Dynamic rheological and structural characterization of fish gelatin - Gum arabic coacervate gels cross-linked by tannic acid

Anvari, M.,Chung, D. IRL Press ; Elsevier Science Ltd 2016 Food hydrocolloids Vol.60 No.-

<P>The propose of this study was to investigate the rheological and structural properties of fish gelatin (FG)-gum arabic (GA) complex coacervate gels treated with oxidized or non-oxidized tannic acid (OX-TA or NO-TA, respectively) at different concentrations ranged from 0.0 to 0.3% (v/v), using compositional, dynamic oscillatory rheological, and Fourier transform infrared (FTIR) analyses. The results revealed that the degree of NO-TA incorporation for cross-linking with FG via hydrogen bindings into the system was more pronounced than affinity of OX-TA for reaction through covalent bindings as evidenced by greater loss in volume fraction, moisture content, and biopolymer content values into the FG-GA coacervate phase. FTIR analysis showed addition of NO-TA led to more molecular disorder into the system, so that higher concentrations (0.2 and 0.3%) of the cross-linker disrupted electrostatic interactions through formation of stronger hydrogen bindings with proteins. Rheological results mentioned that addition and enhancement of (NO- or OX-) TA concentration improved gelling ability and mechanical properties of the FG-GA coacervate gels. However, frequency sweep test results implied that all the gels obtained can be classified as weak gels with shear-thinning behavior. Based on weak gel model, the gels obtained by treated FG-GA coacervates with NO-TA had more developed network structures and stronger intermolecular connectivities than those of obtained by the coacervates modified by OX-TA. The results of the current study provide basic knowledge necessary for the use of reinforced FG-GA complex coacervate gels in many useful applications, such as microencapsulation and hydrogel formation, in food and pharmaceutical industries. (C) 2016 Elsevier Ltd. All rights reserved.</P>

Cold plasma treatments for improvement of the applicability of defatted soybean meal-based edible film in food packaging

Oh, Y.A.,Roh, S.H.,Min, S.C. IRL Press ; Elsevier Science Ltd 2016 Food hydrocolloids Vol.58 No.-

<P>This study investigated the effects of cold plasma treatment (CPT) using various plasma-forming gases on the physical properties of defatted soybean meal (DSM)-based edible film (DSM film). The effect of packaging smoked salmon using a cold plasma (CP)-treated DSM film on the storage stability of salmon was also evaluated. DSM film was formed by casting film-forming solutions (DSM/glycerol at a ratio of 10: 3) prepared by high-pressure (172 MPa) homogenization. Among the O-2-, N-2-, air-, He- and Ar-CPTs, Ar-CPT, which increased elongation and lightness of the DSM film, was optimized against tensile strength, elongation, and water vapor permeability using a response surface analysis. Optimal plasma generation time and power were predicted as 15 min and 400 W, respectively. The tensile strength, elongation, and moisture barrier property of DSM film increased by 6.8%, 13.4%, and 24.4%, respectively, after CPT at optimal conditions. The CPT formed DSM film that decomposed easily and retarded lipid oxidation and hardness reduction of smoked salmon during storage at 4 degrees C. The results from this study suggest the use of CPT for improving the applicability of DSM film in food packaging. (C) 2016 Elsevier Ltd. All rights reserved.</P>

Preparation of antimicrobial agar/banana powder blend films reinforced with silver nanoparticles

Orsuwan, A.,Shankar, S.,Wang, L.F.,Sothornvit, R.,Rhim, J.W. IRL Press ; Elsevier Science Ltd 2016 Food hydrocolloids Vol.60 No.-

<P>Binary blend films of agar and banana powder (A/B) and A/B composite films reinforced with silver nanoparticles (A/B/AgNPs) were prepared using a solution casting method and their properties were characterized. The SEM micrographs and FT-IR results confirmed the formation of physical interactions between polymer matrices and nanofillers. Apparent surface color and transmittance of the composite film were greatly influenced not only by the mixing of banana powder with agar but also by the incorporation of AgNPs. The UV light absorption, water vapor barrier properties, and antioxidant activity of A/B blend films increased with the increase in the concentration of the banana powder, while the mechanical properties decreased. The A/B/AgNPs composite film exhibited distinctive antimicrobial activity against food-borne pathogenic bacteria, Escherichia coli and Listeria monocytogenes with stronger antibacterial activity against Gram-negative bacteria than Gram-positive bacteria. The binary blend of A/B films are expected to be used for the edible film or coating of foods and their nanocomposite films with antimicrobial activity have a potential to be used as food packaging material for maintaining the safety and extending the shelf life of packaged food. (C) 2016 Elsevier Ltd. All rights reserved.</P>

