FOOD CHEM food quali

60問 • 11ヶ月前

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is an important concept because the food people choose depends largely on quality.

food quality

is difficult to define precisely, but it refers to the degree of excellence of a food and includes all the characteristics of a food that are significant that make the food acceptable.

quality

using one or more of the five senses every time they select or eat any food.

subjective judgements

using laboratory equipment are useful for routine quality control, but they cannot measure consumer preference.

objective test

This is done using _____ ____ and asking panelists to taste a food and give their opinion on it.

sensory testing

Both _____ ___ and _______ ____tests are important in evaluating food quality, and ideally they should correlate with or complement each other.

sensory,objective

A. Aspects of Food Quality Size, shape , color , structure, transparency , turbidity, dullness or gloss, degree of wholeness or damage

appearance

A. Aspects of Food Quality (appearance) _____of fruits indicates how ripe , its strength

color

A. Aspects of Food Quality(appearance) _____consumer preference of large over small ( ex eggs )

size

A. Aspects of Food Quality (appearance) ______for baked goods , breads should have many small holes , uniformly spread throughout and not one large hole close to the top

structure

A. Aspects of Food Quality (appearance) ________in beverages for example orange juice must be cloudy because of its pulp while grape juice must be clear without any sediment which would indicate a quality defect

turbidity

A.Aspects of Food Quality qualities of a food that can be felt with the fingers, tongue,palate, or teeth ( crisp of crackers , crunchy celery, hard candy, tender steaks, chewy chocolate chip cookies, and creamy ice cream)

texture

A.Aspects of Food Quality (texture) If fruits or vegetables lose water during storage, they wilt or lose their ____ _____, and a crisp apple becomes unacceptable and leathery on the outside.

turgor pressure

A.Aspects of Food Quality (texture) Bread can become hard and _____ on storage.

stale

A.Aspects of Food Quality (texture) Products like ice cream can become _____ due to precipitation of lactose and growth of ice crystals if the freezer temperature is allowed to fluctuate,

gritty

A.Aspects of Food Quality (texture) Food texture depends on the ________ _______of the food

rheological properties

A.Aspects of Food Quality (texture) is defined as the science of deformation and flow of matter or, in other words,reaction of a food when a force is applied to it.

rheology

A.Aspects of Food Quality (texture) From a sensory perspective, the texture of a food is evaluated when it is _____

chewed

A.Aspects of Food Quality (texture) gives an indirect evaluation of the rheological properties of a food.

texture

A.Aspects of Food Quality (flavor) is a combination of taste and smell

flavor

A.Aspects of Food Quality (flavor) _____ is detected by the taste buds at the tip, sides, and back of the tongue, whereas aromas are detected by the olfactory epithelium in the upper

taste

A.Aspects of Food Quality (flavor) Taste is detected by the taste buds at the tip, sides, and back of the tongue, whereas aromas are detected by the ______ ______ in the upper

olfactory epithelium

A.Aspects of Food Quality Tastes

flavor

A.Aspects of Food Quality (flavor) is a valuable index of quality. A food often will smell bad before it looks bad, and old meat can be easily detected by its smell.

aroma

A.Aspects of Food Quality (flavor) For any food to have an aroma, it must be____

volatile

A.Aspects of Food Quality (flavor) Vanillin can be detected at a concentration of _______of air

2x10-10mg/l

A.Aspects of Food Quality (flavor) Foods that are contaminated with _____ may have no off-odor, so the absence of bad smell is not a guarantee.

pathogens

A.Aspects of Food Quality (flavor) The taste of a food is a combination of five major tastes____,____,____,____,____.

salt,sweet,sour,bitter,umami

A.Aspects of Food Quality (flavor) _____ and ____tastes are detected primarily on the tip of the tongue, and so they are detected quickly

sweet,salt

A.Aspects of Food Quality (flavor) _____ tastes are detected mainly by taste buds at the back of the tongue.

bitter

A.Aspects of Food Quality (flavor) _____ tastes are mainly detected by the taste buds.

