Instrumentation & Calibration Flashcards

A colorimeter reporting CIE L*a*b* values shows a high positive b* reading for a sample. What does this indicate?

Answer: The sample is more yellow

In CIELAB, positive b* indicates yellowness and negative b* indicates blueness.

Before measuring samples, a colorimeter is usually calibrated against which reference?

Answer: A certified white calibration tile

Colorimeters are standardized with a certified white (and sometimes black) tile so readings trace to known reflectance values.

Which instrument test imitates two bites to measure texture properties such as hardness, cohesiveness, and springiness?

Answer: Texture Profile Analysis (TPA)

TPA compresses a sample twice in a row to imitate chewing and produce mechanical texture parameters.

A texture analyzer's load cell should be checked for accuracy using what?

Answer: Certified calibration weights

Load cells measure force, so they are calibrated against traceable masses of known weight.

A handheld refractometer used for juice samples is zeroed with which liquid?

Answer: Distilled water at the specified temperature

Distilled water reads 0 °Brix, so it is the standard zero point for sugar refractometers.

Why does temperature compensation matter when measuring °Brix?

Answer: Refractive index changes with temperature

Refractive index depends on temperature, so readings must be corrected to a reference temperature, usually 20 °C.

A sensory lab wants to show that its instrumental hardness values predict panel hardness ratings. Which analysis fits best?

Answer: Correlation or regression between instrumental and sensory data

Linking instrumental and sensory data calls for correlation or regression modeling across the same samples.