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Long‐term stability studies on stored glycerol monostearate (GMS)‐effects of relative humidity
Author(s) -
Robbins S. James,
Nicholson Sherry H.
Publication year - 1987
Publication title -
journal of the american oil chemists' society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.512
H-Index - 117
eISSN - 1558-9331
pISSN - 0003-021X
DOI - 10.1007/bf02546265
Subject(s) - monoglyceride , chemistry , relative humidity , diglyceride , chromatography , glycerol , hydrolysis , organic chemistry , fatty acid , physics , thermodynamics
The long‐term hydrolysis and isomerizations that occurred in commercial glycerol monostearate (GMS) have been studied under controlled low relative humidity (ca. 30%) and high relative humidity (ca. 90–100%). Acid number values increased 2–3 units over an 84‐day period in high relative humidity, and only 0.5 unit in low humidity. Changes in the total α ‐monoglyceride, β ‐monoglyceride, α,α′ ‐and α,β ‐diglyceride concentrations with time offered a method to observe the processes involved. Changes in monoglyceride and diglyceride concentrations of GMS were monitored using the BSTFA [(N,O)‐bis(trimethylsilyl)trifluoroacetamide] derivative and fused silica capillary gas chromatography. Isomerization was shown to occur before any substantial hydrolysis. Decreases in concentration of α,β or α,α′ ‐diglyceride (after isomerization was essentially complete) corresponded to the acid number rises observed.