Generation of Maillard‐type compounds from triethanolamine alone

Abstract

The mechanism of triethanolamine (TEA) soap browning has been uncovered. The reaction proceeds as follows. Firstly, TEA is degraded into diethanolamine and acetaldehyde. Secondly, diethanolamine is further degraded into monoethanolamine and acetaldehyde. Thirdly, two molecules of acetaldehyde dimerize to crotonaldehyde, which reacts with monoethanolamine to generate brownish products with conjugated double bonds. Thus, TEA alone generates Maillard-type products through a series of degradation and recombination reactions. JAOCS 74, 891-893 (1997).Soaps are widely used in a variety of household and personalcare products. Quality soaps are triethanolamine (TEA) salts of fats or oils and create quick foaming and dense lather. Also, TEA soaps have good low-temperature solubility. However, when stored at moderately high temperatures (more than 50°C), TEA soaps have been known to acquire a brownish color. If stored for a long period, they gradually show this type of color change at lower temperatures. Colors are appealing to consumers, and discoloration damages products. In this article, we clarified the mechanism in which TEA soaps obtain a brownish color. TEA alone generates Maillard-type products (1-4) through a series of degradation and recombination reactions. EXPERIMENTAL PROCEDURESMaterials. All reagents were commercially available and were used without further purification.Qualification and quantitation of amines. A soap solution (2 mL) was mixed with 2 mL of 1M Na 2 CO 3 /NaHCO 3 buffer (pH 9), followed by addition of 100 µL of 12.5% fluorodinitrobenzene/methanol and was incubated at 50°C for 1 h. An aliquot (20 µL) was applied for reversed-phase high-performance liquid chromatography (HPLC) in a C 18 column (4.6 × 250 mm; Shiseido, Tokyo, Japan); flow rate, 1 mL/min; mobile phase, 0.01% trifluoroacetic acid with increased concentration of methanol from 0 to 80% in 30 min. The chromatographic system was equipped with an ultraviolet detector, and absorbance was read at 350 nm. The analysis was carried out at 30°C.Qualification and quantitation of aldehydes. A soap solution (1 mL) was mixed with 4 mL of 0.025% dinitrophenylhydrazine/2N HCl and was incubated for 1 h at room temperature. An aliquot (20 µL) was applied for reversed-phase HPLC as described above.Gas chromatography/mass spectrometry (GC/MS) analysis. All results were obtained with an HP 5972A gas chromatograph/mass spectrometer (Hewlett-Packard, Palo, Alto, CA). Separation of the compounds was achieved on a 15 m × 0.25 mm i.d. methylpolysiloxane (DB-1) fused-silica capillary column (film thickness 0.1 µm) from J&W Scientific (Folsom, CA). Helium was used as a carrier gas at flow rate of 0.55 mL/min. The GC injection port was maintained at 300°C, and the MS interface was maintained at 280°C. The ion source temperature was 280°C. The column oven temperature was raised from 40 to 200°C at 10°C/min and from 200 to 350°C (5 min) at 20°C/min. The mass spectrometer was operated in the scanning mode (range 40-700 m/z). Electron ionization was accomplished wit...

Investigation of Color Instability in a Liquid Laundry Detergent

“…Acetaldehyde is reported to form during storage and is involved in polymerization reactions to form yellow off-color compounds [6]. Acetaldehyde is reported to form during storage and is involved in polymerization reactions to form yellow off-color compounds [6].…”

“…Yellowing or browning of TEA is well known and commercial grades of TEA contain low levels of by-products and degradation compounds including DEA, MEA, and acetaldehyde [5,6]. TEA was found to be an ingredient most frequently associated with color instability in the literature.…”

“…TEA was found to be an ingredient most frequently associated with color instability in the literature. 3a) involves degradation of TEA (2) to yield DEA (4), acetaldehyde (5), and MEA (6). These compounds can react to cause a color change.…”

“…For example, Hsu and Zhu [3] noted that oxidation of phenolic antioxidant ingredients led to yellowing of the detergent if too much antioxidant was used. And TEA alone was found to generate colored products through a series of degradation and recombination reactions [5,6]. And TEA alone was found to generate colored products through a series of degradation and recombination reactions [5,6].…”

Removal of heat stable salts from aqueous solutions of N-methyldiethanolamine using a specially designed three-compartment configuration electrodialyzer

“…This suggested the specially designed three-compartment ED had some advantages over the traditional two-compartment ED such as high HSS removal and short operation time. As we know [14], the anions of Cl − , SO 4 2− , SCN − , HCOO − , H 3 CCOO − , and H 3 CH 2 CCOO − were bonded with MDEA + . The introduction of OH − would lead to the metathesis reaction as mentioned in Eq.…”