It has been shown that dried sugar-beet pulp contains a high percentage of pectose. A number of successive digestions of 1 hour each with 0·5 per cent. ammonium oxalate at 100° C. extracts an amount of pectin equal to 34·5 per cent. of the weight of dried beet pulp, basing the determination on the weight of crude pectin precipitated when the extracts are run into 95 per cent. alcohol. A single prolonged digestion gives a yield of crude pectin equal to 32·2 per cent. of the dried beet pulp.
Digestion with acidic reagents, such as 0·5 per cent. oxalic acid, 0·6 per cent. tartaric acid, N/20 hydrochloric acid, etc., leads to a quicker extraction of pectin, owing to a speeding up of the pectose to pectin hydrolysis. The yield of pectin, however, is not thereby necessarily enhanced, since under such conditions the pectin undergoes a slow secondary hydrolysis during the extraction with the formation of reducing substances not precipitated by alcohol.
Prolonged digestion at 100· C. of dried sugar-beet pulp with water alone also leads to a satisfactory extraction of pectin.