Characterization of Colors in Spice Extracts and Whole Meals by Scanning VIS-Spectrophotometry

 

INTRODUCTION:

Spices are one of the few natural materials that have been documented in recorded history longer than any other topic. Comprised of the many complex chemicals found in any Botanical/Plant material, most Spices are used to alter or contribute to the flavor of a dish. In modern food processes, there is also a valuable aspect of these natural products being used to control the COLOR of the food.

 

Text Box: • Harsh yellow Turmeric is used in most curries, while • Delicate yellow Saffron is reserved for use in Paellas and other Rice dishes. • Paprika lends the classic color to Hungarian Chicken Paprikash, and its Oleo-resin Extract is widely used as a coloring agent in baking products and snack foods. • Tomatoes are colored by Lycopenes • Carrots have Carotenes. • Green plants are colored by some arrangement of the Yellow Chlorophylls A-B-C and the Blue Xanthine peak to generate a characteristic "Green" color.

 

 

 

 

 

 

 

 

PURPOSE:

To evaluate a variety of Colored Spices and generate a "Library" of Known Colors that can be used to compare to the colors of Extracted Samples. We can also the Scanning instrument to "see" a higher resolution of similar Shades of a given color (like Saffron and Turmeric) that may be only barely perceptible with the human eye. Extracts of some known Spices will be tested, and an experiment designed to look at the "COLOR" of an entire MEAL that can be compared to this "Library"

 

 

INSTRUMENTS NEEDED:

 

· 6405 UV-VIS Spectrophotometer

(from Edu-Chem Innovations) INFO/Buy IT!

· 10mm. square QUARTZ or GLASS Cuvettes (must be CLEAN to insure accurate ABS readings)

 

 

 

 

 

 

 

Text Box: FUN-SCI Kit Includes all supplies INFO/Buy IT! SUPPLIES:

  1. Disposable plastic pipettes/eyedroppers
  2. Vials of Standard PURE Spices: Saffron, Turmeric, Paprika and Parsley
  3. Rubbing Alcohol for Extraction of Spices (drug store variety, 70% in water)
  4. Acetone for cleaning out Cuvettes)
  5. Wash-bottles of IPA and DI Water (for rinsing out cuvettes)

 

SAMPLES:

 

Bring in Spices from home, particularly good with the more ethnic students. Prepare dilute solutions of 70:30 Alcohol / Water-soluble Extracts of the following pure Spices and scan according to the procedures listed. Save the Spectra of these "Known" Standards:

 

Annatto (Achiote)

Different Chilies

(cayenne, jalapeno, habanero, tabasco, de arbol, datil, etc.

Different Paprikas

Parsley

fennel tops

carrot tops

cumin

sun-dried tomatoes

bell peppers (green, red, orange, yellow)

fake "saffron"

curry powders

bulk turmeric

 

Bring in a portion of a prepared meal (home or restaurant), extract with 50:50 Alcohol / Water, fill a Cuvette and scan. Compare to the known Spices to identify the source of the color.

 

 

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