Effects of conventional boiling on the polyphenols and cell walls of pears

Pears of the cultivar Gieser Wildeman were cooked for up to 24 h and changes in polyphenol and cell wall components were monitored. The main polyphenols were flavan‐3‐ols (epicatechin and its procyanidin oligomers), with an average degree of polymerisation of 6, and caffeoylquinic acid. Upon cooking, flavan‐3‐ols were retained in the pear tissue while the hydroxycinnamic acids were partially leached into the cooking water. After 1 h of cooking, 65% of the original flavan‐3‐ols and 40% of the original caffeoylquinic acid were still detectable in the pear tissue; the cooking water contained only 2% of the flavan‐3‐ols but 24% of the caffeoylquinic acid. Cell walls represented 23 g kg −1 of the fresh pear and were composed of cellulose, pectins and xylans. The pectic fractions was degraded during cooking while xylans and cellulose were not affected.