scholarly journals Effects of freezing and thawing cycles on the quality of Nile tilapia fillets

2020 ◽  
Vol 40 (suppl 1) ◽  
pp. 300-304
Author(s):  
Jovana Silva Garbelini ZUANAZZI ◽  
Elenice Souza dos Reis GOES ◽  
Fernanda Losi Alves de ALMEIDA ◽  
Marcio Douglas GOES ◽  
Jorge Antônio Ferreira de LARA ◽  
...  
2020 ◽  
Vol 39 (2) ◽  
pp. 177-180
Author(s):  
Hemmat Ibrahim ◽  
Mohamed Hassan ◽  
Reham Amin ◽  
Omayma Maghraby ◽  
ahmed mostafa

Materials ◽  
2019 ◽  
Vol 12 (2) ◽  
pp. 325 ◽  
Author(s):  
Jae Kim ◽  
Sun-Jong Park ◽  
Hong Yim

Under cold environments, the freezing and thawing cycles of water in concrete reduce the lifetime and durability of concrete structures. For enhanced freezing and thawing resistance, entrained air voids are generally required, but malfunctioning of air entrainment is sometimes reported in the field. To evaluate the quality of air entrainment, this study proposes a nondestructive method that is a preceding evaluation before damage to the concrete. A nonlinear resonance vibration method is adopted in samples having an identical air void content. The durable concrete sample with resistance to freezing and thawing cycles shows higher nonlinearity in its resonance. Thus, the quality of air entrainment and, furthermore, the potential freezing and thawing resistance can possibly be evaluated by measuring the nonlinearity parameter of the concrete, which is preliminary study to attempt the preceding evaluation of freezing and thawing resistance using nondestructive method.


Aquaculture ◽  
2020 ◽  
Vol 520 ◽  
pp. 734941
Author(s):  
Carlos Adriano Rocha Silva Morais ◽  
Thaís Pacheco Santana ◽  
Camilo Azevedo Santos ◽  
Rodrigo Augusto Cortez Passetti ◽  
José Fernando Bibiano Melo ◽  
...  

Author(s):  
Zainab Saad Abdulrahman ◽  
Ahmed Alaa Shakir ◽  
Gring Kadir Mustafa

Background: The quality of bread depends not only on the quality of its ingredients, proper techniques during preparation, and storage also played a role in the rate of staling. Aims: The present study aims to investigate the impact of freezing and thawing on the glycemic response of Iraqi local white bread. Methods: In this prospective cross-over study, twelve healthy subjects (seven males, five females), aged 21–53 years, were recruited from Al-Rafidain University Campus and the local community. After overnight fasting, commercial Iraqi local white bread (200 g) was administered as fresh bread, following 1-week or 2-week freezing and thawing. Peak glucose response, 2 hr incremental area under the glucose response curve (AUC0-120) was evaluated as an outcome. Results: The different freezing and thawing conditions resulted in lower blood glucose AUC values compared to fresh white bread. In particular, compared to the fresh bread (AUC 14176±1134 mg min/dl), AUC was significantly lower when the bread was 1-week frozen and thawed (13205±660 mg min/dl, P<0.01), or 2-week frozen and thawed (12828±642 mg min/dl, P<0.01). Meanwhile, compared to the 1-week frozen bread, the 2-week freezing cycle did not produce a significantly lower AUC value. Conclusion: One or two freezing and thawing cycles decreased the glycemic response of the fresh Iraqi local white bread in healthy non-obese volunteers.


Aquaculture ◽  
2018 ◽  
Vol 482 ◽  
pp. 96-102 ◽  
Author(s):  
Nilda L.A.F. Sarmento ◽  
Edenilce F.F. Martins ◽  
Deliane C. Costa ◽  
Cristiano C. Mattioli ◽  
Gustavo S. da Costa Julio ◽  
...  

