ANALYSIS OF SORGHUM WAX QUANTITY AND QUALITY

• Sponsoring Institution: National Institute of Food and Agriculture
• Project Status: TERMINATED
• Funding Source: HATCH
• Reporting Frequency: Annual
• Accession No.: 0183911
• Project No.: NEB-11-119
• Project Start Date: Oct 1, 1999
• Project End Date: Sep 30, 2004

Project Director
Weller, C. L.

Recipient Organization
UNIVERSITY OF NEBRASKA
(N/A)
LINCOLN,NE 68583

Performing Department
BIOLOGICAL SYSTEMS ENGINEERING

Non Technical Summary
Grain sorghum kernels have long been known to be coated with a waxy material. Limited and conflicting information exists on chemical, physical and functional properties. This project will extract waxy material from several types of grain sorghum kernels using different solvents and examine its chemical, physical and functional properties. Extraction and recovery processes will also be evaluated.

Animal Health Component

(N/A)

Research Effort Categories

Basic

35%

Applied

55%

Developmental

10%

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
402	1520	2020	20%
502	1520	2000	20%
502	1520	2020	20%
511	1520	2000	20%
511	1520	2020	20%

Knowledge Area
502 - New and Improved Food Products; 402 - Engineering Systems and Equipment; 511 - New and Improved Non-Food Products and Processes;

Subject Of Investigation
1520 - Grain sorghum;

Field Of Science
2020 - Engineering; 2000 - Chemistry;

Keywords

grain sorghum

extraction

chemical properties

physical properties

functional properties

wax

quantitative analysis

product quality

food

food properties

food chemistry

new products

food engineering

hybrids

yield potential

kernels

solvents

byproducts

waste utilization

Goals / Objectives
The goal of the proposed research is to determine the effects of using different organic solvents on the amount and properties of wax recovered from kernels of four grain sorghum hybrids such that further studies of wax functionality and process economics might be conducted. To reach this goal, the following specific objectives will be realized: 1)Yields of wax from four different grain sorghum hybrids will be determined using two different solvents in a laboratory extraction and recovery method. 2)Selected chemical properties (saponification value, acid value, ester value, iodine value, hydrocarbon chain lengths, fatty acid chain lengths, and alcohol chain lengths) of wax from grain sorghum as affected by sorghum hybrid and extraction solvent will be determined. 3)Selected physical properties (melting point, color, penetration resistance, specific gravity and clarity) of wax from grain sorghum as affected by sorghum hybrid and extraction solvent will be determined. 4)Relationships between chemical and physical properties of wax of grain sorghum as affected by sorghum hybrid, extraction solvent and hybrid-solvent interactions will be determined. 5)Selected functional properties (performance of wax in various applications; each with its own performance criteria) of wax from grain sorghum as affected by sorghum hybrid and extraction solvent will be determined. 6)Scale-up of laboratory extraction process to a percolation system such that processing costs can be estimated using engineering analyses.

Project Methods
To meet the goal of the proposed research, six specific objectives are proposed. Each plays an important part in establishing the characteristics, functionality and economics of sorghum wax. Once that has been established, several industries may seriously consider developing or adapting technology on a commercial scale to recover wax. Meeting the first objective would allow for comparison of wax yields (weight of wax per weight of grain sorghum) resulting from extractions using different solvents. Not only will quality of wax be of interest in any future process analyses but also quantity of wax. The second objective needs to be considered since no agreement has been found among previous researchers in this area. Varied and superficial characteristics of sorghum wax have been reported. We plan to use our fractionation procedure followed by additional chromatographic techniques to begin developing a chemical characterization of sorghum wax. The third objective relates to determining values for selected physical properties of sorghum wax. The task of characterizing sorghum wax physical properties must be undertaken due to the wariness of natural wax compounders (i.e. possible industrial partners). Too many times in the past new waxes have entered the market only to fail due to limited availability. Compounders have been left with a bad taste from these experiences and are reluctant to really seek out new waxes. Relationships between physical properties and chemical properties as affected by the hybrid and solvent may then be established in the fourth objective. The information may play an important role in tailoring either physical or chemical properties on the basis of the type of solvent or the hybrid used in recovery of the sorghum wax. The fifth objective will make use of information from the first four objectives and begin to explore the utility and worthiness of grain sorghum wax in various applications. Wax functional properties of most importance in such explorations and each has its own performance criteria. Application examples may include as a food and industrial polish, as a cosmetic ingredient and as a candle wax. Scale-up and estimation of process economics will comprise the sixth objective. Ultimately, any serious producer or end user of grain sorghum wax will want to know how much it costs to recover and how much will it sell for. Therefore, projecting costs using an engineering analysis will be important.

