León, Mexico - Sept Impact of Ripening & Storage Conditions on Ripe Tomato Quality Marita Cantwell Dept. Plant Sciences Univ. California, Davis, CA micantwell@ucdavis.edu; http://postharvest.ucdavis.edu Factors that influence U.S. Consumers Produce Purchases Brand name Prepackaged Organic Growing region/country Calorie content Bulk (loose) display In-season Size Convenient, prepared Certified safe, testing Storage life Price Nutritional value Appearance Freshness, ripeness Taste/Flavor % of Consumers Fresh Trends,. Vance Research Services. Tomato Quality Attributes Size, shape Condition no damage no decay Texture Firmness, mealiness, juiciness, slice integrity Color Red color and lycopene content Flavor and Composition Sugars Acids Aroma volatiles Vitamins VR Maturity & Ripening Stages GREEN The tomato surface is completely green. The shade of green may vary from light to dark. BREAKERS There is a definite break of color from green to bruised fruit Tannish-yellow, pink or red or % or less of the tomato surface. TURNING Tannish-yellow, pink or red color shows on over % but not more than % of the tomato surface. PINK Pink or red color shows on over % but not more than % of the tomato surface. LIGHT RED Pinkish-red or red color shows on over % but red color covers not more than % of the tomato surface RED Red means that more than % of the tomato surface, in aggregate, is red http://www.tomato.org/ http://www.floridatomatoes.org/ Shelf-life/Storage/Ripening Conditions Temperature and ripening of different tomato types; update conventional tomato chart Impact of lower than recommended storage temperature; slight chilling; differences among varieties Ripening Temperature and ethylene treatment Temperature and RH -Impact on firmness and gloss Table. Effect of temperature on ripening rates of conventional tomatoes. Ripeness stage Mature-green Breaker Turning Pink to full red color at indicated temperature.c F C F.C F C F.C F C F Ethylene Treatment for Ripening MG fruit Ethylene concentration: - ppm Temperature: - C ( to F) Relative humidity: -% Duration: to hours Air circulation: sufficient for distribution of ethylene in ripening room Ventilation: sufficient to prevent accumulation of CO which reduces effectiveness of ethylene
Verde-sazón Quebrante Cambiante Rosado Rojo Claro Rojo Relative Value Respiration Ethylene Time Color rojo Color amarillo Aroma Sabor Azúcares Pectinas solubles Fenoles polimerizados Color verde Acidez Almidón Firmeza Pectinas insolubles Fenoles sencillos Tomato photos: http://www.tomato.org/food/color.html Respiration (µl CO /g-h) Ethylene Production (nl/g-h) cv. Jackpot. C ( F) C ( F) C ( F) Respiration Ethylene - - from Breaker stage Effect of temperature on Tomato fruit ripening Good temperature range: - C (- F) Best temperature: C ( F) Ripened from Breaker Stage Respiration (µl CO.g-h) A. Respiration C ( F) C ( F) average fruits initial stage = (MG) Tomato Ripening & Temperature. C ( F) Ripened from Mature-green Stage C ( F) C ( F) Ethylene production (nl.g-h) B. Ethylene production C. Red color C allows ripening to continue but at much slower rate than at C Similar to ripening bananas and other fruits. C ( F) C ( F) C ( F) Color score =green, =table-ripe Final C C Hue (Red color).. N firmness.. % soluble solids.. % acidity.. Tomatoes ripen into similar quality in temperature range from.- C Temp. C. Initial color to TR Weight loss %.. Firmness N.. Red color Hue.. SS %.. Sugar mg/ml.. TA %.. Vit. C mg/ml.. Storage of Tomatoes............... Ave. C.. Ave..C.. LSD... Cantwell, MCP#, unpublished;................................... ns.......... C ( F) No lower than C ( F) - weeks Controlled atmospheres % O, <% CO Relative humidity ~% http://postharvest.ucdavis.edu/produce/producefacts/veg/tomato.shtml
Avoid chilling temperatures for tomatoes F C Too low temperature (< C < F) Reduces flavor Reduces aroma volatiles Affects ability to ripen Increases decay z--hexanal, ppm Low temperatures reduce aroma volatiles z- hexanal as example of important volatile Table-ripe tomatoes stored for days.... Storage temperature, ºC Cantwell, UC Davis, unpublished z--hexanal at TR, ppm Low temperatures reduce aroma volatiles z- hexanal as example of important volatile Color Stage stored for days, then ripen at C.... Cv Bobcat Initial Color Stage = Stored days. C. C. C. C C = F. C C = F. C C = F It is quite common that tomatoes are held at F. This temp. results in decay and poor color. Cantwell, UC Davis, unpublished Storage temperature, ºC C C Consequences of Storing Tomatoes Below Recommended Temperatures Round Tomatoes,, color stage - Stored at,., and.c for up to weeks Transferred to C to complete ripening maximum days Evaluate respiration and ethylene production rates weight loss, decay, firmness, color composition (%SS, acidity, sugars, lycopene, Vitamin C) Several experiments on rounds & grape tomatoes Respiration, µl CO/g-h Cantwell,, unpublished Respiration Rates during storage and after transfer to C at, and days week transfer week transfer C. C C C week transfer
