chemical Characteristics and Viability of Starter Cultures of Freeze–Dried Sweet Potato Extract–Supplemented Synbiotic Yogurt

2021

The research aimed to determine the sucrose concentration as a cryoprotectant to obtain the chemical properties and the viability of Lactic Acid Bacteria (LAB) and Lactobasillus plantarum in the synbiotic yogurt. It adopted a one–factor Completely Randomized Design (CRD) by including sucrose in concentrations from 0 %, 2.5 %, 5 % to 7.5 %, three replications. The results showed various sucrose concentrations significantly affected the yields of the purple sweet potato extract– supplemented synbiotic yogurt, reduction–sugar level, the total of LAB, and the total of L. plantarum before and after the freeze–drying process, no significant impact on the moisture content and total quantity of LAB…

Characterization of Sicilian Olive Genotypes by Multivariate Analysis of Leaf and Fruit Chemical and Morphological Properties

2013

Leaf and fruit size and shape were measured and mannitol, glucose, sucrose and malic acid were quantified in leaf, bark and fruit of 25 Sicilian olive genotypes. Multivariate analysis was used to individuate groups with similar chemical composition and morphological traits suggesting potential for stress tolerance and/or oil yield and quality. Mannitol content varied greatly among genotypes and was the most abundant carbohydrate in leaf and bark, whereas glucose was the most abundant in fruit. Sucrose and malic acid were generally low indicating a marginal role in olive tissues. Mannitol and glucose were directly related in both leaf and fruit tissues. Genotypes also differed for carbohydra…

Water Dynamics in Biological Systems investigated using Neutron Scattering Techniques

Living systems can not survive in absence of the water environments which play a fundamental role in living functions. Thus in the scienti?c community many studies were and are addressed to characterize water and its dynamics properties in biological systems. However, a clear description of water in such systems has been not reached yet. In fact, the investigations performed with di?erent techniques - those based on Nuclear Magnetic Resonance or those based on Neutron Scattering - look at di?erent di?usive motions and interactions water-biomolecules, leading controversial results and hence generating many debates between scientists. In this thesis we support the idea that two water populati…

MbCo in Saccharide Solid Amorphous Systems: A Combined FTIR and SAXS Study

2011

Saccharides, and in particular trehalose, are known for their efficiency in protecting biostructures against environmental stress [1], although the preservation mechanism is still debated. Experiments and simulations [2,3] on carboxy-myoglobin (MbCO) showed that the protein dynamics is highly inhibited in dry trehalose matrices, the inhibition being dependent on the water content. In these conditions, a mutual protein-matrix structural and dynamic influence is observed.Here we report a combined FTIR and SAXS study on MbCO embedded in dry amorphous matrices of trehalose and sucrose. FTIR measurements were performed at different protein/sugar ratios, focussing on the stretching band of the bo…