Olea ferruginea Royle, Indian olive: an underutilised fruit tree crop of north-west Himalaya

Introduction. Olea ferruginea Royle, generally known as Indian olive, grows widely in the Himalayas from Kashmir to Kumaun up to an altitude of 2400 m. It is a multipurpose, zero-waste, evergreen tree species. It yields a number of useful items including quality fodder, firewood and edible fruits. The leaves, bark, roots, fruits and seeds of this plant are used for treatment of various diseases. The fruits are also a source of olive oil. However, to the best of our knowledge, no study has been carried out to determine the olive oil contents of the fruits and seeds of O. ferruginea and the quality of the oils. Materials and methods. Therefore, investigations were undertaken to determine the olive oil contents and the quality of the oils in the fruits and seeds in terms of fatty acid composition. Four populations of O. ferruginea (Kolibehar, Saioond and Kais from the Kullu district, and Thalaut from the Mandi district of Himachal Pradesh) were selected as the sources of fruits and seeds. Results and discussion. The selected sites differed in respect to their geographical characteristics. The olive oil content was considerably higher in the fruits than in the seeds. The olive oil contents in the fruits varied from 20.67% to 27.40%, with the Thalaut population exhibiting the highest oil content. The olive oil content in the seeds varied from 7.5% to 12.5%; the oil content was the lowest in fruits of the Saioond population and the highest in the Thalaut population. In all the populations, monounsaturated oleic acid was predominant; oleic acid ranged from 61.6% to 66.9% in the fruit oil and 64.4% to 67.2% in the seed oil. Differences in the fatty acid composition between the seed and fruit oils were also seen. Conclusion. Our study suggests that the fruits of O. ferruginea may be a potential source of olive oil. Thus, sustainable use of this potential of the tree could be useful in the socio-economic development and environmental conservation of the areas where it grows.