Firmness and Pectic Substances of Mature-green Mume (Prunus mume) Fruits Packaged with Polyethylene Bags and Ethylene Absorbent

Abstract

Firmness of mume (Japanese apricot) fruits packaged with polyethylene bags and inclusion of ethylene absorbent were measured and relationships with pectic substances, respiration rate and ethylene production were determined. (1) The firmness of the fruits packaged with ethylene absorbent was held at higher level during at 20°C, whereas those of the fruits packaged with perforated or sealed bags lowered rapidly. The sealed-package delayed the occurrence of climacteric rise and lowered the increase of ethylene production from the fruits. The inclusion of ethylene absorbent in the bag markedly enhanced the suppressive effects. (2) The ratios of water soluble-pectin (WP), sodium hexamethaphosphate soluble-pectin, and hydrochloric acid soluble-pectin (HP) contents to total pectin content in the fruits were 29%, 3%, and 68%, respectively, at harvest during the storage at 20°C, total pectin content did not change obviously but increase of WP and decrease of HP occurred markedly as the softening of fruits advanced. Inclusion of ethylene absorbent conspicuously retarded these changes. (3) changes of Sephacryl S-300 gel filtration pattern revealed that higher molecular pectins in HP and WP fractions were decomposed into lower molecular pectins with advance of softening of mume fruit during ripening and these decomposition of pectins was suppressed in the fruit packaged with ethylene absorbent.