Food Color CHLOROPHYLL effects of pH pH 5: chlorophyll has

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Food Color
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• CHLOROPHYLL effects of pH
• pH 5 chlorophyll has its normal vegetable
  green color
• pH lt 5 Mg2 is lost and the color changes to
  the characteristic pheophytin olive green color
• pH gt7 the methyl and phytyl esters are removed,
  producing chlorophyllin which is a bright green
  color.

Chlorophyll Pheophytin
Chlorophyllin
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• CHLOROPHYLL effects of heating
• heating ? loss of Mg ? pheophytin
• CHLOROPHYLL effects of enzymes
• chlorophyllase removes the phytol group (even
  under conditions of frozen storage)
• CHLOROPHYLL effects of light and oxygen
• photodegradation ? irreversible bleaching
• If Mg ion is replaced with either zinc or
  copper ? stable
• green complex at low pH

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Carotenes
Hydroxy- carotenoids
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Beef
Whats for dinner tonight?

• Meat contains both hemoglobin and myoglobin that
  bind oxygen
• The bright red color of fresh cut meat is due to
  oxymyoglobin (oxygenation)
• The red color fades as oxidation occurs,
  converting Fe2 to ferric (Fe3) state

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The Structure of Myoglobin
Myoglobin (MW 17,000) is the pigment in muscle
tissue, whereas hemoglobin (MW 68,000) is the
heme pigment in blood
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Forms of Myoglobin in Meat
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Colors in Fruits and Vegetables

• Natural Colors
• Anthocyanins (grapes, blueberries, etc)
• Betalains (beets)
• Carotenoids (carrots, peach, tomato)
• Chlorophyll (broccoli, spinach)
• Other Colors
• FDC
• Exempt

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Pigments and colorants

• Many natural and artificial colorants
• Some add flavor
• Some are very complex
• Many different compounds
• Often unstable
• Very important food additives
• Not all colorants are legal in foods

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Pigments and Colors

• Pigments can be degraded
• Heat, air, enzymes, etc.
• Brown pigment formation
• Carmelization of sugars
• Maillard reaction reducing sugars and amino
  acids
• Enzymes and oxidation

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Anthocyanins in Fruits and Flowers
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What Are Anthocyanins?

• Natural, water-soluble plant pigments
• Display a variety of pH dependent colors
• Polyphenolic compounds (flavonoid)
• Used as food colorants
• Numerous functional components

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What Are Functional Properties

• General Definition
• Any food or food components that impart a
  physiological benefit that can enhance overall
  health, including the prevention and/or treatment
  of diseases.
• Anthocyanins
• Chemical and physical features that enhance color
  and oxidative stability
• Antioxidant capacity and enzyme/microbial
  inhibition

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Anthocyanins in the Foods We Eat

• Common anthocyanin aglycones
• Delphinidin
• Cyanidin
• Petunidin
• Pelargonidin
• Peonidin
• Malvidin

• Common sugar substitutions
• Glucose
• Rhamnose
• Galactose
• Xylose
• Arabinose

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Altering Functional Properties

• Natural pigments have low stability compared to
  synthetic colorants (Red 40).
• Application range in food is limited due by pH,
  temperature, and complexing factors.
• High raw product costs

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Anthocyanin Color at Varying pH
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1
2
2
3
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Modifications to Anthocyanins

• There are two primary means to augment the color
  of anthocyanins.
• Intramolecular and intermolecular copigmentation
• Both rely on complexation with other compounds
  (usually a phenolic compound)
• Greater color and stability is attained

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Intramolecular copigmentation(Acylated
Anthocyanins)

• Aromatic or aliphatic organic acids bound to the
  sugar moiety of the pigment by an acyl linkage.
• p-coumaric, ferulic, caffeic, vanillic, malonic,
  and acetic acids are most common
• Enzyme induced (acyltransferase)
• More red color in pH 4-5 range
• Increased stability to light, heat, and oxygen
• Red cabbage, black carrot, red radish

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Intermolecular Copigmentation
Cyanidin-3-ß-D-glucoside
Cyanidin-3-(6-O-p-coumaroyl- ß-D-glucoside
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Intermolecular copigmentation

• Add polyphenolics to solutions of anthocyanins
• The compounds stack on top of each other.
• Increases the red color and overall stability
• Slows degradation into qunioidal bases
• Results
• More red color at higher pH levels
• Greater application range in foods

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Copigment Stacking
Co-Factor

Pigment
Co-Factor
Hyperchromic shift Bathochromic shift
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Anthocyanin Color with Copigment
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Anthocyanin Color

