Analysis of the Constituents in Jojoba Wax Used as a Food Additive by LC/MS/MS

Abstract

Jojoba wax is a natural gum base used as a food additive in Japan, and is obtained from jojoba oil with a characteristically high melting point. Although the constituents of jojoba oil have been reported, the quality of jojoba wax used as a food additive has not yet been clarified. In order to evaluate its quality as a food additive and to obtain basic information useful for setting o$cial standards, we investigated the constituents and their concentrations in jojoba wax. LC/MS analysis of the jojoba wax showed six peaks with [MῌH] ῌ ions in the range from m/z 533.6 to 673.7 at intervals of m/z 28. After isolation of the components of the four main peaks by preparative LC/MS, the fatty acid and long chain alcohol moieties of the wax esters were analyzed by methanolysis and hydrolysis, followed by GC/MS. The results indicated that the main constituents in jojoba wax were various kinds of wax esters, namely eicosenyl octadecenoate (C20 : 1ῌC18 : 1) (I), eicosenyl eicosenoate (C20 : 1ῌC20 : 1) (II), docosenyl eicosenoate (C22 : 1ῌC20 : 1) (III), eicosenyl docosenoate (C20 : 1ῌC22 : 1) (IV) and tetracosenyl eiosenoate (C24 : 1ῌC20 : 1) (V). To confirm and quantify the wax esters in jojoba wax directly, LC/MS/MS analysis was performed. The product ions corresponding to the fatty acid moieties of the wax esters were observed, and by using the product ions derived from the protonated molecular ions of wax esters the fatty acid moieties were identified by MRM analysis. The concentrations of the wax esters I, II and III, in jojoba wax were 5.5, 21.4 and 37.8῍, respectively. In summary, we clarified the main constituents of jojoba wax and quantified the molecular species of the wax esters without hydrolysis by monitoring their product ions, using a LC/MS/MS system.

Wax ester profiling of seed oil by nano-electrospray ionization tandem mass spectrometry

“…The most abundant wax ester species were wax esters with 18:1, 20:1, 22:1 or 24:1 as alcohol moieties combined with the acyl moieties 18:1, 20:1 and 22:1 and with the wax ester 22:1/20:1 being the predominant molecular species. This data and the data presented here are also in agreement with previous quantitative profiles relying on the analysis of hydrolyzed jojoba wax esters by GC-FID and GC-MS or the analysis of selected intact species by HPLC-APCI-MS [4,43,63]. …”

“…Furthermore, since the mass data acquisition time for single species is restricted to small peak width, it asks for fast scanning MS to enable recording of many CID mass spectra in parallel. Absolute quantification by the use of an external calibration has been shown for the three main wax ester species of jojoba [43] by HPLC-MS applying multiple reaction monitoring (MRM), but a quantitative profiling method that addresses a high number of wax ester species by HPLC-MS has to our knowledge not been shown yet.…”

Antibacterial and Antifungal Activity of Jojoba Wax Liquid (Simmondsia chinensis)

“…The seeds of Jojoba plant produce more than 45% w/w of colourless, odourless oily material which was discovered by the native Americans who recognised its important medicinal values. 13,14 Due to its high economic value, Jojoba is being cultivated in different parts of the world including the Egyptian dessert and Saudi Arabia. 15,16 Many studies have focused on understanding the antibacterial features of Jojoba.…”

Electrospray mass spectrometry of human hair wax esters

“…Using a different approach, three diunsaturated wax esters that are the major constituents in jojoba oil were analyzed by atmospheric pressure chemical ionization. These species were quantified by measuring the abundance of protonated fatty acid product ions obtained by collisional activation for the [M1H] 1 ions using multiple reaction monitoring (MRM) experiments (12). Only one study has been published concerning the use of electrospray ionization (ESI) to characterize wax esters, perhaps because of the apparent insensitivity of this technique for neutral lipids (13).…”