Haiyan Gao

Comparison of A and B starch granules from three wheat varieties.

Three starches from the wheat varieties AK58, ZM18 and YZ4110 were separated into large (A) and small (B) granules, which were characterized structurally and evaluated for their functional properties. SEM results showed that the size of A-granules from ZM18 and YZ4110 were about the same, but the sizes of A-granules and B-granules from AK58 were larger than those of ZM18 and YZ4110. FTIR spectra showed that all the samples exhibited a similar pattern, with seven main modes with maximum absorbance peaks near 3,500, 3,000, 1,600, 1,400, 1,000, 800, 500 cm−1. The B-granules of ZM18 and YZ4110 had less amylose content, although the difference among the total amylose contents of the three unfractionated starches was not significant. X-ray diffraction (XRD) patterns showed predominantly A-type crystallinity for all the starches. The A-granules showed sharper XRD patterns than the other starches. DSC analysis showed that the A-granules had broader ranges of gelatinization temperatures than the B-granules from the same wheat variety. The gelatinization enthalpy (ΔH) of A-granules was higher than that of B-granules. AK58 exhibited the smallest enthalpy, while ZM18 showed the largest enthalpy. In pasting tests, the A-granule starch of AK58 had higher peak, final and setback viscosity, lower breakdown and pasting temperature, and the B-granule starch and unfractionated starch of AK58 had lower peak, breakdown, final and setback viscosity and higher pasting temperature than ZM18 and YZ4110.

Characterization of Phosphate Monoester Resistant Starch

The properties and structures of corn, wheat, and potato native starches and their phosphate monoester resistant starches were tested and compared. The results indicated that the resistant starch content, light transmittance, and freeze-thaw stability of the phosphate monoester resistant starch increased after modification. The native starches exhibited much higher peak viscosities compared with resistant starch (RS) and phosphate monoester resistant starches. The phosphate monoester resistant starch from corn and wheat starch exhibited a higher peak and final viscosity and lower gelatinization temperatures compared with the resistant starch, while the peak and final viscosity of the potato phosphate monoester resistant starch samples were lower than that of potato resistant starch. In the FT-IR graph, a new peak at 1244 cm−1 (P=O bond) was observed for all kinds of phosphate monoester resistant starch.

Functional properties of wheat starch with different particle size distribution

BACKGROUNDnFunctional properties of wheat starches with different particle size distribution were investigated.nnnRESULTSnA-granules displayed a disc shape and B-granules displayed a spherical shape. A-granules had the highest conclusion temperature (Tc , 80.28 °C) and gelatinisation enthalpy (3.268 J g(-1)) and B-granules had the highest peak temperature (Tp, 66.00 °C) and the lowest gelatinisation enthalpy (2.237 J g(-1)). The gelatinisation onset temperature (To), the peak temperature (Tp), Tc and retrogradation of mixed starches increased with the increase of the ratio of B-granules, while the enthalpy, all the viscosity parameters and syneresis of mixed starches decreased with the increase of the ratio of B granules. B-granules had a higher pasting temperature. The sample of B/A = 0.5/10 had the highest peak, breakdown and final viscosity. The percentage of water separated from B-granule gels was minimal, indicated that B-type gels were more stable than other samples. The ΔH2 of A-granules was obviously higher than that of B-granules. However, during storage, the ΔH2 of the starch paste was dramatically increased and the ΔH2 of B-granules was obviously higher than that of A-granules.nnnCONCLUSIONnB-granules were easier to age than A-granules and most of the properties of wheat starches varied significantly with the ratio of B-granules. The relationship between structure and functionality of wheat starch received further verification.

Arctigenin: a lignan from Arctium lappa

The title compound {systematic name: (3R-trans)-4-[(3,4-dimethoxy-phen-yl)meth-yl]-3-[(4-hydr-oxy-3-methoxy-phen-yl)meth-yl]-4,5-dihydrofuran-2(3H)-one}, C(21)H(24)O(6), has a dibenz-yl-butyrolactone skeleton. The two aromatic rings are inclined at a dihedral angle of 68.75u2005(7)° with respect to each other. The lactone ring adopts an envelope conformation. A series of O-H⋯O and C-H⋯O hydrogen bonds contribute to the stabilization of the crystal packing. The absolute configuration was assigned on the basis of the published literature.

Fructooligosaccharides Impact on the Hydration and Retro-Gradation of Wheat Starch and Gel

In the present work, the hydration and retro-gradation of mixtures of wheat starch and fructooligosaccharides in diluted hydrated matrixes were discussed. Rapid Visco-Analyzer, differential scanning calorimeter, Fourier transform-infrared spectroscopy, scanning electron microscopy, and x-ray diffraction were used to determine the properties of the mixture of wheat starch and fructooligosaccharides. Swelling of the wheat starch showed significant changes when the addition of fructooligosaccharides surpassed 0.1 g/g starch. Water absorption index showed obvious change but there was no regular variation. The water solubility index of starch increased after adding the fructooligosaccharides and the highest value was up to 19.85 as compared with the control (3.61). There was no significantly change for the pasting parameters of the mixture. Fructooligosaccharides significantly affected the enthalpy of wheat starch from the result of differential scanning calorimeter analysis, and enlarged the freezing scope of the mixture gel (from –23.09 ± 0.25ºC to –38.85 ± 0.32ºC). The melting enthalpy of sample with fructooligosaccharides decreased by 9.9 J/g as compared with the control. Fourier transform-infrared spectroscopy results showed that there were no obvious differences between the samples with or without fructooligosaccharides except that the O–H stretching vibration of hydrogen bond of the mixture gel strengthened after storage for 2 or 4 days. Scanning electron microscopy results indicated fructooligosaccharides should be conductive for starch to form fine gel structures and could inhibit the retrogradation of wheat starch. X-ray diffraction spectrum further illustrated the fructooligosaccharides could interfere with the retrogradation of wheat starch during storage.

