Food Research Institute

Stoica-Guzun, A. – Pârvulescu, O. C. – Broşteanu, A. – Chira, N. – Stroescu, M. – Dobre, T.
Influence of sea buckthorn pomace pretreatment and drying conditions on the drying kinetics, quantity and quality of seed oil
Journal of Food and Nutrition Research, 57, 2018, No. 4, s. 363-372

Oana Cristina Pârvulescu, Department of Chemical and Biochemical Engineering, University POLITEHNICA of Bucharest, 1-3 Gheorghe Polizu, 011061, Bucharest, Romania. Tel.: +4021 402 38 10, e-mail: oana.parvulescu@yahoo.com

Received 24 March 2018; 1st revised 22 May 2018; accepted 11 June 2018; published online 16 September 2018

Summary: Sea buckthorn (Hippophae rhamnoides L.) pomace was pre-treated by sonication or freezing and a thin layer of pre-treated or untreated pomace was dried under various conditions. The seeds separated from dried pomace were ground and subjected to batch extraction using hexane as a solvent. Effects of process factors, i.e. drying temperature (40 °C and 50 °C), pomace layer thickness (3 mm and 10 mm), ultrasound amplitude (0 % and 20 %) and pre-treatment temperature (–20 °C and 20 °C), on the drying kinetics, quantity and quality of seed oil were evaluated. Performance of air drying and oil extraction were correlated with the process factors by multiple regression equations, which highlighted a significant effect of pomace layer thickness. A thicker layer led to higher levels of effective diffusivity ((0.141–1.484) × 10^-9 m²·s^-1), oil yield (13.1–14.5 %) and extraction efficiency (90.5–93.5 %) as well as to lower values of mean drying rate (0.144–0.354 kg·kg^-1·h^-1). Mean mass percentages of fatty acids found in the oils extracted from the seeds separated from the pomace dried at 50 °C, i.e. 26.8 % alpha-linolenic, 38.9 % linoleic, 22.7 % oleic, 0.9 % palmitoleic, 7.9 % palmitic and 2.8 % stearic acid, were almost invariant with the process factors.

Keywords: sea buckthorn; pomace; seed oil; air drying; effective diffusivity; fatty acids

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