scholarly journals Changes in myoglobin content in pork Longissimus thoracis muscle during freezing storage

2020 ◽  
Vol 11 (3) ◽  
pp. 651-668
Author(s):  
Jonathan Coria-Hernández ◽  
Rosalía Meléndez-Pérez ◽  
Abraham Méndez-Albores ◽  
José Luis Arjona-Román
Keyword(s):  
Total Reflection ◽  
Attenuated Total Reflection ◽  
Pork Meat ◽  
Chemical Parameters ◽  
Scanning Calorimetry ◽  
Modulated Differential Scanning Calorimetry ◽  
Raw Meat ◽  
Thawing Process ◽  
Color Profile ◽  
Freezing Storage

In this study, pork Longissimus thoracis muscle was used, which was frozen in a chamber and thawed under controlled conditions. The color profile and the surface myoglobin were evaluated. A thermal analysis was performed by modulated differential scanning calorimetry (MDSC), and Fourier-transform infrared spectroscopy with attenuated total reflection (FTIR-ATR). It was found that there were important effects in myoglobin due to the freeze-thawing process in parameters such as pH, luminosity (L*), and chroma values, as well as in activation energies (Ea) and denaturation enthalpy (ΔH) between myoglobin forms. In raw meat, it was found that there was a greater proportion of deoxymyoglobin, and in frozen-thawed samples, metmyoglobin was the most abundant form, indicating that are significant effects which are correlated with the changes in tri-stimulus coordinates and with the thermal and chemical parameters in pork meat.

scholarly journals Effect of Cryostructuring Treatment on Some Properties of Xanthan and Karaya Cryogels for Food Applications

Molecules ◽  
2021 ◽  
Vol 26 (9) ◽  
pp. 2788
Author(s):  
Jonathan Coria-Hernández ◽  
Rosalía Meléndez-Pérez ◽  
Abraham Méndez-Albores ◽  
José Luis Arjona-Román
Keyword(s):  
Food Preservation ◽  
Total Reflection ◽  
Attenuated Total Reflection ◽  
Scanning Calorimetry ◽  
Modulated Differential Scanning Calorimetry ◽  
Indirect Contact ◽  
Freeze Thaw ◽  
Food Applications ◽  
Novel Material ◽  
Scanning Electron

Cryogels are novel materials because the manufacturing process known as cryostructuring allows biopolymers to change their properties as a result of repeated controlled freeze–thaw cycles. Hydrogels of xanthan and karaya gums were evaluated after undergoing up to four controlled freeze–thaw cycles in indirect contact with liquid nitrogen (up to −150 °C) to form cryogels. Changes in structural, molecular, rheological, and thermal properties were evaluated and compared to those of their respective hydrogels. Samples were also analyzed by Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy with Attenuated Total Reflection (FTIR-ATR), Rotational Rheology (RR), Modulated Differential Scanning Calorimetry (MDSC) and zeta potential (ζ). In general, significant differences (p < 0.05) between the numbers of freeze–thaw cycles were found. Karaya cryogels were not stable to repeated cycles of cryostructuring such as the three-cycle xanthan cryogel, which has the best structural order (95.55%), molecular interactions, and thermal stability, which allows the generation of a novel material with improved thermal and structural properties that can be used as an alternative in food preservation.

Exploration for Identification of Sheath-Core Fiber of Ploymer

2014 ◽  
Vol 988 ◽  
pp. 8-12
Author(s):  
Rui Tian Zhu ◽  
Peng Zhang ◽  
Feng Ming Nie
Keyword(s):  
Infrared Spectroscopy ◽  
Accurate Method ◽  
Total Reflection ◽  
Attenuated Total Reflection ◽  
Polymer Fiber ◽  
Reflection Method ◽  
Scanning Calorimetry ◽  
Microscopic Method ◽  
Transmission Technique ◽  
Core Fiber

In this paper, microscopic method, transmission technique and attenuated total reflection method of infrared spectroscopy and differential scanning calorimetry were investigated for analyzing the component of inner and outer layer of sheath-core polymer fiber. Results showed that transmission technique and attenuated total reflection method of infrared spectroscopy was a quick and accurate method for identification of sheath-core fiber of fiber.

scholarly journals Organogels for the cleaning of artifacts

2017 ◽  
Vol 89 (1) ◽  
pp. 3-17 ◽  
Author(s):  
Maria Diletta Pianorsi ◽  
Martina Raudino ◽  
Nicole Bonelli ◽  
David Chelazzi ◽  
Rodorico Giorgi ◽  
...  
Keyword(s):  
Release Rate ◽  
Total Reflection ◽  
Attenuated Total Reflection ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Polymeric Networks ◽  
X Ray Scattering ◽  
Paper Document ◽  
New Formulation ◽  
Differential Thermogravimetry

AbstractThe cleaning of artifacts must not alter the original properties of the objects. While the use of free solvents is risky, their confinement into polymeric networks can allow the safe removal of unwanted layers from artifacts. Recently, a methyl 2-methylprop-2-enoate (MMA)-based organogel was formulated as loaded with butan-2-one (MEK), and used to remove aged varnishes from canvas paintings. However, this formulation is not enough retentive to allow its use on paper, where higher retentiveness is needed to avoid the uncontrolled spreading of MEK and dissolved materials. Here, a new PMMA-MEK gel was designed to overcome this limitation. The amount of cross-linker and monomer used in the synthesis of the gel were tuned to achieve optimal retentiveness. Differential scanning calorimetry (DSC), differential thermogravimetry (DTG), small-angle X-ray scattering (SAXS) and attenuated total reflection fourier transform infrared spectroscopy (ATR-FTIR) provided information on the solvent content, release rate, and mesoporosity of the gel as compared to the previous system. The lower solvent release rate of the new formulation allowed the safe removal of wax that jeopardized a 19th century paper document. The removal was confirmed through optical microscopy and ATR-FTIR, which also highlighted the absence of gel residues on the treated surface.

