Glyceryl monostearate (monoglyceride) is a white waxy flake or bead solid, insoluble in water, and can be dispersed by vigorous shaking with hot water. In water, it is a water-in-oil emulsifier. Soluble in hot organic solvents ethanol, benzene, acetone, mineral oil and fixed oil. The freezing point is not lower than 54℃.
The four chemical properties of glyceryl monostearate are as follows:
1. Sensory properties: Monoglycerides are related to fats and oils, and their sensory properties are similar to fats and oils. Its consistency is related to the fatty acid group, and it can generally be oily, greasy or waxy. Generally speaking, monoglycerides have a higher consistency and melting point than the oils or fatty acids used in them. The changing pattern of the melting point of monoglycerides is: as the carbon chain of the fatty acid is extended, the melting point of monoglycerides increases; The color and smell of ester are related to the corresponding fatty acid group and the source of raw materials. Its smell generally has a grease smell, and its color ranges from brown to milky white.
2. Thermal stability: Monoglyceride is a mixture of 1-monoglyceride and 2-monoglyceride, which is where the acyl group transfer occurs within the molecule As a result, the activation energy of this intramolecular acyl transfer is relatively low, so the monoglyceride is a mixture of the two at any temperature, but the ratio of the two varies with temperature.
3. Crystallization behavior: As a lipid compound, monoglyceride has a homogeneous polycrystalline phenomenon. Distilled monoglycerides crystallize into a metastable α-crystalline form and then convert to a higher melting stable β-crystalline form. Metastable β′-crystalline forms do not exist in technical monoglycerides. When the α-crystalline form cools, a solid-state transition to a third crystalline form, called sub-alpha, occurs.
4. Mesogenic properties: Monoglycerides and water can have very complex interactions, the degree of which depends on the temperature and the interaction between monoglycerides and water. The ratio is also related to the type of fatty acid. The formed material can exhibit both crystalline and liquid properties at the same time, that is, mesogenicity. The mesomorphic phases of monoglyceride include: lamellar mesophase (lamellar phase), α-gel, cubic phase, hexagonal phase, etc. Monoglyceride is β-crystalline at room temperature, which is a lipid bilayer structure. , connected by polar groups relying on hydrogen bonds in the middle, this layer has a strong affinity with water. When the temperature is higher than the Clough point, water begins to penetrate into the polar layer of the bilayer, forming a layered intermediate phase.
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