Effect of Temperature on the Synthesis of Jojoba Wax

Abstract

Seed was collected from jojoba [Simmondsia chinensis (Link) Schneider] plants growing at three field sites in two years. The wax percentage was determined by nuclear magnetic resonance and the compositions of the wax and the ethanolysis products (one site only) were determined by gas chromatography. The mean wax concentration varied from 49.2 to 55.1% over all sites and years. The percentage of long-chain wax esters (>C40) decreased linearly with increase in mean maximum temperature during the period of linear seed growth (r� = 0.93). The decrease in long-chain esters was associated with a decrease in the C22 and C24 fatty acids and alcohols. Data from controlled environment studies and from field studies were used to assess the effect of temperature on the percentage elongation, reduction and esterification of acyl-CoAs of carbon lengths 18-22. High temperature lowered the specificity for elongation of C20-C22 and of C22-C,24 and increased the specificity for reduction of the C20 acid to its corresponding alcohol. The amount of C42 wax ester was greater than would be expected by random association of the alkoxy-acyl groups but this preference was not as great at high temperatures.

Investigation of Liquid Wax Components of Egyptian Jojoba Seeds

“…Certain minor components such as phytosterols and triacylglycerols as well as fatty alcohols were reported 12,13) . Quantitative and qualitative analysis of the fatty acids and alcohols of jojoba wax has been performed by many authors 12,[14][15][16][17][18] . The objective of this work is to study the chemical composition of wax esters, wax alcohols, fatty acids, sterols, tocopherols, isopropenoid alcohols and the sterylglycosides of the oil of locally cultivated jojoba (Simmondsia chinensis) with the help of GLC and HPLC analysis.…”

Effect of female and male genotypes and environment on wax composition in jojoba

“…Calculation of specificities. Calculation of composite specificity for the monounsaturated acyls was performed as described by Pollard et al (15) and by Dunstone et al (10). The method assumes that any acyl may be subjected to one of three competing reactions: chain elongation, reduction, or esterification.…”

“…The content of wax in the mature seed is about 48-58% (7)(8)(9). Wax content may fluctuate for the same clones in response to climatic conditions (10). Clarke and Yermanos (11) showed considerable variability in wax content and composition in a collection of more than a thousand jojoba plants from the wild.…”

“…Clarke and Yermanos (11) showed considerable variability in wax content and composition in a collection of more than a thousand jojoba plants from the wild. Yermanos and Duncan (7) found variability in wax composition with time, and Dunstone et al (10) demonstrated that temperatures prevailing at the time of wax synthesis affect the chain lengths of the FA and fatty alcohols. High temperatures during seed filling lowered the specificity for elongation of 20:1 and 22:1 acyl-CoA and increased their specificity for reduction to fatty alcohols.…”

A reliable gender diagnostic PCR assay for jojoba (Simmondsia chinensis (Link) Schneider)

“…Differing from most of the cultivated crop species, jojoba has slow-growing habit, difficulties in the determination of sex at the early seedling stages, a male-biased (5:1; male: female) ratio and low seed yield (Benzioni and Vaknin 2002;Agrawal et al 2007;Sharma et al 2008). Commercial plantations of jojoba are mainly established using cuttings, or in a few cases grafting, resulting in a narrow genetic diversity that may cause the low seed yield (Dunstone et al 1985). Coates and Ayerza (2008) reported that commercial plantations of jojoba in the Hyder Valley in Arizona and in Catamarca, Argentina dramatically decreased in size and number, going from 10,000 ha in the early 1980s to about 2,000 ha in Arizona, and from 3,000 ha in Catamarca in the late 1990s to approximately 300 ha in 2008.…”