Fabrication of ultrafine fibrous polytetrafluoroethylene porous membranes by electrospinning

2009 ◽  
Vol 24 (9) ◽  
pp. 2755-2761 ◽  
Author(s):  
Jie Xiong ◽  
Pengfei Huo ◽  
Frank K. Ko
Keyword(s):  
Composite Nanofibers ◽  
Total Reflection ◽  
Attenuated Total Reflection ◽  
Poly Vinyl Alcohol ◽  
Porous Membranes ◽  
Scanning Calorimetry ◽  
Blend Ratio ◽  
Technical Parameters ◽  
Thermogravimetric Analyzer ◽  
Before And After

Poly(vinyl alcohol) (PVA) and poly(tetrafluoroethylene) (PTFE) emulsion were blended with different mass concentrations and the blended spinning solutions were electrospun into composite nanofibers. The influence of the blend ratio of PVA to PTFE and electrospinning technical parameters on the morphology and diameter of the composite nanofibers were investigated. According to the result of thermogravimetric analyzer analysis, the composite membrane was sintered at 390 °C. The membranes were then characterized by differential scanning calorimetry, attenuated total reflection-Fourier transform infrared (ATR-FTIR), and scanning electron microscopy, respectively. The mechanical properties of the membranes before and after sintering were analyzed through tensile testing. The results show that the PTFE porous membranes could be electrospun effectively, thus demonstrating their potential application as filter media.

scholarly journals Influence of ZnO, SiO2 and TiO2 on the aging process of PLA fibers produced by electrospinning method

2019 ◽  
Vol 140 (4) ◽  
pp. 1769-1778 ◽  
Author(s):  
Karolina Kosowska ◽  
Piotr Szatkowski
Keyword(s):  
Structural Changes ◽  
Uv Light ◽  
Total Reflection ◽  
Attenuated Total Reflection ◽  
Poly Lactic Acid ◽  
Uv Resistance ◽  
Scanning Calorimetry ◽  
Uv Aging ◽  
Electrospinning Method ◽  
Key Factor

Abstract The aim of this work was to study the effect of ceramics particles addition (SiO2, ZnO, TiO2) on the ultraviolet (UV) aging of poly(lactic acid) nonwovens fabricated using electrospinning method. The resistance to aging is a key factor for outdoor and medical applications (UV light sterilization). Nonwovens were placed in special chamber with UV light. Changes of physicochemical properties were recorded using differential scanning calorimetry and attenuated total reflection Fourier-transform infrared spectroscopy. The fibers’ morphology was studied by using scanning electron microscopy. Obtained results clearly showed that only PLA fibers with ZnO particles gained an increase in UV resistance. The paper presents a description of structural changes taking place under the influence of UV aging processes and describes the mechanisms of this process and the effect of ceramic addition on the lifetime of such materials.

The Attenuated Total Reflection Infrared Analysis of Surface Crystallinity of Polyhydroxyalkanoates

e-Polymers ◽  
2006 ◽  
Vol 6 (1) ◽  
Author(s):  
Shinn-Gwo Hong ◽  
Wei-Ming Chen
Keyword(s):  
Surface Layer ◽  
Petri Dish ◽  
Weight Percent ◽  
Total Reflection ◽  
Attenuated Total Reflection ◽  
Degree Of Crystallinity ◽  
Infrared Analysis ◽  
Scanning Calorimetry ◽  
Solvent Cast ◽  
Penetration Depths

AbstractThe surface crystallization of three different polyhydroxy alkanoates (PHAs), poly(3-hydroxybutyrate) (PHB), PHB-co-5 weight percent 3-hydroxyvalerate (PHBV5), and PHB-co-12 weight percent 3- hydroxyvalerate (PHBV12), under different processing conditions is analyzed with depth profiling attenuated total reflection spectroscopy (ATR) and differential scanning calorimetry (DSC). The results of ATR indicate that there is a crystallinity distribution on the outer 2 microns thick surface layer. The degree of crystallinity in different penetration depths follows the order of 0.92μ > 0.41μ > 1.70μ for all three hot-pressed PHAs studied and the outer surfaces have a much greater crystallinity than the bulk. The surface crystallinity of specimens is in the order of PHB > PHBV5 > PHBV12 regardless of the different penetration depths analyzed which is consistent with the DSC results. It is also obtained that the effect of annealing in enhancing the crystallization of PHAs is more significant in the surface layer. The surface crystallinity of PHAs obtained after annealing follows the trend of Petri-dish side of solvent-cast PHB > hotpress PHB > air side of solvent-cast PHB > PHBV5 > PHBV12. The difference in crystallinity between the surface and the bulk of PHAs decreases with the addition of 3-hydroxyvalerate but increases after annealing. It is confirmed that the film forming method and the substrate contacted affect the surface crystalline state of PHAs which is attributed to the changes in crystallization conditions in the surface materials.

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