The mixture was
centrifuged at 7500
g at 4 C for 15 min. The residue (lignin
thioglycolate) was washed with 10 mL of water, resuspended in
10 mL of 0.5 N NaOH for 18 h at room temperature and centrifuged.
2 mL of concentrated HCl was added to the supernatant. The lignin
thioglycolic acid complex was precipitated at 4 C for 4 h and
centrifuged. The residue was then dissolved in 10 mL of 0.5 N
NaOH. After performing appropriate dilutions, the absorbance was
C. Techavuthiporn, P. Boonyaritthongchai / Postharvest Biology and Technology 117 (2016) 64–70 65
read at 280 nm using a spectrophotometer (UV-1600; Shimadzu
Co., Japan). The lignin content was expressed as mg kg1 on a fresh
weight basis.