Each pineapple waste was chopped into small pieces before
being blended (Philips HR-2011 Blender, China) with cold
distilled water at a 1:1 ratio for 3 min. The resulting blend
was filtered through a cheese cloth and then centrifuged at
10,000 X g at 4 'C for 20 min. The obtained supernatant (crude
enzyme extract) was collected, recorded and used for pH measurement
by using a pH meter (Eutech Instruments pH 510,
Singapore). The total soluble solids were also measured by
using a hand refractometer (Atago Nl-E, Japan) and it was
reported as degrees Brix.