Progress 10/01/99 to 09/30/04

Outputs
Lipid material including fatty aldehydes and fatty acids, and valuable components such as phytosterols, tocols and policosanols (primarily octacosanol and triacontanol) have been recovered from grain sorghum plant materials using procedures in use at the University of Nebraska for several years. The lipid fractions are easily extracted from small pieces of dry grain sorghum plant material. All procedures for determination of the fatty aldehydes, fatty acids and policosanols are well established. Procedures for the determination of grain sorghum phytosterols and tocols are presently being developed by modifying existing procedures for other plant materials. Grain sorghum lipids have been shown to lower plasma cholesterol and LDL cholesterol levels in hamsters.

Impacts
Grain sorghum can be a major source of policosanols, long-chained alcohols, which have beneficial physiological activities. Recovery of additional lipid materials including policosanols from by-products of grain sorghum processing may add up to $2 billion to the value of the by-products.

Publications

• Lochte-Watson, K.R., C.L. Weller and S.L. Cuppett. 1999. Wax extraction parameters of whole grain sorghum kernels and bran. Paper No. 99-6125, ASAE, St. Joseph, MI.
• Weller, C.L., S.L. Cuppett, L.C. Hua, K.R. Lochte-Watson, C. Gaudoin, J. Arrault, C.M. Hubbard and J.P. Mua. 2000. Solvent influence on yield and fractions of grain sorghum wax. Paper No. 00-6134, ASAE, St. Joseph, MI.
• Lochte-Watson, K.R., C.L. Weller and S. L. Cuppett. 2001. Properties of extracted wax from grain sorghum co-products. Paper No. 01-6013, ASAE, St. Joseph, MI.
• Schmidt, B.J., K.T. Hwang and C.L. Weller. 2002. A yield comparison of extraction methods for sorghum wax. Paper No. 02-6147, ASAE, St. Joseph, MI.
• Kim, K.M., K.T. Hwang, C.L. Weller and M.A. Hanna. 2002. Preparation and characterization of soy protein isolate films modified with sorghum wax. J. Am. Oil Chem. Soc. 79(6):615-619.
• Hwang, K.T., S.L. Cuppett, C.L. Weller, M.A. Hanna and R.K. Shoemaker. 2002. Aldehydes in grain sorghum wax. J. Am. Oil Chem. Soc. 79(6):529-533.
• Hwang, K.T., S.L. Cuppett, C.L. Weller and M.A. Hanna. 2002. Properties, composition and analysis of grain sorghum wax. J. Am. Oil Chem. Soc. 79(6):521-527.
• Kim, K.M., D. Marx, C.L. Weller and M.A. Hanna. 2003. Influence of sorghum wax, glycerin and sorbitol on physical properties of soy protein isolate films. J. Am. Oil Chem. Soc. 80(1):71-76.
• Hwang, K.T., C.L. Weller, S.L. Cuppett and M.A. Hanna. 2004. Changes in composition and thermal transition temperatures of grain sorghum wax during storage. Ind. Crops Prod. 19(2):125-132.
• Hwang, K.T., C.L. Weller, S.L. Cuppett and M.A. Hanna. 2004. Policosanol contents and composition of grain sorghum kernels and dried distillers grains. Cereal Chem. 81(3):345-349.
• Lochte-Watson, K.R., C.L. Weller and D.S. Jackson. 2000. Fractionation of grain sorghum using abrasive decortication. J. Agric. Engr. Research. 77(2):203-208.
• Lochte-Watson, K.R., C.L. Weller and K.M. Eskridge. 2000. Fractional composition of grain sorghum (Sorghum bicolor) after wet-peeling in a centrifugal pump. Appl. Eng. Agric. 16(3):253-258.

Progress 10/01/02 to 09/30/03

Outputs
Content and composition of policosanols in long-chained lipids extracted from grain sorghum kernels and sorghum dried distillers grains (DDG), a by-product of ethanol production were determined. Long-chained lipids were extracted using hot hexane or hot ethanol. The major components of the long-chained lipids extracted from grain sorghum kernels, as determined using HPLC, were policosanols (37-44%), aldehydes (44-55%) and acids (4-5%). Long-chained lipids from DDG contained 52% policosanols, 23% aldehydes, 6.4% acids and 17% wax esters/steryl esters. Composition of policosanols in DDG matched the composition in grain sorghum kernels, as determined by GC, even though the content of policosanols in DDG was greater than the content in grain sorghum kernels. Policosonal composition ranges of 0-1% C22:0, 0-3% C24:0, 6-8% C26:0, 1% C27:0, 43-47% C28:0, 1-2% C29:0, 40-43% C30:0 and 1-4% C32:0 were observed.

