can anyone tell me a not complicated way to extract fructans from garlic (i have access to highschool lab). I need this to be able to make an experiment on garlic extract and just fructan from garlic prebiotic activity
It seems that the basic method is just a water extraction - soak some powder from your garlic in water for a period of time. Ideally you would determine experimentally the optimal time and temperature for this using a quantitative method (e.g. HPLC or a biochemical assay of some sort), but you probably don't have access to those.
Here's an example of the method from this paper1
Water extraction procedure Conventional solvent extraction was carried out in a water bath (model WB/0B7-45, Memmert Company, Schwabach, Germany). Ten gram of Serish root powder was suspended with distilled water under treated condition shown in Table 1. The suspension was then filtered through muslin cloth to remove the insoluble residues. The extracted slurry was centrifuged at 4,500 × g for 10 min to collect the supernatant. The resulting solution was diluted with water to obtain a 1 % solution and kept at 4 °C until the day of experiment.
Edited to add:
Note that this won't just get the fructans out, it will get any soluble components including sugars, water soluble proteins, polysaccharides etc - hence the need to quantitate the fructan component to be scientifically accurate. Ideally for proper fructan isolation you would also need to extract the fructan, which I think you could do with a FPLC via ion exchange chromatography. But this is also very unlikely to be part of your high-school's equipment.
1 Pourfarzad et al, J Food Sci Technol. 2015 May; 52(5): 2657–2667.