Sacha inchi (Plukenetia volubilis): A seed source of polyunsaturated fatty acids, tocopherols, phytosterols, phenolic compounds and antioxidant capacity

Fatty acids (FA), phytosterols, tocopherols, phenolic compounds, total carotenoids and hydrophilic and lipophilic ORAC antioxidant capacities were evaluated in 16 cultivars of Sacha inchi (SI) seeds with the aim to valorise them and offer more information on the functional properties of SI seeds. A high a linolenic (a-Ln) fatty acid content was found in all cultivars (x3, 12.8–16.0 g/100 g seed), followed by linoleic (L) fatty acid (x6, 12.4–14.1 g/100 g seed). The ratio x6/x3 was within the 0.83–1.09 range. c- and d-tocopherols were the most important tocopherols, whereas the most representative phytosterols were bsitosterol and stigmasterol. Contents of total phenolics, total carotenoids and hydrophilic and lipophilic antioxidant capacities ranged from 64.6 to 80 mg of gallic acid equivalent/100 g seed; from 0.07 to 0.09 mg of b-carotene equivalent/100 g of seed; from 4.3 to 7.3 and, from 1.0 to 2.8 lmol of Trolox equivalent/ g of seed, respectively, among the evaluated SI cultivars. Results showed significant differences (p < 0.05) among the evaluated SI cultivars in the contents of x3, x6, antioxidant capacities and other evaluated phytochemicals. SI seeds should be considered as an important dietary source of health promoting phytochemicals. 2013 Elsevier Ltd. All rights reserved. 1. Introduction The Amazonian region is the most important area in terms of biodiversity. It hosts many important crops for the world’s agriculture (e.g., cassava, pineapple, cocoa, rubber among others). Still, numerous under exploited Amazonian plant species, with promising economic value, remain little-known and neglected by science (Krivankova et al., 2007). Sacha inchi (Plukenetia volubilis Linneo), also known as Inca peanut, wild peanut, sacha peanut or mountain peanut, is an oleaginous plant that belongs to the Euphorbiaceae family. It grows in the lowlands of the Peruvian Amazon, having been cultivated for centuries by the indigenous population (Guillén, Ruiz, Cabo, Chirinos, & Pascual, 2003; Gutiérrez, Rosada, & Jiménez, 2011; Hamaker et al., 1992; Krivankova et al., 2007). The Sacha inchi (SI) plant grows in warm climates, at altitudes of up to 1500 m above sea level. SI seeds are a good source of oil (35–60%) and protein (27%) and contain heat-labile substances with a bitter taste. SI oil is characterised predominantly by high levels of essential fatty acids, namely, C18:3 x3 (a-Ln, cis,cis,cis- 9,12,15-octadecatrienoic acid; a-linolenic) and C18:2 x6 (L, cis,- cis-9,12-octadecadienoic acid; a-linoleic) fatty acids, representing about 82% of the total oil content. The ratio of x6/x3 has been reported to be approximately 0.81 by Hamaker et al. (1992). The presence of other bioactive compounds, such as tocopherols (Follegatti- Romero, Piantino, Grimaldi, & Cabral, 2009), carotenes (Hamaker et al., 1992), polyphenolic compounds (Fanali et al., 2011) and phytosterols, have been previously reported in SI oil (Bondioli, Della Bella, & Rettke, 2006). In addition, the amino-acid profile of the SI protein fraction showed a relatively high level of cysteine, tyrosine, threonine and tryptophan, compared to other oilseed sources (Hamaker et al., 1992). SI seeds are used in different forms by the Amazonian population. The oil is used in the preparation of various meals, the seeds are consumed roasted and the leaves are cooked and consumed (Fanali et al., 2011). SI seeds are also used as a traditional remedy in the Amazon region to treat rheumatic problems and aching muscles. A wide range consumption of bioactive is important in our diet in terms of health. Thus, a-Ln and L FA are very important for the prevention of coronary heart disease and hypertension, showing a hypocholesterolemic effect (Simopoulos, 2011). In addition, numerous health benefits have been attributed to phytosterols, 0308-8146/