| dc.description.abstract | Pseudomonas aureofaciens and Ps. putida were found in spoiled skim milks. To know the type of spoilage, due to activities of these two species, the role of Ps. aureofaciens and Ps.putida to organoleptic evaluation and flavour compounds of skim milks stored at ~ O C , for 10 and 20 days, after the use by date, were observed. Uninoculated skim milks, were used as control. Organoleptic evaluation were assessed by experienced panelists. Gas Chromatography Mass Spectrometry, retention times (r.t), 5- 15' and 15-30', were used to detect the flavour compounds. The results showed that after storage 10 and 20 days, organoleptic scores of skim milks decreased, flavours were stale/rotten, and arbitrary units (a.u.) >50 of majority flavour compounds increased, compared with control. The higher units of flavour compounds of skim milks, inoculated Ps. aureofaciens, stored 10 and 20 days, than of control (a.u. > 1000), were mercapto-acetic acid, r.t. 5.97' (6066 a.u., 10 days, and 2109 a.u., 20 days ), and 4-methyl-2-pentanone, r.t. 16.29' (1401 a.u., 10 days, and 1 196 a.u.. 20 days). While the higher units of flavour compounds, inoculated Ps. putida, stored 10 days, were rnercapto-acetic acid (3 189 a.u., r.t. 5.97'), 4-methyl-2-pentanone (2633 a.u.. r.t. 16.3 1 '), and ethyl-butanoate (4753 a.u., 19.44'), and stored 20 days, was mercapto-acetic acid (4910 a.u., r.t. 5.97'). The organoleptically decrease of flavours, and increase of majority flavour compounds units of inoculated skim milks at storage, compared with control, showed the change of quality of stored skim milks, due tb activities of Ps. aureofaciens and Ps.putida. | id |
