The effect of antifungal hot-water treatments on papaya postharvest quality and activity of pectinmethylesterase and polygalacturonase

Abstract

The effect of antifungal hot-water treatments (AHWT) at 55°C for 0, 3, 6 and 9 min on quality attributes and cell-wall enzymatic activity during storage at 25°C was investigated in papaya fruit. The total soluble solids (TSS), pH, titratable acidity (TA), firmness and fresh weight loss were not affected, whereas color on skin was negatively affected by the treatments of 6-and 9-min. However, the skin color was not different between the 3-min treated fruit and the untreated fruit during the storage. Decay was delayed and reduced by AHWT. We observed that the 3-min treatment of 55°C did not affect softening and quality of papaya cv Maradol when applied as a pesticide-free treatment at color-break stage of papaya. PME (Pectinmethylesterase) and PG (Polygalacturonase) activities were not significantly affected by AHWT. We concluded that the AHWT did not affect the softening process from papaya pulp since the cell-wall enzyme activity (PME and PG) was not altered by treatments.

The role of hydrolases in the loss of firmness and of the changes in sugar content during the post-harvest maturation of Carica papaya L. var solo 8

“…According to the same authors, the carbon necessary for the synthesis of sucrose originated from the cell wall (30 % cellulose, 30 % hemycellulose, 25 % pectin, and 5 % proteins). Other studies showed a decrease of galactose and an increase of glucose due to the degalactosylation of polysaccharide chains in apples, strawberries, tomatoes, and in germinating seeds (Ignacio et al 2011;Brett and Waldron 1996;Pressey 1983). This rapid metabolization of galactose explains why Gomez et al (2002) did not find free galactose in ripped papayas.…”

“…Ohtani and Misaki (1983) showed that the seeds of Carica papaya L. exhibited a high level of α-D-galactosidase and α-D-mannosidase activities. Other studies indicated that cellulase activities increase during the maturation of avocados, peaches, strawberries, tomatoes, and papayas (Ignacio et al 2011;Awad and Young 1979;Hobson 1981;Paull and Chen 1983).…”

Control of post-harvest anthracnose infection in guava (Psidium guajava) fruits with phosphites, calcium chloride, acetyl salicylic acid, hot water, and 1-MCP

“…The delay of ripening, senescence, and the degradation of antifungal compounds might occur during the application of HW; moreover. it could control the activity of pectinmethylesterase and polygalacturonase (Chávez-Sánchez et al, 2013). Treatment of this type associated with Rhodotorula glutinis was shown to reduce blue mold (Penicillium espansum) in pears, where fruits treated for 15 min for 46°C showed a lower incidence of this disease (Zhang et al, 2008).…”

Effectiveness of Hydrothermal‐Calcium Chloride Treatment and Chitosan on Quality Retention and Microbial Growth during Storage of Fresh‐Cut Papaya

“…Hydrothermal treatments have been shown to be effective as a nonchemical alternative to improve the postharvest quality of several horticultural products. These treatments may affect ripening and protect against physiological disorders, but they have also been effective for decay control (Chávez‐Sánchez and others ). Chitosan is a natural polysaccharide that has a huge variety of useful physicochemical and biological properties, such as nontoxicity for the human organism, and chelating, biocompatible, biodegradable, and film‐forming ability, as well as antimicrobial activity against a wide variety of microorganisms (Erben and others ).…”