2.5. Evaluations of fruit firmness (FF), soluble solids content (SSC), and titratable acidity (TA)

Fruit firmness of 15 fruit per replicate was measured at two opposite sides of the equator of each fruit after removing 2‐mm‐thick peel disks using a hand‐held hardness meter (FHM‐1, Chuk Eatate Co.) with a 12‐mm conical probe. The maximum force was recorded and expressed in newton (N). After FF determination, twenty grams of wampee fruit was juiced. SSC was determined using a refractometer (N‐1α, Atago Ltd), and data were expressed as percentage (%). TA was determined by titrating 5 ml juice and 50 ml distilled water plus three drops of phenolphthalein to pH 8.3 with 0.1 mol/L NaOH using pH meter (ST20, OHOUS Company) and expressed as the equivalent percentage of citric acid.