Effect of kafirin protein coating on sensory quality and shelf-life of 'Packham's Triumph' pears during ripening

Abstract

BACKGROUND: Pears are exported in large quantities from South Africa resulting in large revenues. Minimisation of quality losses once the fruit has reached the export destination is as important as following strict export and distribution protocols. Kafirin can form edible films. An edible coating, made from a 2 % (w/w) kafirin coating solution was applied as a post-havest treatment to retard quality deterioration of ‘Packham’s Triumph’ pears during storage at the typical ripening temperature (20° C). The changes in physic-chemical and sensory quality were studied over a period of 24 days. RESULTS: The kafirin coating was unable to retard the onset of ripening but decreased the respiration rate and retarded the progression of senescence. However, moisture loss was exacerbated in the kafirin-coated fruit during ripening at 20° C especially towards the end of the shelf-life. CONCLUSION: The coating extended the eat-ripe quality of the pears between one and two weeks. However, appearance of the fruit was unacceptable after 14 days of storage in terms of wrinkled skin. Further work is needed to improve the water barrier properties of the kafirin coating by incorporating a wax or triglyceride into the coating formulation or more simply by applying a kafirin coating to waxed fruit.