sour

A.Aspects of Food Quality (flavor) _____ (such as vinegar, lemon juice, and the many organic acids present in _____.

acids,fruits

A.Aspects of Food Quality (flavor) saltiness is due to salts, including _____ _____

sodium chloride

A.Aspects of Food Quality (flavor) bitter tastes are due to ______ such caffeine, theobromine, quinine, and other bitter compounds.

alkaloids

A.Aspects of Food Quality (flavor) _____ is a taste that recently has been added to the other four.

umami

A.Aspects of Food Quality (flavor) It is a _____ taste given by ingredients such as ____ ____ (MSG) and other flavor enhancers.

savory,monosodium glutamate

A.Aspects of Food Quality (Chemical Analysis) ______residues of bacteria in food and beverage samples can be analyzed with test kits for bacterial toxins.

toxic

A.Aspects of Food Quality Bacterial Counts

chemical analysis

A.Aspects of Food Quality (Chemical Analysis) Common test formats for microbial food testing are ____ ____,__-___ ____ ___,____ ___,____ ____.

elisa assays,real-time PCR tests,nutrients plates,agar plates

B. Taste Sensitivity _______depends on the length of time allowed to taste a substance.

sensitivity

B. Taste Sensitivity _____ and ____ tastes are detected quickly (in less than a second), because they are detected by taste buds on the tip of the tongue;

sweet,salt

B. Taste Sensitivity _____ compounds, on the other hand, may take a full second to be detected because they are detected at the back of the tongue.

bitter

B. Taste Sensitivity ______concentration is defined as the concentration required for identification of a particular substance.

threshold

B. Taste Sensitivity ____ foods generally taste stronger and sweeter than cold foods.

warm

B. Taste Sensitivity There are two reasons for the effects of temperature on flavor.

volatility,bud receptivity

B. Taste Sensitivity ____of substances is increased at higher temperatures, and so they smell stronger.

volatility

B. Taste Sensitivity ____ ____ ___also is an important factor.

taste bud receptivity

B. Taste Sensitivity Taste buds are most receptive in the region between ___ - ___F (20 and 30 ͦC), and so tastes will be more intense in this temperature range.

68-86

B. Taste Sensitivity _______ _____also affect taste sensitivity and perception. Judgments about flavor are often influenced by pre-conceived ideas based on the appearance of the food or on previous experience with a similar food.

psychological factors

B. Taste Sensitivity _____ ____also affects flavor perception. A stronger color may cause perception of a stronger flavor in a product, even if the stronger color is simply due to the addition of more food coloring.

color intensity

B. Taste Sensitivity _____also can be misleading. A thicker product may be perceived as tasting richer or stronger simply because it is thicker and not because the thickening agent affects the flavor of the food.

texture

B. Taste Sensitivity Other psychological factors that may come into play when making judgments about the flavor of foods include ____ _ __.

time of day

B. Taste Sensitivity General sense of well-being, health, and previous reactions to a particular food or taste.

remember!

C. 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 .

sensory evaluation

C. Sensory Evaluation _____ ____utilizes one or more of the five senses to evaluate foods.

sensory testing

C. Sensory Evaluation ____ _____comprising groups of people, taste specific food samples under controlled conditions and evaluate them in different ways depending on the particular sensory test being conducted.

taste panels

C. Sensory Evaluation Sensory methods may be used to determine: 1. whether foods differ in taste, odor, juiciness, tenderness, texture, and so on. 2. to what extent foods differ. 3. to ascertain consumer preferences and to determine whether a certain food is acceptable to a specific consumer group.

remember!

C. Sensory Evaluation test that determine the extent of difference in specific sensory characteristics

descriptive test

C. Sensory Evaluation test that determine how well the products are liked or which products are preferred.

affective or acceptance/preference test

C. Sensory Evaluation The tray should contain a ______ that gives specific instructions on how to evaluate the samples and a place for the panelist’s response.

ballot

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