2020 ◽  
Vol 12 (1) ◽  
pp. 125-131
Author(s):  
Raudhah Mahfudhah ◽  
Kartini Eriani ◽  
Zainal Abidin Muchlisin ◽  
Cut Ruhul Muthmainnah

The cryopreservation process might reduce the quality of spermatozoa due to an increase in the production of reactive oxygen species (ROS) compounds during cooling, freezing, and thawing. The quality of spermatozoa can be maintained by adding glutathione as an exogenous antioxidant into cryo-diluent. This study aimed to examine the effect of the addition of different doses of glutathione in cryopreservation of Aceh Local catfish (Clarias gariepinus) spermatozoa after freezing. The method used was a completely randomized design (CRD) with four treatments and four replications. Fresh semen was diluted in Ringer, 15% DMSO, and 20% Fetal Bovine Serum (FBS) and then added with glutathione antioxidants of 0.0 mgL-1, 0.5 mgL-1, 1.0 mgL-1, and 2.0 mgL-1. The parameters observed in this study were motility, integrity of the plasma membrane, fertility, and DNA integrity. The results showed that the concentration of glutathione had no effect on motility, integrity ofthe plasma membrane, or fertility, but had an effect on DNA integrity. The highest percentage of motility and plasma membrane integrity respectively was 40.50% (P3) and 70.87% (P2). Furthermore, the assessment of DNA integrity showed that there was no DNA fragmentation both treatments and fresh spermatozoa. This research is the first study regarding glutathione supplementation in cryo-diluent of Aceh Local catfish spermatozoa. Finally, the results obtained can provide information about the exact concentration of glutathione in the extender on the quality of spermatozoa of Aceh Local catfish (C. gariepinus) after the cryopreservation process. These results can also increase the success of fertility be used by the seed hall unit and the aquaculture industry to increase the productivity and supply high quality seeds.


Author(s):  
Genadijs Sahmenko ◽  
Sandis Aispurs ◽  
Aleksandrs Korjakins

Traditionally, sculptural and decorative elements of building facades are created from mortar mixes based on lime, gypsum or Portland cement. Generally these materials have porous and permeable structure, which determines their accelerated degradation, especially in the aggressive environment of modern cities. High performance cement composites (HPCC) have been considered for production and restoration of sculptural elements in historical buildings. For this purpose, fine-graded, multi-component and highly workable mixes were elaborated. Mix compositions were modified with micro-fillers, plasticizing and stabilizing admixtures, as well as fibers to improve material ductility and control shrinkage cracking. Basic mechanical properties and durability (such as water absorption, frost resistance) were determined and two types of HPCC were compared (>50 MPa: HPCC and >120 MPa: UHPCC). It has been confirmed that cement composite mixes are characterized by self-consolidating effect, high compressive strength, extremely high resistance versus freezing and thawing cycles and low water absorption. Surface quality was evaluated and initial water absorption (tube tests) were performed for laboratory samples and real sculptural elements after 5 years of exploitation. The results confirmed good potential for using HPCC for creating more attractive and durable architectural shapes and façade elements compared to elements made using traditional cement and lime mortar.


Materials ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 1850
Author(s):  
Jinjun Guo ◽  
Ting Guo ◽  
Shiwei Zhang ◽  
Yan Lu

The freezing and thawing of construction concrete is becoming an increasingly important structural challenge. In this study, a shrinkage-compensating concrete based on a double expansive admixture was developed and its frost resistance was assessed through rapid freezing and thawing cycling. The frost resistance of the concrete was derived through the measurement and calculation of the relative dynamic modulus of elasticity (RDME) and the mass loss rate (MLR), and the freezing- and thawing-cycle microstructures and products of concretes with different expansive agents were analyzed using scanning electron microscopy (SEM). It was shown that changes in the properties of the concrete under freezing and thawing could be divided into three stages: slow-damage stage, fast-damage stage, and stable stage. Compared to concrete without an expansive agent, a single-expansive-agent concrete demonstrated excellent frost resistance during the slow-damage stage, but the frost resistance rapidly decreased during the fast-damage age. After 150 cycles (the stable-damage stage), the concrete with a U-type expansive agent (UEA): MgO expansive agent (MEA) mix proportion of 2:1 had the best frost resistance, with RDME and MLR values 17.35% higher and 25.1% lower respectively, than that of an expansive-agent-free concrete. These test results provide a basis for the study of frost resistance in large-scale hydraulic concrete structures.


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