IMPORTANCE OF FLAVOR Consumer perception of meat quality After appearance and tenderness flavor is most important Specifically cooked meat flavor Flavor is a key factor for acceptance Understanding flavor is therefore crucial –Analysis of flavor compounds (Machiels and Istasse)
Tenderness Juiciness Flavor Flavor often considered the most important when tenderness is acceptable Result of volatile compounds produced during cooking MEAT PALATABILITY
TASTE vs. FLAVOR Taste refers to the five basic receptors: sweet, salty, sour, bitter and umami Flavor is the perception of chemical compounds reacting with receptors in the oral and nasal cavities (aroma) in combination with taste
Olfactory receptors Taste receptors Posterior nares Anterior nares Tongue Perception of Flavor (Taste and Aroma) Aroma Detected in nose Small, volatile, fat soluble molecules Taste Detected on tongue and in mouth Large, water soluble molecules (L. J. Farmer)
TASTE Salt and sour receptors are well understood while bitter and sweet receptors appear to be more complex.
UMAMI Umami [oo-MOM-ee], known as the fifth taste, is described as meaty and savory or delicious derived from umai, the Japanese word for delicious Glutamates – the salts of an amino acid - and other small molecules called nucleotides Although umami has been known for quite awhile, recently umami receptors have been clearly identified so this is a bona fide fifth taste.
5 TASTES Detection of these five tastes has been key to our survival throughout the ages Sweet means energy-giving carbohydrates Salt indicates essential minerals for life-sustaining cell functions and wound healing Sour says to “proceed with caution,” since many foods sour as they deteriorate. Umami signifies life-giving protein. And bitter warns “spit it out, don’t touch it” because many natural toxins taste bitter
FLAVOR CHEMISTRY What is flavor chemistry? A study of compounds which elicit a chemosensation or flavor sensation What produces flavor sensations? Chemical compounds reacting with receptors in the oral and nasal cavities Specifically ingested volatile compounds (Christen and Smith)
FLAVOR CHEMISTRY Over 200 flavor compounds associated with cooked beef Sulferous and carbonyl compounds are predominate contributors Maillard reaction products End products result from sugars and amino groups Lipid breakdown products Higher concentrations may produce undesirable flavors (Calkins and Hodgen)
MAILLARD REACTION Reducing sugar and free amino acid Results in the production of H 2 O, Therefore reaction does not occur with moist heat cookery reducing sugar + amine = brown pigments + flavors
Flavor Compounds Formation by Maillard Reaction Reducing Sugars and -amino acids N-glycosylamine or N-fructosylamine 1-Amino-1-deoxy-2-ketose (Amadori intermediate) or 2-Amino-2-deoxy-1-aldose (Heynes intermediate) Reductones and Dehydroreductones Furans Thiophenes Pyrroles Retroaldol Reaction H 2 S NH 3 Strecker degradation Amino Acids Hydroxyacetone Hydroxyacetylaldehyde Acetoin Acetylaldehyde Glyoxal Pyruvaldehyde Glycerolaldehyde Strecker Aldehydes + CO 2 + -aminoketone (Methional, NH 3, H 2 S) Heterocyclizaion Pyrazines Pyridines Oxazoles Thiazoles Pyrroles + +
FLAVOR COMPOUND ANALYSIS Volatile compounds must be extracted Head space solid phase microextraction (HS-SPME) Separation of compounds may be done via gas chromatography (GC) Compounds may then be identified and sensory evaluated Identified: purified standards and/or mass spectral library Sensory evaluation: olfactometry (Frank and others)
DISCUSSION Flavor is important to overall palatability of meat Flavor compounds may be studied by chemical and sensory evaluation Maillard reaction and lipid breakdown products are dependent on the type and condition of meat
Species Red meat species and poultry Breed Bos indicus vs Bos taurus? Sex Androstenone, skatole Diet Grain-fed vs. Grass-fed Age Young lamb vs. mutton Packaging MAP, over-wrap, vacuum FACTORS AFFECTING MEAT FLAVOR
Fat Amount and type Muscle Location effect Aging Dry vs. wet Enhancement Brine solution containing salt Cooking method Dry vs. moist heat Degree of doneness FACTORS AFFECTING MEAT FLAVOR