Meadowfoam (Limnanthes alba) is a specialty oilseed crop that contains a high percentage of C20 and C22 fatty acids. Specialty oilseed crops require different processing conditions than commodity oilseeds. Meadowfoam seeds were conditioned at moisture levels of 4, 6, or 8%, and temperatures of 70, 90, or 110 °C prior to expelling to investigate the effects of conditioning on press oil properties. The quality and yield of the resulting press oils were evaluated. Increasing the moisture content and temperature of seeds prior to expelling increased the levels of free fatty acids (FFA) in the press oils, 0.51% at 70 °C and 4% moisture compared with 1.77% at 110 °C and 8% moisture. The oil yield and corresponding fatty acid profiles were not altered by the various treatment conditions.

Introduction

Meadowfoam (Limnanthes alba ) is an alternative oilseed crop that represents a renewable source of triglycerides for the preparation of lubricants, surfactants, and related industrial products (Miller et al., 1964; Princen and Rothfus, 1984; Burg and Kleiman, 1991; Carlson et al., 1994). Meadowfoam is an oilseed crop grown in the Northwestern United States that produces triglycerides with predominately C20 and C22 D5 mono-unsaturated fatty acids.

This study was undertaken to examine the effect of seed conditioning on press oil quality and yield. Conditioning seeds at elevated temperature and moisture levels prior to pressing can inactivate enzyme systems, e.g. lipase and lipoxygenase, and preserve oil quality (Orthoefer, 1996). Meadow-foam seeds in particular may benefit from such conditioning due to the presence of glucosinolate compounds such as limnanthin. The enzymatic degradation of glucosinolates can produce nitrile and isothiocyanate compounds that require addi- tional processing to remove. These compounds have been connected to off-flavors and odor development in vegetable oils (Vaughn et al., 1996; Shahidi et al., 1997).