Quality Enhancement of Tapioca Starch Gel using Sucrose and Xanthan Gum

Author(s):  
Duenchay Tunnarut ◽  
Rungnaphar Pongsawatmanit

AbstractThe quality of starch gel could be enhanced by sugar and hydrocolloid. Sucrose (0, 10 % and 20 %) and xanthan gum (Xan) (0.3125 %) were added in the tapioca starch (TS) gels (25 %w/w TS and TS/Xan gels) for quality investigation. Sucrose increased gelatinization temperatures of starch mixtures. Moisture content and water activity decreased with increasing sucrose content and Xan addition. Freeze–thaw stability of TS and TS/Xan gels with and without sucrose was evaluated. Sucrose and Xan decreased water separation from repeated freeze–thaw cycles. A regression model for predicting water separation from Xan, sucrose and selected freeze–thaw cycle was developed and showed a good predictability. After keeping the TS and TS/Xan gels at 5 °C for 7 and 14 days, the hardness of TS and TS/Xan gels increased with increasing sucrose content but was retarded by adding Xan (p<0.05), suggesting Xan impeded the structure formation contributed from amylose molecule association during cold storage.

2016 ◽  
Vol 19 (4) ◽  
pp. 50-63
Author(s):  
Duyen Dang My Nguyen ◽  
Le Thi Pham

Gelatinization of tapioca starch is retrograded during the frozen – storage. This retrogradation affects the quality of the starchy food. This paper studied the influence of various types of sugars: glucose, fructose, sucrose and maltose in different concentrations: 0 %, 2 %, 4 %, 6 %, 8 % (w/w) on the stability of tapioca starch gels over 5 freeze – thaw cycles. The syneresis, turbidity (OD) and the hydrolysis degree by apha–amylase of starch gels were determined to analysis the effect of sugars on the stability of the tapioca starch gels. Our result showed that the freeze – thaw stability of tapioca starch gels could be improved by adding sugars. The improvement of the syneresis (%) was in the order: maltose > sucrose > glucose > fructose. The result also showed that disaccharides (sucrose, maltose) were more effective than monosaccharides (glucose and fructose) in reducing the syneresis and turbidity. Adding maltose at 8 % (w/w) was the most effective in the reduction of the starch retrogradation


2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Zhongju Feng ◽  
Jianwei Huo ◽  
Haibo Hu ◽  
Ruixin Zhao ◽  
Fuchun Wang ◽  
...  

This study investigated the corrosion damage and bearing characteristics of bridge pile foundations under a dry-wet-freeze-thaw cycle of composite salt in an alpine salt marsh area using an in situ test, laboratory test, and numerical simulations. The in situ test showed that the dry-wet-freeze-thaw cycle has little effect on the quality of the concrete specimens and rebar. The area of the rebar at a depth of 0.25 m had the highest corrosion rate of 91%. The application of epoxy resin on the surface improved erosion resistance. After one year of outdoor dry-wet-freeze-thaw cycle test, due to the interaction of compound salts, the quality of specimens is reduced under the denudation of chloride ions, while the mass of specimens is increased by the corrosion products formed under the joint action of carbonate and sulfate, resulting in less obvious change of specimen quality, the antierosion coefficient of the specimens decreased, the maximum loss rate of compressive strength was 38.2%, and the pile foundation began to deteriorate. The laboratory test showed that expansive substances, such as Friedel salt, appeared in the concrete specimens of pile foundation during 225 cycles of dry-wet-freeze-thaw cycles, the relative dynamic elastic modulus was reduced by 60.9%, the antierosion coefficient was reduced to 0.51, and the compressive strength loss rate was 65.9%. As such, the pile foundation was seriously damaged. The numerical simulation shows that, with an increase of the peeling thickness and the corrosion depth, the bearing capacity of the pile foundation will gradually decrease after 8 years. Without maintenance, the bearing capacity of a pile foundation will decrease by 34.45% in the 20th year.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Longxiao Chen ◽  
Kesheng Li ◽  
Guilei Song ◽  
Deng Zhang ◽  
Chuanxiao Liu

