For packaged fruit juice: This may also need to be
strained through cheesecloth if it contains a lot of pulp
or seeds.
For fruits and vegetables: Cut a 100 g sample into small
pieces and grind in a mortar and pestle. Add 10 mL
portions of distilled water several times while grinding
the sample, each time decanting off the liquid extract
into a 100 mL volumetric flask. Finally, strain the ground
fruit/vegetable pulp through cheesecloth, rinsing the
pulp with a few 10 mL portions of water and collecting
all filtrate and washings in the volumetric flask. Make
the extracted solution up to 100 mL with distilled water.
Alternatively the 100 g sample of fruit or vegetable
may be blended in a food processor together with
about 50 mL of distilled water. After blending, strain
the pulp through cheesecloth, washing it with a few
10mL portions of distilled water, and make the extracted
solution up to 100 mL in a volumetric flask