Prebiotics are class of functional foods which resist digestion in small bowel and stimulate the growth of beneficial bacteria in the gut. Galacto-oligosacchraides (GOS) are class of prebiotics that are naturally present in human milk and impart many health benefits. Prebiotics are class of functional foods which resist digestion in small bowel and stimulate the growth of beneficial bacteria in the gut. Galacto-oligosacchraides (GOS) are class of prebiotics that are naturally present in human milk and impart many health benefits. The research was conducted in three phases. During 1st phase characterization of liquid oligomate (galacto-oligosaccharides preparation) was performed. During second phase prebiotic (galacto-oligosaccharides) based functional beverage was developed by adding different concentrations of GOS. Functional beverages was prepared with the addition of GOS @ 1.00, 1.50, 2.00 and 2.50% of final beverage volume. On the basis of sensory evaluation and other analysis, one sample was selected for further use in third phase that is efficacy study by determining its glycemic index. Accordingly the significant outcomes of the present research are summarized hereafter.
Proximate analysis of Galacto-oligosaccharide sample showed that the results for dry matter are (0.832 ±0.009) for crude protein the values are (0.729±0.126) and for crude fat the result shows (1.366±0.321). For NFE is -0.0957±0.0001 and for moisture is 1.1667±0.011547. The lower values for protein, fat and fiber shows that composition of oligomate is solely based on the presence of galacto-oligosaccharides and has no other impurities present in them.
The results for GOS for acidity shows the value of (0.14±0.02) for specific gravity the values are (1.36±0.0001) and for pH the values are (3.51± 0.01)
The results for acidity of beverages indicated that the inclusion of galactooligosaccharides has significantly affected the acidity of the beverage (P?0.001). All the treatments for different beverages and storage and the interaction between the storage treatments showed that statistically they are highly significant (P ?.0.05).

The results indicated that the inclusion of Galacto-oligosaccharides has significantly affected the specific gravity of the beverage (P?0.00). It is evident from the results that the storage of these beverages is also statistically significant but the interaction between the treatments and storage intervals showed non-significant effect on specific gravity of different beverages
The statistical analysis regarding pH of beverages prepared from different levels of galacto-oligosaccharide shows that all the treatments for different beverages and storage and the interaction between the storage treatments are highly significant (p ? 0.01).
The statistical results for total soluble solids indicated that TSS of different beverages were significantly affected by treatments; however, storage intervals showed slightly significant result and interaction between storage and treatments showed highly significant effect on TSS of different beverages(P?0.01)
The results indicated that the addition of Galacto-oligosaccharides has significant effect on color "a", "b", " L" , "chroma" , "hue angle" parameter (P?0.001). The sensory scores for color, flavor, taste and consistency were non significant while scores for overall acceptability showed that they varied significantly with treatments.
After storage of beverages for 60 days prepared with the addition of GOS at various levels the interaction between treatment and storage level showed non-significant effect for the flavour, color, consistency, taste and overall acceptability.
The statistical results regarding blood glucose concentration after consumption of control and functional beverage with time intervals are statistically significant. The interactive effect of intervals and different food types shows that the blood glucose concentration at fasting for glucose and control beverage is non-significant and functional beverage comparatively to glucose is significant. It shows that the response of control is similar to the reference taken as glucose.
The statistical results regarding glycemic index shows that the GI with respect to beverage type and person code is non-significant. The glycemic index for control beverage shows the results (58.63±8.15) and for functional beverage (63.74±4.50). The statistical analysis regarding glycemic load with respect to person code shows that they are non-significant but with beverage type they are slightly significant. The glycemic load of control beverage is 17.08±2.37 and for functional beverage values are 19.38±1.36. Functional beverage showed slightly increased glycemic load as compared with control beverage.