Definition

1. Noun:
   • A chemical measurement: The acid value is a number that indicates the amount of free acid present in a substance like fat or oil. It is measured by finding the mass in milligrams of potassium hydroxide (KOH) needed to neutralize one gram of the sample.

Usage

• The acid value is a critical quality parameter in industries that produce or use fats, oils, and waxes.
• It is used to assess the freshness or degree of spoilage (rancidity) of fats and oils, as spoilage creates free fatty acids.
• A higher acid value typically indicates a greater level of decomposition or lower purity.

Examples

• Noun:
  • The laboratory report showed an acid value of 2.0 for the new batch of olive oil, which is within the acceptable range for extra virgin quality.
  • Monitoring the acid value over time helps predict the shelf life of the cosmetic product.
  • An increasing acid value in the stored butter confirmed that it was beginning to turn rancid.

Advanced Usage

• "To determine the acid value": This is a standard phrase used in analytical chemistry procedures.
  • The protocol requires us to determine the acid value of all incoming oil shipments.
• "Acid value determination": Refers to the analytical process or test itself.
  • Acid value determination is performed via titration with a potassium hydroxide solution.

Variants and Related Words

• Acid Number (n): A fully synonymous term for acid value, used interchangeably in chemistry and industry.
  • The specification sheet lists the maximum permissible acid number.
• Free Fatty Acid Content (n): A related concept often expressed as a percentage; it is directly correlated to the acid value.
• Saponification Value (n): Another important chemical number for fats, measuring the amount of base needed to saponify the fat, often discussed alongside acid value.

Synonyms

• Acid Number: The direct synonym.
• Neutralization Value: A less common but accurate synonym describing what is measured.

Related Phrases

• Acid value test: The specific procedure or experiment to find the acid value.
  • We run an acid value test on every production lot.
• To have a high/low acid value: Describes the state of the measured substance.
  • This batch of wax has a surprisingly low acid value, indicating high purity.

Noun

1. (chemistry) the amount of free acid present in fat as measured by the milligrams of potassium hydroxide needed to neutralize it
   • as the glycerides in fat slowly decompose the acid value increases