FATTY ACID COMPOSITION OF 'MAXI GALA' APPLE PEEL WAX STORED UNDER STATIC AND DYNAMIC CONTROLLED ATMOSPHERE AND EFFECT OF 1-MCP APPLICATION

Ethylene is an important regulator of cuticular wax biosynthesis of stored fruit. The use of 1-MCP (1-methylcyclopropene) associated with new storage technologies could alter this wax regulation, and it can be correlated with postharvest losses. The objective of this work was to compare the amount and wax composition of the apple peel stored in static controlled atmosphere (CA) and dynamic controlled atmosphere by chlorophyll fluorescence (-CF) and quotient respiratory (-QR; at two levels QR1.3 and 1.5) for 8 months, with and without the application of 1-MCP. The waxes were extracted from 10 cm2 of the epidermis homogenized in 5 mL of distilled water and added of 2 mL of extraction solvent (chloroform) plus twice partitions with 1 mL of chloroform, 4 mL of dispersion solvent (acetone) and shaking for 30 min in each extraction cycle. From extract were obtained the extraction yield (gravimetrically), identification and quantification of fatty acids carried out in GC-FID by comparison of the retention times with the FAME_Mix-37 standard and use of internal standard, respectively. Ethylene (With/Without_1-MCP: AC: 14.82/0.05; DCA-CF: 2.68/0.07; DCA-RQ1.3: 0.52/0.02; DCA-RQ1.5: 0.32/0.03 ng.kg-1s-1) and respiration rate (With/Without: AC: 2.47/2.87; DCA-CF: 0.92/1.48; DCA-RQ1.3: 1.14/0.94; DCA-RQ1.5: 1.10/1.05 µg.kg-1s-1) were suppressed with 1-MCP for most treatments. The amount of wax extracted did not differ among treatments (mean of 1.50 mg cm-2; p<0.05). The total fatty acid fraction was lower in CA with 1-MCP but did not differ for the DCA treatments (With/Without 1-MCP: CA: 127.3/348.2; DCA-CF: 209.5/203.9; DCA-RQ1.3: 216.7/201.3; DCA-RQ1.5: 216.2/218.6 mg g-1 of wax). Similar behavior was observed in the fatty acid composition, being C22:2 the major fatty acid in all treatments, followed by C16:0, C18:0 C18:1n9, C18:2n6. The use of 1-MCP affected apples stored in CA, but it association with DCA shows that the regulation of wax biosynthesis is not directly related to ethylene.