Effects of the Incorporation of Male Honey Bees on Dough Properties and on Wheat Flour Bread's Quality Characteristics.

Two different levels (5 and 10%) of male honey bees (drones) in powder form were incorporated into wheat flour, and their impact on dough properties and on bread-quality characteristics were investigated. The incorporation of the drone powder to the wheat flour caused a decrease in the extensibility and energy of the dough in the extensograph and an increase in the dough's maximum resistance with increasing levels of the added drone powder. The elongational viscosity values of the dough fortified with drone powder were significantly higher than those of the control wheat flour dough. The breads supplemented with 10% drone powder exhibited lower lightness (L*) values compared to the control bread. The addition of drone powder led to an increase in the total dietary fiber content and insoluble dietary fiber content in the fortified bread. Significant differences in the specific volume values were observed between the control bread and the corresponding ones with 10% drone powder. Upon storage, the moisture content of the crumb of the control bread and of the fortified breads were both significantly decreased, while the addition of the drone powder to the wheat flour bread increased the crumb hardness and gumminess but decreased the cohesiveness of the breads.

Effect of caseinate salt addition on the structural characteristics of kefiran systems.

Sodium caseinates-kefiran systems were studied to explore whether any potential interactions between them might exist. The study was performed using low-deformation rheological techniques, which were dynamic and creep tests. The systems were prepared under various experimental conditions such as heating and acidification. Besides, the structure development of the systems in relation to time was also monitored using oscillatory shear rheometry. The results indicated that the structural characteristics of the systems were mainly affected by the state of the caseinates such as the formation of aggregates and to a lesser degree by the interactions of kefiran molecules with the caseinates. Freeze-thaw treatment produced cryogels with good thermal stability and fairly satisfactory mechanical properties. The morphology of the caseinate-kefiran systems was also investigated by means of confocal laser scanning microscopy.

Characterization and properties of non-granular thermoplastic starch-Clay biocomposite films.

Biocomposite films were prepared using as raw materials non-granular normal maize starch plasticized with glycerol and Na-montmorillonite clay particles in various concentrations. The physicochemical properties of films were studied, and their structure and morphology were investigated using XRD analysis, Thermal analysis, Scanning Electron Microscopy combined with Element Microanalysis. The mechanical characteristics were investigated through tensile test. The results indicated that the presence of clay particles in the starch matrix reduced the water absorption rate of films in comparison to starch films containing glycerol but not clay particles. The biocomposite films exhibited enhanced tensile properties at low glycerol and high clay contents. Best results were obtained for films containing 20 wt% glycerol and 10-20 wt% clay content. It is suggested that the non-granular maize starch, is a suitable raw material for the preparation of biocomposite films with improved structural and mechanical characteristics in comparison to films prepared using granular starch.

Dynamic light scattering and electrophoretic mobility studies of starch-fatty acid complexes in solution.

Electrophoretic mobility and dynamic light scattering measurements were carried out to investigate the physical characteristics of amylose inclusion complexes with a series of long chain fatty acids, in alkaline solution (0.1 N or 0.01 N KOH). Amylose molecules exhibited lower values of electrophoretic mobility compared to those of the amylose-fatty acid complexes. The presence of amylopectin affected the electrophoretic mobility of starch-fatty acid complexes. Particle size distribution measurements of amylose-fatty acid complexes in aqueous suspension (pH 4.6) were performed employing the laser light scattering technique. The size of the diameter of the complexes in alkaline solution was found to be much smaller than that of the size of the complexes in aqueous suspension. The results are discussed in the light of solvent contribution to the conformational changes of the complexes occurred in the environments employed.

Morphological characteristics, oxidative stability and enzymic hydrolysis of amylose-fatty acid complexes.

Complexes of amylose with fatty acids varying in carbon chain length and degree of unsaturation were prepared at 30, 50 or 70°C by dissolving amylose in 0.1N KOH and mixing with fatty acid potassium soap solution. The complexes were obtained in solid form as precipitates after neutralization. SEM microscopy revealed that the morphology of the complexes was that of ordered lamellae separated from amorphous regions whereas confocal laser scanning microscopy showed images of the topography of the guest molecules in the complex matrix. FTIR spectroscopy revealed that the absorption peak attributed to carbonyl group of free fatty acid was shifted when the fatty acid was in the form of amylose complex. Thermo-gravimetry showed that the unsaturated fatty acids were effectively protected from oxidation when they were complexed with amylose whereas enzymic hydrolysis experiments showed that the guest molecules were quantitatively released from the amylose complexes.

An investigation into the structure, morphology and thermal properties of amylomaize starch-fatty acid complexes prepared at different temperatures.

Amylomaize (Hylon VII) starch-fatty acid (capric, myristic, palmitic, stearic, oleic) complexes prepared at 30, 50 or 70°C were studied using XRD, DSC, SEM, TGA and FTIR techniques. XRD diffractograms displayed the typical V-form of complexed amylose regardless the temperature of preparing the complexes. The degree of crystallinity of the complexes increased while the size of the crystals formed decreased as the preparation temperature of the complexes increased. DSC thermograms showed that the dissociation temperature of the complexes was increased proportionally to the chain length increase of the fatty acid. TGA indicated that oleic acid was adequately protected in the form of complexes. SEM micrographs showed the presence of crystals of the complexes either in the form of spherulites or in the form of lamellae. Enzymatic hydrolysis of the complexes led to quantitative recovery of the guest molecules. Hylon VII proved to be a suitable prospective complexing agent for the production of complexes of lipids.

Amylose-fatty acid inclusion complexes as examined by interfacial tension measurements.

Amylose forms complexes with fatty acids under certain conditions, these complexes affect the functional properties of foods and could be potentially used as delivery systems of essential fatty acids in the human organism. This work uses dynamic and equilibrium interfacial tension measurements in order to investigate these complexes. First, the interfacial tension at the water/air interface under the conditions of complex formation (KOH 0.1N, pH=12.7) was measured for three fatty acids (capric, myristic and oleic) at different concentrations. Then, amylose-fatty acid complexes were formed at three different fatty acid to amylose ratios covering a range above and below the saturation concentration of the amylose helix. For all examined systems the dynamic interfacial tension of the mixed amylose-fatty acid solution was significantly higher than this of the fatty acid solution, showing that some of the fatty acid was no longer available to adsorb at the interface and suggesting its inclusion in the complex. Besides, the dynamic interfacial tension of the mixed system was lower compared to the pure amylose solution indicating that some of the fatty acid did not participate in the complexes even at fatty acid/amylose ratios well below the saturation concentration of amylose. Using the isotherm of the three fatty acids it was shown that the fatty acid excess depended on fatty acid-to-amylose ratio.