Varietal and crop year effects on lipid composition of walnut (Juglans regia) genotypes

Abstract

The FA, unsaponifiable, and volatile constituents of oil from three walnut varieties from two consecutive crop years were studied. The walnut oils (WO) were rich in PUFA and low in saturated FA. The tocopherol fraction consisted mainly of γ-tocopherol. High contents of β-sitosterol were found, together with campesterol and ∆ 5 -avenasterol in similar amounts. Methylsterols present in WO were identified as cycloartenol, cyclolaudenol, cycloeucalenol, and 24-methylenecycloartanol. The hydrocarbon fraction was characterized by the predominance of C 14 -C 20 n-alkanes. The major volatiles were aldehydes produced through the linoleic acid oxidative pathway. FA, methylsterols, and some hydrocarbons presented statistically significant differences among varieties. Most of this variation was due to the genotype. The Franquette variety was noteworthy by its higher oil and oleic acid contents. In contrast, tocopherols and volatile compounds showed minor differences among varieties; they were strongly influenced by the crop year. Chemical data were subjected to principal component analysis. The parameters that gave the greatest discrimination between the walnut varieties were oleic and linolenic acids, tetradecane, eicosane, tetracosane, cycloartenol, and 24-methylenecycloartanol. These components presented the major varietal influences and could be useful to determine the identity of walnut genotypes.

Genotype and year variability of the chemical composition of walnut oil of Moroccan seedlings from the high Atlas Mountains

“…Oil content ranged between 54.4 and 67.48%, and protein between 11.58 and 14.5% in 2009, (Table 1), whereas in 2010 these ranges were between 55.29 and 66.25% for oil, and between 11.99% and 14% for protein (Table 1). Protein content agreed with previous reports (Amaral et al, 2003;Savage et al, 1999), as well as fat content, although the lowest fat value was lower than any previous report (Crews et al, 2005;Amaral et al, 2003;Martinez et al, 2006;Bada et al, 2010). The significance of the year×genotype interaction (Table 2) indicated that oil content variability was significant between years for some genotypes, as a result of the specific response by these genotypes to the environmental conditions of the year.…”

“…Protein content was significantly different between years (Table 2), with a higher mean value in 2009 (Table 1). The effect of year was not significant for oil content (Table 2), although it had been significant in three other walnut cultivars (Martinez et al, 2006). Oil content ranged between 54.4 and 67.48%, and protein between 11.58 and 14.5% in 2009, (Table 1), whereas in 2010 these ranges were between 55.29 and 66.25% for oil, and between 11.99% and 14% for protein (Table 1).…”

“…The major constituents of walnut oil are triglycerides, in which the fatty acid (FA) profile shows that unsaturated FA (UFA) amount to about 70% of the walnut kernel oil. Monounsaturated FA (MUFA, mainly oleic acid) and polyunsaturated FA (PUFA, mainly linoleic and α-linolenic acids) are present in high amounts (Crews et al, 2005;Martinez et al, 2006). Their ratios are indices of the economic and nutritional value of the nut.…”

Nutritional quality of fresh and heated Aleppo pine (Pinus halepensis Mill.) seed oil: trans-fatty acid isomers profiles and antioxidant properties

“…Using rancimat test, fresh APSO showed a low oil stability index OSI (5.4 h) which, dramatically, decreased to 0.86 h at the end of the heating process. In fact, high levels of linoleic and linolenic acids may result in a lower oxidative stability and a shorter shelf life of the oils as declared by Martíneza et al (2006). Having a very low O/L ratio (0.4), APSO showed detectable trans isomerization level for palmitoleic, linoleic and eicosenoic acids before and after applying the heat treatment.…”

Proximate composition, minerals and fatty acid composition of Juglans Regia L. genotypes and cultivars grown in Turkey

“…The PUFA/MUFA ratio varied from 1.54 to 3.97. Martinez et al (2006) reported that the PUFA/MUFA ratio changed from 2.22 to 4.54 in the walnut cultivars Franquette, Chandler and Criolla. In the current study, some walnut genotypes and cultivars contained higher amounts of oleic acid, linoleic acid, palmitic acid and linolenic acid than some other walnut genotypes.…”