2.4. Fruit quality analysis
Eight fruits of each experimental unit were analysed for qual-
ity parameters. Fruit shape index (SI), was determined as the ratio
of width to length. Zucchini fruit colour was measured using a 10
Minolta CR-200 chromameter (Minolta Camera Co. Ltd, Osaka,
Japan) with an 8 mm measuring aperture in CIE L* , a* , b* mode with
CIE standard illuminant C. The instrument was calibrated with a
Minolta standard white reflector plate before sampling. The readings were taken in the mid part of the upper and lower surface of zucchini squash.
The total soluble-solids (TSS) content was measured by an Atago
N1 refractometer (Atago Co. Ltd., Japan) and expressed as ◦Brix.
Acidity was determined by potentiometric titration with 0.1 M NaOH up to pH 8.1. Results were expressed as percentage citric acid in the juice. The fruit dry matter (DM) and the pH of the fruit juice (pH meter, HI-9023; Hanna Instruments, Padova, Italy) were also measured.