Abstract
Cocoon characters of fourteen original Thai polyvoltine strains of the silkworm, Bombyx mori were investigated in males and females separately such as cocoon shell ratio, cocoon color by CIELAB system, degumming loss, sericin recovery by degumming and antioxidant activity of sericin. Considerable variation was observed. In males, the largest in cocoon shell ratio was Gaa-Gee, 16.16±1.23 % and the smallest Nang-Tui, 12.88±1.45 %. In females, the largest in cocoon shell ratio was Gaa-Gee, 13.28±0.86 % and the smallest Nang-Tui, 10.86±0.47 %. Measurement of cocoon color by CIELAB system identified color of cocoons for each strain, which can be used for identification of strains from the CIELAB data. Degumming conditions were studied and degumming loss of each strain was determined. In males, the highest in degumming loss was SP2, 28.18±1.5 % and the lowest Roi-Et 5, 17.95±5.1 %. In females, the highest in degumming loss was NNK 8, 29.84±6.9 % and the lowest On-Yon, 18.53±8.2 %. In sericin recovery by degumming in males, higher values in sericin recovery were found in three strains; SP2, 4251±179 μg/ml, Nang-Sew, 4488±152 μg/ml and Pak-Chong 21, 4037±131 μg/ml. The lowest was Som-Rong, 3272±220 μg/ml. In females, higher values in sericin recovery were observed in four strains; On-Yon, 4167±349 μg/ml, SP2, 4100±79 μg/ml, Nang-Sew, 4344±93 μg/ml and Pak-Chong 21, 4266±301 μg/ml. The lowest was Som-Rong, 3420±128 μg/ml. The highest in antioxidant activity by ABTS＊＋ IC50 test was NNK 8 both in male and female; in male 88.05±4.56 μg/ml and in female, 88.59±6.99 μg/ml. In TEAC test, the highest in antioxidant activity was male, Pak-Chong 21, 0.1304±0.0009 mM Trolox/g and female, Nang-Lai, 0.1332±0.0127 mM Trolox/g. Variation in cocoon characters is present among original Thai polyvoltine silkworm strains and the specific strain could be utilized for specific purpose of cosmetics applications of sericin.
