Vernier Software and Technology
Vernier Software & Technology

Determination of Chlorophyll in Olive Oil

Introduction

Olive oil is made by pressing or extracting the rich oil from the olive fruit. It seems like a simple matter to press the olives and collect the oil, but many oil extraction processes exist for the many different types of olives grown around the world. To complicate things further, there are also various grades of olive oil, and carefully selected groups of officials meet to define and redefine the grading of olive oil. To help make our experiment a more scientific and less political exercise, we will winnow our investigation of olive oil down to a manageable few variables.

After processing, olive oil comes in three common grades: extra virgin, regular, and light. Extra virgin olive oil is considered the highest quality. It is the first pressing from freshly prepared olives. It has a greenish-yellow tint and a distinctively fruity aroma because of the high levels of volatile materials extracted from the fruit. Regular olive oil is collected with the help of a warm water slurry to increase yield, squeezing every last drop of oil out of the olives. It is pale yellow in color, with a slight aroma, because it contains fewer volatile compounds. Light olive oil is very light in color and has virtually no aroma because it has been processed under pressure. This removes most of the chlorophyll and volatile compounds. Light olive oil is commonly used for frying because it does not affect the taste of fried foods, and it is relatively inexpensive.

The visible light absorbance spectrum of chlorophyll gives interesting results. The chemistry of chlorophyll (some references site four types: a, b, c, and d) creates absorbance peaks in the 400–500 nm range and in the 600–700 nm range. The combination of visible light that is not absorbed appears green to the human eye, but different sources of chlorophylls will have different ratios of these peaks, which create various shades of green. The ability of chlorophyll to soak up light energy across a wide swath of the visible range helps power photosynthesis at optimum efficiency in plants.

Objectives

In this experiment, you will

  • Measure and analyze the visible light absorbance spectra of three standard olive oils: extra virgin, regular, and light.
  • Measure the absorbance spectrum of an “unknown” olive oil sample.
  • Identify the unknown olive oil as one of the three standard types.

Sensors and Equipment

This experiment features the following Vernier sensors and equipment.

Additional Requirements

You may also need an interface and software for data collection. What do I need for data collection?

Standards Correlations

See all standards correlations for Advanced Biology with Vernier »

Advanced Biology with Vernier

See other experiments from the lab book.

1ADiffusion through Membranes
1BOsmosis
2AEnzyme Action: Testing Catalase Activity
2BEnzyme Action: Testing Catalase Activity
3Mitosis & Meiosis
4APlant Pigment Chromatography
4BPhotosynthesis
5ACell Respiration (CO2 and O2)
5BCell Respiration (CO2)
5CCell Respiration (O2)
5DCell Respiration (Pressure)
6ApGLO™ Bacterial Transformation
6BAnalysis of Precut Lambda DNA
6BForensic DNA Fingerprinting
7Genetics of Drosophila
8Population Genetics and Evolution
9Transpiration
10ABlood Pressure as a Vital Sign
10BHeart Rate and Physical Fitness
11Animal Behavior
12ADissolved Oxygen in Water
12BPrimary Productivity
13The Visible Spectra of Plant Pigments
14Determination of Chlorophyll in Olive Oil
15Enzyme Analysis using Tyrosinase
16Introduction to Neurotransmitters using AChE
17Macromolecules: Experiments with Protein

Experiment 14 from Advanced Biology with Vernier Lab Book

<i>Advanced Biology with Vernier</i> book cover

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