Intro. to Sensory Analysis

Intro. to Sensory Analysis

1. Grading Systems

   • Analyst must optimize 4 factors
     • Defintion
       • Of the problem
     • Test Design
       • Eliminate subsectivity. Aware of Bias. Minimal testing to get required results
     • Instrumentation
       • Selected test subjects must be trained to give a re-producible verdict
     • Interpretation of results
       • Using Stats. Null Hypothesis, Alternative Hypothesis and conclusion from results.

2. Sensory Attributes

   • Of the food/drink are detected by Taste, Smell, Sight, Hearing and touch
   • Olfactory system
     • Odour and aroma are detected by the olfactory system. The amount of Volatiles released depends on the temperature and nature of the volatile present
     • Aromatics
       • Olfactory perceptions caused by volatile substances released from a product in the mouth
   • Flavour
     • The sum of perceptions resulting from stimulation of sensory receptors grouped together in the mouth or entrance to the respiratory tract
   • Taste
     • Gustatory perceptions caused by a soluble substance in the mouth
     • Sweetness
       • Sweet taste receptors: There must be complementary groups within the receptor protein of the taste bud to which the sweet compound binds in order to ellicit the sweet sensation
     • Saltiness
       • Saltiness is elicited by many inorganic salrs. Na+ Ions are presented naturally within many foods and have a major role in their flavour. Salts also tend to decrease the sweetness of sugars and give a richer, more rounded flavour in many food products
     • Sourness
       • Is usually associated with solutions with a low PH. But undissasociated organic acid found within acidic foods are also very important...Citric acid and Malic acid are important organic acids found in fruit
     • Bitterness
       • Back of the tongue. Several distinct classes of substance, including certain inorganic salts and phenolic substances. Larger Ions are bitter and smaller ions are salty. Phenolic substances in the form of flavanoids contribute to the bitter flavour in fruit juice e.g Narigen in grapefruit juice
     • Astringency
       • A sensation related to Bitterness. Sensed with the oral cavity as well as the tongue. Important in red wine and Tea. High content of polyphenolic substances, which also contribute to odour. Tannins in Tea and Wine
     • Pungency
       • Sensed with the entire oral cavity
   • Chemical Feeling Factors
     • Stimulate the nerve endings in the soft membranes of the buccal and nasal cavities and include perception astrigngency

3. Food Attributes

   • Appearance, Odour, aroma, consistency, texture, flavour Hardness-Force to attain a given deformation Cohesiveness-Degree to which the sample deforms Adhesiveness-force required to remove sample from a given surface denseness-Compactness of cross section Springiness-Rate of return to original shape after some deformation
   • Viscosity - Homogenous newtonian Liquids
   • Consistency - Non-Newtonian or heterogenous/Semi Solids
   • Texture - Solids and Semi Liquids

4. Smell

   • Olfactory Epithelium --> Odorant Binding Proteins --> Electrical Signals --> Olfactory Bulbls

5. Olfactory Epithelium

   • 3 Kinds of Cells: Sensory neurons with a primary cilium. Supporting Cells between them Basal cells, regularly divide producing a fresh layer of sensory neurons that replace these that die