Content variations in compositions and volatile component in jujube fruits during the blacking process.

Dried jujube () was incubated at high temperature and humidity for 96 hr in blacking process and sampled every 12 hr. Results showed that the saccharose reduced from 195.6 to 3.1 g/kg rapidly in 24 hr. The total acid content was mild with 8.82 g/kg and increased to 23.45 g/kg by 177.21% with thermal processing for 96 hr. The contents of total polyphenols were enhanced during 0-48 hr processing, and the amount of the compound increased with treatment by 50.99%. The total reducing sugar increased 29.79% on 60 hr. cAMP was decreased with aging and ripening by 65.85%. 5-HMF was keep growing to 3.52 g/kg. The volatile component had great change in black jujube fruits compared to untreated jujubes, especially treated in 12 hr. The results indicated that backing pretreatment can facilitate the generation of functional food materials and support the development of this nutrition product.