CUTICLE INTEGRITY REPRESENTS AN IMPORTANT FACTOR IN FRUIT QUALITY OF SWEET CHERRIES. PLANTS HORMONES, ESPECIALLY ABSCISIC ACID (ABA), ARE INVOLVED IN FRUIT CUTICLE INTEGRITY. THE EFFECT OF PRE-HARVEST APPLICATION OF ABSCISIC ACID ON CHERRY FRUIT CUTICLES WAS INVESTIGATED. CHANGES OF THE CONCENTRATIONS OF SEVERAL PHYTOHORMONES, EXPRESSION LEVELS OF GENES RELATED TO CELL WALL-MODIFICATION, AND TO WAX- AND CUTIN BIOSYNTHESIS WERE MEASURED FIVE DAYS AFTER APPLYING ABA TO SWEET CHERRY TREES (PRUNUS AVIUM CV. BING) AT THE STAGE OF FRUIT SET. AT THE RIPE STAGE CHANGES IN CELL WALL POLYMERS AND FRUIT CUTICLE COMPOSITION WERE MEASURED. OUR RESULTS SHOW THAT PRE-HARVEST APPLICATION OF 0.1 MM ABA AT THE STAGE OF FRUIT SET RESULTED IN INCREASED LEVELS OF ZEATIN RIBOSE (204-FOLD), ZEATIN (126-FOLD), SALICYLIC ACID (30-FOLD), AND ABA (19-FOLD). TRANSCRIPTION LEVELS OF KEY GENES INVOLVED IN CUTICLE BIOSYNTHESIS, THE TRANSCRIPTION FACTOR PAWINA AND THE WAX BIOSYNTHESIS-RELATED ENZYME PALACS1 (5.8- AND 3.4-FOLD INCREASE), AS WELL AS FOR THE KEY ENZYME PANCED1, INVOLVED IN ABA BIOSYNTHESIS (6.9-FOLD INCREASE), WERE INCREASED. AT THE RIPE STAGE, CONTENTS OF COVALENTLY-BOUND PECTINS AND HEMICELLULOSES WERE HIGHER WITH A CONCOMITANT REDUCTION OF WATER-SOLUBLE POLYMERS IN ABA-TREATED FRUITS. AMOUNTS OF LINEAR LONG-CHAIN ALIPHATIC WAX COMPOUNDS, ESPECIALLY C27, C29, AND C31 ALKANES, WERE INCREASED (1.2-, 1.3- AND 2.3-FOLD, RESPECTIVELY), WHEREAS NO EFFECT OF ABA ON PENTYCYLCIC TRITERPENOIDS WAS OBSERVED. WE CONCLUDE THAT ABA TREATMENT OF CHERRY TREES AT THE STAGE OF FRUIT SET POSITIVELY AFFECTS SWEET CHERRY FRUIT QUALITY AT RIPENING BY ENFORCING THE CELL WALL AND MODIFYING THE CUTICLE COMPOSITION.

THE CRACKING OF SWEET CHERRIES CAUSES SIGNIFICANT CROP LOSSES. SWEET CHERRIES (CV. BING) WERE COATED BY ELECTRO-SPRAYING WITH AN EDIBLE NANOEMULSION (NE) OF ALGINATE AND SOYBEAN OIL WITH OR WITHOUT A CACL2 CROSS-LINKER TO REDUCE CRACKING. COATED SWEET CHERRIES WERE STORED AT 4 °C FOR 28 D. THE BARRIER AND FRUIT QUALITY PROPERTIES AND NUTRITIONAL VALUES OF THE COATED CHERRIES WERE EVALUATED AND COMPARED WITH THOSE OF UNCOATED SWEET CHERRIES. SWEET CHERRIES COATED WITH NE + CACL2 INCREASED CRACKING TOLERANCE BY 53% AND INCREASED FIRMNESS. HOWEVER, COATED SWEET CHERRIES EXHIBITED A 10% INCREASE IN WATER LOSS AFTER 28 D DUE TO DECREASED RESISTANCE TO WATER VAPOR TRANSFER. COATED SWEET CHERRIES SHOWED A HIGHER SOLUBLE SOLID CONTENT, TITRATABLE ACIDITY, ANTIOXIDANT CAPACITY, AND TOTAL SOLUBLE PHENOLIC CONTENT COMPARED WITH UNCOATED SWEET CHERRIES. THEREFORE, THE USE OF THE NE + CACL2 COATING ON SWEET CHERRIES CAN HELP REDUCE CRACKING AND MAINTAIN THEIR POSTHARVEST QUALITY.

EDIBLE FILMS AND COATINGS HAVE BEEN APPLIED ON FRUITS TO IMPROVE THEIR QUALITY DURING GROWTH AND DEVELOPMENT AS WELL AS DURING POSTHARVEST STORAGE. A RESPONSE SURFACE METHODOLOGY WAS USED TO DETERMINE THE EFFECTS OF OIL CONCENTRATION, NUMBER OF PASSES AND CALCIUM CHLORIDE CONCENTRATION ON THE PHYSICAL, MECHANICAL AND TRANSPORT PROPERTIES OF OIL-ALGINATE COMPOSITE FILMS. ALGINATE-BASED FILMS WERE DEVELOPED USING ALGINATE (1.0% W/V), SOYBEAN OIL (0.5%, 1.0% AND 1.5% V/V) AND TWEEN 80® (1% V/V). COARSE EMULSIONS WERE PASSED 2, 4 AND 6 TIMES THROUGH A MICROFLUIDIZER AT 200 MPA. CALCIUM CHLORIDE SOLUTIONS (0%, 1.5% AND 3%) WERE THEN APPLIED ON THE CAST FILMS TO CROSSLINK THEM. THE OIL PARTICLE SIZES RANGED FROM 360 TO 445 NM, REGARDLESS OF THE EMULSION COMPOSITION AND NUMBER OF PASSES. THE LOWEST WATER PERMEABILITY VALUE (1.8857E-10 G/MSPA) WAS OBTAINED FOR 1.5% OIL CONCENTRATION, 6 PASSES AND NO CROSSLINKING. THE POROSITY OF THE FILMS AT LOW OIL CONCENTRATIONS INCREASED WITH AN INCREASE IN CROSSLINKING LEVEL. IN COMPARISON, THE POROSITY OF THE FILMS AT HIGH OIL CONCENTRATIONS DECREASED WITH AN INCREASE IN CROSSLINKING LEVEL. EMULSIFIED FILMS SHOWED REDUCED STRENGTH AND INCREASED ELONGATION WITH AN INCREASE IN OIL CONCENTRATION. FILMS TREATED WITH CALCIUM CHLORIDE SHOWED LOWER STRENGTH DUE TO GREATER EFFECTS FROM OIL THAN CALCIUM CHLORIDE. IN CONCLUSION, OIL INCORPORATION IN FILMS WAS THE PREDOMINANT FACTOR IN IMPROVED FILM PROPERTIES, ESPECIALLY FOR WATER VAPOR PERMEABILITY.