Sensory Perception and Evaluation Module 2

Importance!

What is sensory analysis? “Sensory evaluation has been defined as a scientific method used to evoke, measure, analyze, and interpret those responses to products as perceived through the senses of sight, smell, touch, taste and hearing.”

Objectives Identify aspects of food selection based on the five senses Understand the role sensory perception plays in food selection Evaluate food using basic sensory attributes and scales Select an appropriate testing method to obtain needed information

Sensory Perception When most people choose a particular food, they evaluate it using the sensory perceptions:

Sight The first impression of food is created by its appearance, which is received by the eye: Serving size Shape, color, consistency Presence of defects

Color can denote… Ripeness green vs. yellow vs. black banana Strength Almost white vs. brown chocolate milk Degree of heating Red vs. brown bulgogi Flavor Orange vs. red candy

Food Presentation The combination of food on a plate, in a grocery store display, or at a restaurant also contributes to or detracts from its appeal.

Smell / Odor Smell is almost as important as appearance when people evaluate a food item for quality and desirability. Most people can differentiate between 1,000 to 2,000 different “smells” E.g. Mozzarella vs. Provolone

Odor/smell Odor Detection Aids in the evaluation of quality and desirability Thresholds dependent on product/chemical/person Odor adaptation Volatile molecules Olfactory patch 2.5 cm2 in humans 12.5 cm2 in cats! Fruits – do they smell ripe and characteristic of the fruit, meats do they have any off-odors, oils (rancid) What is detection threshold? Adaptation – Odor is strong but as time goes by you become adapted to the smell. Your home, perfume Volatile – hot apple pie (smell great, travels down hall and into other rooms vrs cold apple pie (maybe you smell it as you eat it), more intense As molecules travel through air, they reach olfactory epithelium in upper part of nasal cavity. Only volatile molecules in form of gas carry odor, heat converts into gas

Taste Taste substances must be dissolved in saliva to be detected by the taste buds. Taste buds are located all over the mouth, but mostly on the tongue.

Chemical Basis of Taste Stimuli Sweet The sweetness of sugar comes from the chemical configuration of its molecule. Sour Related to the concentration of hydrogen ions (H+), which are found in the natural acids of fruits, vinegar, and certain vegetables. Bitter Imparted by compounds such as caffeine (tea, coffee), theobromine (chocolate), and phenolic compounds (grapefruit and vegetables). Salty Comes from salt ions [Na+] in sodium chloride (NaCl) or other salts found naturally in some foods. Umami Comes from monosodium glutamate (MSG) and other compounds – brothy, savory taste

Taste Interactions Each item used in food preparation contains a number of compounds, and bringing these items together creates new tastes when all their compounds interact. Examples: Sugar: decreases sourness, adding sugar to yogurt makes it less sour Monosodium glutamate (MSG): Enhances flavor in soup or stew and on snack foods

Other Sensations - Trigeminal Sensations from chemical irritation (with food these usually occur in the nose and mouth) Examples: Astringency Burn (e.g. from peppers – not temperature) Metallic Cooling (e.g. from mint – not temperature)

Flavor Taste and flavor are not synonymous terms. Flavor is the combined sense of taste, aroma, and trigeminal sensations.

Factors Affecting Taste & Flavor Person Temperature of the product Fat in product Color of the food Time of day Hunger Consumption patterns Medication Sickness

Touch The sense of touch – inside the mouth or by the fingers – conveys a food’s tactile, or physical properties: Texture Consistency Temperature

Hearing/Sound The sounds associated with foods can play a role in evaluating their quality. Examples: Tapping of a watermelon to determines its ripeness/sweetness Crunchiness of crackers/chips Sizzling of steak on the grill Popping of popcorn Fizzing of soda pop Bubbling sound of a boiling soup

Purpose of Food Evaluation The food industry uses an array of testing methods to measure the sensory factors in food selection and to evaluate food quality.

How is food evaluation used? New product development Product improvement Develop “Gold Standard” Ingredient changes Cost reduction Quality control/assurance Gauging consumer acceptance Claims tests

Type of tests Analytical Affective Difference/discrimination Descriptive Affective Acceptance/preference Consumer attitude

Two basic types of tests 1) objectivemeasurement of a specific attribute or product differences Difference tests Duo-trio Triangle Descriptive tests aroma, flavor, texture, appearance describe product using attributes (terms) rate intensity of the attribute on a scale

Difference Testing

Descriptive panelists at work

Descriptive Ballot Surface Appearance Color 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Surface Shine 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Texture Firmness 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Terms, Definitions, and References Color Light to dark evaluation of a brown color of the sample. Reference: Porter Paints 6846-2 Color Chip = 9.0 Surface Shine The amount of gloss or shine perceived on the surface of the product. Reference: Land O’Lakes Sour Cream = 10.0 Firmness The force required to compress product between the tongue and palate, using constant steady force. Use ½ teaspoon of product. (Not at all Firm to Extremely Firm) References: Land O’Lakes Sour Cream = 5.0 Philadelphia Fat Free Brick Cream Cheese = 9.0

2. Affective - acceptance or liking of specific attributes or products Consumers are evaluated for their preferences or acceptance of a product rather than their evaluation of differences. Consumer preference Prefer one product or the other Consumer acceptance Rate how much you like the pizza

Affective Test Ballot

Focus Group Testing Qualitative testing with the purpose to develop insights and direction. Researchers are interested in Attitudes Opinions as they relate to products, services, and concepts.

Applying Sensory Evaluation to Food Science Everyday Things to consider when tasting food: Focus on the characteristics of the food What’s good quality, poor quality Don’t focus on what you like Questions to ask: Would you be proud to serve the food? Is the product the best quality you can get, if not, then how can you make it better quality?

Coffee Wheel

Chocolate Wheel

Olive Oil Wheel