Benzyl-aminopurine (BAP) treatments delay wall degradation and softening, improving quality maintenance of refrigerated summer squash

MASSOLO, JF; LEMOINE, ML; CHAVES, AR; CONCELLÓN, A; VICENTE, A.R

POSTHARVEST BIOLOGY AND TECHNOLOGY

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2014 vol. 93 p. 112 - 129

0925-5214

Round summer squash are harvested before reaching full maturity and even though they are highlyperishable, fruit postharvest handling is mostly based on storage at non-chilling temperatures. Find-ing complementary treatments minimizing deterioration and reducing postharvest losses would beextremely useful. In this work we evaluated the effect of postharvest cytokinin (CK) treatments on refrig-erated round soft rind squash. Fruit were harvested at commercial maturity and sprayed with 1 mmol L−1benzylaminopurine (BAP) or water (control) prior to storage at 5◦C for 0, 13 or 25 days. Quality wasassessed upon removal from cold storage as well as after a 2 day shelf-life period at 20◦C. CK-treatedfruit showed slower deterioration and dehydration and remained firmer than the control. BAP spraysdid not affect color, respiration or sugar-acid balance. The treatments prevented phenolic compoundaccumulation, and decreased pectin solubilization. By the end of the storage period BAP-treated squashhad higher levels (45%) of tightly-bound polyuronides than untreated controls, indicating a substantialdelay in cell wall dismantling. CK sprays also reduced neutral sugar solubilization from pectin-rich frac-tions, but no changes were found in the cross-linking glycans or cellulose. To our knowledge, this is thefirst work showing that CK can regulate pectin disassembly in developing fruit. Postharvest BAP sprayspreventing texture deterioration may be a simple treatment to complement refrigeration of round, softrind, summer squash.