Phytosterol Variability in Almond Germplasm

Abstract

<jats:p>Phytosterols are important dietary components that contribute to reducing serum cholesterol levels. The objective of this research was to assess genetic diversity for total content and profile of free and esterified phytosterols in a world germplasm collection of almond [<jats:italic>Prunus amygdalus</jats:italic> Batsch; syn. <jats:italic>P. dulcis</jats:italic> (Mill.) D.A. Webb]. Steryl glycosides and acylated steryl glycosides were not measured. Fruit from 160 almond accessions were collected in 2009 and 2010. Kernel phytosterol content ranged from 1126 to 2769 mg·kg<jats:sup>−1</jats:sup> in 2009 and from 1191 to 2777 mg·kg<jats:sup>−1</jats:sup> in 2010. The phytosterol fraction was mainly made up of β-sitosterol (from 59.1% to 84.1% in 2009 and from 55.9% to 84.6% in 2010) and Δ<jats:sup>5</jats:sup>-avenasterol (from 8.9% to 25.4% in 2009 and from 8.5% to 28.2% in 2010). Significant genotypic effects were observed for kernel phytosterol content and concentration of major phytosterols. Kernel oil content was positively correlated with kernel phytosterol content in both years. The results suggested that almond germplasm contains genetic variability for both phytosterol content and profile that can be used for developing cultivars with increased levels of phytosterols and contrasting phytosterol profiles. Positive correlation between kernel phytosterol content and kernel oil content suggests the feasibility of simultaneous selection for both traits.</jats:p>

Variability of Phytosterols in Jatropha curcas Germplasm

“…b-Sitosterol content was negatively correlated with stigmasterol (r = -0.68 in August, r = -0.73 in November, P \ 0.01), D 5 -avenasterol (r = -0.63 in August, r = -0.77 in November, P \ 0.01), and D 7stigmastenol contents (r = -0.57 in August, r = -0.75 in November, P \ 0.01). These negative correlations have also been reported in sunflower [9] and almond [16]. Stigmasterol was positively correlated with D 5 -avenasterol content (r = 0.49 in August, r = 0.49 in November, P \ 0.05), though the correlation was not significant in absence of accession BGJC-29.…”

“…However, oil phytosterol content does not provide useful genetic information, as the trait depends upon the phytosterol content in the seeds, the oil content in the seeds, and the efficiency of the oil extraction method. For this reason, methods for the analysis of phytosterols in seeds have been developed and used for germplasm evaluation and genetic analyses [9,[15][16][17]. This is the approach that we have also used for studying variability in Jatropha germplasm.…”

“…The studio of within-accession variation in November showed that all the plants of this accession had increased high D 5 -avenasterol content, which ranged from 11.8 to 13.2 %. High levels of D 5avenasterol (around 30 %) are found in some olive [25] and almond cultivars [16], but major oilseeds such as soybean, rapeseed and sunflower contain low levels (\5 %) of this phytosterol [3,26].…”

A review of the impact of processing on nutrient bioaccessibility and digestion of almonds

“…Almonds are a valuable dietary source of lipid (comprising mainly monounsaturated fatty acids), protein, dietary fibre, vitamins (e.g. vitamin E), minerals, phenolic compounds and phytosterols (Bolling et al, 2011;Yada et al, 2011;Fernandez-Cuesta et al, 2012) (Table 1).…”

“…Almonds also contain a wide variety of phenolic compounds, mainly proanthocyanidins, flavonoids and phenolic acids (Perez-Jimenez et al, 2010;Bolling et al, 2011;Xie et al, 2012), which are located predominantly in the skin and are responsible for their antioxidant properties (Mandalari et al, 2010b). Phytosterols are also found in significant amounts (~270 mg 100 g À1 ) in almond kernels, b-sitosterol being the predominant type (Fernandez-Cuesta et al, 2012;Alasalvar & Bolling, 2015;Forcada et al, 2015). Evidence suggests that the phytosterols reduce blood concentrations of LDL cholesterol and so these compounds may also contribute to the reduced risk of cardiovascular disease associated with consuming almonds (Plat & Mensink, 2005;Berryman et al, 2015).…”