• The poor stability of anthocyanins creates the
  need to modify stability or find new sources
• Increase color and oxidative stability
• Result
• More red color at higher pH levels
• Greater application range in foods
• Enhanced antioxidant capacity health benefits

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Traditional Anthocyanins Sources and
Applications

• Grape skin
• Red cabbage
• Elderberry
• Purple carrots
• Purple potatoes
• Red radish
• Strawberry, blueberry, blackberry, bilberry,
  chokeberry, cranberries, black current, hibiscus,
  roselle

• Soft drinks
• Instant drinks
• Fruit drinks
• Liquors
• Confectionery
• Fruit jellies
• Jams

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Natural, Non-Certified or Exempt Colors

• Consist of 20 colorants made up of dyes,
  pigments or other substances capable of coloring
  a food that are obtained from various plant,
  animal or mineral sources
• Must be proven safe and meet FDA approval
• Caramel (brown)
• Annatto extract (red/orange/yellow achiote)
• ß-carotene (yellow/orange paprika)
• Beet powder (red)
• Cochineal extract (red carmine)
• Grape skins (red/purple)
• Ferrous gluconate (black)

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FYI

• Cochineal extract (red carmine)

• Carminic acid is derived from the shells of an
  insect and produces a magenta red color
  (cochineal extract).
• The Carmine Cochineal feeds on certain cactus
  species in central and south America.

Yummy
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Synthetic or Certified

• Widely used, some controversy with consumers
• Each batch certified by FDA
• Less than 10 synthetic colors are actually
  certified
• The FDA has approved certain dyes for use in
  foods FDC Colorants
• Blue 1 (Brilliant blue)
• Blue 2 (Indigotine)
• Green 3 (Fast green)
• Yellow 5 (Tartrazine)
• Yellow 6 (Sunset yellow)
• Red 3 (Erythrosine)
• Red 40 (Allura red)
• Orange B
• Citrus Red 2
• Another class of certified colors FDC lakes.
• Lakes are aluminum or calcium salts of each
  certified color
• Lakes of all of the FDC dyes except Red 3 are
  legal

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Food Flavor

• Chapter 11 in your textbook

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• Flavor Chemistry
• Flavor is a combination of taste and aroma
• Taste
• Sweet, sour, bitter, salty
• Sensed on the tongue (protein receptors)
• Nerves sense metallic and astringent flavors
• Aroma
• Volatiles released directly from the food
• Volatiles that are released in the mouth, then
  sensed in the nasal cavity (retro-nasal).

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Artificial andAlternative Sweeteners
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Molecular Basis of Sweetness

• -OH groups
• Acree and Shallenberger AH/B concept

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Acree and Shallenberger

• (Shallenberger Acree) published a paper
  entitled the "Molecular Theory of Sweet Taste" in
  Nature 1969.
• The model developed in that paper for sweetness
  was based on a structure-activity relationship
  between the simplest sweet tasting compounds and
  their structural features of the stimulants and
  has become known as the AH-B theory.
• The theory described with considerable success
  the structural features necessary for sweetness,
  but it was not sufficient to predict sweetness.
• That is, not all compounds that satisfied the
  theory tasted sweet nor was the theory able to
  predict potency level especially for very high
  potency sweeteners.
• However, all sweet compounds seemed to have an
  identifiable AH-B feature.

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Artificial andAlternative Sweeteners
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Sweeteners

• Non-nutritive (no calories)
• Cyclamate (banned in 1969)
• Saccharin (Sweet N Low, 300-fold)
• Aspartame (warning label) aspartic acid and
  phenylalanine (180-fold)
• Acesulfame-K (Sunette, 200-fold)
• Alitame (Aclame, 2,000-fold)
• Sucralose (Splenda, 600-fold)

Sucralose
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The perception of sweetness is proposed to be due
to a chemical interaction that takes place on
the tongue Between a tastant molecule and
tongue receptor protein
THE AH/B THEORY OF SWEETNESS A sweet tastant
molecule (i.e. glucose) is called the AH/B-
glycophore. It binds to the receptor B-/AH
site through mechanisms that include H-bonding.
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AH / B-
?
B
Glycophore
Hydrophobic interaction
AH
?
AH
B
Tongue receptor protein molecule
For sweetness to be perceived, a molecule needs
to have certain requirements. It must be soluble
in the chemical environment of the receptor site
on the tongue. It must also have a certain
molecular shape that will allow it to bond to
the receptor protein. Lastly, the sugar must
have the proper electronic distribution. This
electronic distribution is often referred to as
the AH, B system. The present theory of
sweetness is AH-B-X (or gamma). There are three
basic components to a sweetener, and the three
sites are often represented as a triangle.
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Identifying the AH and B- regions of two sweet
tastant molecules glucose and saccharin.
Gamma (?) sites are relatively hydrophobic
functional groups such as benzene rings,
multiple CH2 groups, and CH3
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Sucralose