Impacts
Grain sorghum can be a major source of policosanols, long-chained alcohols, which have beneficial physiological activities. Recovery of additional lipid materials including policosanols from by-products of grain sorghum processing may add up to $2 billion to the value of the by-products.

Publications

• Kim, K.M., D. Marx, C.L. Weller and M.A. Hanna. 2003. Influence of sorghum wax, glycerin and sorbitol on physical properties of soy protein isolate films. J. Am. Oil Chem. Soc. 80(1):71-76.

Progress 10/01/01 to 09/30/02

Outputs
Grain sorghum kernels and dried distillers grains from ethanol processing were shown to contain lipid materials in a precipitate formed at freezing temperature from a hexane extract including fatty aldehydes, fatty acids, fatty alcohols (policosanols), tocols and phytosterols. The aldehydes, acids and alcohols were the primary compounds with 30-40% by weight of each of the aldehydes and alcohols. C28 and C30 components predominated.

Impacts
Recovery of additional lipid materials including wax from by-products of grain sorghum processing may add up to $2 billion to the value of the by-products.

Publications

• Hwang, K.T., S.L. Cuppett, C.L. Weller, M.A. Hanna and R.K. Shoemaker. 2002. Aldehydes in grain sorghum wax. J. Am. Oil Chem. Soc. 79(6):529-533.
• Hwang, K.T., S.L. Cuppett, C.L. Weller and M.A. Hanna. 2002. Properties, composition and analysis of grain sorghum wax. J. Am. Oil Chem. Soc. 79(6):521-527.
• Hwang, K.T., S.L. Cuppett, C.L. Weller and M.A. Hanna. 2002. HPLC of grain sorghum wax classes highlighting separation of aldehydes from wax esters and steryl esters. J. Sep. Sci. 25(9):619-623.

Progress 10/01/00 to 09/30/01

Outputs
Grain sorghum wax was confirmed to contain 40% aldehydes (C28 and C30) by weight as its primary component. Other components are long-chained acids, long-chained alcohols and hydrocarbons. Effects of auto-oxidation on functional and physical properties of the wax need to be established to optimize utilization of the wax.

Impacts
Recovery of additional lipid materials including wax from by-products of grain sorghum processing may add up to $2 billion to the value of the by-products.

Publications

• Weller, C.L., K.M. Kim, K.T. Hwang, S.L. Cuppett and M.A. Hanna. 2001. Chemistry of grain sorghum wax and its relation to film and coating applications. In Proc. Active Biopolymer Films and Coatings for Food and Biotechnical Uses Pre-Congress Short Course of IUFoST, 111-141. Seoul, KR, 21-22 April.
• Lochte-Watson, K.R., C.L. Weller and S.L. Cuppett, 2001. Properties of extracted wax from grain sorghum co-products. Paper No. 01-6013, ASAE, St. Joseph, MI.

Progress 10/01/99 to 09/30/00

Outputs
Effect of solvent, hexane or ethanol, on yield, and physical and chemical characteristics of wax for 86 commercial grain sorghum hybrids was studied. Surface wax of grain sorghum has physical properties similar to carnauba wax. Wax yields ranged from 0.160% to 0.309% across the hybrids and growing seasons of 1993-1997. Wax yields in 1996 were generally lower than yields in other years. Fractionation of hexane-extracted and ethanol-extracted wax revealed 5 major groups of compounds. Two of the groups were confirmed as hydrocarbons and alcohols.

Impacts
No appreciable differences were noted in properties for the present-day grain sorghum variety versus those of the earlier varieties. Wax yields on a dry basis for the 86 hybrids of grain sorghum were all almost over 0.20% in four out of five years. Confirmation on the other groups of compounds and further analysis are necessary to determine differences between hexane-extracted wax and ethanol-extracted wax.

Publications

• Weller, C.L., S.L. Cuppett, L.C. Hua, K.R. Lochte-Watson, C. Gaudoin, J. Arrault, C.M. Hubbard and J.P. Mua. 2000. Solvent influence on yield and fractions of grain sorghum wax. Paper No. 00-6134, ASAE, St. Joseph, MI.