scholarly journals Cryoprotective effect of trehalose and maltose on washed and frozen stored beef meat

2011 ◽  
Vol 29 (No. 1) ◽  
pp. 15-23 ◽  
Author(s):  
D. Kovačević ◽  
K. Mastanjević
Keyword(s):  
Differential Scanning Calorimetry ◽  
Protein Solubility ◽  
Frozen Storage ◽  
Thermal Transition ◽  
Scanning Calorimetry ◽  
Beef Meat ◽  
Native Proteins ◽  
Mass Fractions ◽  
Extractable Protein ◽  
Meat Samples

The cryoprotective effects of trehalose and maltose (w = 2&ndash;10%) on washed beef meat were investigated. Washed beef meat produced from fresh beef meat was frozen and stored for 360 days at &ndash;30&deg;C. Myofibrillar protein functional stability was monitored by salt extractable protein (SEP) and differential scanning calorimetry (DSC). Salt extractable protein (SEP) showed that the addition of trehalose and maltose causeda smaller loss of protein solubility during the frozen storage. Peak thermal transition (T<sub>p</sub>) and denaturation enthalpy (&Delta;H) of myofibrillar proteins were evaluated. Differential scanning calorimetry (DSC) revealed a shift in the peak thermal transition temperature (T<sub>p</sub>) of myosin and actin to higher temperature as the mass fractions of trehalose and maltose increased. The transitions enthalpies of myosin and actin of the washed beef meat samples showed a higher increase with the increase of mass fraction of trehalose then of that of maltose. Since the value of denaturation enthalpy is directly related to the amount of native proteins, higher values of &Delta;H point to higher cryoprotective effects of trehalose.

scholarly journals Cryoprotective effect of polydextrose on chicken surimi

2011 ◽  
Vol 29 (No. 3) ◽  
pp. 226-231 ◽  
Author(s):  
D. Kovačević ◽  
K. Mastanjević ◽  
J. Kordić
Keyword(s):  
Thermal Analysis ◽  
Differential Scanning Calorimetry ◽  
Transition Temperature ◽  
Freezing Point ◽  
Thermal Transition ◽  
Scanning Calorimetry ◽  
Native Proteins ◽  
Mass Fractions ◽  
Initial Freezing ◽  
Kappa Carrageenan

Two thermal analysis techniques &ndash; Differential scanning calorimetry (DSC) and Differential thermal analysis (DTA), &ndash; were used to study the cryoprotective effects of polydextrose on chicken surimi. The samples of chicken surimi were mixed with: (a) different mass fractions of polydextrose (w = 2&ndash;10%), (b) &kappa;-carrageenan (w = 0.5%) and different mass fractions of polydextrose (w = 2&ndash;10%), and (c) NaCl (w = 2%) and different mass fractions of polydextrose (w = 2&ndash;10%). Chicken surimi was produced following a modified procedure of Dawson et al. (1988) on a broiler (Sasso, 12 weeks, and 1.73 kg live wt.), that was quickly frozen and stored for 3 months at &ndash;25&deg;C. Initial freezing point (<sub><sup>T</sup>i</sub>), thermal transition temperature (T<sub>p</sub>), and denaturation enthalpy (&Delta;H) were evaluated. The greatest effects of the cryoscopic depression of the initial freezing point T<sub>i</sub> were exhibited by the samples of chicken surimi with added 2% NaCl and 10% polydextrose. Differential scanning calorimetry (DSC) revealed a shift in the thermal transition temperature of myosin and actin to a higher temperature as the mass fraction of polydextrose increased. Since the denaturation enthalpy is directly related to the amount of native proteins, higher values of &Delta;H indicate higher cryoprotective effects of polydextrose. &nbsp;

scholarly journals Freeze-Concentrated Phase and State Transition Temperatures of Mixtures of Low and High Molecular Weight Cryoprotectants

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Alma J. Flores-Ramírez ◽  
Pedro García-Coronado ◽  
Alicia Grajales-Lagunes ◽  
Raúl González García ◽  
Miguel Abud Archila ◽  
...  
Keyword(s):  
State Transition ◽  
Frozen Storage ◽  
Thermal Transition ◽  
Transition Temperatures ◽  
Calorimetric Measurements ◽  
Mathematical Expressions ◽  
Mass Fractions ◽  
Long Term Preservation ◽  
Selection Of

Although numerous studies have been conducted on the use of cryoprotectants to prevent the deterioration of food during freezing and frozen storage, scarce reports exist on the thermal transition properties of aqueous cryoprotectant solutions at frozen temperatures. The selection of a suitable cryoprotective medium for the long-term preservation of food requires knowledge of the effects of cryoprotectants and their concentration on the freeze-concentrated unfrozen phase and state transition temperatures known asTg′,Tm′, andTm. Calorimetric measurements were conducted to determine theTg′,Tm′, andTmvalues of thirty frozen aqueous solutions containing maltodextrin, polydextrose, and glucose, in which a distance-based experimental design was used for mixtures of four components to establish their corresponding mass fractions in the mixtures. Thermograms, measured during heating/rewarming from –70 to 20°C, were used to identify the glass transition and freezing temperatures. Mathematical expressions forTg′,Tm′, andTmas a function of the mass fractions of cryoprotectants and water and their interactions (p< 0.05) were developed to aid the formulation of cryoprotective media involving more than two cryoprotectants for adequate frozen conservation of high and intermediate moisture foodstuffs.

