2.5 Sapota fruit quality analysis
The weight of individual fruit, pulp and peel weight (g) was determined
with the help of an analytical balance while a digital display vernier
caliper was used to measure fruit diameter and length (mm). Uniform
matured fruits were harvested randomly from each treatment and
transported to the laboratory. After washing in tap water, fruits were
allowed to ripen at the ambient room temperature. Fifteen uniformly
ripened fruits from each treatment were peeled and deseeded to separate
fruit pulp to evaluate quality parameters. The fresh fruit juice was
obtained by filtering the pulp through a three-layered muslin cloth to
determine TSS and TA. Vitamin C, reducing, non-reducing and total sugars
were determined using fresh fruit pulp. For antioxidants enzyme assay
and total phenol content, the pulp was homogenized and stored at 4 °C to
prevent enzymatic browning until further analysis.
The portable refractometer was used to determine TSS after calibration
with distilled water and it was expressed in oB. TA
was estimated using 0.1N NaOH using phenolphthalein indicator until a
pink color persisted (AOAC, 1990). Vitamin C, total soluble sugars
content and reducing sugar content in the pulp were determined by
following the protocol developed by AOAC (2005), DuBois, et al. (1956)
and Somogyi (1952), respectively. Total antioxidants activity in the
fruit samples was estimated using FRAP assay as per method given by
Sreeramulu et al., (2009). The total phenol content was determined by
following the protocol of Malick & Singh (1980).