Hydrolysis of Native and Heat-Treated Starches at Sub-Gelatinization Temperature Using Granular Starch Hydrolyzing Enzyme

The effect of heat treatment below the gelatinization temperature on the susceptibility of corn, mung bean, sago, and potato starches towards granular starch hydrolysis (35°C) was investigated. Starches were hydrolyzed in granular state and after heat treatment (50°C for 30 min) by using granular starch hydrolyzing enzyme for 24 h. Hydrolyzed heat-treated starches showed a significant increase in the percentage of dextrose equivalent compared to native starches, respectively, with corn 53% to 56%, mung bean 36% to 47%, sago 15% to 26%, and potato 12% to 15%. Scanning electron microscopy micrographs showed the presence of more porous granules and surface erosion in heat-treated starch compared to native starch. X-ray analysis showed no changes but with sharper peaks for all the starches, suggested that hydrolysis occurred on the amorphous region. The amylose content and swelling power of heat-treated starches was markedly altered after hydrolysis. Evidently, this enzyme was able to hydrolyze granular starches and heat treatment before hydrolysis significantly increased the degree of hydrolysis.     

Photoluminescent nematic liquid crystalline elastomer actuators

Nematic liquid crystalline elastomer (LCE) actuators possessing both photoluminescent (PL) and stimuli-responsive functions were fabricated and studied. PL-dyes (1-pyrenemethyl acrylate and 4-bromo-2,6-bis-(1?-methyl-benzimidazolyl) pyridine loaded with Eu(III) ion) were synthesised and characterised, and then the dyes were mixed with an acrylate side-on liquid crystalline monomer, a cross-linker and a photo-initiator. Through magnetic field alignment, well-defined LCE micropillar PL actuators were fabricated from the mixed samples by a method combining soft lithography and photo-polymerisation/photo-cross-linking. Microscopic observations indicated that the LCE micropillars showed reversible thermomechanical deformation at the nematic-to-isotropic transition temperature. During the reversible contraction and extension process, the LCE actuator containing 1-pyrenemethyl moieties showed stable photoluminescence, while for the LCE actuator doped with 4-bromo-2,6-bis-(1-methyl-benzimidazolyl)pyridine/Eu(III) complex, the PL emission was quenched at about 100°C, which was before the pillars contraction occurring at a higher temperature. When cooled down to room temperature, the contracted LCE micropillars recovered their original shape and the initial PL emission state. The micron-sized LCE actuators can be used for thermomechanical devices and machines with different PL functions at the same time.     

Comparison of interactions between beta-hairpin decapeptides and SDS/DPC micelles from experimental and simulation data

Background  

We applied a combined experimental and computational approach to ascertain how peptides interact with host and microbial membrane surrogates, in order to validate simulation methodology we hope will enable the development of insights applicable to the design of novel antimicrobial peptides. We studied the interactions of two truncated versions of the potent, but cytotoxic, antimicrobial octadecapeptide protegrin-1, PC-72 [LCYCRRRFCVC] and PC-73 [CYCRRRFCVC].     

Effects of NaOH treatment of cereal starch granules on the extent of granular starch hydrolysis

Effect of NaOH treatment on granular hydrolysis of cereal starches was studied and granular starch hydrolyzing enzyme is used to hydrolyze native and NaOH-treated starch for 24?h. The dextrose equivalent value of NaOH-treated starch increased significantly compared to native starch, i.e., 28–38?% for corn, 7–37?% for rice, but no significant increase for corn starch. Scanning electron microscopy micrographs showed that NaOH treatment caused an enlargement of pores and degrades the surface of starch granules. Hydrolyzed-treated starch exhibited rougher surface and more porous granules compared to native starch. The swelling power and pasting properties of NaOH-treated starches were markedly altered after hydrolysis. X-ray pattern of all starches showed no changes and the amylose content decrease significantly after hydrolysis, which could due to extensive degradation of amorphous region. Evidently, NaOH treatment below gelatinization temperature was effective in enhancing the degree of granular starch hydrolysis.