Transcript Food Science

Food Science
Ag Processing Technology
Unit 1
Agriscience: Fundamentals and
Applications Unit 33
Objective
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To explore the nutrient requirements for
human health and the processes used in
food science to ensure an adequate and
wholesome food supply
Introduction
Food: a material containing or consisting
of carbohydrates, fats, proteins, and
supplementary substances such as
minerals
 This unit is to explores the foods that
humans need to maintain health and
sustain growth and how those foods reach
our tables from their beginings as raw
products
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Reading Assingment
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Read p. 639-643 (Stop at Food Customs of
Major World Populations)
Food Customs of Major World
Populations
Availability of food and technology to
prepare that food dictates eating habits
 What are the eating habits of these major
world populations
 Asia
 Mexico
 United States
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Methods of Processing, Preserving and
Storing Food
Oldest ways are fermenting and pickling
 Controlled fermentation is used to produce
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Cheese, wines, beers, vinegars, pickles,
sauerkraut
Primary Objective of Processing and
Preserving
Change raw commodities into stable forms
 Due to refrigeration and various
processing techniques we now expect
almost all foods to be available at any
time during the year
 But do they always taste as good?
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Slowing Deterioration
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Tomatoes and cucumbers that will be sold raw are waxed to
retard shriveling while they are in the grocery store
Apples are treated with decay inhibitor
Grapes are fumigated with sulfur dioxide to control mold
Silos where grain is stored are purged with 60% carbon
dioxide to control insects
Carbon dioxide inhibits the growth of bacteria and is used
in the process of controllled atmosphere, an example is the
preservation of lettuce—it is transported in a controlled
atmosphere to keep the edges from turning brown
Humidity should also be controlled for optimum storage
Other Ways of Slowing Deterioration
Refrigeration
 Blanching
 Canning
 Dehydration
 Freeze-drying
 Oxidative deterioration
 Dehydrofreezing
 Irradiation
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Packaging That Can Improve Shelf Life
Cardboard Boxes
 Molded Pulp trays to prevent bruising
 Plastic wraps
 Retortable pouches provide protection
from light, heat, mouisture and oxygen
transfer
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Flexible, consist of two layers of film with a
layer of foil between them
Benefits—increased shelf life (1-2 years)
Potatoes
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Potatoes are offered up to us in a variety
of ways
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Raw
Fried
Frozen
Cooked & canned
Dehydrated
We are going to dehydrate our own
potatoes and then compare them (taste,
texture, look, etc) to raw, fried, frozen and
cooked & canned potatoes.
Food Additives to Enhance Sales of
Food Commodities
Processing may reduce the natural
nutritional value of the product
 To compensate for that loss vitamins and
minerals are added back in to restore
nutritional value
 Sugar is the most widely used food
additive.
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Reading Assingment
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Read Food Preparation Techniques
Food Products From
Crops
Food Products from Crops
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Food from plants help meet body
requirements for food in four of the five
food groups
Fruits, Vegetables, Nuts
Nearly ready to eat at harvest
 Processing can be as simple as picking,
washing and eating or the foods may take
a journey through many processes
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Cereal Grains
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Compose the major diet of the world
Economical to process because they can be left
on the plant until nearly dry
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However, each year much of the worlds food grain is lost
due to rotting in the field, improper storage, birds,
insects and rodents
WHY????
Grain processing means separating or milling the
grain in to its basic parts- hulls, bran, flour and
germ
These components are then used to make cereal,
bread, pasteries, pasta and thousands of other
products
Oil Crops
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Soybeans, cottonseed, peanuts, rape, palm nuts, coconuts,
olives and corn are all rich in vegetable oils
 These oils are used for cooking, frying, baking, and for
other food products such as dressings, coffee creamers,
shortening
 Also used to make industrial products such as paints,
laquers and plastics
Seeds, nuts and other oil rich parts are crushed or ground
and heated
The oil is extracted by solvents and purified for food and
industrial uses
The meal is dried and ground and used for livestock feed
See fig. 33-15 on p. 651
Food Products From
Animals
Food Products From Animals
Meats
 Fish
 Poultry
 Dairy
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Dairy Products
37% of milk consumed in the US is in the
fluid form
 Remainder is used to make cheese, butter,
frozen foods, dried whole milk, cottage
cheese, evaporated milk and condensed
milk
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Milk and Milk Products
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Major componenets
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Water
Fat
Protein
Sugar
minerals
Milk and Milk Components: Water
Makes up 88% of fluid milk
 Water is the carrier for disolved,
suspended and emulsified components
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Milk and Milk Componenets: Protein
Milk provides a substantial portion
 Predominante protein: casein
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Casein is found only in milk
Makes up about 82% of the milk protein
Exsists in suspended form and is easily
coagulated by the action of acids and enzymes
High quality
 Contain all the essential amino acids in
proper balance for good nutrition
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Milk and Milk Components: Milk Fat
Concentrated sources of energy
 Many different fats that give milk its
distinctive, pleasing flavor
 High in fat soluable vitamins- A,D, E, K
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Milk and Milk Components: Lactose
Major carb of milk
 Makes up ½ the nonfat solids in milk
 Relative sweetening power of lactose is
about 1/6th that of sucrose (common table
sugar)
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Milk and Milk Components: Minerals
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Contains 7 major minerals and several in
minor and trace amounts
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Calcium and phosphorus
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Essential to human nutrition for building bones and
certain metabolic processes
Milk is the chief source of calcium in the diet in the
US
Phosporus is contained in the same biological
relationship to calcium as occurs in the growing
