Abstract:
Guava (Psidium guajava L.) is a major commercial fruit with great export potential in Sri Lanka
but has a shorter shelf life due to its climacteric nature. Therefore, this study aimed to investigate
the potential of yellow passion fruit (Passiflora edulis forma flavicarpa) peel pectin as a base
material for an edible coating in extending the shelf life of guava. Pectin was extracted using an
acidified aqueous method (citric acid, pH 2; solvent: solute ratio 40:1; 75 min at 85°C), identified
using Fourier Transform Infrared Spectroscopy (FTIR) and characterized for yield, equivalent
weight and degree of esterification. Matured apple guavas were coated with pectin solutions (1%,
2%, 3%) and stored at 25 ± 3°C, 75% RH for 16 days. The quality parameters of guava including
appearance, weight loss, firmness, pH, titratable acidity, total soluble solids, total chlorophyll
content were monitored at regular intervals of 4 days. The pectin yield from passion peel was
25.25% (dry basis), indicating the potential value-addition of this agro-industrial by product. The
moisture content (8.00%), ash content (7.20%), equivalent weight (806.04 mg), and the degree
of esterification (64.25%), exhibited the suitability of pectin for gel formation. The FTIR data
confirmed characteristic peaks at 3359 cm⁻¹ (O-H stretching), 2924 cm⁻¹ (C-H stretching), 1718
cm⁻¹ (C=O stretching), and 1629 cm⁻¹ (C=C stretching), corresponding to the functional groups.
The 3% coating solution was effective until the day 16, and significantly (P ≤ 0.05) reduced weight
loss (13.42%), maintained firmness (43.00 kPa), and preserved quality parameters (pH 4.30,
soluble solids 12.40°Brix, chlorophyll 81.30 µg/g, titratable acidity 7.20%) of coated guava
compared to control (treated with distilled water). The 2% solution was effective until day 8,
while 1% showed no significant difference from the control (P≥0.05). Therefore, this study
concluded that the passion peel-derived pectin has a significant potential in preserving the
postharvest quality of guava by regulating various physiological processes.
