I will remove the pectin from hemp fibres with Bioprep 3000L pectinase. How can I measure the % of pectin before and after for loose fibres? I only found a way to measure it for fabric, but I will perform this test on just loose hemp fibres.

  • $\begingroup$ The meter for measurement for fabrics is called: ruthenium red dye method. $\endgroup$ – Marguérite Apr 21 '15 at 7:39

Note that I do not have professional experience in the textile industry!

Supposed that the stems have been (mechanically) treated, and the "bark" is removed, the ruthenium red method should work.

In Crystal-Structure of Ruthenium Red and Stereochemistry of its Pectic Stain by Clarence Sterling, Am. J. Bot. 1970, 57, 172-175, the specific binding of Ruthenium Red (RR, CAS-RN: 11103-72-3) along a pectin chain, that is, between a $\ce{COOH}$ of one galacturonic acid unit and the $\ce{OH}$ of the next, has been described.

In a more recent publication, Qualitative distinction of carboxyl group distributions in pectins with ruthenium red, published in Bot. Bull. Acad. Sin., 1999, 40, 115-119 (PDF), the method was applied to orange peel pectines of different origin. Here, the dye-pectin adducts were precipitated by addition of $\ce{CaCl2}$ and centrifugated. Then, the absorbtion of the supernatant solution and a stock solution of the dye at $\lambda = 534\,\mathrm{nm}$ were compared.

Consequently, it should be possible to take fibre samples, suspend them and detemine whether they decrease the absorption of RR (= still contain pectin).

Are you planning to bleach these fibres in a way recently discussed in another question? It might be interesting to figure out whether these conditions (alkaline hydroperoxide) are sufficent to (partly) degrade the pectin.


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.