PRODUCTION SITE AND POSTHARVEST TREATMENTS EFFECT ON RIND PITTING AND PHYSICO-CHEMICAL PROPERTIES OF ‘TURKEY’ SWEET ORANGE

Abstract

Rind pitting disorder has been shown to negatively affect sweet orange however, the causes of rind pitting are still unknown. This study was conducted to investigate the production site and postharvest treatments effect on rind pitting development and physico-chemical properties of ‘Turkey’ sweet orange. Fruit were harvested from Tzaneen, Groblersdal and Musina, during 2016 and 2017 seasons. Afterwards, fruit were subjected to the following treatments: T1 = no wax and dehydration, T2 = wax and dehydration and T3 = wax and no dehydration; fruit were dehydrated for 3 days at 25°C, thereafter stored at -0.6 and 4.5°C for 28 days. Treatments were replicated three times. Fruit were evaluated for rind pitting, weight loss percentage (WL%), firmness, total electrolyte leakage (TEL), total soluble solids (TSS), titratable acidity (TA) and TSS: TA ratio. Results showed that fruit harvested from Musina exposed to T1 had higher incidence of rind pitting than Groblersdal and Tzaneen stored -0.6 and 4.5°C. Meanwhile, fruit harvested from Musina had the highest TEL when compared with Groblersdal and Tzaneen irrespective of treatments and storage temperatures. Significantly higher WL% was observed in Musina fruit harvested from Tzaneen exposed to T3 at both storage temperatures. Furthermore, an increase in TSS was observed after storage across all production site and postharvest treatments. In conclusion, the study showed that production site and postharvest treatments had a significant influence on rind pitting and total electrolyte leakage. Furthermore, fruit treated with no wax + dehydration was found to be more susceptible to rind pitting.