Thermal Transition Properties of Spaghetti Measured by Differential Scanning Calorimetry (DSC) and Thermal Mechanical Compression Test (TMCT)

2009 ◽  
Vol 4 (8) ◽  
pp. 1422-1431 ◽  
Author(s):  
Mohammad Shafiur Rahman ◽  
Wijitha Senadeera ◽  
Ahmed Al-Alawi ◽  
Tuyen Truong ◽  
Bhesh Bhandari ◽  
...  
Keyword(s):  
Differential Scanning Calorimetry ◽  
Compression Test ◽  
Thermal Transition ◽  
Mechanical Compression ◽  
Scanning Calorimetry

Thermal Stability of N-Heterocycle-Stabilized Iodanes – A Systematic Investigation

2019 ◽  
Author(s):  
Andreas Boelke ◽  
Yulia A. Vlasenko ◽  
Mekhman S. Yusubov ◽  
Boris Nachtsheim ◽  
Pavel Postnikov
Keyword(s):  
Thermal Stability ◽  
Differential Scanning Calorimetry ◽  
Thermogravimetric Analysis ◽  
Systematic Investigation ◽  
Scanning Calorimetry ◽  
Thermal Stability Of

<p>The thermal stability of pseudocyclic and cyclic <i>N</i>-heterocycle-stabilized (hydroxy)aryl- and mesityl(aryl)-l<sup>3</sup>-iodanes (NHIs) through thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) is investigated. NHIs bearing <i>N</i>-heterocycles with a high N/C-ratio such as triazoles show among the lowest descomposition temperatures and the highest decomposition energies. A comparison of NHIs with known (pseudo)cyclic benziodoxolones is made and we further correlated their thermal stability with reactivity in a model oxygenation. </p>

Optimasi Proses Pembuatan dan Karakterisasi Fisik Niosom Sinkonin

2019 ◽  
Vol 16 (2) ◽  
pp. 178
Author(s):  
Hariyanti Hariyanti ◽  
Sophi Damayanti ◽  
Sasanti Tarini
Keyword(s):  
Differential Scanning Calorimetry ◽  
Particle Size ◽  
Hair Follicle ◽  
Scanning Calorimetry ◽  
Span 60

Sinkonin praktis tidak larut dalam air, sedikit larut dalam kloroform dan alkohol. Hal ini berdampak pada rendahnya penetrasi transfollicular sinkonin, karena hanya bahan aktif hidrofilik yang mampu melewati hair follicle. Dengan demikian dibutuhkan satu sistem penghantaran yang mampu menurunkan hidrofobisitas sinkonin untuk meningkatkan penetrasi sinkonin ke follicle. Niosom merupakan vesikel ampifilik dengan struktur lapisan rangkap yang terbentuk dari hidrasi kombinasi surfaktan nonionik dan kolesterol yang mampu menurunkan hidrofobisitas sinkonin. Penelitian ini bertujuan untuk menentukan proses pembuatan niosom sinkonin yang optimum. Pembuatan niosom sinkonin diawali dengan menentukan temperatur gelasi (Tg) dari span 60 dengan Differential Scanning Calorimetry (DSC), kemudian dilanjutkan dengan optimasi proses meliputi: optimasi kecepatan rotavapor pembentukan film lapis tipis, temperatur hidrasi, kecepatan rotavapor hidrasi, waktu hidrasi, dan waktu sonikasi. Karakteristik vesikel niosom yang optimal meliputi: ukuran partikel dan indeks polidispersitas dengan menggunakan Particle Size Analized (PSA) serta efisiensi penjeratan sinkonin dengan menggunakan KCKT. Temperatur gelasi (Tg) span 60 45±2 oC, kecepatan rotavapor pembentukan film lapis tipis niosom 210 rpm, temperatur hidrasi 55±2 oC, kecepatan rotavapor hidrasi 210 rpm, waktu hidrasi 20 menit, waktu sonikasi suspensi niosom 1 menit. Ukuran vesikel yang diperoleh adalah 100–200 nm, indeks polidispersitas 0,2–0,4 dan efisiensi penjeratan niosom sinkonin 84,49±0,0025%. Proses pembuatan niosom sinkonin memiliki pengaruh besar terhadap hasil ukuran vesikel dan efisiensi penjeratan niosom sinkonin.

Improving Wire Sweep Performance by Measuring Degree of Cure of Epoxy Mold Compounds

2011 ◽  
Author(s):  
Sheila Liza B. Dal
Keyword(s):  
Differential Scanning Calorimetry ◽  
Shelf Life ◽  
Trial And Error ◽  
Active Components ◽  
Scanning Calorimetry ◽  
Degree Of Cure ◽  
Electronic Package ◽  
Viscosity Changes ◽  
Epoxy Mold Compounds

Abstract The choice of epoxy mold compound (EMC) for an electronic package is based mostly on how much protection it provides to the active components in the package. But the choice is not a straightforward process. Rather it is mostly trial and error using different assembly parameters to find the most robust material while assembly defects are monitored. One such defect associated to EMC processing is wire sweep, and many studies have shown that it is mainly caused by viscosity changes in the EMC. In this study, samples of EMC in various stages of shelf life and staging times were analyzed for degree of cure using a method called differential scanning calorimetry (DSC). Samples are then processed at assembly for wire sweep measurement. It was found out that degree of cure increases with staging time at different rates for each shelf life. It was also found out that wire sweep did not only increase with degree of cure but it was also found to be predictable with respect to the latter. Using this information, the age and staging limit for each material was identified that would not cause wire sweep issues.

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