KNH 504 Exam 1

advantages of sensory evaluation

-helps a food company understand what consumers like, and why

-can also tell a company if consumers can tell a difference when a product is modified (ex. ingredient substitution for lowering production cost)

-can aid in quality control assessment of food production

disadvantages of sensory evaluation

-time consuming process

-there can be large variability in product assessment due to individual sensitivity to flavors, preferences, human error, etc.

sensory evaluation

designed to assess food characteristics that involve the five senses (color/sight, taste/specific flavors, aroma/smell, and texture(sight, taste, possibly hearing))

sensory panelists

food companies employ trained ___________ to begin their evaluation of new food products

focus

other than sensory panels, companies also conduct product testing via __________ groups that may be interested in that product

odor

one of the first cues to a person that food is acceptable to eat

odor recognition

occurs when aromatic compounds from the food travel to the part of your nose where olfactory receptor neurons are located

ways to perceive odors

-sniffing a food

-swallowing a food

-vigorous inhale through the nose after swallowing a food

10,000

humans have around _______ taste receptors, mostly on the tongue

papillae

rough bulges in the surface of the tongue, some of which contain taste buds; found on the sides and tips of the tongue, as well as the back of the tongue in a “V” formation

taste buds

children have additional ___________ in their cheeks and palates, whicch atrophy in adultfood, decreasing the stronger perceptions of taste that children have

basic tastes

sweet, sour, bitter, salty, umami/savory, oleogustus

visual food cues

-shape

-texture

-color

color

________ can often trigger your mind to expect a specific flavor; can also be evaluated objectively

high

_______ temperature=volatile aromatic compound

cold/cool

________ temperature=low volatility of aromatic compounds

same

if you plan to include aroma in sensory evaluation, it is crucial that all food samples are served at _________ temperature

acceptability

usually, aroma of a food product is simply utilized to assess the acceptability of a product, rather than a comparison of strength of the aroma

flavor

assessment of taste+odor; may be impacted by sensations of mouthfeel, such as burning, cooling, and astringency; may simply be used to evaluate overall acceptability of a food product

temperatures

extreme ___________ can make flavor difficult to percieve

texture

needs to be defined in detail for specific food products in order to be accurately evaluated by a sensory panelist; often relies on characteristics as mouthfeel, such as grittiness, slickness, hardness, crispness, toughness, stickiness, moistness, viscosity

ideal environment for sensory evaluation

-individual testing booths

-comfortable temperature

-appropriate lighting (potentially consider colored lighting if coloring can cause bias)

consistent

in sensory eval, sample size of food product should be ___________, and from the same location of a food product if applicable

single sample

sensory eval test; tests one product only, typically to test overall acceptability of product; may be useful in determining direction of future product development, alteration, testing, etc.

descriptive testing

sensory eval testing; characterizes a product through scoring fo specific attributes of each food sample; typically uses a scorecard that contains specific word descriptions to shape the form of responses of each panelist, and panelist selects specific description that best matches sample being evaluated; testing can be accomplished in group setting if needed

affective testing

sensory eval testing; panelists evaluate acceptability of product; valuable in development of food products, determining market potential of a product and/or evaluating quality of a current food product; this type of testing may ask a panelist to determine preference for one product over another product, or rank product samples in order of preference

difference testing

sensory eval testing; 4 types: paired comparison, duo-trio test, triangle test, rank order

paired comparison

sensory eval difference testing; 2 samples are presented and panelist is asked to identify sample with greater amount of characteristic being measured

duo-trio test

sensory eval difference testing; control sample is presented first, then two more samples are presented: one is same as control, one different; panelist is asked to identify sample that is different from control sample

triangle test

sensory eval difference testing; 3 samples are presented at the same time, 2 of 3 samples are the same with one “test” sample; panelist is asked to identify the ”odd” sample

rank order

sensory eval difference testing; samples are ranked in order of intensity of characteristic being tested

hedonic

when developing a scorecard, consider a _______ scale for gathering info about overall acceptability (1-10)

advantanges of objective testing

-consistent

-accurate

-provides a standard by which to measure products and variations of products

disadvantages of objective testing

-higher cost for tools

-regular maintenance is required for equipment

-objective tests cannot replace or duplicate human taste/perception/acceptability

goals of objective testing

-uses laboratory testing to obtain highly reliable data

-produces quantifiable results

-supplements sensory evals

-measures something very specific in a food product

several

conduct _________ objective tests that are specific to characteristics you are evaluating via sensory panel, as equipment is available

seed displacement

objective tests for volume: uses a volumeter; method is pouring seeds into box until it can be leveled off, pour seeds into graduated cylinder to measure volume of box, subtract volumes of seeds before and after product was added for volume measurement

volumeter

an instrument for measuring volumes of solids by displacement of a liquid, solid, etc.

