Kinetics of Thermomechanical Destruction of Thiamin During Extrusion Cooking

2008 ◽  
Vol 63 (2) ◽  
pp. 312-316 ◽  
Author(s):  
S. ILO ◽  
E. BERGHOFER
2020 ◽  
Vol 16 (4) ◽  
pp. 592-600
Author(s):  
Sajad A. Wani ◽  
Tariq A. Bhat ◽  
Nawaz A. Ganie ◽  
Pradyuman Kumar

Background: The extrusion cooking is the most widely used process so the development and consumption of extruded snack products having health and nutritious benefits would help increase the health status of the population. Objective: The aim of this study was to investigate the effect of storage days on physical, microbial activity and sensory characteristics of extruded snacks and kinetics of extruded snacks. Methods: Extruded snacks were produced by extrusion cooking at optimized conditions of temperature, moisture and screw speed of 110°C, 12% (db) and 200 rpm. The products were packed in lowdensity polyethylene (LDPE) and laminated pouches (LP) and were stored at an accelerated temperature condition of 40 ± 2°C. The storage stability in terms of quality parameters such as moisture, hardness, bulk density, color, lateral expansion, sensory characteristics and total plate count was investigated. Results: An increase (p≤0.05) in the value of moisture, bulk density, a*, and total plate count was observed during the storage period, whereas hardness, L*, b*, ΔE and sensory characteristics showed significant (p≤0.05) decreased order with storage period. No significant effect on the lateral expansion of the extruded product was observed. A significant decrease in total carbohydrate, fat and protein content was found during the storage period. The average sensory score and microbial analysis suggested that extruded snacks packed in LDPE pouches can only be acceptable up to the 60th day and extruded snacks packed in LP can be acceptable to more than 90th day. The kinetics of color and hardness suggest first order kinetics. Conclusion: Overall investigation suggested that extruded snacks were more stable in the LP as compared to LDPE pouches.


2020 ◽  
Vol 15 (2) ◽  
pp. 591-602
Author(s):  
Andri Cahyo Kumoro ◽  
Diah Susetyo Retnowati ◽  
Ratnawati Ratnawati

The presence of glucomannan in Konjac (Amorphophallus oncophyllus) tuber flour has promoted its various applications, especially in the food, drink, drug delivery and cosmetics. Starch is the main impurity of Konjac tuber flour. Although the common wet refining method may result in a high purity Konjac tuber flour, it is very tedious, time consuming and costly. This research aimed to study the kinetics of starch degradation in the extrusion cooking process of dry refining method to produce high quality Konjac tuber flour. In this research, Konjac tuber flour with 20% (w/w) moisture was extruded in a single screw extruder by varying screw speeds (50, 75, 100, 125, 150 and 175 rpm) and barrel temperatures (353, 373, 393, 413 and 433 K). The results showed that the starch extrusion cooking obeys the first reaction order. The reaction rate constant could be satisfactorily fitted by Arrhenius correlation with total activation energy of 6191 J.mol−1 and pre-exponential factor of 2.8728×10−1 s−1. Accordingly, thermal degradation was found to be the primary cause of starch degradation, which shared more than 99% of the energy used for starch degradation. Based on mass Biot number and Thiele modulus evaluations, chemical reaction was the controlling mechanism of the process. The results of this research offer potential application in Konjac tuber flour refining process to obtain high quality flour product. Copyright © 2020 BCREC Group. All rights reserved 


Author(s):  
J. F. DeNatale ◽  
D. G. Howitt

The electron irradiation of silicate glasses containing metal cations produces various types of phase separation and decomposition which includes oxygen bubble formation at intermediate temperatures figure I. The kinetics of bubble formation are too rapid to be accounted for by oxygen diffusion but the behavior is consistent with a cation diffusion mechanism if the amount of oxygen in the bubble is not significantly different from that in the same volume of silicate glass. The formation of oxygen bubbles is often accompanied by precipitation of crystalline phases and/or amorphous phase decomposition in the regions between the bubbles and the detection of differences in oxygen concentration between the bubble and matrix by electron energy loss spectroscopy cannot be discerned (figure 2) even when the bubble occupies the majority of the foil depth.The oxygen bubbles are stable, even in the thin foils, months after irradiation and if van der Waals behavior of the interior gas is assumed an oxygen pressure of about 4000 atmospheres must be sustained for a 100 bubble if the surface tension with the glass matrix is to balance against it at intermediate temperatures.


Author(s):  
R. J. Lauf

Fuel particles for the High-Temperature Gas-Cooled Reactor (HTGR) contain a layer of pyrolytic silicon carbide to act as a miniature pressure vessel and primary fission product barrier. Optimization of the SiC with respect to fuel performance involves four areas of study: (a) characterization of as-deposited SiC coatings; (b) thermodynamics and kinetics of chemical reactions between SiC and fission products; (c) irradiation behavior of SiC in the absence of fission products; and (d) combined effects of irradiation and fission products. This paper reports the behavior of SiC deposited on inert microspheres and irradiated to fast neutron fluences typical of HTGR fuel at end-of-life.


Author(s):  
Shiro Fujishiro ◽  
Harold L. Gegel

Ordered-alpha titanium alloys having a DO19 type structure have good potential for high temperature (600°C) applications, due to the thermal stability of the ordered phase and the inherent resistance to recrystallization of these alloys. Five different Ti-Al-Ga alloys consisting of equal atomic percents of aluminum and gallium solute additions up to the stoichiometric composition, Ti3(Al, Ga), were used to study the growth kinetics of the ordered phase and the nature of its interface.The alloys were homogenized in the beta region in a vacuum of about 5×10-7 torr, furnace cooled; reheated in air to 50°C below the alpha transus for hot working. The alloys were subsequently acid cleaned, annealed in vacuo, and cold rolled to about. 050 inch prior to additional homogenization


Author(s):  
L. J. Chen ◽  
L. S. Hung ◽  
J. W. Mayer

When an energetic ion penetrates through an interface between a thin film (of species A) and a substrate (of species B), ion induced atomic mixing may result in an intermixed region (which contains A and B) near the interface. Most ion beam mixing experiments have been directed toward metal-silicon systems, silicide phases are generally obtained, and they are the same as those formed by thermal treatment.Recent emergence of silicide compound as contact material in silicon microelectronic devices is mainly due to the superiority of the silicide-silicon interface in terms of uniformity and thermal stability. It is of great interest to understand the kinetics of the interfacial reactions to provide insights into the nature of ion beam-solid interactions as well as to explore its practical applications in device technology.About 500 Å thick molybdenum was chemical vapor deposited in hydrogen ambient on (001) n-type silicon wafer with substrate temperature maintained at 650-700°C. Samples were supplied by D. M. Brown of General Electric Research & Development Laboratory, Schenectady, NY.


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