Title: ORIGIN OF SEED COAT FRAGMENTS IN GINNED LINT Author
Submitted to: ASABE Annual International Meeting
Publication Type: Proceedings
Publication Acceptance Date: June 1, 2006
Publication Date: July 12, 2006
Citation: Boykin Jr, J.C. 2006. Origin of seed coat fragments in ginned lint. ASABE Annual International Meeting. Paper #061025 17pp. Interpretive Summary: Approximately 20 million bales of cotton are produced in the U.S. annually, most of which is exported. It is important that this cotton is processed efficiently while maintaining the quality demanded by domestic and foreign consumers. One issue that is becoming increasingly important is problems associated with fragments of cottonseed that remain in cotton bales after ginning. These seed coat fragments (SCF) can cause the yarn to break resulting in costly down time in the mill. In addition, when the yarn or fabric is dyed, the SCF absorb the dye differently than the cotton lint and cause discoloration that is undesirable in the finished product. There has been much research conducted in mills to deal with this contamination, and cotton breeders have attempted to engineer better cottons. Cotton gin machinery has been modified to prevent or remove SCF, but success has been limited due to the poor understanding of this contaminant. The purpose of this experiment was to determine the origin of SCF by tracking their formation in cotton processed through a typical sequence of gin machinery. As suspected, the majority of SCF were produced in the gin stand. These SCF were shown to originate from immature and normal seed that were damaged or completely destroyed in the gin stand. Analysis of seed meats in seed cotton cleaner waste showed that a significant amount of SCF were formed before the gin stand, and it was suspected that a large portion were formed in the field. Results from this report will be vital to future research aimed at preventing or reducing SCF contamination in cotton bales. Implementation of this knowledge will help to increase the competitiveness of U.S. cotton.
Technical Abstract: Seed coat fragment (SCF) contamination in cotton bales causes processing problems in textile plants. This experiment was designed to determine the origin of SCF by tracking their occurrence through a conventional sequence of gin machinery. Samples of cotton, lint, seed, and waste material were collected from each machine as three cottons were processed. On average, there were 8.82 SCF totaling 12.65 mg and averaging 1.45 mg in each gram of lint before lint cleaning. Tests on lint after the lint cleaner showed a 60% reduction in the weight of SCF. Lint cleaner waste analysis provided similar results and showed that heavier SCF were removed. The lint cleaner reduced mote weight by 26%, but no conclusion was made on the amount of SCF created from motes. Seed meats recovered from the seed roll were 0.8% of all seed ginned and were estimated to account for 30% of SCF formed in the gin stand. Small seed eliminated from the distribution by the gin stand were 2.3% of all seed ginned and accounted for 14% of SCF formed in the gin stand. Seed that were damaged in the gin stand but remained intact were 7% of all seed, but there was no estimate for SCF resulting from this damage. There were 4.5 mg SCF/g lint found in seed cotton at the gin stand feeder, and seed meats found in seed cotton cleaner trash explained only 1.0 mg SCF/g lint. Most seed meats (57%) were found in the first seed cotton cleaner, so much of the damage before ginning may have occurred in the field. These preliminary results suggest that small/immature seed were more likely to form SCF as they passed through the gin stand. Seed destroyed in the gin stand was the major source of SCF, followed by seed that were only damaged in the gin stand.