Title: Optimization of Screw Press Extraction Parameters for Oil Recovery from Sacha Inchi (Plukenetia volubilis L.) Seeds Cultivated in Vietnam
Authors: Phan The Duy, Le Thi Dien, Nguyen Thi To Oanh, Nguyen My Anh
Volume: 10
Issue: 6
Pages: 73-78
Publication Date: 2026/06/28
Abstract:
Sacha inchi (Plukenetia volubilis L.) has drawn growing interest as a plant-based source of omega-3 fatty acids, yet systematic data on the mechanical extraction of oil from seeds cultivated in Vietnam remain limited. This study examined how three screw press parameters - pre-heat temperature (75-120°C), seed particle size (1-5 mm), and screw rotation speed (40-80 rpm) - affect oil yield and quality using seeds harvested in Daklak Province. Experiments followed a sequential one-factor-at-a-time (OFAT) design. Fatty acid composition was determined by GC-MS; acid, iodine, and peroxide values were measured by standard methods; and antioxidant activity was evaluated by the DPPH radical scavenging assay. The combination of pre-heating at 90°C, a particle size of 3-5 mm, and a screw rotation speed of 70 rpm yielded the highest extraction efficiency (91.54%). Below 90°C, incomplete seed softening limited oil expression; above 100°C, marginal yield gains were offset by oil darkening and off-odour development. Fine particles (< 2 mm) failed to generate adequate back-pressure within the barrel, while speeds exceeding 70 rpm shortened material residence time and increased frictional heat loss. Under the optimised conditions, the crude oil exhibited an iodine value of 176.37 g I?/100 g, an acid value of 2.29 mg KOH/g, a peroxide value of 8.95 meq O?/kg, and a DPPH IC?? of 90.58 mg/mL. The fatty acid profile was dominated by ?-linolenic acid (?-3; 39.5%) and linoleic acid (?-6; 34.4%), with an ?-6/?-3 ratio of 0.87. These results provide a practical reference for the mechanical processing of Vietnamese-grown Sacha inchi and support the oil's potential as an omega-3-rich functional food ingredient.