Role of the water-air interface in determining the surface tension of aqueous solutions of sugars, polysaccharides, proteins and surfactants

2019 ◽  
Vol 48 (2) ◽  
pp. 28-35
Author(s):  
Вера Евелева ◽  
Vera Eveleva ◽  
Татьяна Черпалова ◽  
Tatyana Cherpalova ◽  
Елена Шиповская ◽  
...  

Common characteristic of salad products is presence of cut raw vegetables in its composition. Cold cutting helps surface microorganisms penetrate into deep layers of the product. Hygienic cleanliness of raw ingredients is the major factor which contributes to storage stability of salad products. One of the most effective methods that helps enhance salad storage stability is initial treatment of vegetable raw materials with antimicrobial solutions. The author presents information on using solutions of hydrogen peroxide and peroxyacetic acid, sodium hypochlorite and compositions containing peroxide compounds and acetic, benzoic, sorbic, ascorbic, citric, lactic and other acids as well as their salts and containing guanidylic compounds. The article reveals that antimicrobial action of lactate-containing processing aids improves sufficiently if polymer cation-active compounds are introduced into their composition. The goal of the research is to study application effectiveness of new processing aids for treatment of raw peeled cut vegetables to reduce bacterial content and enhance storage stability before thermal treatment (boiling). The author tested the aids based on lactate-containing components. Physicochemical and physical parameters of the aids and their aqueous solutions are the following: active acidity (pH), titratab6le acidity, water and volatiles mass fraction, dynamic viscosity, surface tension. The article presents the data which characterize change in surface tension of aqueous solutions of the aids at the water-air interface depending on their concentration. It also gives quality indicators and microbial parameters of raw peeled cut vegetables after their processing with solutions of the aids. It was found out that treatment of raw peeled cut vegetables with processing aids based on lactate containing components prolongs their shelf life from 3 hours according to the applicable technology up to 48 hours.


2021 ◽  
Vol 5 (4) ◽  
pp. 53
Author(s):  
Bronisław Jańczuk ◽  
Anna Zdziennicka ◽  
Katarzyna Szymczyk ◽  
Maria Luisa González-Martín

Measurements of the surface tension of the aqueous solution of SDDS mixture with fluorocarbon surfactants (FC) were carried out and considered in light of the surface tension of aqueous solutions of individual surfactants. Similar analyses were made for many other aqueous solutions of binary and ternary mixtures, taking into account the literature data of the surface tension of aqueous solutions of TX100, TX114, TX165, SDDS, SDS, CTAB, CPyB and FC. The possibility of predicting the surface tension of the aqueous solution of many surfactant mixtures from that of the mixture components using both the Szyszkowski, Fainerman and Miller and Joos concepts was analyzed. The surface tension of the aqueous solutions of surfactant mixtures was also considered based on the particular mixture component contribution to the water surface tension reduction. As a result, the composition of the mixed surface layer at the solution–air interface was discussed and compared to that which was determined using the Hua and Rosen concept. As follows from considerations, the surface tension of the aqueous solution of binary and ternary surfactant mixtures can be described and/or predicted.


Langmuir ◽  
2011 ◽  
Vol 27 (3) ◽  
pp. 1009-1014 ◽  
Author(s):  
Hernán Ritacco ◽  
Dominique Langevin ◽  
Haim Diamant ◽  
David Andelman

2020 ◽  
Vol 106 ◽  
pp. 105883 ◽  
Author(s):  
V.B. Fainerman ◽  
E.V. Aksenenko ◽  
A.V. Makievski ◽  
D.V. Trukhin ◽  
S. Yeganehzad ◽  
...  

1995 ◽  
Vol 60 (4) ◽  
pp. 527-536 ◽  
Author(s):  
Martin Breza ◽  
Alena Manová

Using semiempirical MNDO method of quantum chemistry the optimal geometries and corresponding electronic structures of [Pb3(OH)n]6-n model systems as well as of their hydrated [Pb3(OH)n(H2O)8-n]6-n analogues (n = 4, 5) are investigated. The most stable trinuclear lead(II) complexes present in aqueous solutions correspond to cyclo-(μ3-OH)(μ2-OH)3Pb32+, Pb(μ-OH)2Pb(μ-OH)2Pb2+, cyclo-(μ3-OH)2(μ2-OH)3Pb3+, Pb(OH)(μ-OH)2Pb(μ-OH)Pb(OH)+ and Pb(OH)(μ-OH)2Pb(μ-OH)2Pb+ systems. The key role of OH bridges (by vanishing direct Pb-Pb bonds) on the stability of individual isomers is discussed.


1996 ◽  
Vol 118 (1) ◽  
pp. 103-109 ◽  
Author(s):  
W. R. McGillis ◽  
V. P. Carey

The Marangoni effect on the critical heat flux (CHF) condition in pool boiling of binary mixtures has been identified and its effect has been quantitatively estimated with a modified model derived from hydrodynamics. The physical process of CHF in binary mixtures, and models used to describe it, are examined in the light of recent experimental evidence, accurate mixture properties, and phase equilibrium revealing a correlation to surface tension gradients and volatility. A correlation is developed from a heuristic model including the additional liquid restoring force caused by surface tension gradients. The CHF condition was determined experimentally for saturated methanol/water, 2-propanol/water, and ethylene glycol/water mixtures, over the full range of concentrations, and compared to the model. The evidence in this study demonstrates that in a mixture with large differences in surface tension, there is an additional hydrodynamic restoring force affecting the CHF condition.


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