The Elements of Taste Flavor in Fruits and Vegetables Chuck Marr K-State Research and Extension Horticulture

A New Area of Study Anatomical and sense in 1920s and 1930s Organoleptic differences Modern ‘sensory analysis’ began in 1950s First book on ‘sensory analysis’ in 1959 Taste or flavor characteristics of fruits and vegetables not very important in the ‘selection factors’ used by plant breeders until recently. Now being factored in along with other characteristics.

Topics Difference between taste and flavor How we perceive taste and flavor Differences among us Measuring or predicting flavor Some ways we can determine flavor differences

Taste We are able to taste only 4 things Sweet Sour Salty Bitter These are sensed in specific locations on the tongue

Taste sensation areas on the tongue Bitter Sour Salty Sweet

Moves into taste bud in liquid (saliva or juice) Initial taste fades quickly- must be rejuvenated with a new movement of liquid

Trigeminic Receptors or “Pain Receptors” in the mouth Hot- (Capsaicin in hot peppers, mustard oil in radish, mustards) Cold- (Menthol, cucurbitacin in cucumber) Astringent (Pucker in persimmon) Induce a pain response. Tolerance varies among individuals. May build up a resistance

Taste- A little controversy We are able to taste only 4 things Sweet Sour Salty Bitter Orientals claim to taste another Umami (you mommy)- Glutamate Evidence is that it appears to be a legitimate taste factor; however, it is unknown where the taste is sensed on the tongue.

Taste Combinations Sweet-Sour Sweet- Salty Sugar Acid Ratio We can mask or alter some tastes by combinations with others. For example, we can make taste less sour by adding sweet…. Actual acidity or sweetness levels may not be exact reflections of what we taste. Taste + Trigeminic Responses Sweet - Hot

Taste vs Flavor Taste- those 4 tastes determined by the tongue Flavor= Taste + Aroma or Smell While we can only determine 4 taste factors, it is estimated that we can differentiate over 10,000 aromas or flavors in foods.

Aroma is sensed in the nasal passages and usually is a volatile or aromatic compound that moves into the nasal chamber. Aroma is slower to respond that taste because it’s beyond the tongue.

Flavor Aroma May be able to sense prior to entering the mouth. May activate or excite the tasting process= “mouth watering” saliva formation anticipating a pleasant taste sensation Lots of pleasant and unpleasant sensations- some very closely related

Important volatile compounds influencing flavor Aromatic compound group- example compound= edible crop example Hydroxy compounds- geosmin=“earthy” Aldehydes- hexenal=apples Ketones- 2,3 butanedione=celery Acids- acetic acid=vinegar Esters- methyl anthranilate= Concord grape Sulfur compounds- dimethyl sulfide=asparagus Oxygen hetrocycles- furaneol= pineapple Nitrogen hetrocycles- pyroles= peppers Sulfur heterocycles- thiophenes= fried onion Other compounds- iodine=edible seaweed

Aroma as part of food flavor Compounds that form the primary flavor of a fruit or vegetable are called “character-impact compounds” There are several classes of foods where these compounds can be identified and duplicated. Largely 1 compound Mixture of a small number of compounds Large number of compounds- no single one Foods that number of compounds is so large or complex that we can’t duplicate

Some foods with character-impact compounds Single compound Banana, lemon, pear, cucumber, pepper Small number Apple, raspberry, tangerine, celery, onion, tomato Large number Peach, lime, pineapple, walnut Very complex-not easily duplicated Strawberry, chocolate

Flavor complex in tomato Sugars Volatile flavor compounds hexanal trans-2-hexanal cis-3-hexanal cis-3-hexen-1-ol 2-isobutylthiozole Acids (primarily citric)

Saturation when additions don’t create a sense of increases May become disagreeable or cause you to lose sensation if concentration is too great Taste Sensation Increases Threshold when you can first sense No 2 people may be the same in when the threshold occurs or when saturation occurs or how long saturation lasts until a decline starts. Concentration of Taste or Flavor Element

Differences Among Us Age Age dulls the senses Youth- sweet Older- bitter Age dulls the senses Illness or physical limitations (colds, etc) Male vs female Musk aromas sensed differently Ethnicity or background What we like established by what we’re exposed to “Life Altering Experiences”

Sensory Analysis Methods Trained ‘taste panel’- 3-5 Expert panel- 5-10 Consumer preference 40-50

Quantifying Sensory Analysis Triangle test (3 samples- 2 the same) Hedonic ratings (1-10 scale) Offer several sub questions Taste, color, texture, eye appeal, etc Be very specific in establishing the questions How used, family likes, economy, etc

Several other components of flavor Texture or ‘mouth feel’ Grainy, mushy, crunchy, slimy, chalky Color Appealing color for the product Both these factors are independent of taste or flavor but contribute to our determinations of sensory quality.

Predicting Sensory Quality pH- acidity Optimum size or maturity index Refractometer (sugar content) Instron ‘shear press’ (tenderness) Chromatography (gas or liquid)