Effects of Food Processing on the Nutrients in Foods

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Effects of Food Processing on the Nutrients in
Foods
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• Many consumers rely on packaged and processed
  foods for convenience and speed
• Lose control over what foods contain
• Food processing involves trade-offs
• Makes food safer, or gives food a longer useable
  lifetime, or cuts preparation time
• At cost of some vitamin and mineral losses

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• Most forms of processing aim to extend the usable
  life of a food
• To preserve a food, a process must prevent three
  kinds of events
• Microbial growth
• Oxidative changes
• Enzymatic destruction

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Canning

• A method of preserving food by killing all
  microorganisms present in the food and then
  sealing out air
• The food, container, and lid are heated until
  sterile
• As the food cools, the lid makes an airtight
  seal, preventing contamination

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Do Canned FoodsLose Nutrients?

• Fat-soluble vitamins and most minerals are
  relatively stable
• Not affected much by canning
• Three vulnerable water-soluble vitamins
• Thiamin
• Riboflavin
• Vitamin C

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Do Canned FoodsLose Nutrients?

• Some minerals are added when foods are canned
• Important in this respect is sodium chloride,
  salt, which is added for flavoring

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Freezing

• A method of preserving food by lowering the
  foods temperature to a point that halts life
  processes
• Microorganisms do not die but remain dormant
  until the food is thawed
• Dramatically slows enzymatic reactions

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Freezing

• Frozen foods may have a nutrient advantage over
  fresh
• Fresh foods are often harvested unripe
• Frozen foods are first allowed to ripen in the
  field
• Allows the food to develop nutrients to their
  fullest potential

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Drying

• A method of preserving food by removing
  sufficient water from the food to inhibit
  microbial growth
• Eliminates microbial spoilage
• Microbes need water to grow
• Reduces the weight and volume of foods
• Foods are mostly water

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Drying

• Commercial drying does not cause major nutrient
  losses
• Foods dried in heated oven at home may sustain
  dramatic nutrient losses
• Vacuum puff drying and freeze drying
• Take place at cold temperatures
• Conserve nutrients especially well

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Extrusion

• A process by which the form of a food is changed
• Such as changing corn to corn chips
• Not a preservation measure
• In this process, the food is heated, ground, and
  pushed through various kinds of screens to yield
  different shapes

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• Results in considerable nutrient losses
• Nutrients are usually added to compensate
• Foods this far removed from the original state
  are still lacking significant nutrients (notably
  vitamin E) and fiber

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Food Additives

• Substances that are added to foods but are
  normally not consumed by themselves as foods

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Food Additives

• Compared with unregulated and untested dietary
  supplements sold directly to consumers, the
  3,000 food additives in the U.S. are strictly
  controlled and pose little cause for concern

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• Manufacturers use food additives to give foods
  desirable characteristics
• Color
• Flavor
• Texture
• Stability
• Enhanced nutrient composition
• Resistance to spoilage

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Regulations Governing Additives

• The FDA has the responsibility for deciding what
  additives shall be in foods
• To obtain permission to use a new additive in
  food products, a manufacturer must test the
  additive and satisfy the FDA that
• It is effective
• It can be detected and measured in the final food
  product
• It Is safe for consumption

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The GRAS List

• Many substances were exempted from complying with
  the FDA procedure when it was first instituted
  because they had been used for a long time and
  their use entailed no known hazards
• Some 700 substances were all put on the generally
  recognized as safe (GRAS) list

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Additives must not be used

• In quantities larger than those necessary to
  achieve the needed effects
• To disguise faulty or inferior products
• To deceive the consumer
• Where they significantly destroy nutrients
• Where their effects can be achieved by
  economical, sound manufacturing processes

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Antimicrobial Agents

• Preservatives that protect food from the growth
  of microbes that can spoil the food and cause
  foodborne illnesses

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Antimicrobial Agents

• Salt and Sugar
• The best-known and most widely used antimicrobial
  substances
• Salt is used to preserve meat and fish
• Sugar preserves jams, jellies, ad canned and
  frozen fruits
• Both work by withdrawing water from the food
• Microbes cannot grow without water

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Antimicrobial Agents

• Nitrites
• Added to meats and meat products to
• Preserve their color
• Enhance their flavor
• Protect against bacterial growth

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How Do AntioxidantsProtect Food?

• Food can go bad when it undergoes changes in
  color and flavor caused by exposure to oxygen in
  the air (oxidation)
• Often these changes involve little hazard to
  health
• But they damage the foods appearance, taste, and
  nutritional quality
• Antioxidant preservatives protect food from this
  kind of spoilage

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• Examples of common antioxidant additives
• Vitamin C
• Vitamin E (tocopherol)
• Sulfites
• BHA and BHT

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• Sulfites
• Prevent oxidation in many processed foods,
  alcoholic beverages, and drugs
• Were used to keep raw fruits and vegetables in
  salad bars looking fresh
• Practice was banned after a few people
  experienced dangerous allergic reactions to the
  sulfites
• FDA now prohibits sulfite use on food meant to be
  eaten raw
• With the exception of grapes

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• BHA and BHT
• Prevent rancidity in baked goods and snack foods

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Artificial Colors
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• Only about 10 of an original 80 synthetic color
  additives are still on the GRAS list
• Among the most intensively investigated of all
  additives, artificial colors are much better
  known than the natural pigments of plants

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• Food colorants only make foods pretty
• Other additives, such as preservatives, make
  foods safe
• With food colors we can afford to require that
  their use entail no risk
• With other food additives, we must weigh the
  risks of using them against the risks of not
  using them

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• Close to 2,000 artificial flavors and enhancers
  are approved
• Safety evaluation of flavoring agents is
  problematic because so many are already in use
• The flavors are strong and are used in tiny
  amounts unlikely to impose risks
• And they occur naturally in a wide variety of
  foods

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Incidental Food Additives

• Are really contaminants from some phase of
  production, processing, packaging, or consumer
  preparation
• Include tiny bits of plastic, glass, paper, tin
  and the like from packages and chemicals from
  processing, such as solvents used to decaffeinate
  some coffees

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Nutrient Additives

• Include
• Enrichment nutrients added to refined grains
• Iodine added to salt
• Vitamins A and D added to dairy products
• Nutrients used to fortify breakfast cereals

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• REMEMBER
• The more heavily processed foods are the less
  nutritious they become