Supramolecular threading of peptide hydrogel fibrils

There is an increasing demand for biocompatible materials in biomedical applications. Herein, we report a modified α-helical decapeptide segment from the cardiac troponin C, which self-assembles into fibers with a secondary β-sheet structure. These fibers cross-link via a novel supramolecular threading mechanism which results in an atypical stiff hydrogel (G′ ≈ 13 kPa). In this work, we provide a first insight into the understanding of such remarkable cross-linking mechanism, which will aid in the development of new biomaterials with unique properties

Characteristics and Properties of Gelatin from Seabass (Lates calcarifer) Swim Bladder : Impact of Extraction Temperatures

Purpose This study aimed to investigate the impact of various extracting temperatures on yield and properties of gelatin from swim bladder of seabass (Lates calcarifer), a byproduct from processing. Methods Gelatin from seabass swim bladder was extracted at different temperatures (45, 55, 65 and 75 degrees C). The gelatins obtained using various extraction temperatures were characterized. Results The yield and recovery of gelatin from swim bladder (44.83-71.95% and 49.08-74.83%, based on dry weight) increased with increasing extraction temperatures. All gelatins contained a-chains as the predominant components, followed by alpha-chain. Gelatin from seabass swim bladder showed a high imino acid content (195 residues/1000 residues). FTIR and CD spectra revealed the loss of triple helix during heating via breaking down hydrogen bonds between a-chains. Gel strength generally increased as the extraction temperature increased up to 65 degrees C (P < 0.05). Gelatin extracted at 65 degrees C for 6 h showed a higher gel strength, compared to bovine gelatin (P < 0.05). Gelling and melting temperatures were 10.419.7 and 19.3-28.4 degrees C, respectively, depending on extraction temperature. Conclusion Properties of gelatin from swim bladder were affected by extraction temperature. Therefore, sea-bass swim bladder could serve as an alternative collagenous material for gelatin production, when the appropriate extraction condition was implemented

Flavonoid-Rich Extract of Actinidia macrosperma (A Wild Kiwifruit) Inhibits Angiotensin-Converting Enzyme In Vitro

Increasing interest in flavonoids in kiwifruit is due to the health-promoting properties of these bioactives. Inhibition of the angiotensin-converting enzyme (ACE) is one of the main therapeutic targets in controlling hypertension. The present study investigated the ACE inhibitory activity of flavonoid-rich extracts obtained from different kiwifruit genotypes. The flavonoid-rich extracts were prepared from fruits of Actinidia macrosperma, Actinidia deliciosa cv Hayward (Green kiwifruit), and Actinidia chinensis cv Hort 16A (Gold kiwifruit) by steeping the lyophilized fruit samples in 70% aqueous acetone, followed by partitioning the crude extracts with hexane. The composition of each extract was analyzed using ultrahigh-performance liquid chromatography-mass spectrometry (UPLC-MS/MS). The ACE inhibitory activity of the fruit extracts was performed using a fluorescence-based biochemical assay. The subclass flavonol was the most abundant group of flavonoids detected in all the extracts tested from three different kiwifruit cultivars. Quercetin-3-O-galactoside, quercetin-3-O-glucoside, quercetin-3-O-rhamnoside, quercetin-3-O-rutinoside, quercetin-3-O-arabinoglucoside, catechin, epigallocatechin gallate, epigallocatechin, chlorogenic, ferulic, isoferulic, and caffeic acid were prominent phenolics found in A. macrosperma kiwifruit. Overall, the flavonoid-rich extract from A. macrosperma showed a significantly (p &lt; 0.05) high percentage of inhibition (IC50 = 0.49 mg/mL), and enzyme kinetic studies suggested that it inhibits ACE activity in vitro. The kiwifruit extracts tested were found to be moderately effective as ACE inhibitors in vitro when compared to the other plant extracts reported in the literature. Further studies should be carried out to identify the active compounds from A. macrosperma and to validate the findings using experimental animal models of hypertension

X-ray diffraction investigation of amorphous calcium phosphate and hydroxyapatite under ultra-high hydrostatic pressure

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The effect of transglutaminase on reconstituted skim milks at alkaline pH

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Retrogradation of Maize Starch after High Hydrostatic Pressure Gelation: Effect of Amylose Content and Depressurization Rate.

High hydrostatic pressure (HHP) has been employed to gelatinize or physically modify starch dispersions. In this study, waxy maize starch, normal maize starch, and two high amylose content starch were processed by a HHP of the order of 600 MPa, at 25°C for 15min. The effect of HHP processing on the crystallization of maize starches with various amylose content during storage at 4°C was investigated. Crystallization kinetics of HHP treated starch gels were investigated using rheology and FTIR. The effect of crystallization on the mechanical properties of starch gel network were evaluated in terms of dynamic complex modulus (G*). The crystallization induced increase of short-range helices structures were investigated using FTIR. The pressure releasing rate does not affect the starch retrogradation behaviour. The rate and extent of retrogradation depends on the amylose content of amylose starch. The least retrogradation was observed in HHP treated waxy maize starch. The rate of retrogradation is higher for HHP treated high amylose maize starch than that of normal maize starch. A linear relationship between the extent of retrogradation (phase distribution) measured by FTIR and G* is proposed