planimeter

objective tests for volume: a tool designed to measure distance by tracing entire outline of food sample on a photocopy; tool can follow all indentation and protrusions of a sample; final measurement represents exact circumference of food sample

press fluid

objective tests for moisture: succulometer or pressometer; method is weigh food sample, machine applies controlled pressure to sample for controlled length of time, sample is weighed again, difference between two weights represents amount of moisture/juice contained in original sample

dry product

objective tests for moisture: utilizes a drying oven or microwave; method is weigh food sample, food is dried until dried weight remains constant, difference between two weights is divided by initial weight and multiplied by 100 to calculate percentage of moisture in original sample

Warner-Bratzler Shear

objective tests for texture: commonly used to measure the tenderness of meat; measures force required to “shear” the meat

penetrometer

objective tests for texture: machine that measures tenderness of a food sample by determining the distance a cone penetrates a food over a defined period of time; the larger the reading, the more tender the product; good for measurements of gels or baked products (ex. custards, puddings)

shortometer

objective tests for texture: determines the force required to break a product; designed to measure the tenderness of tender, crisp foods (ex. pastries, crisp cookies, etc.)

universal testing machine

includes several different testing devices that can be used to measure different aspects of texture in a wide array of foods

rheology

the study of flow matter and the deformations that result from flow

viscosity

the resistance to flow

consistometer

objective tests for rheology: measures the consistency (viscosity) or spread of semisolid foods; measures spread of flow of a product over a specific length of time

line-spread test

objective tests for rheology: measures viscosity; product sample is placed in a column centered on measured, concentric rings and is allowed to flow for a specific amount of time, spread at each 90 degree increment of circles is read

viscometer

objective tests for rheology: measures viscosity via force required to drag a rotating spindle through a test sample

pH meter

objective tests for pH: measures effective hydrogen ion concentration of the food sample

acidic

lower pH=more _________

alkaline

higher pH=more __________

chromatography

used to identify the numerous volatile and non-volatile substances that combine to produce the overall flavor impression of a specific food; the goal of this research is to synthesize flavors in the laboratory, and then be able to produce them for industrial use; two types: gas-liquid and high-pressure liquid; objective test for flavor

gas-liquid chromatography

objective tests for flavor: this method passes the food sample with carrier gas; a machine that separates individual compounds from a mixture by passing them with a carrier gas along a special column; the column absorbs and releases each individual compounds (flavor, aroma) at different rates

high-pressure liquid chromatography

objective tests for flavor: uses pressure to separate a sample dissolved in liquid; a machine that is under pressure, separates a sample dissolved in liquid into its individual components (flavor, aroma, etc.) as they are absorbed along a special column and finally passed individually from the column

carbohydrates

composed of carbon, hydrogen, and oxygen; catergories include monosaccharides, disaccharides, oligosaccharides, and polysaccharides

monosaccharides

carbohydrate containing only one saccharide unit; includes glucose, fructose, and galactose; simple sugar; sweet taste, soluble in many solutions, contributes to mouthfeel in candies and syrups, contributes to browning at high temperatures, contributes to volume in baked products

disaccharides

carbohydrate formed by the union of two monosaccharides includes sucrose, lactose, and maltose; simple sugars; sweet taste, soluble in many solutions, contributes to mouthfeel in candies and syrups, contributes to browning at high temperatures, contributes to volume in baked products

sucrose

glucose+fructose

lactose

glucose+galactose

maltose

glucose+glucose

complex carbs

include starches, cellulose, hemicellulose, gums, pectins,

starch

a complex carb that is mostly used for thickening ability

cellulose/hemicellulose

complex carb; modify product textures when added to foods; can produce a “harsh" mouthfeel in food products (ex. addition of whole grains, bran, nuts, etc. to a food)

gums/pectin

used as thickening agents; a low-calorie contribution to food products

lactose

least sweet disaccharide; crystalizes easily

sweetness

physical property of sugars; the temperature of a solution containing sugar influences sweetness; as temperature increases, sweetness decreases

hygroscopicity

physical property of sugars; the ability to attract and hold water; can aid in maintaining freshness of baked products

