Ronald A Holser

Synthesis and characteristics of polyhydroxy triglycerides from milkweed oil

The milkweed family Asclepiadaceae comprises many genera including the genus Asclepias syriaca, otherwise known as the common milkweed. This plant had been considered a nuisance and serious efforts made toward its eradication. However, milkweed has become an industrial crop of growing significance on account of market demand for its hypoallergenic floss in pillows, comforters and other industrial uses. Processing of milkweed pods gives three product streams of floss, seed and pod hulls. The seed contains about 25% by weight of very highly unsaturated oil with some unusual fatty acids. The objective of this study was to generate value-added products from milkweed oil. To achieve this, the triglycerides of A. syriaca seed were oxidized to the polyoxirane and polyhydroxy triglyceride derivatives by means of an in situ peroxy acid method. The epoxy triglycerides produced exhibited high stability and highly viscous behavior, whereas the polyhydroxy triglycerides showed additional unusually stable emulsifying properties for oil in water emulsions.

Pilot-scale isolation of simmondsin and related jojoba constituents

Abstract Simmondsin and several related compounds are present in jojoba meal at about 13% concentration. Industrial scale processes have been developed to extract the meal with water to yield a simmondsin concentrate that contains 43% simmondsin and analogues. This research was undertaken to develop a practical process to purify further the active constituents. Acetone, acetonitrile, chloroform, ethanol, isopropanol, methanol, and water, alone and in various combinations and at various solvent:solids ratios were tested. Extraction with absolute ethanol followed by 80:20 ethanol–water increased the concentration of simmondsins from 42 to 75% in the ethanol extract, recovered the remaining simmondsins in the second extract and left a sugar and protein residue low in residual simmondsins. Subsequent preparative chromatography gave fractions greater than 95% purity. From the preparative HPLC, 77% of the recovered fractions was of pharmaceutical grade and 20% was acceptable for further refinement or recycling into the feed solution.

Properties of refined milkweed press oil

The seed floss from Asclepias is currently harvested as a hypoallergenic fiber fill material for use in pillows and comforters. Milkweed seed is harvested with the floss although the oil contained in the seed is not used commercially. Milkweed oil was investigated as an alternative source of triglycerides for potential industrial applications. Processing conditions were investigated to produce degummed, refined, and bleached press oil. Milkweed oil was expelled from whole seed using a pilot-scale press and processed in the laboratory to produce refined and bleached oil. A high quality oil with a Lovibond color of 2Y and 0.2R was obtained following degumming with 3 wt.% water, refining with 3 M sodium hydroxide, and bleaching with 5% activated earth.

Extraction of simmondsins from defatted jojoba meal using aqueous ethanol

Abstract The development of a new crop may be enhanced by the recovery of secondary metabolites that have new applications. Simmondsin compounds were extracted from commercially defatted jojoba meal in laboratory experiments with solutions of 80–100% aqueous ethanol. Batch extractions performed with 80% ethanol at a 1:10 meal to solvent ratio and at 25°C for 30 min exhibited increased selectivities for simmondsin and simmondsin ferulate as compared to similar extractions performed with deionized water. The extraction of simmondsin compounds from defatted jojoba meal with aqueous ethanol is feasible and offers the advantages of a solvent with low toxicity and low volatility. Aqueous ethanol is compatible with equipment currently used in the vegetable oils industry and would require only modest changes in operating conditions and plant layout to be implemented on a large scale.

Simmondsin and wax ester levels in 100 high-yielding jojoba clones

Abstract This 3-year study examines differences in simmondsin and wax ester production by 100 previously identified high-yielding jojoba clones. Over the past 3 years the USDA, ARS, National Center for Agricultural Utilization Research (NCAUR) analyzed seed samples from Purcell Jojoba International’s (PJI) large 17-year-old Variety Trial program. These 100 clones were the top producers out of 1523 clones that had been mass-selected from more than 1.5 million, open-pollinated, female plants. Broad selection criteria were applied to retain a healthy degree of the natural plants’ heterogeneity and hybrid vigor. In this study, one female clone produced 82% higher simmondsin levels than the mean of the 100 clones analyzed. Another clone produced 16% higher liquid wax ester levels than industry average. A few clones had high levels of both simmondsins and esters. In addition, the differences in fatty acid and fatty alcohol among the clones were also studied. These analyses help provide a strong foundation for major growth of the jojoba industry.

