Test 1 Study Guide Flashcards by Amirah El-Amin

What are the major food components to be discussed in this course?

-Carbohydrates
-Proteins
-Lipids
-Minerals
-Ash
-Moisture

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Which of the following is not a macronutrient ?

a. Proteins
b. Carbs
c. Fats
d. Vitamins

d. Vitamins

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Which of the following is an example of a macronutrient ?

a. Iron
b. Calcium
c. Vitamin C
d. Carbohydrates

d. Carbohydrates

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Which of the following is a source of complete protein?

a. Rice
b. Lentils
c. Chicken
d. Potatoes

c. Chicken

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Which of the following is an example of a saturated fat?

a. Oilve oil
b. Avocado
c. Butter
d. Salmon

c. Butter

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Why do we want to measure the abundance of specific molecular components or groups of these components in foods?

to understand their nutritional value
to assess food safety and quality
develop new food products
understand the impact of food on human health

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Carbohydrates are composed of ______ and _____

a. Carbon, water
b. Zinc, aluminum
c. Hydrogen, oxygen
d. Gold, calcium

a. Carbon, water

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Food composition analysis is carried out

a. To meet consumers demands
b. To meet governmental requirements
c. To determine nutritional benefits
d. For quality control
e. All of the above

e. All of the above

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Food analysis includes ________

a. Chemical analysis and characterization of food components
b. Physical properties and analysis of food
c. Microbiological analysis
d. Sensory analysis
e. All of the above

e. All of the above

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Which of the following is false? Method selection in food analysis involves consideration of ______

a. Objective of assay
b. Characteristics of method
c. Validity of method
d. Consideration of food composition
e. None of the above

e. None of the above

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Rapid, secondary methods (vs. official, primary methods) of analysis would most likely be used for:

a. Nutrition label testing
b. Tests for authenticity
c. Routine quality control
d. Testing to ensure product meets government standards
e. None of the above

c. Routine quality control

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The most widely used set of official methods of analysis for foods in general, appropriate for nutrition labeling purposes, is established by _________

a. AACC International
b. American Oil Chemists Society
c. FDA
d. USDA
e. AOAC International

e. AOAC International

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Which of the following is false? Proximate composition includes the food component ______

a. Protein
b. Total carbohydrate
c. Vitamins
d. Ash
e. More than one of the answers

c. Vitamins

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Identify the organization that published a set of standard methods of analysis that would be most appropriate to analyze soybean oil

a. AOCS
b. AOAC International
c. AACC International
d. American Public Health Association
e. Codex Alimentarius

a. AOCS

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Which of the following is described as “test samples from official organizations, that allow results from your lab to be compared statistically to other subscribing labs”?

a. Standard reference samples/materials
b. Check samples
c. Internal reference samples/materials
d. None of the answers
e. All of the answers

b. Check samples

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Which of the following is false? With regard to regulations relevant to food analysis, the FDA _______.

a. Has primary authority over the labeling of foods (except for meats/meat products)
b. Establishes and enforces standards of identity (except for meats/meat products)
c. Works with NMFS and EPA to ensure seafood safety
d. Administers voluntary grading service for fruit and vegetable products
e. More than one of the above

d. Administers voluntary grading service for fruit and vegetable products

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Identify the US governmental agency that has regulatory and/or other responsibility for quality assurance related to table wine

a. EPA
b. FDA
c. USDA
d. TTB
e. More than one of the above

d. TTB

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Which of the following does the USDA regulate/do relevant to food analysis?

a. Has primary authority over the labeling of foods
b. Establishes and enforces standards of identity for meats/meat products
c. Establishes standard of quality
d. Works with NMFS and EPA to ensure seafood safety
e. More than one of the above

e. More than one of the above

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Which of the following characteristics is not commonly specified by the NSSP (administered by the FDA) regarding shellfish?

a. Pesticide residue
b. Mercury
c. Sodium
d. Natural toxins
e. None of the above

c. Sodium

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Which of the following federal agencies in the US administers a voluntary grading service for numerous food products, the specifications for which often require chemical analyses?

a. FDA
b. NMFS
c. EPA
d. TTB
e. USDA

e. USDA

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Which term below related to reliability of analyses is described as follows: “The lowest possible amount that we can detect with some degree of confidence”?

a. Sensitivity
b. Coefficient of determination
c. Confidence interval
d. Limit of detection
e. Relative error

d. Limit of detection

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Systematic errors lead to a lack of:

a. Accuracy in the measurement
b. Significant digits in the measurement
c. Precision in the measurement
d. Grading of measuring instrument

a. Accuracy in the measurement

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Which of the following types of errors can be traced to a defect in the measuring instrument?

a. Systematic
b. Random
c. Gross

a. Systematic

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In proximate analysis, which of the following elements can be measured?

a. % Moisture content
b. % Carbon
c. % Hydrogen
d. % Nitrogen

a. % Moisture content

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Precision pertains to all of the following expect a. Reproducibility of measurements b. Agreement among numerical values c. Sameness of measurements d. Closeness of a measurement to an accepted value

d. Closeness of a measurement to an accepted value

A chemist who frequently carries out a complex experiment is likely to have high a. Accuracy, but low precision b. Accuracy c. Precision d. Precision, but low accuracy

d. Precision, but low accuracy

Five darts strike the center of the target. Whoever threw the dart is a. Accurate b. Precise c. Both accurate and precise d. Neither accurate nor precise

c. Both accurate and precise

You have carried out a series of repeated measurements, what statistical function would you calculate to give you the precision of your measurement? a. Mean b. Standard deviation c. Coefficient of variation d. Standard Error e. Analysis of Variance

