Translucent Gel Research Articles

Sodium Chloride Effect on Autoxidation of the Lard Component of a Gel

SUMMARY: Stable gels composed of lard, sodium carbomethoxy cellulose and water were used for the examination of factors involved in the pro‐ and antioxidant activities of sodium chloride, other inorganic salts, heme compounds, meat fractions and other additives. Autoxidation processes were evaluated by peroxide and monocarbonyl determinations. The solid translucent gels, in which additives had been incorporated, were stored frozen, freeze‐dried or allowed to oxidize without physical change. The hydrated gels were well aerated in preparation and oxidized in the dark at a convenient pace at 20°C. When the gel was freeze‐dried, a sponge‐like structure was obtained which, after an induction period, autoxidized rapidly. Freezer‐stored gels autoxidized at a rate roughly similar to freezer‐stored meat. Sodium chloride had a direct pro‐oxidant action on the lard of freezer‐stored and dehydrated gels. Hydrated gels containing NaCl when stored at 20°C had an inhibiting autoxidation pattern somewhat similar to the quantitative influence of NaCl on pH. Ethylene‐diaminetetraacetate (EDJA) had a powerful antioxidant influence. Sodium chloride accelerated heme catalysis regardless of the presence of antioxidant or chelator. Interesting differences in monocarbonyl patterns and monocarbonyl/peroxide ratios as influenced by additives and moisture content of the gels were observed.

Gelation of soluble fibrin in plasma by ethanol.

At room temperature, the thrombin time of plasma is markedly shortened by ethanol. This effect is restricted to the polymerisation phase. In contrast to other fibrinoplastic substances, such as dextran or calcium, ethanol causes rapid end‐to‐end aggregation of fibrin, producing translucent gels. Such gels are obtained with fibrin concentrations, otherwise soluble in plasma. Gelation by ethanol seems to be specific for fibrin and is favourized by a high fibrinogen concentration, whereas fibrinoplastic substances exert the opposite effect. The presented data indicate that the ‘ethanol test’ might be used for detection of soluble fibrin in circulating blood.

Viscometric behavior of polyacrylate ion in concentrated salt solutions

AbstractViscosities of polyacrylate ion in the presence of potassium bromide, sodium bromide, lithium bromide, sodium iodide, sodium hydroxide, and hydrochloride acid in aqueous solution were measured over the approximate ranges 0.0–0.6% polymer and salt up to saturation with respect to polyacrylate or to salt. The general initial effect of added electrolyte is to reduce the ratio ηsp/c and to convert the curve characteristic of polyelectrolytes into a straight line, which can be extrapolated to zero polymer concentration to given [η], the intrinsic viscosity of the polymer in the presence of excess salt. Sodium hydroxide and sodium bromide produce minima in plots of [η] against salt concentration. Sodium iodide precipitates polyacrylate at 1.5 N iodide as a translucent gel, which redissolves at 3.0 N and finally reprecipitates at 6 N. In the latter range of concentration, [η] exhibits a maximum. Both by‐ions and counter‐ions have specific effects on the viscosity of the polyion.