Ethylene, nl/g-h Ethylene Production Rates during storage and after transfer to C at, and days C. C C C Cantwell,, unpublished Color score Color Changes during storage and after transfer to C at, and days = full red C. C C C Cantwell,, unpublished A. Red Hue color, (lower, Hue the redder) Test# () Red color, Hue A. Hue (lower, the redder) Color stage % color Fruit stored At temperatures For up to weeks. After storage, Complete ripening For days at C. Ara and Cantwell, Test# Cv Bobcat, Initial color = Lycopene, mg/kg FW Hue color value. C ( F) LSD. C ( F).C C ( F) C ( F) B. Lycopene LSD.. C ( F) C ( F).C C ( F) C ( F) Weeks storage Color stage - -% color Fruit stored At temperatures For up to weeks. After storage, Complete ripening For days at C. Ara and Cantwell, Test# Cv Bobcat, Initial color = - Hue color value Lycopene, mg/kg FW LSD.. C ( F) C ( F).C C ( F) C ( F) B. Lycopene B. Lycopene LSD.. C ( F) C ( F).C C ( F) C ( F) Weeks storage Round Tomato () stored weeks + days C ( F). C ( F) C ( F) Greenhouse Round LSL Tomato stored at and C No changes over weeks in soluble solids, sugars, ph or acidity Initial color stage = Decrease in firmness but no significant difference between temperatures Increase in weight loss and different between temperatures (. and.% after wk at and C) Differences in red color values, lycopene, Vitamin C contents due to storage temperature
Greenhouse Round LSL Tomato stored at and C Greenhouse Round LSL Tomato stored at and C Lycopene C ( F) C ( F) LSD. Vitamin C C ( F) C ( F) LSD. Initial color stage = Lycopene, mg/kg Initial color stage = Lycopene, mg/kg Week storage Week storage Grape Cherry Tomato Type & Composition Tomato Type Orange Cluster Round Roma Round Cluster % Soluble Solids...... % Titratable Acidity...... Storage of Grape Tomatoes Grape tomatoes respond to storage temperatures as do other tomatoes However, new marketing opportunities involve holding grape tomatoes at C for long periods (as component of vegetable trays for example) Also grape tomatoes are very susceptible to water loss and symptoms of shrivel Therefore, as shown in some of the following data, fruit can be acceptable when stored at C; transfer to a warm temperature after low temperature storage results in the expected chilling injury symptoms and decay Data Test# A. Visual Quality B. Weight Loss C d C d =excellent, =unuseable LSD. percent C ( F) C ( F) C ( F) C ( F) C. Firmness D. Red color Visual quality of packaged grape tomatoes after days. Newtons-force Hue color value C d Grape Tomatoes (cv Amsterdam) stored in consumer packaging and evaluated at storage temperatures. Cantwell, unpublished,.
Visual quality vs shrivel. A. Shrivel score vs % weight loss Grape tomatoes show typical chilling symptoms when transferred. Visual quality (=excellent, =unuseable) y = -. x +. R =. Shrivel =none, =severe.... y =. x +.. R =.. Initial + d C % weight loss Shrivel (=none, =severe) B. Firmness vs % weight loss Grape tomatoes and consequences of weight loss Newtons-force d C + d C y = -. x +. R =. % weight loss -MCP treated tomatoes Held days C Initial maturity=breaker Untreated Tomatoes Held days Initial maturity=breaker ppb Cantwell, Tomato MCP#, h@c C C. C Cantwell, Tomato MCP# to table-ripe to table-ripe to table-ripe C ( F) LSD. =. days C ( F) C ( F) Control -MCP ( ppb).... -MCP and Tomatoes Considerations for effective use Tomato type and cultivar Stage of maturity/ripeness -MCP concentration Temperature Cantwell,, unpublished % water loss to reach table-ripe % water loss to reach table-ripe % water loss to reach table-ripe. C ( F) LSD. =.%.. Control. -MCP ( ppb)....... C ( F)......... C ( F).............. -MCP results in Increased time to ripen Concerns Increased weight loss May decrease firmness Fruit less shiny Cantwell,, unpublished Initial color stage Initial color stage
Tomatoes and -MCP (SmartFresh ) ppb -MCP at C ~. C Storage -MCP is a powerful regulator of tomato fruit ripening Easy to overdose and have poor final quality Important to determine where -MCP can add value to the tomato category IMPORTANT FACTORS FOR Postharvest Quality of Tomatoes Variety Maturity at harvest Minimize physical injury Storage: temperature & duration Ripening conditions Review Paper: The use of -MCP on fruits and vegetables. C.B. Watkins.. Postharvest Biology Technology : -.