Optimization of Aqueous Enzymatic Extraction of Flat-Europe Hybrid Hazelnut (Corylus heterophylla Fisch. × C. avellana L.) Oil and Analysis of Its Components

Abstract

Aim: The research aimed to evaluate the technological factors of the composite enzymatic extraction of Flat-European hybrid hazelnut oil, and analyze the fatty acid composition, to lay the foundations for the industrialized production of this oil. Study Design: Based on single factor tests, the best conditions for the aqueous enzymatic extraction of the oil determined by response surface analysis. Place and Duration of Study: Food Science College, Shenyang Agricultural University between March 2014 and December 2015. Methodology: The composition of Flat-European hybrid hazelnut was determined using GC-MS. Results: Selection of suitable commercial enzymes is an important factor that can affect the extraction efficiency. Based on single factor tests, best conditions for the aqueous enzymatic extraction of the oil, determined by response surface analysis, were as follows: pH 6.13, enzymatic hydrolysis temperature of 59.9°C, dose of papain equal to 6% of seed weight, dose of α-amylase equal to 4% of seed weight, seed/water ratio of 1:5 (w/v), and enzyme hydrolysis time of 4.78 hours. By means of GC-MS analysis oleic acid (77.22%), linoleic acid (14.06%), linolenic acid (0.13%), palmitic acid (5.04%), stearic acid (2.35%), and arachidonic acid (0.44%) were identified as the major compounds of the flat-European hybrid hazelnut oil. Conclusion: The mixture of papain (6% of seed weight) and α-amylase (4% of seed weight) was the best enzyme combination for the aqueous enzymatic extraction of flat-European hybrid hazelnut oil. The best technological parameters for the oil extraction process were: seed/water ratio of 1:5 (w/v), pH value of 6.13, reaction temperature of 59.90°C, and reaction time of 4.78 h. With these conditions, the oil yield was 82.36%, where unsaturated fatty acids were 92% of the total.