AbstractRock deterioration under freeze–thaw cycles is a concern for in-service tunnel in cold regions. Previous studies focused on the change of rock mechanical properties under unidirectional stress, but the natural rock mass is under three dimensional stresses. This paper investigates influences of the number of freeze–thaw cycle on sandstone under low confining pressure. Twelve sandstone samples were tested subjected to triaxial compression. Additionally, the damage characteristics of sandstone internal microstructure were obtained by using acoustic emission (AE) and mercury intrusion porosimetry. Results indicated that the mechanical properties of sandstone were significantly reduced by freeze–thaw effect. Sandstone’ peak strength and elastic modulus were 7.28–37.96% and 6.38–40.87% less than for the control, respectively. The proportion of super-large pore and large pore in sandstone increased by 19.53–81.19%. We attributed the reduced sandstone’ mechanical properties to the degenerated sandstone microstructure, which, in turn, was associated with increased sandstone macropores. The macroscopic failure pattern of sandstone changed from splitting failure to shear failure with an increasing of freeze–thaw cycles. Moreover, the activity of AE signal increased at each stage, and the cumulative ringing count also showed upward trend with the increase of freeze–thaw number.


2021 ◽  
Vol 28 (3) ◽  
pp. 954-967
Author(s):  
Jie-lin Li ◽  
Long-yin Zhu ◽  
Ke-ping Zhou ◽  
Hui Chen ◽  
Le Gao ◽  
...  

2020 ◽  
Vol 2020 ◽  
pp. 1-13 ◽  
Author(s):  
Huren Rong ◽  
Jingyu Gu ◽  
Miren Rong ◽  
Hong Liu ◽  
Jiayao Zhang ◽  
...  

In order to study the damage characteristics of the yellow sandstone containing pores under the freeze-thaw cycle, the uniaxial compression test of saturated water-stained yellow sandstones with different freeze-thaw cycles was carried out by rock servo press, the microstructure was qualitatively analyzed by Zeiss 508 stereo microscope, and the microdamage mechanism was quantitatively studied by using specific surface area and pore size analyzer. The mechanism of weakening mechanical properties of single-hole yellow sandstone was expounded from the perspective of microstructure. The results show the following. (1) The number of freeze-thaw cycles and single-pore diameter have significant effects on the strength and elastic modulus of the yellow sandstone; the more the freeze-thaw cycles and the larger the pore size, the lower the strength of the yellow sandstone. (2) The damage modes of the yellow sandstone containing pores under the freeze-thaw cycle are divided into five types, and the yellow sandstone with pores is divided into two areas: the periphery of the hole and the distance from the hole; as the number of freeze-thaw cycles increases, different regions show different microscopic damage patterns. (3) The damage degree of yellow sandstone is different with freeze-thaw cycle and pore size. Freeze-thaw not only affects the mechanical properties of yellow sandstone but also accelerates the damage process of pores. (4) The damage of the yellow sandstone by freeze-thaw is logarithmic function, and the damage of the yellow sandstone is a power function. The damage equation of the yellow sandstone with pores under the freezing and thawing is a log-power function nonlinear change law and presents a good correlation.


2012 ◽  
Vol 455-456 ◽  
pp. 781-785
Author(s):  
Ping Lu ◽  
Xin Mao Li ◽  
Xue Qiang Ma ◽  
Wei Bo Huang

. This paper mainly studied the properties of PAE polyurea coated concrete under coactions of salt fog and freeze-thaw. After exposed salt fog conditions for 200d, T3, B2, F2 and TM four coated concrete relative dynamic elastic modulus have small changes, but different coated concrete variation amplitude is different. T3 coated concrete after 100 times of freeze-thaw cycle the relative dynamic elastic modulus began to drop, 200 times freeze-thaw cycle ends, relative dynamic elastic modulus variation is the largest, decrease rate is 95%, TM concrete during 200 times freeze-thaw cycle, relative dynamic elastic modulus almost no change, B2 concrete and F2 concrete the extent of change between coating T3 and TM. After 300 times the freeze-thaw cycle coated concrete didn't appear freeze-thaw damage phenomenon. Four kinds of coating concrete relative dynamic elastic modulus variation by large to small order: T3 coated concrete > B2 coated concrete >F2 coated concrete > TM coated concrete, concrete with the same 200d rule. Frost resistance order, by contrast, TM coated concrete > B2 coated concrete > F2 coated concrete > T3 coated concrete.


2005 ◽  
Vol 27 (9) ◽  
pp. 655-660 ◽  
Author(s):  
Dong-Wook Han ◽  
Hak Hee Kim ◽  
Mi Hee Lee ◽  
Hyun Sook Baek ◽  
Kwon-Yong Lee ◽  
...  

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