Chelators added to pectinase-rich enzyme mixtures increase the efficiency of enzyme retting of flax. The multitude of available chelators requires research to optimize enzyme retting for cost and fiber quality. Of several chelators tested, ethylenediaminetetraacetic acid (EDTA) is the most effective in sequestering calcium from solution, with substantial activity even at pH 4 or 5. Phosphate is also effective, but only at high pH. EDTA and Mayoquest 200, a commercial product with -37% EDTA, in combination with Viscozyme L or Lyvelin, commercial enzymes with polygalacturonase activities, yield high Fried test scores, indicating efficient separation of fibers from core tissues. Neither chelator nor enzyme at the levels tested alone effectively rets flax at a pH of around 5. In contrast, EDTA at 20 mmol/L levels and alkaline pH yields high Fried test scores. The addition of BioPrep, a commercial pectate lyase, does not influence retting measured by the Fried test with EDTA at alkaline pH, but the enzyme does improve retting with the weaker chelator sodium tripolyphosphate. The quality of fibers, as determined by the yield of fine fibers obtained by passing retted flax through the Shirley analyzer, is substantially greater with EDTA plus Viscozyme at pH 5 than alkaline chemical retting with EDTA, sodium tripolyphosphate, or sodium oxalate without enzyme. EDTA is the most effective chelator at acidic pH levels for stimulating flax retting by various commercial pectinase-rich enzyme mixtures. However, other less expensive candidates require additional study for more cost-effective formulations and applicable fiber properties. Retting is the process by which fibers in flax (Linum usitatissimum L.) stems and other bast plants are separated from the nonfiber tissues. This process, which is usually microbial, is the major limitation in producing linen fibers [25]. For commercial flax fiber operations, flax stems are pulled from the ground and dew retted, in which indigenous fungi colonize and degrade the nonfiher tissues to liberate fibers. After dew retting, the stems are mechanically cleaned to remove shive and other contaminants from fibers for use in linen yarns and fabrics. While currently the method of choice, dew retting is restricted to geographical regions with appropriate climates, and the resulting fibers are often inconsistent in quality with significant amounts of dirt and contaminants [21, 25]. Therefore, considerable research has focused on alternative chemical and enzymatic methods to improve the consistency of fiber quality [1, 4, 5, 9, 10, 14, 21, 22, 25]. Increasing U.S. interest in flax fibers for use as cottonized fibers in textiles [4] and for bio-composites [19] globally provides a strong impetus to improve flax retting. The importance of pectin as a binder between cells and the necessity to remove it during retting has been acknowledged for several decades [25]. Therefore, pectinases, and in particular endopolygalacturonases, are effective in retting flax [2, 4, 11, 12, 17, 25, 26]. However, pectin is a complicated polysaccharide that varies in structure [16]. In nonmethylated pectins, often Ca2+ binds carboxyl groups of adjacent molecules, thus stabilizing pectins and thereby plant structure [20]. In flax, recent research has indicated that acidic pectins and Ca2+ are located preferentially in the epidermal regions of flax [18], likely contributing to the structural integrity of the stem and bast fibers. Therefore, complex formers, e.g., chelators, such as ethylenediaminetetraacetic acid (EDTA) to remove Ca2+ have proven useful in retting flax and in facilitating enzyme retting [4, 7, 9, 11, 21].
> On July 11,2000, the Tennessee Board of Medical Examiners passed a position paper limiting the use and promotion of Chelation therapy. They found the therapy is in violation of Tennessee Code Annotated 63-6-314 which states it is illegal to advertise prevention or cure or any illness or to perform Chelation therapy unless it is in an approved clinical trial in an academic institution or used for heavy metal poisoning in accordance with FDA approved uses.
Oral Chelation
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