Loss of Flavor Precedes Loss of Appearance Quality. General Principles. General Principles Dietary Guidelines for Americans

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1 Dietary Guidelines for Americans Loss of Flavor Precedes Loss of Appearance Quality Marita Cantwell Mann Lab, Dept. Plant Sciences, UC Davis FOODS TO INCREASE Half the plate should be fruits and vegetables Switch to fat-free or low-fat (%) milk. BALANCE CALORIES Enjoy your food, but eat less. Avoid oversized portions. FOOD TO DECREASE Eat foods with lower sodium Drink water instead of sugary drinks. General Principles Consumers judge quality of products on basis of appearance and freshness at time of purchase Satisfaction for eating quality (texture and flavor) affects repeat purchases Consumers also interested in nutritional quality and safety 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 6 % of Consumers Fresh Trends,. Vance Research Services. QUALITY Appearance Freshness, ripeness Taste/Flavor General Principles Fresher the product (time), better the flavor True for vegetables More complicated for fruits that require ripening Adhering to storage and handling guidelines results in better flavor Postharvest treatments may extend shelflife but not preserve flavor References: Flavor-life and Shelf-life Baldwin, Plotto and Goodner.. Shelf-life versus flavour-life for fruits and vegetables: how to evaluate this complex trait. Stewart Postharvest Review, :. Kader.. Perspective. Flavor quality of fruits and vegetables. J. Sci. Food Agric : 6. Shewfelt and Brückner.. Fruit and Vegetable Quality. An integrated view. Technomic Publ., Basel. Barrett, Beaulieu and Shewfelt.. Color, Flavor, Texture, and Nutritional Quality of Fresh-Cut Fruits and Vegetables: Desirable Levels, Instrumental and Sensory Measurement, and the Effects of Processing. Critical Rev. Food Sci. Nutr. : 6. Forney, C.H.. Flavour loss during postharvest handling and marketing of fresh-cut produce. Stewart Postharvest Review, :.

2 Quality Definitions Quality is the degree of excellence or superiority Quality is the totality of features and characteristics of a product that affect ability to statisfy Quality is any feature that makes something what it is Quality if the state of being free from defects, deficiencies, significant variations Modified from slides of Kader and Mitcham, UC Davis Flavor-Life vs Shelf-life Definitions are difficult: Everyone has own criteria Acceptability; below certain limit, product is rejected Shelf-life is the time before the product attributes drop below the acceptance limit Flavor-life is the time.. Consumer integrates all sensory inputs (appearance, texture, taste, aroma, off-flavors) for a final judgement Tijskens.. Acceptability. Ch in Shewfelt and Brückner. Based on on Flavor & Nutritional Quality Based on on Firmness & Texture Based on on Appearance () Flavor life Flavor quality is a complex assessment. Loss of flavor or end of flavor-life is associated with losses in sugars, acids and aroma volatiles (especially esters) Loss of flavor may also be due to development of off-flavors (fermentative metabolism or odor transfer) 6 % Postharvest Life Under Optimum Conditions Kader,. A Perspective on Postharvest Horticulture. HortScience : Slide adapted from Kader, UC Davis Why don t we routinely evaluate flavor life when evaluating shelf-life? Flavor analysis is complex Sugars, acids Volatiles; which impact flavor; threshold Sensory work can be difficult for fresh fruits and vegetables Sensory perception of flavor affected by texture Use physical and chemical measurements to approximate flavor and sensory evaluations How are objective/subjective evaluations related to sensory quality? Do they approximate sensory quality? Echeverria et al.. Assessment of relationships between sensory and instrumental Quality of controlled-atmosphere-stored Fuji apples by multivariate analysis. J. Food Sci. 6: S6.

3 Quality Changes in Cilantro During Storage Storage temp. % Green Color F (C) F (C) F (.C) F (C) F (C) F (.C) F (C) F (C) F (.C) days 6 6 days days days % % Temperature Effects on Retail Packaged Salads..... Oxygen ºC ºC ºC Carbon Dioxide 6 mmol/kg mmol/kg Acetaldehyde Ethanol 6 Score (=excellent) 6 Score (=severe) Off-Odors 6 Peiser and Cantwell Challenges for Melon Quality Fresh-cut products APPEARANCE QUALITY COLOR FIRMNESS FLAVOR; EATING QUALITY Maturity: sugars vs firmness Taste-life vs Shelf-life days Relative Importance of Temperature and Modified Atmospheres for Fresh-cut melon. C ( F) C ( F). C (6 F) Air % O Air + % CO % O + % CO Soluble Solids (%) Sugar loss in fresh-cut cantaloupe at C may be considerable, but Soluble solids do not change much; Sugar loss typically is not as extreme as in this example. Soluble Solids 6 Sugars (Average varieties) 6 Stage (</ slip Stage (/ slip) Stage (full slip) 6 6 Typical loss over days at C ( F): S.S. -% Sugars -% Sugar content (mg/ g fr.wt.) Off-odors Fresh-cut Cantaloupe: Temperature and Atmosphere 6 CA %O +%CO Air Air CA C F. 6. CA Cantwell, unpublished