solubility

physical property of sugars; the amount of sugar that dissolve in a solution; as temperature increases, this increases as well; higher typically leads to a softer/more desirable textured product

carmelization

physical property of sugars; when sugars are heated, they melt; they can burn if not carefully watched, but if done properly, can create a pleasing color and flavor

maillard reaction

physical property of sugars; non-enzymatic browning that occurs when a protein and a sugar are heated or stored together for a length of time; does not require as high a temperature as caramelization, can occur at room temp over time

functional properties of sugars

-sweeter taste

-color

-texture

-stabilizing (ex. egg white meringues)

increase

a measured ________ in sugar can lead to a desirable increase in tenderness and volume of a baked product

granulated sugar

most common market form of sugar

confectioners’ sugar

pulverized form of granulated sugar; most commonly named powdered sugar; contains a little cornstarch to keep the sugar dry

loaf sugar

sugar syrup is poured into a mold; commonly known as sugar cubes

light brown sugar

in the processing of granulated sugar, many impurities are removed, one of these being molasses; still has some molasses in it, which changes the flavor and maintains higher moisture content

dark brown sugar

in the processing of granulated sugar, many impurities are removed, one of these being molasses; still has some molasses in it, which changes the flavor and maintains higher moisture content; higher amount of molasses=stronger flavor and moisture content

corn syrup

a sweet syrup of glucose produced by hydrolysis of cornstarch

high fructose corn syrup

a type of corn syrup; sweet corn syrup made by converting glucose to fructose

molasses

brown syrup that remains after sugarcain juice has been boiled; byproduct of sugar production; light _______ is made by boiling sugar cane juice, prolonged boiling leads to dark _______

sorghum

sugar made by the boiling of juice of this grain; used in some beer

honey

sugar that is high in fructose; richest source of fructose in natural foods

agave

sugar that is produced from the juice that is extracted from this plant; light _____ flavor resembles light honey, and dark _____ flavor is like brown sugar or maple syrup; about 1.5x sweeter than sugar

maple syrup

sugar from maple trees; pure is more expensive

pancake syrup

essentially corn syrup of maple flavoring

fructose

sugar that can be purchased in dry powder or liquid form; also found naturally and is made from sucrose

alternative sweeteners

purpose is to add sweetness to a food product without adding natural sugar; useful for consumers who need to limit or regulate total daily sugar/carbohydrate intake

genetic

the ability to perceive bitterness and/or other aftertaste of alternative sweeteners varies between person to person and is ___________

cancer

if a food additive is shown to cause ____________, even only if in high doses, there is no margin of safety allowed and the food additive cannot be used

polyhydric alcohols (polyols)

naturally occurring compounds in foods and approved as generally recognized as safe (GRAS) additives; ex. erythritol, lactitol, maltitol, sorbitol, xylitol; these are not sugars, but can contribute some sweetness to food products; utilized mostly in commercial settings; absorbed much more slowly in the body than sugars, has some merit for diabetics; prolonged digestive time in intestines can cause gas, discomfort, and diarrhea when consumed in larger quanitites

xylitol

polyols: 2.4 kcal/g; used in chewing gum; gives a cooling sensation as it dissolves

sorbitol

polyols: 2.6 kcal/g; used in baked goods and beverages; has water-binding capabilities that can help limit mold growth, extending shelf life of food products

mannitol

polyols: 1.6 kcal/g; used in chewing gum and in powdered products because water is not attracted to this alcohol

saccharin

major alt. sweetener used, Sweet N’ Low; originally used primarily by diabetics, but now used as a non-calorie sweetener; strong, metallic, and bitter aftertaste; 300x sweeter

aspartame

alt. sweetener; NutraSweet, Equal; 4 kcal/g; 200x sweeter; contains phenylalanine, so this sweetener has to carry a warning label for those with PKU; not used in baking because sweetness decreases with addition of heat; used in diet drinks or to enhance fruit flavors

acesulfame K

alt. sweetener; Sweet-One, Sunett; 4 kcal/g; 200x sweeter; the “K” stands for potassium; best when blended with other sweeteners; similar in sweetness to aspartame, but is stable to heat, therefore, this sweetener can be used in baked products

stevioside

alt. sweetener; Stevia in the Raw, Truvia, Sun Crystals; comes from a plant; 300x sweeter

sucralose

alt. sweetener; Splenda; marketed as natural made from sugar, so it tastes like sugar; still chemically made; heat stable and lacks any unpleasant aftertaste; can be used in place of sugar in cooking and baking; 600x sweeter