Amelioration of obesity in high-fat diet-fed mice by chestnut starch modified by amylosucrase from Deinococcus geothermalis

Lee, E.S.,Lee, B.H.,Shin, D.U.,Lim, M.Y.,Chung, W.H.,Park, C.S.,Baik, M.Y.,Nam, Y.D.,Seo, D.H. IRL Press ; Elsevier Science Ltd 2018 Food hydrocolloids Vol.75 No.-

The ameliorative effect of enzymatically modified chestnut starch on high-fat diet (HFD)-induced obesity in a mouse model and the underlying mechanism were investigated. Chestnut starch was enzymatically modified by amylosucrase from Deinococcus geothermalis (DGAS). In vitro analyses including Englyst's assay and determination of the starch digestive pattern to investigate starch digestibility revealed that chestnut starch naturally contained higher slowly digestible starch and resistant starch than corn starch. Modification of chestnut native starch by DGAS increased the proportion of resistant starch, rendering it unavailable for catalysis by small-intestinal mucosal α-glucosidase. The amylose ratio and branch-chain of amylopectin in chestnut starch were increased by DGAS. In an in vivo study, HFD (45% kcal from fat)-induced obese C57BL/6 model mice were orally administered DGAS-modified chestnut starch at the dose of 1500 mg/kg b.w for 10 weeks. Supplementation of DGAS-modified chestnut starch to obese mice significantly reduced features of obesity as compared with HFD- or native chestnut starch-fed mice. Food intake and the gut hormones PYY and GLP-1 were not significantly changed. However, we found that feeding DGAS-modified chestnut starch led to a significant increase in empty cecum weight, indicating short-chain fatty acid production in the cecum. Additionally, DGAS-modified chestnut starch induced the short-chain fatty acid receptor GPR43-mediated suppression of insulin signaling. Changes in all these factors were resistant starch content-dependent. In conclusion, DGAS modification of chestnut starch increases non-digestible resistant starch and this ameliorates diet-induced obesity via GPR43-mediated suppression of insulin signaling, thereby presumably reducing fat accumulation in white adipose tissue.

Effect of heat-moisture treatment under mildly acidic condition on fragmentation of waxy maize starch granules into nanoparticles

Kim, J.H.,Park, D.H.,Kim, J.Y. IRL Press ; Elsevier Science Ltd 2017 Food hydrocolloids Vol.63 No.-

Waxy maize starch was modified by a heat-moisture treatment (HMT) under acidic conditions followed by homogenization to create starch nanoparticles. Waxy maize starch was heated at 130 <SUP>o</SUP>C for 3, 5, or 8 h under mildly acidic conditions (0.00, 0.10, or 0.15 N sulfuric acid solution) and homogenized for up to 60 min. The crystalline, molecular, and granular structures of starch were effectively changed without severe loss of starch substance (less than 25%) by the HMT under acidic conditions. The HMT under acidic conditions enhanced short-range order of starch granules based on the results of FT-IR but decreased the proportion of amylopectin long chains. The data suggest that the amorphous region of the starch granule was readily hydrolyzed by the acidic condition during the HMT. Moreover, homogenization after the HMT (0.15 N for 8 h) induced fragmentation of starch granules into nano-sized particles with diameters less than 40 nm.

Effects of amidation and/or methylesterification of pectin on aroma release at different calcium concentration

Kim, M.J.,Ju, H.K.,Kim, Y.,Yoo, S.H.,Kim, Y.S. IRL Press ; Elsevier Science Ltd 2016 Food hydrocolloids Vol.52 No.-

Four different types of low methoxyl pectins (LMPs) were prepared via amidation and methylesterification to investigate the release of 14 aroma compounds from different pectin gel systems at different calcium concentration. The release of aroma compounds was determined using static headspace gas chromatography analysis. Amidation and amidation combined by methylesterification increased aroma release from LMP gels compared to the non-treated ones at diverse calcium concentration, except amidated LMP at 0.09% calcium. On the other hand, methylesterified LMP reduced the release of most aroma compounds at 0.03-0.09% calcium concentration. Furthermore, treatment with pectin methylesterase increased the release of aroma compounds from amidated pectin but reduced their release from nonamidated pectin. Comparison of the release of a series of esters with different numbers of carbon atoms revealed increased release of compounds with up to six carbons, and then a decrease of those with up to ten in LMP, amidated LMP, and amidated and methylesterified pectin gel systems.