Mobilization of primary metabolites and phenolics during natural fermentation in seeds of Pangium edule Reinw.
Andarwulan, N.; Fardiaz, S.; Apriyantono, A.; Hariyadi, P.; Kalidas Shetty;
Process Biochemistry Year: 1999 Vol: 35 Issue: 1/2 Pages: 197-204 Ref: 25 ref.
1999
บทคัดย่อ
Fermented seeds of the tropical tree P. edule (poisonous due to their cyanogenic glucoside content), are a speciality in Indonesia and have been used as spices. The fermentation process of the seeds is a natural spontaneous process, which occurs during 40 days following seed maturity and treatment. This study reports some biochemical changes, especially primary metabolites, and antioxidant activity associated with mobilization of lipids and phenolics during seed fermentation. Fruits were harvested on 30 November 1997 and placed in the field for 10 days until the fruit was tainted. Seeds were then removed, washed and boiled for 3 h, then placed in a hole in the ground and covered with ash. Postharvest fermentation began on 4 December and proceeded until 14 January (40 days). During fermentation, seed lipid content increased slightly (46.07-50.95% db) although the dominant fatty acid composition did not change. The dominant fatty acids were oleic acid (C18:1n-9) and linoleic acid (C18:2n-6). Durin
g fermentation, the decrease in fatty acid content in the lipid coincided with the increasing acid value, which indicated that free fatty acids increased in seeds during fermentation. The dominant tocol in the seeds, gamma -tocotrienol, increased (69.8-123.3 micro g/g freeze-dried seeds) during fermentation. In general, overall protein content and amino acid composition did not change but non-soluble protein increased while soluble protein decreased. The changes in carbohydrate fraction showed that total crude carbohydrate, neutral detergent fibre (NDF, as cellulose, hemicellulose, and lignin) decreased, but reducing sugar increased and starch content did not change. Enzyme assays showed that microorganisms may be involved in the fermentation process. beta -Glucosidase, an enzyme that can cleave glycosidic bonds of conjugated phenolics, and guaiacol peroxidase (GPX) activities increased. The total phenolics content in seeds increased substantially corresponding to the increase in beta -glucosidase but antiox
idant activity of phenolic extracts did not change.