Polyglycerol esters of fatty acids are nonionic surfactants, which are broadly used for the food, cosmetic and the other industries. However, general commercial products are mixtures of many different components. That is, glyceroles with varying polymerization degree from glycerol to higher condensates of glycerol, are combined into fatty acids with different chain lengths. Furthermore, the estrification degree is changeable. Aqueous solutions of homogeneous polyglycerol monolaurates, which were synthesized in laboratory, were examined for surface tension, foaming property, interfacial tension, detergency, immersion wetting and solubility ability. Despite the low degree of glycerol polymerization, the interfacial activity of triglycerol monolaurate was the best, because the hydrophilic and lipophilic parts might be well balanced. On the other hand, highly refined polyglycerol esters of fatty acids, which are made from pentaglycerol with more than 60% purity have been already commercialized. Physicochemical properties of these esters were shown to be superior by various tests. Highly refined polyglycerol esters of fatty acids are applied to foods broadly. I described two examples of the application. The first is the micro-emulsion preparation, called“SuperEmulsion”. The second is“TAISET”, which can be used to improve the physical properties of oils and fats, that is, induce solidification or viscosity increase of oils and fats as well as control the size of emulsified oil droplets.
Okara (soybean curd waste), a by-product of tofu and soybean protein manufacturing, is treated as industrial waste. Maeda has proposed a method of extracting soybean water-soluble polysaccharides (SSPS) from okara, and has used the preparation as an emulsifier or viscoelastic reagent. SSPS had a high emulsifying ability of d-limonene in acid conditions as gum arabic (GA) . An emulsified solution of ethyl butyrate with GA was very unstable but SSPS could emulsify ethyl butyrate at pH 3-6. SSPS was also a superior emulsifier for hydrophilic oil compounds such as ethyl caproate and hexanol.
Thermolysin (EC 188.8.131.52) was suspended in organic solvents containing a small amount of water (aqueous buffer solution) by two different methods, and the catalytic activity as well as the conformational changes in the enzyme were compared. In one method (Method 1), dried powder enzyme was directly suspended in organic solvents containing a small amount of water while in the second method (Method 2), the dried enzyme was first dissolved in the buffer solution and then added to the anhydrous organic solvents containing the same final water content as that used in Method 1. In Method 2, the enzymes showed a catalytic activity 2-10 times as high as that in Method 1. The ratio of the activity obtained in Method 2 to that in Method 1 strongly depended on kinds of organic solvents, and its dependency was reasonably explained by the ET (30) values, which represent the extent of polarity of an organic solvent. The Fourier transform infrared spectroscopy (FT-IR) analyses indicated that the enzyme conformation in Method 2 was closer to its native one than that in Method 1. The influences of the suspension method on the enzyme activities of the different forms of the enzyme (as donated, dialyzed, and cross-linked) and the courses of the enzyme activities during incubation in Methods 1 and 2 were also investigated