Comparison of antigenicity and conformational changes to β-lactoglobulin following kestose glycation reaction with and without dynamic high-pressure microfluidization treatment

Previous work indicated that conformational changes of β-lactoglobulin (β-LG) induced by dynamic high pressure microfluidization (DHPM) was related to the increase of antigenicity. In this study, β-LG glycated with 1-kestose and combined with DHPM decreased the antigenicity of β-LG. The antigenicity of control, β-LG-kestose (0.1 MPa) and β-LG-kestose (80 MPa) were 100, 79 and 42 μg/mL respectively. The molecular weight of β-LG conjugated to kestose increased from 18.4 to 19.6 kDa and its conformation scarcely changed. Conversely, combined with DHPM treatment (80 MPa), β-LG conjugated to kestose formed two conjugates with molecular weight of 18.8 and 19.8 kDa, respectively. Furthermore, the unfolding of β-LG as a result of the treatments is reflected by a decrease of intrinsic and synchronous fluorescence intensity and changes to the secondary structure. The conformational changes induced by DHPM and glycation treatments synergistically decrease the antigenicity of β-LG due to more masked or disrupted epitopes

The influence of pH and monovalent ions on the gelation of pectin from the fruit seeds of the creeping fig plant

Pectin from the fruit seeds of the creeping fig plant was extracted and its chemical composition and rheological properties determined. It was found to consist of ~87% galacturonic acid with a degree of methoxylation of ~20%. The polysaccharide produced a viscous solution at pH 4.5 and was shown to form strong gels when the pH was reduced by the addition of glucono-delta lactone. It was concluded that as the pH was lowered, the reduction in electrostatic repulsions between the pectin chains facilitated chain association mainly through hydrogen bonding. The rate of gelation increased considerably as the pH was reduced. Although the pectin was in the form of a solution at pH 4.5, the addition of Na+ and K+ salts resulted in gel formation. The strength of the gels was found to be dependent on both the concentration and nature of the added electrolyte in accordance with the Lyotropic series. It has been suggested that the role of the electrolyte was to reduce the electrostatic repulsions between the carboxylate groups along the pectin chains thus facilitating chain association. Association is promoted by the presence of a low concentration of Ca2+ ions (1.88% w/w) naturally present in the extracted material which facilitated the crosslinking of the pectin chains in addition to the association through hydrogen bonding

Physicochemical and structural properties of pregelatinized starch prepared by improved extrusion cooking technology

Pregelatinized starch was made from indica rice starch using a so-called "improved extrusion cooking technology" (IECT) under 30%-70% moisture content. IECT-pregelatinized starch (IPS) had higher water solubility and water absorbability compared to native starch at low temperature. For pasting properties, the breakdown and setback viscosities of IPS were significantly (p < 0.05) lower than native starch, suggesting improved gel stability and reduced short-term retrogradation. The rice starch granules lost their integrity in IPS, and formed a honeycomb-like structure with increased moisture content in the raw material. These properties can be explained in terms of molecular structural features, particularly the large reduction in the size of molecules, but without significant changes in the chain-length distributions of amylopectin component, and no significant change in amylose fraction. These results indicate that IECT is suitable for preparing IPS with desirable water solubility and gel stability properties. (C) 2017 Elsevier Ltd. All rights reserved

Modification of retrogradation property of rice starch by improved extrusion cooking technology

Modifications of molecular structure, and of short- and long-term retrogradation properties, in rice starch by an "improved extrusion cooking technology" (IECT) were studied. IECT decreased starch molecular size in the order high speed / high temperature > low speed / high temperature > high speed / low temperature > low speed / low temperature. Degradation was mostly of amylopectin and insignificant for amylose. The reduction of water mobility and the increase of storage modulus were both less than normal in extrusion: IECT inhibited short-term retrogradation. Crystallinity and retrogradation enthalpy were increased after long storage: IECT accelerated the long-term retrogradation of starch. The greater the starch degradation by IECT, the more short-term retrogradation was inhibited and long-term retrogradation accelerated. These results show that, under appropriate conditions, IECT is a type of extrusion which can be used to change retrogradation properties of rice starch that have not been previously available

Total Phenolic content and total antioxidant activity of raw (A, C) and processed (B, D) cereal grains.

<p>* Significantly (<i>p</i> < 0.05) different from raw cereals.</p

The content of bioaccessible phenolics and antioxidant compounds of raw and processed cereals.

<p>The content of bioaccessible phenolics and antioxidant compounds of raw and processed cereals.</p

The content (μg/g) of phenolic acids in raw and processed cereals determined by HPLC.

<p>The content (μg/g) of phenolic acids in raw and processed cereals determined by HPLC.</p

The Profile and Bioaccessibility of Phenolic Compounds in Cereals Influenced by Improved Extrusion Cooking Treatment

<div><p>The aim of this study was to investigate the effect of Improved Extrusion Cooking Treatment (IECT) on the phenolics and its bioaccessibility in cereals, represented by brown rice, wheat, and oat. Data showed that total phenolic content and total antioxidant activity in free form were significantly decreased, while the bound form was increased after IECT. After IECT, the total free phenolic acids of brown rice and wheat were significantly decreased by 5.88% and 45.66%, respectively, while the total bound phenolic acids of brown rice, wheat, and oat were significantly increased by 6.45%, 8.78%, and 9.10%, respectively. Brown rice provided the most bioaccessible phenolics and antioxidant compounds, followed by oat and wheat. IECT significantly decreased the bioaccessible phenolics of brown rice and oat by 31.09% and 30.95%, while it had minimal effect on the bioaccessible phenolics of wheat. These results showed that IECT greatly affected the phenolics and its bioaccessibiltiy of cereals, with the effect depending on cereal matrix and the sensitivity of free and bound phenolics. Furthermore, bioaccessible phenolic acids of raw and processed cereals were considerably low, and it slightly contributed to the bioaccessible phenolics.</p></div

Comparison of antigenicity and conformational changes to β-lactoglobulin following kestose glycation reaction with and without dynamic high-pressure microfluidization treatment

Previous work indicated that conformational changes of β-lactoglobulin (β-LG) induced by dynamic high pressure microfluidization (DHPM) was related to the increase of antigenicity. In this study, β-LG glycated with 1-kestose and combined with DHPM decreased the antigenicity of β-LG. The antigenicity of control, β-LG-kestose (0.1 MPa) and β-LG-kestose (80 MPa) were 100, 79 and 42 μg/mL respectively. The molecular weight of β-LG conjugated to kestose increased from 18.4 to 19.6 kDa and its conformation scarcely changed. Conversely, combined with DHPM treatment (80 MPa), β-LG conjugated to kestose formed two conjugates with molecular weight of 18.8 and 19.8 kDa, respectively. Furthermore, the unfolding of β-LG as a result of the treatments is reflected by a decrease of intrinsic and synchronous fluorescence intensity and changes to the secondary structure. The conformational changes induced by DHPM and glycation treatments synergistically decrease the antigenicity of β-LG due to more masked or disrupted epitopes