Subcritical Butane Extraction of Wheat Germ Oil and Its Deacidification by Molecular Distillation.

Jinwei Li,Lige Qian,Dewei Sun,Yuanfa Liu

doi:10.3390/molecules21121675

Abstract

Extraction and deacidification are important stages for wheat germ oil (WGO) production. Crude WGO was extracted using subcritical butane extraction (SBE) and compared with traditional solvent extraction (SE) and supercritical carbon dioxide extraction (SCE) based on the yield, chemical index and fatty acid profile. Furthermore, the effects of the molecular distillation temperature on the quality of WGO were also investigated in this study. Results indicated that WGO extracted by SBE has a higher yield of 9.10% and better quality; at the same time, its fatty acid composition has no significant difference compared with that of SE and SCE. The molecular distillation experiment showed that the acid value, peroxide value and p-anisidine value of WGO were reduced with the increase of the evaporation temperatures, and the contents of the active constituents of tocopherol, polyphenols and phytosterols are simultaneously decreased. Generally, the distillation temperature of 150 °C is an appropriate condition for WGO deacidification with the higher deacidification efficiency of 77.78% and the higher retention rate of active constituents.

Highlights

Wheat germ is a by-product of the wheat milling industry
Compared to supercritical carbon dioxide extraction (SCE), subcritical butane extraction (SBE) positively affected the yield of wheat germ oil (WGO) and increased it by 3.64%
Acid value (AV), peroxide value (POV), and p-anisidine value (PAV) were analyzed according to the method described by Li et al [32]

Summary

Introduction

Wheat germ is a by-product of the wheat milling industry. It contains about 8%–14% oil and plays a crucial role in the food industry [1]. WGO is the most important source of tocopherol of all vegetable oils, up to about 2500 mg/kg [2], especially the content of α-tocopherol, which represents around 60%. WGO is a rich source of unsaponifiable phytosterols, in particular sitosterol (60%–70%) and campesterol (20%–30%) [3], polycosanols (POC), thiamine, riboflavin and niacin. Tetracosanol, hexa-cosanol, and octacosanol are the major POC components in all varieties of WGO [4,5,6]. WGO is high in human essential unsaturated fatty acids, including about

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