Comparison of the lipid profile and tocopherol content of four Peruvian quinoa (Chenopodium quinoa Willd.) cultivars ('Amarilla de Maranganf', 'Blanca de Juli', INIA 415 'Roja Pasankalla', INIA 420 'Negra Collana') during germination

摘要

Quinoa (Chenopodium quinoa Willd.) is an Andean pseudocereal that has acquired a commercial interest in recent decades, partly due to its nutritional characteristics and lack of gluten. Controlled seed germination has been used to improve the nutritional value of different species for human consumption, besides reducing anti-nutritional factors. Polyunsaturated fatty acids are important in a balanced diet, particularly omega-3 fatty acids whose ratio to omega-6 fatty acids has been reported to be increased by germination. However, the fatty acid profile of the seeds of each species and variety behaves differently during germination, and few studies have addressed quinoa and its different cultivars. In this study, four Peruvian quinoa cultivars from Puno and Cusco were germinated in the dark at 25 degrees C and analysed for their fatty acid profile after 24 and 48 h by GC-FID. The lipids were extracted by a mixture of hexane/isopropanol and the determination of tocopherols was performed by HPLC with a fluorescence detector. The content of lipids and tocopherols was carried out until 72 h. A slight increase in lipid content was found in three of the cultivars, which may be because of better extractability of quinoa seed lipids caused by germination. The highest average lipid content was presented by INIA 415 'Roja Pasankalla' (5.89%, db), which did not vary significantly during germination the first 48 h of germination. The lipid content of the quinoa seeds tested did not vary between 48 and 72 h. With regard to the fatty acid profile, linoleic, oleic and palmitic acids were predominant for all cultivars. The INIA 420 'Negra Collana' cultivar had the highest content of linoleic acid (56.24 +/- 2.22%, on average). The PUFAs content increased mostly during germination and the omega-6/omega-3 ratio improved for all cultivars, even for 'Roja Pasankalla' which showed the slightest variations in its fatty acid profile. The increase of the concentration of omega-3 benefited notably INIA 420 'Negra Collana', although the cultivar with the best ratio omega-6/omega-3 and alpha-tocopherol was 'Amarilla de Maranganr after 48 h of germination. Only the 'Blanca de Juli' white seed cultivar show a decrease in total tocopherol content at the end of germination (from 1354 to 1011 ppm). The germination of quinoa seeds for 48 h has improved the profile of fatty acids and a-tocopherol content, although it is necessary to investigate the effect of storage on the metabolism of each fatty acid to understand new ways of optimising this process.