Preliminary Investigation for Application of Supercritical Fluid Extraction Technology for Garlic Oil Extraction

Project Overview

Project Type: Graduate Student
Funds awarded in 2004: $10,000.00
Projected End Date: 12/31/2006
Grant Recipient: Clemson University
Region: Southern
State: South Carolina
Graduate Student:
Major Professor:
Terry Walker
Clemson University

Annual Reports


  • Vegetables: garlic


  • Farm Business Management: feasibility study, new enterprise development


    A small&medium farm-oriented supercritical fluid extraction (SFE) system was developed and demonstrated for garlic oil extraction as an example of high value crop plant process. The extraction conditions and operation procedure were suggested as a guideline. The potential application of this technology on farm was preliminarily investigated by visiting an organic farm in South Carolina and discussing with the farmer, extension professional and researcher. The evaluation of the scale-up system was conducted based on the current small system and future work was suggested for this technology to be extended to farm use.

    Tables, figures or graphs mentioned in this report
    are on file in the Southern SARE office.
    Contact Sue Blum at 770-229-3350 or for a hard copy.


    The growing nutraceutical and functional food market (global market estimated to be $63B in 2004 with an annual growth of 14%, which is expected to grow to $167 B by 2010, as published by is anticipated to supply an opportunity for farmers to increase their income and employment. The problem is how farmers may benefit from this growing market as much and as early as possible. Garlic oil is currently 20-100 times the value of raw garlic.
    There are potential avenues for the farmers to increase their profits via by-passing the collector or processor. These alternative avenues allow for increased profit space for the farmer. For the farmers to actually increase profits in the nutraceutical market, they would not only harvest the field, but also take part in processing of the raw material. Operation of economic, smaller-scale, sustainable, separation equipment for extraction of garlic oil would increase value of the product and decrease transportation cost.
    Garlic (Allium sativum) is a perennial plant of the Alliaceae related to onions, chives, shallots, and leeks. It is mainly used as a food flavoring agent and condiment in various foods and spices such as mayonnaise, salad dressing, spaghetti, pickles, etc. Garlic has been revered for its medicinal properties for centuries. This reverence has been propelled in recent years by the emergence of data revealing that in addition to antimicrobial properties it may also reduce the risk of heart disease and cancer. Commercially available garlic preparations in the form of garlic oil, rich in allicin and allyl sulfur compounds known as contribute to medicinal properties, are widely used for certain therapeutic purposes, including lowering blood pressure and improving lipid profile (Robert, 2001).
    About 250 million pounds of garlic are produced in the United States. About 80% to 90% of this amount is produced in California. Garlic grows best during cool weather and is usually planted in the early winter in South Carolina for early summer harvest. Commercial garlic is only produced in Southern part of state. South Carolina has great potential for local farms to produce garlic due to its promising climate for this crop and develop value-added nutraceuticals. Supplying the processed or semi-processed garlic oil for nutraceutical manufacturers, instead of selling raw garlic, is a potential avenue for the farmers to increase their profits.
    An environmentally safe processing method known as supercritical fluid extraction (SFE) would bring opportunities to local farm owners to run their “plants” and provide a feasible method to produce semi-processed & processed products for nutraceutical manufacturers. Demonstration of SFE technology for industrial applications was reported by Zosel at the Max Planck (Zosel, 1969). Because SFE has several distinct advantages, such as non-toxic, non-explosive, and low solvent temperatures, it has been regarded as a promising alternative technique to conventional solvent extraction methods. Today, SFE has become an acceptable extraction technique used in many areas, far beyond decaffeination coffee and extracting hops for beer flavoring. SFE of active natural products from herbal or more generally, from plant and microbial materials has become one of the most important application areas (McHugh and Castro, 1994). Additionally, SFE technology using carbon dioxide as solvent is GRAS or "green" status accepted in both Europe and the U.S.
    Miles and Quimby (1990) extracted garlic product using supercritical CO2 and analyzed its compounds by GC with atomic emission detection. Elizabeth (1994) extracted garlic allicin by SFE. The yield of allicin from a water homogenate of fresh garlic was 98.2% and 124.6% relative to yields obtained with methylene chloride extraction, respectively using a solvent trap and a solid-phase trap. Though the study of the SFE of garlic oil is less reported in the literature, garlic oil produced from SFE is commercially available and the market is growing in recent years. The garlic oil production using SFE is only an example of a large nutraceutical industry. Crop-based nutraceuticals sold in store are at least dozens. The SFE application will be extended with the growing nutraceutical industry. At present, there is not local farm-adopted SFE technology and equipment. We have initiated this development and intend to transfer this technology to farmer’s hand by the demonstration of SFE technology to produce garlic oil.

    Project objectives:

    The objectives are:
    (1)To investigate the pathway and key points to SFE technology extension on small & medium-size local farms.
    (2)To further optimize SFE kinetics parameters of garlic oil on the basis of on site operation.
    (3)To investigate the criteria for developing the small & medium-size farm-adopted SFE equipment.

    Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.