No abstract

No abstract

The isothermal melt crystallization of poly(trimethylene terephthalate) (PTT) has been investigated using differential scanning calorimetry (DSC), optical microscopy, and Fourier transform infrared (FTIR) spectroscopy. Triple-melting endotherms were dominant at crystallization temperatures (T(c)) below 195 °C, while double-melting endotherms were dominant at T(c) above 195 °C. These multiple-melting behaviors were attributed to melting and recrystallization as well as thermal stability of the crystallites. The difference in crystallinity observed between melt-crystallized PTT films before and after cooling to room temperature was attributed to lamellar thickening. The kinetics of isothermal melt crystallization of PTT was analyzed using an Avrami equation, and the rate constant (k) and t(1/2) increased with increasing T(c). An Avrami exponent n = 2-3 was obtained for the PTT melt crystallized from 150 to 205 °C, suggesting two-dimensional to three-dimensional growth with heterogeneous nucleation and was confirmed by polarized optical microscopy. The bands at 1358 and 976 cm(-1) associated with gauche and trans conformations of -OCH(2)CH(2)CH(2)O- were used to determine gauche and trans conformations assuming a two-phase conformational model. The crystalline and the amorphous gauche conformations were separated by combining them with DSC crystallinity. It was shown that the crystalline gauche conformation increased at the expense of the amorphous trans conformation. No significant change in the amorphous gauche conformation was found. On the other hand, the crystalline and amorphous gauche conformations were found to increase with the annealing temperature (T(a)) at the expense of the trans conformations during the annealing of PTT. The difference between melt crystallization and annealing was also discussed.

This study aimed to evaluate the influence of sourdough fermentation on the estimated glycemic index (eGI), in vitro starch digestibility, and textural and sensory properties of eight experimentally prepared sourdough breads. Wheat and whole wheat flour bread samples were produced under different fermentation conditions (25 °C and 30 °C) and fermentation methods (type-1 and type-2). In type-1 fermentation, sourdough was obtained via spontaneous fermentation. Indigenous strains (Lactobacillus brevis ELB99, Lactiplantibacillus plantarum ELB75, and Saccharomyces cerevisiae TGM55) were used for type-2 fermentation. Fermentation type and temperature significantly affected eGI, the hydrolysis index (HI), the starch fraction, and the textural properties of the samples (p < 0.05). The resistant starch (RS) content increased after fermentation, while rapidly digestible starch (RDS), HI, and eGI decreased. RS values were significantly higher in type-2 than in type-1 at the same temperature for both flour types (p < 0.05). At 25 °C, RS values were higher in both fermentation types. In the white flour samples, eGI values were in the range of 60.8–78.94 and 62.10–78.94 for type-1 and type-2, respectively. The effect of fermentation type on eGI was insignificant (p < 0.05). In the whole flour samples, fermentation type and temperature significantly affected eGI (p < 0.05). The greatest eGI decreases were in whole wheat sourdough bread at 30 °C using type-2 (29.74%). The 30 °C and type-2 samples showed lower hardness and higher specific volume. This study suggests that fermentation type and temperature could affect the eGI and the textural and sensory properties of sourdough bread, and these factors should be considered during bread production. The findings also support the consumption of wheat and whole wheat breads produced by type-2 fermentation due to higher RS and slowly digestible starch (SDS) and lower RDS and eGI values.

Dietary supplementation with hardaliye affect the MDA, DC and homocysteine levels in blood, possibly due to the presence of antioxidant compounds. Dose response was only observed for homocysteine. Further studies need to be performed to assess the effects on antioxidant capacity.

No abstract

Crystallization of poly(trimethylene terephthalate) (PTT) by annealing was examined using density measurement, differential scanning calorimetry, and far‐infrared spectroscopy (FIR). Crystallinity, measured by density, increased slowly up to the Ta of 185 °C and increases rapidly once Ta exceeds 185 °C. It was found that thermally induced crystallization is mainly temperature‐dependent above Ta = 185 °C and temperature‐ and time‐dependent below Ta = 60 °C. Two melting transitions, T and T, were observed for those samples annealed above 120 °C. No significant change in T was observed as a function of Ta while T showed strong dependency on Ta. Digital subtraction of the amorphous contribution from the semicrystalline FIR spectra provided characteristic spectra of amorphous and crystalline PTT. The bands at 373, 282, and 92 cm−1 were assigned to the crystalline phase, while the bands at 525, 406, and 351 cm−1 were attributed to the amorphous phase. It was shown that FIR spectroscopy can be used as a means to estimate the degree of crystallinity of PTT. The band ratio of 373 and 501 cm−1 was plotted against crystallinity measured by density and reasonably good correlation was obtained. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 1675–1682, 2007

The polyphenol content of propolis has received a lot of attention due to the benign biological properties noted in the chemical composition studies. However, there are very limited studies about other chemical components found in trace amounts in nature which contribute to the therapeutic properties of propolis. The present study, therefore, investigated the amino acid and vitamin composition of propolis. Propolis harvested by 60 colonies of Apis mellifera caucasica belonged to local non-migratory beekeepers. The A. m. caucasica is known for its distinctive propolis collecting capability which native to the secluded Ardahan Province of Turkey. Vitamin (Thiamine, Riboflavin) combinations of propolis were determined using the HPLC (High-Performance Liquid Chromatography) fluorescent detector. An amino acid analysis was also performed with the UFLC (Ultra-Fast Liquid Chromatography) system consisting of binary pump and UV/VIS. Our findings record that the vitamin and amino acid content of propolis samples collected from three areas of different altitudes in the same region differed from each other. Vitamin B1 content and Vitamin B2 content ranged between 0.025-0.16 mg/100g, and 0.304-0.777mg/100g, respectively. A maximum amount of amino acid was reported as leucine, while a minimum amount of amino acid was seen as tryptophan in Ardahan propolis. Consequently, the vitamin and amino acid content of propolis, which derived from secondary plant metabolites of resin, varied depending on their geographical altitudes. Those vitamin and amino acids found in the propolis composition are believed to have beneficial therapeutic properties.