Influence of water activity and dry-heating time on egg white powders quality

Gelling properties stability of the Maillard-type and dry-heating egg white proteins (MEW and DEW) were investigated. MEW were prepared by storing sugar-preserved egg white proteins and glucose at 60 °C and 79% relative humidity for 2 days, and DEW were prepared by storing at 80°C in dry state (7.5% moisture content) for 7 days. The results showed that both MEW and DEW have excellent gelling properties. After storage at room temperature for 180 days, gel hardness, spring and cohesiveness of MEW increased by 1.92%, 1.89% and 4.24% respectively, water holding capacity of MEW gel decreased by 1.42%, while storage time had a considerable effect on those of DEW gels. A tight and more uniform network with constant stability in the course of storage was observed in the gel of MEW (500×), while gaps in EWP gel network were larger and the gel texture became looser with storage time. The results demonstrated that gelling properties stability of MEW is better than DEW.

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Influence of water activity and temperature on conidial germination and mycelial growth of ochratoxigenic isolates ofAspergillus ochraceus on grape juice synthetic medium. Predictive models

Journal of the Science of Food and Agriculture ◽

10.1002/jsfa.2171 ◽

2005 ◽

Vol 85 (10) ◽

pp. 1681-1686 ◽

Cited By ~ 19

Author(s):

Ester Pardo ◽

Ursino Lagunas ◽

Vincente Sanchis ◽

Antonio J Ramos ◽

Sonia Marín

Keyword(s):

Water Activity ◽

Predictive Models ◽

Mycelial Growth ◽

Synthetic Medium ◽

Grape Juice ◽

Conidial Germination ◽

Influence Of Water

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Influence of Water Activity on Protease Adsorbed on Biochar in Organic Solvents

Journal of Materials Science Research ◽

10.5539/jmsr.v6n4p96 ◽

2017 ◽

Vol 6 (4) ◽

pp. 96 ◽

Cited By ~ 2

Author(s):

Hidetaka Noritomi ◽

Jumpei Nishigami ◽

Nobuyuki Endo ◽

Satoru Kato ◽

Katsumi Uchiyama

Keyword(s):

Thermal Stability ◽

Catalytic Activity ◽

Organic Solvents ◽

Water Activity ◽

Initial Rate ◽

Butyl Ester ◽

Nitrogen Atmosphere ◽

Bamboo Charcoal ◽

Influence Of Water ◽

Hydrolysis Of

We have found that the organic solvent-resistance of Alpha-chymotrypsin (Alpha-CT) is enhanced by adsorbing Alpha-CT onto bamboo charcoal powder (BCP), which is obtained by pyrolyzing bamboo waste under nitrogen atmosphere, and is markedly dependent on the thermodynamic water activity (aw) in organic solvents. When BCP-adsorbed　Alpha-CT was immersed in acetonitrile at an appropriate water activity, it effectively enhanced the transesterification of N-acetyl-L-tyrosine ethyl ester (N-Ac-Tyr-OEt) with n-butanol (BuOH) to produce N-acetyl-L-tyrosine butyl ester (N-Ac-Tyr-OBu), compared to the hydrolysis of N-Ac-Tyr-OEt with water to give N-acetyl-L-tyrosine (N-Ac-Tyr-OH). When the water activity was 0.28, the initial rate of transesterification catalyzed by BCP-adsorbed Alpha-CT was about sixty times greater than that catalyzed by free Alpha-CT. Regarding the reaction selectivity which is defined as a ratio of the initial rate of transesterification to that of hydrolysis, BCP-adsorbed α-CT was much superior to free Alpha-CT. The catalytic activity of BCP-adsorbed Alpha-CT was markedly dependent on the reaction temperature. Furthermore, concerning the thermal stability at 50 oC, the half-life of BCP-adsorbed Alpha-CT exhibited 3.8-fold, compared to that of free Alpha-CT.

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