4 Sensory Fresh-cut melon altered after days at C Visual appearance acceptable up to days C C C D A= Air + %CO B= %O + %CO C= %O + %CO Fresh-cut green pepper stored in air and CA. Flavor and texture affected before declines in visual quality Nicolais et al.. Preliminary study on the shelf life of minimally processed cantaloupe melon stored in protective atmosphere. Acta Hort. 6:. Beaulieu et al. 6. Volatile changes in cantaloupe during growth, maturation, and in stored fresh-cuts prepared from fruit harvested at various maturities. J. Amer. Soc. Hort. Sci. :-. Bett-Garber, K.L., Beaulieu, J.C. and Ingram, D.A.. Effect of storage on sensory properties of fresh-cut cantaloupe varieties. J. Food Qual. 6:-. Lopez-Galvez et al. Quality of red and green fresh-cut peppers stored In controlled atmospheres. Fresh-cut Fruits Flavor vs Shelf-life Freshcut honeydew melon stored in air at C for 6 days: good appearance but lacked acceptable texture and had flat flavor Fresh-cut pineapple stored at C had excellent visual appearance after to days, but off flavors associated with microbial fermentation. Fresh-cut orange segments at C had acceptable appearance after days, but unacceptable flavor quality after days Sliced watermelon had good appearance and odor after days at C, but flavor not acceptable. Flavour loss during postharvest handling and marketing of fresh-cut produce Charles F Forney Agriculture and Agri-Food Canada, Atlantic Food and Horticulture Research Centre, Main Street, Kentville, Nova Scotia, Canada The contribution of metabolic and diffusional processes in determining flavour change of fresh-cut fruits and vegetables during postharvest handling and marketing needs to be determined for fresh products. Determination of the significance of these processes and how packaging and postharvest treatments can affect them could lead to new technologies to preserve flavour quality in fresh-cut produce. Examples from Forney and Barrett et al.. Stewart Postharvest Review, June, Grape Tomatoes stored days at C in air or CA and flavor change after about days at C under all atmospheres Test# GRAPE TOMATO Test# =full, typical, =none, atypical Trt A: %O+%CO Trt B: %O+%CO Trt C: %O+%CO Trt D: %O+%CO Trt E: Air =full, typical, =none, atypical Trt A: %O+%CO Trt B: %O+%CO Trt C: %O+%CO Trt D: %O+%CO Trt E: Air Off-flavor Off-flavor A B C D E Air O+CO =none, =severe =none, =severe Good quality, near ripe grape tomatoes will tolerate C for about days under a range of atmospheres Cantwell, UC Davis 6 at C 6 at C Cantwell, UC Davis

5 Shelf-life/Handling and Flavor Quality Tomato as Example Ripe fruit appearance acceptable and fruit marketable cm drop during ripening; internal bruising affected chemical composition of locule and pericarp tissues (decrease acids, Vit C, carotenoids) Panelists could distinguish flavor of bruised and unbruised fruit when red (bruised were bland ) Internal bruising affects aroma volatile profiles in tomato; changes in synthesis from lipid, carotenoid and amino acid pathways due to bruising Apples Flavor Quality and Storage Moretti et al. Proc. Fla State Hort Soc : Moretti et al.. J. ASHS : 66 Moretti et al.. HortScience :. CA and -MCP treatments maintain firmness in stored apples Storage conditions and time result in decreased aroma volatile production Consumers prefer crispy less aromatic apples over softer, more aromatic apples Based on on Flavor & Nutritional Quality WHAT TO DO?. Shorten visual shelf-life to meet Flavor-life: improved logistics. Increase flavor-life to meet visual shelf-life: improved biochemistry Based on on Firmness & Texture Based on on Appearance () Hoehn et al.. Ripening regulation and consumer expectations. Acta Hort 6: Fellman et al.. Flavor regeneration after CA storage of apples. PH Biol. Tech. : Bai et al.. Response of four apple cultivars to -MCP treatment and CA storage. HortScience :. 6 % Postharvest Life Under Optimum Conditions Kader,. A Perspective on Postharvest Horticulture. HortScience : Do these fresh-cut fruits taste as good as they look? AA Kader, UC Davis