The oxidative stability, lipid profiles and total phenolics of almonds (Prunus amygdalus L.) and pistachios (Pistacia vera L.)
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Date
2011
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Abstract
Nuts contain bioactive constituents that elicit cardio-protective and anticancer effective containing phenolic compounds, healthy lipids, tocopherols, sterols and squalene. This study was undertaken to identify some bioactive constituent levels of almonds (Prunus amygdalus L.) consumed in Datça, Aegean Area, Turkey markets and pistachio (Pistacia vera L.) nuts consumed in Aegean Area, Southeastern Anatolia, Turkey markets. Total lipids, fatty acid (FAs) profiles, tocopherols, sterols and oil stability were determined on the oil extracted from the fresh nuts. Lipid content of the nuts varied between 41.2-59.8% (p<0.05) and the peroxide values (PV) of the fresh oils were 0.13-3.48 meq O2/kg oil (p<0.05). Mean monounsaturated fatty acid (MUFA) contents of almonds and pistachios were found 70.46 ± 0.67 and 62.36 ± 0.61 as % of total lipid, respectively. The major MUFA was oleic acid (C 18:1) (42.3-69.8%) while linoleic acid (C 18:2) (21.76-32.13%) was the most prevalent polyunsaturated fatty acid in almonds and pistachios. The PUFA levels ranged from 21.07-32.61 % (p<0.05). Unsaturated FAs/saturated FAs ratio was detected as 10.9 and 9.94 for almonds and pistachios, respectively. The major tocopherol was alfa-tocopherol in almonds (36.8 ± 4.7 mg/100 g oil) whereas gamma tocopherol level was major in pistachios (37.3 ± 3.4 mg/100 g oil) (p<0.05). The major sterol was identified as beta-sitosterol and its content was avg. 2155.2 ± 11.3 mg/g oil in almonds while that of content was 4706.5 ± 73.2 mg/g oil in pistachios (p<0.05). Total phenolics (TPs) of almonds with skin, TPs of almonds without skin and TPs of pistachios were avg. 313.6 ± 1.28; avg. 57.44 ± 1.1; avg. 922.6 ± 2.8 as mg of gallic acid equivalent (GAE)/100 g, respectively. All data obtained from almond and pistachios was evaluated by multivariate analysis using SPSS (ver.13.0) statistical package program. Almond and pistachios were differantiated with good separation based on the functional lipids, lipid constituents and total phenolic contents via Principal Component Analysis (PCA). In this context, almonds and pistachios can be consumed as good energy snacks in daily nutrition and the multivariate techniques can differentiate these nuts based on their oxidative stability, lipid profiles and total phenolics.