Thermal degradation kinetics of sugars under typical processing conditions found in Brazilian sugar and ethanol factories

2018 ◽  
pp. 520-533
Author(s):  
Jonas Nolasco Jr ◽  
Pilar Rodriguez de Massaguer

The thermal profile of juice from clarification to syrup including the transfer pipes in a Brazilian sugar mill was determined to estimate the sugar losses through kinetics. Two cane juice flow rates (100% and 60% of maximum) were studied under technical conditions. At the maximum cane juice flow rate and considering only the evaporation set, the total thermal hydrolysis of sucrose and degradation of total sugar as invert sugar, TSAI, were 1.09% and 0.32%, respectively. Including clarification with its residence time of 70 min, losses increased to 1.67% and 0.53%, respectively. At the lower flow rate, losses were 0.99% and 0.30%, respectively and increased to 1.58% and 0.51%, respectively taking clarification into account. The tools used in this work are widely applied in the food industry to optimize thermal processes to achieve maximum retention of nutrients and shelf life of products.

Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1597
Author(s):  
Iman Jafari ◽  
Mohamadreza Shakiba ◽  
Fatemeh Khosravi ◽  
Seeram Ramakrishna ◽  
Ehsan Abasi ◽  
...  

The incorporation of nanofillers such as graphene into polymers has shown significant improvements in mechanical characteristics, thermal stability, and conductivity of resulting polymeric nanocomposites. To this aim, the influence of incorporation of graphene nanosheets into ultra-high molecular weight polyethylene (UHMWPE) on the thermal behavior and degradation kinetics of UHMWPE/graphene nanocomposites was investigated. Scanning electron microscopy (SEM) analysis revealed that graphene nanosheets were uniformly spread throughout the UHMWPE’s molecular chains. X-Ray Diffraction (XRD) data posited that the morphology of dispersed graphene sheets in UHMWPE was exfoliated. Non-isothermal differential scanning calorimetry (DSC) studies identified a more pronounced increase in melting temperatures and latent heat of fusions in nanocomposites compared to UHMWPE at lower concentrations of graphene. Thermogravimetric analysis (TGA) and derivative thermogravimetric (DTG) revealed that UHMWPE’s thermal stability has been improved via incorporating graphene nanosheets. Further, degradation kinetics of neat polymer and nanocomposites have been modeled using equations such as Friedman, Ozawa–Flynn–Wall (OFW), Kissinger, and Augis and Bennett’s. The "Model-Fitting Method” showed that the auto-catalytic nth-order mechanism provided a highly consistent and appropriate fit to describe the degradation mechanism of UHMWPE and its graphene nanocomposites. In addition, the calculated activation energy (Ea) of thermal degradation was enhanced by an increase in graphene concentration up to 2.1 wt.%, followed by a decrease in higher graphene content.


Materials ◽  
2017 ◽  
Vol 10 (11) ◽  
pp. 1246 ◽  
Author(s):  
Samson M. Mohomane ◽  
Tshwafo E. Motaung ◽  
Neerish Revaprasadu

2002 ◽  
Vol 86 (4) ◽  
pp. 957-961 ◽  
Author(s):  
Priyadarsi De ◽  
Sujay Chattopadhyay ◽  
Giridhar Madras ◽  
D. N. Sathyanarayana

2018 ◽  
Author(s):  
Abdullah Al-Yami ◽  
Vikrant Wagle ◽  
Walmy Cuello Jimenez ◽  
Paul Jones

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