b. Standard deviation

You need to determine the moisture content of a breakfast cereal product for nutrients labeling purposes. Which method would you best use? a. Near infrared b. Rapid moisture analyzer c. Forced draft oven d. Toluene distillation e. Microwave drying oven

c. Forced draft oven

A physical method instrument widely used one simple sugar solution as a rapid method to measure soluble solids ( or % moisture) is ______ A. Karl Fischer instrument b. Hydrometer c. Rapid moisture analyzer d. Refractometer e. More than one of the above

e. More than one of the above

A condition/reaction that would result in an overestimation of moisture content when a food sample is dried to determine the moisture content is _______ a. Maillard browning b. Case hardening c. Too large a particle size d. Sucrose hydrolysis e. More than of the above

a. Maillard browning

For n < 25 you would use a Z value in a confidence interval calculation a. True b. False

b. False

For a completely normal distribution of data, the mean, median, and mode are all the same a. True b. False

a. True

The term”absolute error” refers to the different between the experimental value and the true value, relative to the true value. a. True b. False

b. False

What is the name of the term SD/mean x 100?

Coefficient of variation

What is the name of the term, mean - True value / True value ? -more useful that absolute error

Relative error

Sucrose is commonly referred to as a. Salt b. Sugar c. Carbs d. Glucose

b. Sugar

_____ is the most common polysaccharides to food products a. Water b. Glucose c. Salt d. Starch

d. Starch

Identify the complex carbohydrate that cannot be digested a. Fiber b. Sugar c. Cellulose d. Fat

c. Cellulose

Which of the following statements about moisture analysis is false? a. Uses a gravimetric method b. Result gives total ash content c. Indirect method d. Inexpensive, easy, short time

b. Result gives total ash content

The process of moisture content during thermogravimetric analysis is by the process of _____ a. Water vaporization b. Freezing c. Oven drying d. Sun drying

a. Water vaporization

The oven drying methodology consists of heated by _____ a. Conduction b. Convection c. Radiation d. Both radiation and convection

b. Convection

________ of moisture measurement is based on chemical reactions. a. Lyophilization b. Karl Fischer method c. Halogen drying d. Infrared drying

b. Karl Fischer method

You need to determine the moisture content of cocoa (a powdered product) and need an official-type accurate method. What method would you best use? a. Hydrometer b. Karl Fischer method c. Rapid moisturize analyzer d. Forced draft oven e. Vacuum oven

b. Karl Fischer method

Wet ashing of samples will not give a value for the ash content a. True b. False

a. True

The ash content of a sample represents the total mineral content in the sample. a. True b. False

a. True

Wet ashing of a sample is generally preferable to dry ashing for total ash content determination because it is faster. a. True b. False

a. True

The ash content of a sample is mathematically equal to the total of all of the minerals present in the sample a. True b. False

a. True

The two chemicals most commonly used for digestion in the wet ashing procedure are _____ and _____. ______ is used at the end to complete digestion, but must be used with extreme caution since it is a violent oxidizing agent and is unstable

Nitric acid and sulfuric acid. Perchloric acid is used at the end

Which of the following is false? An advantage of wet ashing is a. Requires little time and attention by the technician, if conventional version of wet ashing is used b. Minerals will usually stay in solution c. Little or no loss from volatilization d. Requires no blank values to be subtracted e. More than one of the above

e. More than one of the above

Which of the following is false? “Dry ashing”_______ a. Uses acid, oxidizing agent, and heat to digest a sample to remove all organic material b. Uses simply a high temperature to incinerate all organic matter c. Is best used to measure the total ash content of a sample d. Can be done using a muffle furnace e. More than one of the above

a. Uses acid, oxidizing agent, and heat to digest a sample to remove all organic material

Which of the e following is false? “Wet ashing”_________ a. Uses acid, oxidizing agent, and heat to digest a sample to remove all organic material b. Uses simply a high temperature to incinerate all organic matter c. Is best used as a treatment prior to individual mineral analysis d. Can be done using a muffle furnace e. More than one of the above

e. More than one of the above

Term for the difference between experimental value and true value

Absolute error

Use n in the denominator for 30 or more samples; otherwise use n-1. T or F

True

- Represents the ratio of the standard deviation to the mean - A statistical measure of the dispersion of data points in a data series around the mean - useful statistic for comparing the degree of variation from one data series to another

Coefficient of Variation

Small CV represents a high level of precision. Example. CV = 0.453%. T or F?

True

Use Z values for > 25 samples. T or F?

True

Use t values for < 25 samples. T or F?

True

Term for when results consistently deviate from true value. Example. Pipettor calibrated incorrectly

Systematic error

Term for “can fluctuate and are unavoidable” . Example. Differences between balances

Random error

Term for “big screwup”. Example. Pipetting 0.5 ml instead of 1 ml

Blunders

Term for measuring only what you’re interested in

Specificity

Term for magnitude of change in measurement with change in concentration of compound

Sensitivity

Moisture analysis is required for nutrition label calculations. T or F?

True

These procedures are perhaps the greatest potential source of error in any analysis

Sample collection and handling

The greatest temperature variation exists in a __________

Convection oven

_________ has the least temperature differential across the interior of all ovens

Forced draft ovens

________is the method of choice for determination of water in many low moisture foods such as dried fruits and vegetables, candies, chocolate, roasted coffee, oils and fats, or any low moisture food high in sugar or protein

Karl Fisher Method

A colorimetric method for determination of inorganic phosphate

Fiske-Subbarow Method

A solution for which the concentration is accurately known

Standard solution

Represents the relationship between absorbance and concentration

A standard curve