Surface activity of the lipid products hydrolyzed with lipase and phospholipase A-2

Enzymatic preparation and characterization of soybean lecithin-based emulsifiers

Simple enzymatic methods were developed for the synthesis of lysolecithin, glycerolyzed lecithin and hydrolyzed lecithin. The products were characterized in terms of their acetone insoluble matter, hexane insoluble matter, moisture, phospholipid distribution and fatty acid composition. The HLB value ranges of different products with different acid values were detected. The efficiency of optimally hydrolyzed lecithin was examined at high calcium ion, low pH, and aqueous solutions and compared with commercially available standard lecithin-based emulsifiers. Overall, lysolecithin powder was proven to be the best emulsifier even at strong and medium acidic conditions.

Modification of milk and whey surface properties by enzymatic hydrolysis of milk phospholipids

Phospholipase A1 were shown to improve foaming properties of skim milk and whey, implying that phospholipases can be useful tools for modifying the functionality of dairy products and ingredients. The ability of three fungal phospholipases and porcine pancreatic phospholipase A2 to hydrolyze milk phospholipids was investigated by using sodium deoxycholate-solubilized milk phospholipid and whole milk. The enzyme with the highest activity in milk was Fusarium venenatum phospholipase A1. Milk and whey were subsequently characterized using tensiometry and interfacial shear rheology. The lysophospholipids released from the fat globule membrane decreased the surface tension of skim milk and whey. A dramatic decrease in the surface shear viscous and elastic moduli indicated a shift from a protein-dominated to a surfactant-dominated interface. The surface shear moduli did not correlate with the foam stability, which was improved by phospholipase A1.

Wetting behavior of bile salt-lipid dispersions and dissolution media patterned after intestinal fluids

The wetting properties of bile salt-lipid solutions and dispersions patterned after the contents of the upper intestine in the fed and fasted states were evaluated using poly(methyl methacrylate) (PMMA) as a model substrate. The surface tension of the solutions and their contact angles on PMMA were measured. Media compositions for the intestinal fed and fasted states were estimated on the basis of physiologic data. The effect of various individual lipids and media composition was also evaluated relative to the adhesional, immersional, and spreading stages of wetting. In micellar systems, both the type and concentration of lipid present in the bile salt solution had an influence on wetting. The wetting of media patterned after gastrointestinal contents showed marked differences with respect to the fed or fasted state compositions. For the fed state compositions, alteration of the solution pH from 7.5 to 5.0 resulted in a significant change in wetting. The surface tension of the medium representative of the fasted state was 15 mN/m higher than that of the fed state. The wetting properties of the physiologically representative media formulated in this study were markedly different compared with other media proposed in the literature. Analysis of the wetting behavior of individual lipids as a function of concentration in bile salt solutions showed that they adsorb in a manner that progressively reduces the expected wetting of the surface. The results have implications for the design and formulation of both biorelevant and surfactant-based dissolution media.