Chemical composition and antioxidant activity of borage (Borago officinalis L.) seeds

Abstract

Recently the interest in borage seeds (mericarps) as an important source of γ-linolenic acid and a good natural antioxidant has increased, yet the knowledge about these properties of seeds developed by borage grown in Poland remains very scanty. Seeds collected from borage plants cultivated in the south-eastern region of Poland in the years 2017 and 2018 were characterized by following parameters: length - 5.0 mm, width - 2.7-2.8 mm, thickness 2.2 mm, weight of 1000 seeds - 17.2-19.4 g. The seeds contained 93.7% of dry matter, and in this 32.0% of lipids, 23.7% of protein and 1.1-1.8% of total sugars on average. Seventeen compounds were identified in the lipids with linoleic acid (35.1%), oleic + elaidic acids (20.8%), γ-linolenic acid (17.9%), palmitic acid (11.4%), stearic acid (5.3%), cis-11-eicosenoic acid (4.1%), and erucic acid (2.6%) as major ones. Other fatty acids constituted less than 2%. Saturated fatty acids constituted 17.5% of the total fatty acids. Flavonoids and phenolic acids accounted for 0.012% and 1.60-1.73% of seeds dry weight respectively. Antioxidant activity measured by FRAP assay and Foli Ciocalteau method accounted for 1225 µmol of ferrous equivalent Fe (II) and 29.7 mg of polyphenols per gram of seeds dry weight respectively. Using antiradical activity against DPPH radical following average parameters were obtained: T 50% - 49, DPPH rem - 73.7%, AE - 0.024 dm3(µmols)-1. 100 g of seeds d.w. contained 0.27-0.34 ml of essential oil. Content of four macroelements expressed as % of seeds d w. was following: P - 0.70, K - 0.48, Ca - 1.37 and Mg - 0.41.