Lecture 7: Food Colors, Additives, and Processing

Question 1

Why do we process foods?

Answer 1

• Preservation
• Improve taste
• Increase variety of foods
• Convenience

Question 2

How does preservation contribute to food safety

Answer 2

Used to extend the shelf life of a food by controlling the growth of pathogenic bacteria and decrease toxin formation in foods by:

• Decreasing the water activity of food
• Decrease the pH of a food (make it more acidic)
• Decrease the temp a food is stored at

Question 3

What are the most important factors to control in food?

Answer 3

• Water content
• pH (acidity)
• Temp

Question 4

Water content and food safety

Answer 4

• Bacteria need a high moisture content to grow
• Drying foods decreases the risk of getting sick as bacteria can’t grow on them
• Bacteria need protein to grow

Question 5

pH and food safety

Answer 5

• pH measure the acidity of a food
• Bacteria thrive in a neutral environment (pH 7)
• Food with a pH above 8 tend to be bitter and unappealing
• Foods with a pH below 6 tend to be tart and sour
• pH below 4.6 = safety zone where bacteria can’t grow

Question 6

Temperature and food safety

Answer 6

• Temp danger zone (40 - 140 F) = rapid multiplication of microorganisms
• Refrigeration(< 40 F) = very slow growth
• Freezing (< 28 F) = no growth
• > 140 F = death of microorganisms

Question 7

Drying

Answer 7

• Removal of free water so bacteria can’t grow

- Through sun, air, heat, fire, or vacuum

Question 8

Water activity

Answer 8

• Scale of 0 - 1
• Partial pressure of water above the soln normalized to the partial pressure above pure water
• Pure water has an activity of 1
• Higher activity = bacteria grows more easily

Question 9

Freeze drying

Answer 9

Freezing of foods and subsequent removal of water from the frozen food through use of a vacuum

Question 10

Smoking

Answer 10

• Addition of smoke and heat to preserve food

- Action of the chemicals in the wood smoke and the partial drying of food

Question 11

Curing

Answer 11

• Addition of a chemical compound (salt, sugar, sodium nitrate) to a food to slow bacterial growth (especially in meats)
• These compounds “grab” water and hold onto it, making it less available for bacteria

Question 12

Fermentation

Answer 12

Use of special bacteria, molds or yeasts to prevent spoilage by converting the elements of a food that spoil easily (sugar) to more stable elements that act as preservatives (alcohol, acid, CO2)

Question 13

Sterilization

Answer 13

• Any process that removes or kills all forms of microbial life, including fungi, bacteria, viruses, spore forms
• Can be done in glass jars, cans or synthetic materials

Question 14

Aseptic packaging

Answer 14

Process by which a sterile (aseptic) food product is packaged in a sterile container in a way that maintains sterility

Question 15

Irradiation

Answer 15

• Exposing a food to ionizing radiation to sterilize the food
• Destroys insects, fungi, or bacteria that cause human disease or food spoilage

Question 16

Pasteurization

Answer 16

• Heating a food (usually a liquid) to a specific temp for a defined length of time, then immediately cooling it down
• Reduces number of viable pathogens so they’re unlikely to cause disease
• Made popular by Nicolas Appert

Question 17

Refrigeration

Answer 17

< 40 F

-Lowering of temp of a food to inhibit the growth of bacteria, molds and yeasts

Question 18

Freezing

Answer 18

< 28 F

• Lowering of temps of a food to stop the growth of bacteria, molds and yeasts and to kill parasites
• Exception = listeria (can grow in cold temps)

Question 19

What are food additives?

Answer 19

• Any substance or mixture of substances, other than the basic foodstuff, that is present in food as a result of any phase of production, processing, packaging, or storage
• Ex) salt to preserve meat, sugar to preserve fruit, vinegar to pickle veggies

Question 20

What do food additives do?

Answer 20

• Maintain product consistency (emulsifiers, thickeners)
• Improve or maintain nutritional value (fortification of vitamins, minerals)
• Maintain palatability and wholesomeness (preservatives, antioxidants)
• Provide leavening or control pH (baking soda, tartarate)
• Enhance flavor or color (spices, dyes, synthetic flavors)

Question 21

Intentional additives

Answer 21

• Compounds purposely added to foods to perform specific functions
• Ex) preservatives, antibacterial agents, sweeteners, colors, flavors

Question 22

Incidental additives

Answer 22

• Constituents that result from production, processing, storage or packaging
• Typically present in trace quantities
• Ex) metal, insects, packaging material

Question 23

GRAS

Answer 23

Substances whose use is “Generally Recognized As Safe” by experts, based on their history of use in food before 1958 or based on published scientific evidence

Question 24

Name the 5 primary types of food additive agents

Answer 24

• Antimicrobial agents
• Sweeteners
• Coloring agents
• Flavoring agents
• Antioxidants

Question 25

Antimicrobial agents

Answer 25

- Compounds that suppress microbial growth/activity and prevent deterioration of foods - Most are GRAS - Ex) benzoic acid and its salts, sorbates, sulfites, nitrates, nitrites, acetates

Question 26

Sweeteners

Answer 26

- Natural sugars (sucrose, lactose, maltose) - Non-nutritive sugar substitutes originally synthesized to sweeten foods for diabetics - Popular for weight control - Avg American consumes ~ 20 tsp of sugar a day

Question 27

Aspartame

Answer 27

- Nutrasweet or Equal - James Schlatter - Made up of 2 amino acids, aspartic acid, and phenylalanine as the methyl ester - Limited to cold, non basic foods - FDA approved as safe except in individuals with genetic disorder phenylketonuria (PKU)

Question 28

Coloring agents

Answer 28

- Stimulate a color that is perceived by the consumer as natural - Offset color loss due to light, air, heat, moisture and storage conditions - Mask natural variations in color - Enhance naturally occurring colors - Provide identity to foods for effect, decorative, or artistic purposes (green ketchup, cake icing)

Question 29

Artificial vs. Natural coloring agents

Answer 29

- Certified colors (artificial) = derived primarily from petroleum and are known as coal-tar dyes - Exempt from certification (natural) = obtained largely from mineral, plant or animal sources

Question 30

Flavor

Answer 30

That property of a food or beverage that causes the simultaneous reaction of taste on the tongue and odor in the olfactory center of the nose - Aroma (odor, smell) - Taste (sweet, sour, bitter, salty, savory) - Chemical irritation (pungency)

Question 31

Flavor agents

Answer 31

Substance added to foods that evoke the simultaneous responses of taste on the tongue and odor in the olfactory center of the nose

Question 32

Uses of flavoring agents

Answer 32

- Impart, augment, compliment, or modify a flavor - Mask original flavor - Antioxidant agents - Anti-microbial agents

Question 33

Antioxidants

Answer 33

- Protect against oxidative deterioration of vitamins and essential fatty acids - Retard off-odors and extend shelf life - Retard production of toxic by-products

Question 34

Oxidation

Answer 34

- Can decrease the nutritional values of food - Oxidation of unsaturated fatty acids produces rancidity - Sources = heat (cooking), metals, oxygen exposure, light exposure (transparent packaging), storage

Question 35

What makes a good food antioxidant?

Answer 35

- Active at low concentrations - Non-toxic - Able to partition interfaces (oil/water) - Stable during processing and storage conditions - Low cost - Doesn't affect flavor, odor, color

Question 36

Classes of food antioxidants

Answer 36

- Synthetic | - Natural