Improving Tenderness of Goose Breast by Ultra-High Pressure

Ultra-high pressure treatment was used to tenderize the goose meat. The conditions of ultra-high pressure were optimized by response surface methodology. Goose meat was subjected to ultra-high pressures of 100, 200, 300, 400, and 500 MPa for 10, 15, 20, 25, and 30 min at 20°C, respectively. Subsequently the cooking loss rate, water holding capacity, texture, and scanning electron microscope of the products were determined. The pressure and holding time significantly influenced the hardness values (p < 0.05), but did not significantly affect cooking loss rate and water holding capacity (p > 0.05). The hardness significantly decreased after ultra-high pressure treatment. Scanning electron microscope analysis showed that fracture of the rod-like muscle was observed in ultra-high pressure treated samples. Response surface methodology results showed that pressure (213 MPa) and holding time (15.35 min) at 20°C was helpful to decrease the hardness of goose breast.

Characteristics of Corn Flour Fermented by Some Lactobacillus Species

Corn flours with different particle sizes were prepared and fermented by some Lactobacillus species isolated from the traditional process of corn fermentation. The main components, physicochemical, apparent viscosity and pasting properties of the fermented corn flours were studied. The results showed that there were little difference of fermentation kinetics of the flours with different particle sizes. After fermentation, the total acid and reducing sugar contents of the flours increased but pH value decreased. The great differences in the swelling power, solubility, water binding capacity and pasting properties of the fermented flours were observed. After fermentation for 24 h, the apparent viscosity of the flour slurries was significantly increased. The obtained result of our study could be used to improve the cold viscosity of corn flour and the quality of cereal food by using lactobacillus fermentation.

Chemoenzymatic synthesis of sialylated lactuloses and their inhibitory effects on Staphylococcus aureus

Background Sialylated glycoconjugates play important roles in physiological and pathological processes. However, available sialylated oligosaccharides source is limited which is a barrier to study their biological roles. This work reports an efficient approach to produce sialic acid-modified lactuloses and investigates their inhibitory effects on Staphylococcus aureus (S. aureus). Methods A one-pot two-enzyme (OPTE) sialylation system was used to efficiently synthesize sialylated lactuloses. Silica gel flash chromatography column was employed to purify the sialylated products. The purity and identity of the product structures were confirmed with mass spectrometry (MS) and nuclear magnetic resonance (NMR). The inhibitory effect of sialylated lactuloses against S. aureus was evaluated by using microplate assay, fluorescence microscopy, DAPI (4,6-diamidino-2-phenylindole) fluorescence staining and protein leakage quantification. Results Neu5Ac-containing sialylated lactuloses with either α2,3- or α2,6-linkages were efficiently synthesized via an efficient OPTE sialylation system using α-2,3-sialyltransferase or α-2,6-sialyltransferase, respectively. Neu5Ac-α2,3-lactulose and Neu5Ac-α2,6-lactulose significantly inhibited the growth of S. aureus. Fluorescence microscopy and DAPI fluorescence staining indicated that the sialylated lactuloses might disrupt nucleic acid synthesis of S. aureus. Conclusions Neu5Ac-containing sialylated lactuloses had higher antibacterial activity against S. aureus than non-sialylated lactulose. The inhibitory effect of Neu5Ac-α2,3-lactulose was superior to that of Neu5Ac-α2,6-lactulose. The sialylated lactuloses might inhibit S. aureus by causing cell membrane leakage and disrupting nucleic acid synthesis.

Optimization of Preparation of Corn Starch Phosphates of High Thermal Viscosity by Response Surface Methodology

The preparation of corn starch phosphates which possess height thermal viscosity was optimized in this study. A central composite design of response surface methodology involving phosphate (sodium dihydrogen phosphate and disodium hydrogen phosphate) concentration, ratio of sodium dihydrogen phosphate and disodium hydrogen phosphate, phosphorylation temperature and urea concentration was used, and second-order model for thermal viscosity was employed to generate the response surface. The optimum condition for preparation of corn starch phosphates of high thermal viscosity was as follows: phosphate concentration 4.94%; ratio of sodium dihydrogen phosphate and disodium hydrogen 0.80, phosphorylation temperature 145°C; urea concentration 5.5%. The predicted value for thermal viscosity of corn starch phosphates at the optimum condition was 7652 cP. Experimental verification gave value of 7550±25 cP.

alpha-amylase and Glucose Oxidase as Promising Improvers for Wheat Bread

The effects of alpha-amylase and glucose oxidase as bread improvers on the textural and thermal properties of bread were evaluated by the rapid viscosity analysis and differential scanning calorimetry. It was found that alpha-amylase and glucose oxidase could improve the specific volume and crumb porosity, retard the bread staling and increase the flour ethanol index. Therefore, alpha-amylase and glucose oxidase could be considered as the potential texture modifier for baked food.