Eating with Your Eyes: The Chemistry of Food Colorings
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Why is green-colored ketchup not found on supermarket shelves?
Although green colored ketchup has existed, consumers prefer red because this color matches the color they associate with the flavor of ketchup (and tomatoes).
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Why do people often avoid multicolored food?
People avoid multicolored food because it looks like it might be moldy and should not be eaten.
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What is the reason for adding food coloring to hot dogs?
Without the addition of food coloring, hot dogs would be gray and unappealing to customers.
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Describe a property of beta-carotene that makes it suitable for use as a coloring agent for dairy products.
Beta-carotene is fat soluble so it will dissolve in fatty dairy products such as butter giving them color.
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What makes anthocyanin molecules water-soluble?
The polar nature of anthocyanin molecules makes them water-soluble.
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What groups on anthocyanin molecules are responsible for their water solubility?
It is the –OH groups that make the anthocyanin molecules polar.
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Why did Starbucks remove cochineal dye from its strawberry flavored products?
Starbucks removed cochineal dye from its strawberry flavored products in response to customer complaints about eating bugs.
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Why do manufacturers prefer artificial- to natural-coloring substances for their products?
Manufacturers prefer artificial- to natural-coloring substances because they are cheaper and can be mass produced.
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How do the elements that compose the molecular formula of Red No. 3 differ from the elements present in the other formulas shown in Table 1?
The molecular formula of Red No. 3 contains iodine (I) and does not contain sulfur (S) which is present in all the other molecular formulas.
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What is the base material currently used to produce most synthetic food dyes?
The base material currently used to produce most synthetic food dyes is petroleum or crude oil.
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What happens when ionic food-coloring molecules dissolve in water?
Ionic food-coloring molecules dissolve in water when the ions that form the solid become associated with the partial negative and partial positive charges on polar water molecules.
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In what ways do food scientists claim that eating involves more than just taste?
Food scientists claim that the smell, sound, feel and sight of food are just as important as its taste.
Tooth Decay: A Delicate Balance
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Name the three main constituents of the hard parts of the tooth.
The three main constituents of the hard parts of the tooth are mineral, proteins and water.
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What is hydroxyapatite?
Hydroxyapatite is the mineral that makes tooth enamel hard. Its formula is Ca5(PO4)3(OH).
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Why does the author say the hydroxyapatite in your teeth “is dynamic”? The author mentions that the hydroxyapatite in your teeth “is dynamic” because there is an equilibrium occurring between demineralization and mineralization of the hydroxyapatite, as food is eaten which reduces pH that increases the rate of demineralization, and the subsequent release of saliva with a slightly higher pH that increases the rate of mineralization.
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What are the products of the demineralization of hydroxyapatite?
The products of the demineralization reaction of hydroxyapatite are calcium ions (Ca2+), phosphate ions (PO43–) and hydroxide ions (OH–).
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How does pH differ between that of the mouth and that of the body?
The pH in the body differs from that in the mouth in that the blood pH is closely controlled at a slightly alkaline value of 7.4, while the pH of the mouth can vary between 6.2 and 7.4.
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How does the body control blood pH (e.g., after exercising)?
When exercising, lactic acid is produced in the muscles, adding H+ ions to the bloodstream. To relieve this equilibrium shift, according to Le Chatelier’s Principle, bicarbonate ions react with the H+ ions and produce carbonic acid. Then the carbonic acid build-up causes an increase in the amount of carbon dioxide and water (which is exhaled through the lungs). This returns the body to a new state of equilibrium and a normal pH.
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How does saliva maintain the pH of the mouth after bacteria produce acid from the carbohydrates we’ve consumed?
Saliva maintains the pH balance in the mouth by secreting bicarbonate ions, produced in the salivary ducts, which combine with and neutralize the H+ ions produced in the fermentation process.
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What happens next to maintain equilibrium?
As the excess H+ ions from the previous question are consumed, the amount of carbonic acid builds up. To maintain the right amount of carbonic acid in the mouth, some of the excess carbonic acid breaks back down into carbon dioxide and water. The excess carbon dioxide then diffuses out from the saliva.
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What are the results of a consistently low pH in the mouth?
Consistently low pH in the mouth results in small holes or pits to form in the enamel of the tooth, which eventually exposes the dentin below the enamel. Dentin, being less resistant to acid than enamel (only 70% hydroxyapatite vs. 96% for enamel), is more quickly and easily demineralized, resulting in more rapid tooth decay.
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What are the two main materials used to fill a decayed tooth, once the decay has been removed?
The two main materials used to fill a decayed tooth are composite resins and mercury amalgams.
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Name three problems with the use of amalgams for filling teeth.
Three problems with using amalgams to fill teeth are:
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More of the healthy part of a tooth must be removed in order to pack the amalgam into the cavity in such a way that it ensures no movement of the filling,
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Amalgams block X-rays, making it more difficult for the dentist to obtain a useful 3-dimensional panoramic picture of your entire mouth, and
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Amalgams need to be properly disposed of, since they contain hazardous mercury.
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(Not mentioned in article: Amalgam fillings appear silver or black, making them obvious and not very attractive.)
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