• Splenda
• 1998, approved for table-top sweetener and use in
  various foods
• Approved already in UK, Canada before US
• Only one made from sugar
• There was a law suit last year of this claim
• Splenda lost.not a natural compound.a bit of a
  deceptive marketing.
• Clean, sweet taste and no undesirable off-flavor

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Saccharin

• Sweetn Low, The 1st artificial sweetener
• Accidentally found in 1879 by Remsen and Fahlberg
• Saccharin use increased during wars due to sugar
  rationing
• By 1917, common table-top sweetener in America
• Banned in 1977 due to safety issue
• 1991, withdrew ban, but with warning label
• 2000, removed warning label
• Intensely sweet, but slight bitter aftertaste

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Aspartame

• Nutrasweet, Equal
• Discovered in 1965 by J. Schlatter
• Composed of aspartic acid and phenylalanine
• 4 kcal/g, but 200 times sweeter
• Approved in 1981 for table-top sweetener and
  powdered mixes
• Safety debating
• 1996, approved for use in all foods and beverage
• Short shelf life, not stable at high temperature

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Acesulfame K

• Sunette, Sweet One
• Discovered in 1967 by Hoechst
• 1992, approved for gum and dry foods
• 1998, approved for liquid use
• Blending with Aspartame due to synergistic effect
• Stable at high temperature and long shelf life
  (3-4 years)
• Bitter aftertaste

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Neotame

• Brand new approved sweetener (Jan. 2000)
• 7,000 13,000 times sweeter than sugar
• Dipeptide methyl ester derivative structurally
  similar to Aspartame
• Enhance sweetness and flavor
• Baked goods, non-alcoholic beverages (including
  soft drinks), chewing gum, confections and
  frostings, frozen desserts, processed fruits and
  fruit juices, toppings and syrups.
• Safe for human consumption

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Reb-A (diterpene glucoside)
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Food flavors Mixtures of natural and/or
artificial aromatic compounds designed to impart
a flavor, modify a flavor, or mask an
undesirable flavor Natural versus
Artificial Natural - concentrated flavoring
constituents derived from plant or animal
sources Artificial - substances used to impart
flavor that are not derived from plant or animal
sources
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• Most natural flavors are concentrated from
  botanicals
• plants, trees, fruits, and vegetables
• Most artificial flavors are synthesized with high
  purity
• - pharmaceutical flavors

Isolation techniques - Steam distillation - mint
and herbal oils - Solvent extraction - vanilla
oleoresins - Expression - citrus oils -
Supercritical fluid extraction targeted
extractions
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Natural flavors can also be enzymatically or
chemically produced - Fermentation reactions -
Microbial enzymes Saccharomyces
Sp. Lactobacillus Sp. Bacillus Sp. Molds
Maillard flavor compounds Glucose
Glutamic acid chicken Glucose
Lysine burnt or fried potato Glucose
Methionine cabbage Glucose
Phenylalanine caramel Fructose
Glutamic acid chicken Fructose
Lysine fried potato Fructose
Methionine bean soup Fructose
Phenylalanine wet dog
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Artificial Flavors Typically are esters Esters
have pleasant fruity aromas, derived from
acids a condensation reaction ACID
ALCOHOL --gt ESTER WATER Most
artificial flavors are simple mixtures of
esters i.e. Isobutyl formate isobutyl
acetate raspberry
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FERMENTATION and FLAVOR O O
Diacetyl (CH3 C - C CH3 ) is a compound
produced by Yeasts via fermentation of
carbohydrates Major compound in the flavor of
cultured dairy products Butter and butter-like
flavor
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- Green flavors - cis 3-hexenol green leafy -
trans 2-hexenal green apple - Citrus flavors
are mixtures of - Aldehydes - Aromatic
esters - Terpenes - Alcohols - Terpenes -
Limonene sweet citrus/ orange peel - Alpha
pinene warm resinous/ pine-like - Dipentene
fresh citrus/ lemon like
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• Brown flavors
• - Caramelized, roasted or burnt character
• Bread-yeast, caramel, chocolate, coffee, maple,
  peanut
• - Sweet brown compounds
• Vanillin sweet/ chocolate-like
• Maltol sweet/ malty/ brown
• Di-hydrocoumarin sweet/ caramel/ nutlike
• - Non-sweet brown compounds
• - Dimethyl pyrazine nutty/roasted
• - 2,3,5 trimethyl pyrazine chocolate/ roasted

