Food Selection and Evaluation Understanding Food Food Selection and Evaluation

Food Selection Criteria Sensory Criteria: Sight Odor Taste Touch Hearing People make food choices based on several things. Why do you choose the foods you do? Taste, $, health, availability? In this class we will be evaluating different foods and so we will start with sensory criteria. This is what you will be using in the foods lab. The five senses are………

Food Selection Criteria Sensory Criteria: Sight The eyes receive the first impression of foods: shapes, colors, consistency, serving size, and the presence of any outward defects Any examples you can think of that affect desireablity of food? I have had people tell me they don’t like non-fat milk because it is “blue” What color of plate makes food look best? Undesireable?

Food Selection Criteria Sensory Criteria: Odor Volatile molecules: Molecules capable of evaporating like a gas into the air. Olfactory: Relating to the sense of smell. Think of: Smell of bacon, coffee, popcorn. How do these influence your decisions? How does your food taste when you have a stuffy nose? Volatile molecules escape from the food and you detect them in special receptors. If you want to keep all of the flavor in a food, don’t let the volative molecules escape (example, pot roast)

Food Selection Criteria Sensory Criteria: Taste Taste is usually the most influential factor in people’s selection of foods. Gustatory: Relating to the sense of taste. Flavor: The combined sense of taste, odor, and mouthfeel. The Five Taste Stimuli: Sweetness Sour Bitterness Salty Savory Flavor is a broader concept with aroma providing about 75 percent of the impression of flavor. When food comes into the mouth bits of it are dissolved in the saliva pools and there come into contact with the cilia in the gustatory cells. They relay a message to the brain which translates it into taste. Sweetness- from sugars and sugar alcohols Sour – acids Bitterness – certain compounds such as caffeine, throbromine (chocolate) and phenolic compounds (grapefruit) Alkaloids are often poisonous Salty – ionized salts such as NaCl Savory – amino acids such as found in glutamic acid (monosodium glutamate. Flavor combines taste and aroma.

Start with about 9-10 thousand taste buds. Decreases with age.

Food Selection Criteria Sensory Criteria: Touch Consistency: Describes a food’s firmness or thickness. Astringency: A sensory phenomenon characterized by a dry, puckery feeling in the mouth. How many of you rely on mouth feel? It can tell you a lot about a food. Example triscuits Texture- sight, touch of fingers and/or eating utensils, mouth feel Ever tried buttered popcorn flavored taffy? Tenderness is a term we will be using in the lab Consistency is expressed in terms of brittleness, chewiness, viscosity, thickness, thinness and elasticity.

Food Selection Criteria Sensory Criteria: Hearing Sizzling, crunching, popping, bubbling, swirling, pouring, squeaking, dripping, exploding (think of an egg yolk in a microwave), and crackling can communicate a great deal. Most sounds are affected by water content. Gives clues to a food’s freshness and/or doneness. Most sounds affected by water content and thus give clues to freshness and or doneness. Tap on loaf of homemade bread.

Nutritional Criteria Dietary Guidelines and the Food Guide Pyramid help with diet planning and improvement. Calorie (kcal): The amount of energy required to raise 1 gram of water 1°C (measured between 14.5° and 15.5°C at normal atmospheric pressure). Antioxidant: A compound that inhibits oxidation, which can cause deterioration and rancidity. http://www.mypyramid.gov

Nutritional Criteria In this class you will be learning the science of food. In the lab you will be demonstrating some of the principles you learn in class. As you evaluate the products you will be primarily using subjective tests. Subjective tests: Evaluations of food quality based on sensory characteristics and personal preferences as perceived by the five senses.

Nutritional Criteria Objective tests: Evaluations of food quality that rely on numbers generated by laboratory instruments, which are used to quantify the physical and chemical differences in foods. If you go on to take Experiment Foods you will be doing several objective tests. In this class we will be a lab early on that involves weighing and measuring baking ingredients by different methods to demonstrate the room for error if care is not observed. This is important for our labs to turn out.

Nutritional Criteria Objective Evaluation Tests Volume: A measurement of three-dimensional space that is often used to measure liquids. Density: The concentration of matter measured by the amount of mass per unit volume. Objects with a higher density weigh more for their size. Viscosity :The resistance of a fluid to flowing freely, caused by the friction of its molecules against a surface. How much does a cup weigh? Depends on what is in it. A measuring cup says 8 oz but this is for water. What if we put oil in it? What do you think is denser, granulate sugar or brown sugar.