In this work we present near-IR spectra ( HK-band ) of a sample of 107 sources with mid-IR excesses at 7 and 15 \mu m detected during the ISOGAL survey .
Making use of the DENIS interstellar extinction map from Schultheis et al .
( 1999 ) we derive luminosities and find that the M _ { bol } vs . ^ { 12 } CO and M _ { bol } vs . ~ { } H _ { 2 } O diagrams are powerful tools for identifying supergiants , AGB stars , giants and young stellar objects .
The majority of our sample are AGB stars ( \sim 80 % ) while we find four good supergiant candidates , nine young stellar objects and 12 RGB candidates .
We have used the most recent K _ { 0 } - [ 15 ] 
relation by Jeong et al .
( [ ] ) based on recent theoretical modeling of dust formation of AGB stars to determine mass-loss rates .
The mass-loss rates of the supergiants are comparable with those in the solar neighbourhood while the long-period Variables cover a mass-loss range from -5 < log \dot { \it { M } } < -7 .
The red giant candidates lie at the lower end of the mass-loss rate range between -6.5 < log \dot { { \it { M } } } < -9 .
We used the equivalent width of the CO bandhead at 2.3 \mu m , the NaI doublet and the CaI triplet to estimate metallicities using the relation by Ramírez et al .
( [ ] ) .
The metallicity distribution of the ISOGAL objects shows a mean [ Fe/H ] \sim -0.25 dex with a dispersion of \pm 0.40 dex which is in agreement with the values of Ramírez et al .
( [ ] ) for Galactic Bulge fields between b = -4 ^ { o } and b = -1.3 ^ { o } .
A comparison with the solar neighbourhood sample of Lançon & Wood ( [ ] ) shows that our sample is \sim 0.5 dex more metal-rich on average .