No abstract

Phytosterols are natural compounds that contribute to lower serum cholesterol in humans. Sunflower seeds and oils are rich sources of phytosterols. Breeding for phytosterol content in sunflower has been scarce thus far, mainly because of the lack of analytical methods suitable for use in plant breeding. The objective of this research was to validate a method for the analysis of phytosterols in small seed samples of sunflower. Samples consisting of six seeds were analyzed for phytosterol content in a set of 87 inbred lines using a method adapted to small samples. The accuracy of the method was evaluated through the standard error of the analysis of replicates of ground samples, which was 72.12 mg/kg compared to average values of 1665.3 and 1887.2 mg/kg seed in the samples. Sunflower inbred lines showed ranges of variation from 1426.0 to 4710.0 mg/kg seed and from 2855.2 to 9752.0 mg/kg oil. The method correlated strongly with the conventional method based on the analysis of extracted oils (r ¼ 0.85). The results indicated that analysis of phytosterols on samples consisting of sunflower seeds is an accurate approach for breeding and genetic studies, in which extraction of the seed oil is not feasible.Practical applications: Phytosterols are usually analyzed in extracted oils. However, studies in plant breeding and plant sciences often require a direct analysis of phytosterols in seeds, without previous oil extraction (e.g. large-scale screening of germplasm in breeding programs or genetic studies). Our results will be useful for plant scientists interested in the analysis of phytosterols in small samples of plant tissues.

Selection for oil quality is commonly conducted at the latest stages of olive breeding programs, as oil quality traits are measured in extracted oils. At the initial stages of breeding, the number of genotypes is high and fruit production is low, which makes it difficult to conduct oil extraction. The objective of this research was to evaluate the feasibility of conducting selection for some important oil quality traits in olive by analyzing fruit flesh instead of extracted oils. Fatty acids, tocopherols, phytosterols, and squalene were measured in fruit flesh and extracted oils from 22 individual olive trees showing variability for oil quality traits. Correlation coefficients between analyses conducted on fruit flesh and extracted oils were r = 0.98 for the main fatty acids palmitic, oleic, and linoleic acid, r = 0.96 for tocopherol content, r = 0.89 for phytosterol content, r = 0.97 for squalene content, and r = 0.91 and 0.94 for the concentrations of the two main sterols b-sitosterol and D 5 -avenasterol, respectively. The results revealed that selection for the mentioned oil quality traits can be efficiently conducted through the analysis of fruit flesh instead of extracted oil, which facilitates selection on larger numbers of genotypes at the initial stages of olive breeding programs.

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 [Prunus amygdalus Batsch; syn. P. dulcis (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−1 in 2009 and from 1191 to 2777 mg·kg−1 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 Δ5-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.