Exam 1 Flashcards

1
Q

What is proximate analysis?

A
  • Measures the major components of food
  • Moisture, ash, lipid, protein, carbs
  • No structural information
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2
Q

What do the letters TD and TC mean on a piece of glassware?

A
  • To Deliver - graduated cylinders/volumetric pipettes

- To Contain - volumetric flask

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3
Q

What are the objectives of food analysis?

A

Trade, legal, official, QC

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4
Q

List 7 reasons for evaluating the composition of foods.

A
  • Quality assurance
  • Product development
  • Process development
  • Nutritional labeling
  • Health claims
  • Safety
  • Regulation compliance
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5
Q

List 5 types of samples and why they would be analyzed.

A
  • Raw materials - prevent fraud
  • Process control - check if production meets standards
  • Final product - nutritional labeling
  • Consumer complaints - possible recall
  • Competitor products - product comparison
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6
Q

What are the 3 basic steps in food analysis?

A

1) Select and prepare analysis
2) Perform the assay
3) Calculate and interpret results

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7
Q

List the full name and abbreviation of 3 organizations that publish “official” methods for food analysis.

A
  • Association of Analytical Communities International (AOAC)
  • American Association of Cereal Chemistry (AACC)
  • American Society of Oil Chemistry (AOCS)
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8
Q

What agency regulates most foods manufactured in the US?

A

FDA

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9
Q

What are the two fundamental provisions of the FD&C Act of 1938?

A
  • Assured consumers that food was safe, wholesome, and truthfully labeled
  • Addressed misbranding, allowing for SOIs
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10
Q

What organization is responsible for regulating the composition of meat products in the US?

A

USDA

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11
Q

What organization is responsible for assuring that products imported into the US are safe and not economically deceptive?

A

US Customs Service

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12
Q

What is Codex Alimentarius?

A
  • Book of Food
  • Collection of standards, codes of practive, guidelines and recommendations regarding food/food production/food safety
  • Collaboration between UNFAO and WHO
  • Voluntary compliance
  • Used internationally
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13
Q

What organization is responsible for advertising related to food?

A

Federal Trade Commission

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14
Q

What is accuracy and what statistics are used to assess it?

A
  • Proximity to true value

- Mean, % error and confidence interval

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15
Q

What is precision and what statistics are used to assess it?

A
  • Reproducibility

- Mean, std dev, %CV

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16
Q

Define absolute error.

A

Difference btwn experimental value and true value

17
Q

Define relative error.

A

Difference btwn experimental value and true value against true value

18
Q

5 techniques for assessing precision

A
  • Std dev
  • CV
  • Confidence Interval
  • Relative deviation
  • Relative error
19
Q

What is the formula for %CV?

A

(Std dev)100%/mean

20
Q

What fraction of a normally distributed data set can be found within 1, 2 and 3 SD of the mean value?

A

1- 68%
2- 95%
3- 99.7%

21
Q

Define systematic error and give an example.

A
  • Results consistently deviate from true value

- Example: pipette calibrated incorrectly

22
Q

Define random error and give an example.

A
  • Can fluctuate and are unavoidable

- Example: differences btwn balances

23
Q

Define blunders and give an example.

A
  • Big “screw-ups”

- Example: pipetting 0.5 mL instead of 1 mL

24
Q

Define sensitivity.

A

Magnitude of change in measurement with change in concentration of compound

25
Q

Define the term limit of detection.

A

Lowest possible increment that we can detect with statistical significance

26
Q

Describe the Q-test and how it can be used to reject analytical data.

A
  • A Q-value is calculated and compared to table values
  • If calculation is larger than table value, then the questionable measurement can be rejected at the 90% confidence level
27
Q

What are the units of “Normality”?

A

Mole equivalents of solute/liter of solution

28
Q

Define the term equivalent weight.

A

Molecular weight / number of equivalent

29
Q

Define titratable acidity.

A
  • Total acidity
  • Better predictor of acid’s impact on flavor than pH
  • Not so useful for microbial issues
30
Q

Describe volatile acidity.

A

Difference between titratable acidity and fixed acidity.

31
Q

Define predominant acid.

A
  • The most abundant acid present in a food

- Kept in mind when calculating TA

32
Q

At what pH does the phenolphthalein indicator go from colorless to pink? Why is this value important?

A
  • pH 8.0-9.6; 8.2

- This is the equivalence point where there are equal equivalence numbers of both acid and base

33
Q

Describe the three types of water in food.

A
  • Free water - not chemically bound
  • Adsorbed water - held tightly within other structures
  • Water of hydration - chemically bound
34
Q

What is the purpose of the addition of sand during drying of some products?

A

Prevent surface crust from forming and to disperse the sample so evaporation of moisture is less impeded.

35
Q

What is an operational definition?

A

Something unobservable can be legitimate in science if the concept can be linked to something observable

36
Q

What is attribute sampling?

A

Performed to decide on the acceptability of a population based on whether the sample possesses a certain characteristic or not

37
Q

What is case hardening and how can it be minimized?

A
  • When sample burns during drying
  • Higher surface temperatures create dry skin that traps moisture on inside, negatively affect drying rate
  • Use sand