Rheological properties of lesquerella gum fractions recovered by aqueous extraction

Abstract Lesquerella fendleri seeds contain a cross-linked carbohydrate gum with viscoelastic properties that may be used for industrial and edible applications. Laboratory studies compared the rheological behavior of gum isolates obtained from whole seed, defatted hull, and defatted meal fractions. Gum yields and rheological properties were determined for gum isolates from each of these fractions. All gum isolates exhibited positive hysteresis, which provided evidence of structure formation in 1% solutions. Values of storage and loss modulus were reported from oscillatory experiments over an angular frequency range of 0.1 to 100 rad/s using a controlled-stress rheometer. Whole seed meal appears to be the most cost-effective fraction from which to recover gums.

Milkweed seedmeal: a control for Meloidogyne chitwoodi on potatoes

Abstract Milkweed (Asclepias) is a new crop being produced for its fiber in pillows and comforters. Cardiac glycosides (cardenolides), are endemic in milkweed and may hinder utilization of its seed as an animal feed. In an ongoing effort to develop new coproducts for milkweed fiber, we found that the defatted seedmeal is an effective nematicide and pesticide for army worms. A procedure for separating the cardenolides from milkweed seedmeal has also been developed.

Rheological characterization of jet-cooked Lesquerella fendleri seed gum and cornstarch solutions

Lesquerella is a potential new seed crop that contains hydroxy fatty acid triglycerides and approximately 15% seed coat gums. The polysaccharide gum of the Lesquerella fendleri seed was isolated and jet-cooked with cornstarch in a series of laboratory experiments to investigate the viscoelastic properties of gum-modified starch solutions. The Lesquerella gum was combined with cornstarch at 1, 5, and 10% levels to produce a jet-cooked and drum dried material with potential application as a thickening or suspension agent. Flow curves were determined for 1% solutions of jet-cooked starch and gum combinations. All materials investigated were biodegradable and exhibited positive thixotropic behavior.

Interlaboratory comparison of simmondsin analysis

Abstract Eleven samples containing various amounts of simmondsin (S), simmondsin ferulate (SF), demethyl simmondsins (DMS) and didemethyl simmondsins (DDMS) were analyzed by five different laboratories. The samples were made from chromatographically pure simmondsin, animal feed formulations containing jojoba meal, defatted jojoba meal, water extracts of jojoba meal and combinations of these ingredients. Where mixes were made, all materials were ground together in a coffee mill and sieved. Four laboratories analyzed for simmondsin and related components and one laboratory analyzed for only S. The means of the S, SF, DMS and DDMS percentages in the samples were determined to be: high performance liquid chromatography (HPLC) purified simmondsin, 94.1% S, 0 SF, 6.30% DMS, 0.52% DDMS; recrystallized simmondsin, 99.6% S, 0 SF, 1.01% DMS, 0 DDMS; water extract of jojoba meal 1, 29.2% S, 2.62% SF, 3.45% DMS, 9.47% DDMS; water extract of jojoba meal 2, 20.6% S, 2.00% SF, 2.81% DMS, 8.66% DDMS; formulated pet food with simmondsin, 0.59% S, 0 SF, 0 DMS, 0.01% DDMS; defatted jojoba presscake 7.05% S, 1.55% SF, 1.34% DMS, 3.48% DDMS. Using a Rank-Sum test, no laboratory demonstrated a consistently higher or lower bias compared to other laboratories for simmondsin analysis. Simmondsin analysis had less variability (C.V.=44) than other component analyses. Reproducibility for a blind duplicate sample of defatted jojoba presscake demonstrated that four of the five laboratories were consistent in simmondsin analysis. Water extracts of jojoba meal were shown to be highly variable in simmondsin content.