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Flavor Compounds Formation by Maillard Reaction
Reducing Sugars and ?-amino acids
N-glycosylamine or N-fructosylamine
1-Amino-1-deoxy-2-ketose (Amadori intermediate)
or 2-Amino-2-deoxy-1-aldose (Heynes intermediate)
Reductones and Dehydroreductones
H2S NH3
Strecker degradation
Amino Acids


Retroaldol Reaction
Glyoxal Pyruvaldehyde Glycerolaldehyde
Strecker Aldehydes CO2 ?-aminoketone
(Methional, NH3, H2S)
Furans Thiophenes Pyrroles
Hydroxyacetone Hydroxyacetylaldehyde Acetoin Acet
ylaldehyde
Heterocyclization
Pyrazines Pyridines Oxazoles
Thiazoles Pyrroles
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• Flavors complex mixtures of many compounds
• -Amyl, butyl, ethyl esters
• - Amyl acetate sweet fruity/ banana/ pear
• - Amyl caproate sharp fruity/ pineapple
• - Amyl formate sweet/ fruity
• Organic acids containing aldehydes , aromatic
  esters,
• alcohols, ketones
• - Acetic acid vinegary
• - Propionic acid sour milk
• - Butyric acid buttery

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• - Woody compounds
• - Alpha lonone woody/balsamic/violet/red
  raspberry
• Beta lonone woody/balsamic/black raspberry
• - Spicy compounds
• Cinnamic aldehyde cinnamon
• Eugenol cloves
• Thymol thyme
• Zingerone ginger oil
• Capsicum peppers
• - Sulfur compounds
• - Diallyl disulfide garlic onion
• - Methyl mercaptan natural gas
• - Methyl thio butyrate sour milk

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SOURNESS and sour taste is often thought of as
acid However there is not a simple
relationship between acid concentration (pH) and
sourness Organic acids differ in
sourness CITRIC ACID (0.05 N solution) fresh
taste sensation LACTIC ACID (0.05 N solution)
sour, tart PROPIONIC ACID (0.05 N solution)
sour, cheesy ACETIC ACID (0.05 N solution)
vinegar PHOSPHORIC ACID (0.05 N solution)
intense MALIC ACID (0.05 N solution)
green TARTARIC ACID (0.05 N solution) hard
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• Flavors are typically encapsulated
• - Spray drying
• - Use of excipients
• Plating - coat flavor onto sugar or salt
• Inclusion complex - beta cyclodextrins
• Secondary coatings - high melting temperature fat

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BITTERNESS cqn be attributed to several
inorganics and organics KI CsCl
MgSO4 Certain amino acids and peptides (dipeptide
leucine-leucine) Alkaloids derived from pyridine
(N-containing 6-membered ring) and purines
A caffeine (1, 3, 7 trimethylxanthine) B
theobromine (from cacao)
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GYCOSIDES are sugars that have been added to a
natural compound. Grapefruits generally have a
bitter taste to them. This is due to the
flavonoid compound Naringin. Naringin actually
has 2 sugars (both glucose) as part of its
structure. Compound is still intensely
bitter. Removal of these sugars with
naringinase, will render the compound
tasteless. Naringin is then converted to
Naringinin. The de-bittering of grapefruit
juice can be done, if desired.
Where rutinoside is the sugar
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SALTY depends on the nature of the cation and
anion in the ionic salt crystal structure high
molecular weight salts may be bitter some
salts may even exhibit sweetness
Examples NaCl NaBr NaI KCl LiBr
NaNO3 salty KBr salty bitter Lead
acetate (toxic) sweet
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HOTNESS (pungency) is characteristic of
piperine in black pepper and capsicum in red
pepper and gingerols in ginger
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Sunlight Flavor
Sunlight will induce oxidized flavor and sunlight
flavor and hay-like flavor. Oxidized
flavor Sunlight flavor burnt and / or
cabbage
Riboflavin Effect on Sunlight Flavor

• Riboflavin is a catalyst for production of the
  sunlight flavor.
• Milk protein and riboflavin sunlight
  sunlight flavor
• 2) Riboflavin increase in milk will increase the
  sunlight flavor
• 3) Riboflavin removal prevents the sunlight
  flavor

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According to the TG Lee Website

• Studies at the Silliker Laboratories in Illinois,
  the University of Michigan and other leading labs
  and universities concluded that both sunlight and
  the fluorescent lighting in stores could decrease
  the freshness and flavor of milk and the potency
  of vital vitamins in it. But this research also
  showed that the majority of natural and
  artificial light could be blocked by containers
  that were yellow instead of white.