skeleton
Recommended daily amounts of dietary calcium can
not be met without using milk
Milk and Milk Components: Vitamins
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All vitamins required by humans are found in milk
Some are fat soluable and are associated with butterfat,
those that are water soluable are found in the non-fat
portion of milk
Vitamin A and carotene are present in high concentrations
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Vitamin D content of fresh milk is low
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Carotene gives milk its color
Commercially pasteurized milk is fortified with Vitamin D to
balance the product for optimum nutrition
Abundant source of riboflavin (Vitamin B2)
Important source of niacin because it is in fully available
form
Significant amount of thiamine (Vitamin B1), biotin, vitamin
B12, folic acid, choline
Processed Milk Products
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Fluid milk
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sold pasteurized for safety and homogenized to keep
the milk fat in suspension
Whole milk is sold with 3.5% milk fat
2%, 1% and non-fat (skim) milk are also available
Fortified (A & D) milk is also sold
Cream
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Component of milk that contains up to 40% butterfat
Butter is made from cream
Made by concentrating the fat portion of the milk by
running it through a seperator
Whipping cream is 40% fat, table cream 18-20%, Half
and Half approx. 12%
Processed Milk Products
Ice cream, ice milk and sherbet
 Nonfat dried milk
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Used for humans and animals
Often used in dairy and other food products
Cheese
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Made by exposing milk to certain bacterial
functions or by exposing it to enzymes
Both methods coagulate some of the proteins
found in milk
Many types and varieties of cheese
Processed Milk Products
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Cottage Cheese
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Made from skimmed milk
Condensed and evaporated milk
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Both are canned
Produced by removing large portions of water
from whole milk using a vacuum pan
Condensed milk is further treated by adding
sugar
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This makes condensed milk important to the baking
and ice cream industries
Meat Products
Beef
 Lamb
 Pork
 Poultry
 Fish
 Game
 All are processed by slaughtering the
animal and then dressing the animal for
market purposes
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Beef Slaughtering Process
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Render the animal insensible
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This is done to comply with the Humane Slaughter Act of 1958
Several methods of accomplishing this
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Single blow
Gunshot
Electrical current
Carbon dioxide gas
After the animal is insensible to pain it is shackled, hoisted
and stuck in a large artery to permit bleeding
The head may also be removed during or following the
bleeding
Removal of the hide is next. It is cut open at the midline of
the belly and a mechanical hide puller pulls the hide off in
one piece.
The Breast and rump bones are also split at this time by
sawing
Beef Slaughtering Process
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All the internal organs or viscera are
removed, except for the kidneys
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All USDA regulated plants must inspect the
carcass and the viscera to confirm good health
Next the hide is split down the center of
the backbone and washed with warm
water
 The carcasses are then shrouded and
cooled for a minimum of 24 hours before
the carcass is ribbed and further
processed
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Aging Beef
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To age or ripen means to leave the carcass
undistrubed for a period of time while the beef
cools.
Fresh beef is not in its most tender state
immediately following slaughter so aging allows
the natural biological changes to occur that
change muscle to meat
3 methods of aging
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Traditonal
Fast
Vacuum Packaging
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Time, temperture and technology help define these three
methods
Selling Beef
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Sold in three ways
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Block beef
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Fabricated boxed beef
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Shipped in exposed halves, quarters or wholesale cuts to
be cut into retail cuts at the supermarket
Meat is ready for sale over the “block” or counter
This method creates concern over sanitation, shrinkage,
spoilage and discoloration
Carcass is divided into smaller cuts, vacuum sealed, boxed,
moved into storage and shipped to retailers
Processed meats
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Scraps that are not suitable for sale over the block.
These meats have the bones removed and are sold as
boneless cuts. They are also canned, made into sausage,
dried or smoked.
Sheep
Rendered insensible and bled
 Front feet, pelt, head, hind feet are
removed
 Carcass is opened and eviserated
 Because a lamb carcass is small the front
legs are folded at the knees and held with
a skewer
 Washed and cooling procedures are similar
to those used with beef
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Hogs
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Rendered insenible
Shackled and hoisted and bled
Carcass is then plunged into 150 degree water for 4
minutes to loosen the hair
The carcass is then dehaired by a dehairing machine
The hog is then returned to the rail where it is washed and
singed and the head is removed
Next the carcass is opened, eviscerated and split
Leaf fat is removed
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Leaf fat is the fat inside the body
It is used to make lard which is used in cooking and baking
Kidneys and facing hams are inspected
Carcass is sent to a 34 degree cooler
Poultry
Bird is secured to a conveyor belt and bled
 Next the animal is scalded and then
picked
 After picking the bird is singed to remove
the fine hairs that cover the bird under the
feathers
 Bird is washed, eviscerated and the giblets
are cleaned
 Bird is then cooled to 40 degrees usually
with ice
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Fish
Processing procedure depends on the type
of fish
 Evisceration, scaling and head removal
along with washing and cooling all occur
 Process really depends on how the fish is
to be consumed
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Tuna can be left whole or cut up and processed
Shell fish like crab and lobster are kept alive
until cooking
Game
Processing begins in the field
 Same basic processing procedure is
followed
 Most are processed by hunters or small
hometown lockers instead of big
processing plants
 Large game is processed in a fashion
similar to cattle
 Fowl are dressed in a fashion similar to
poultry
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Kosher Slaughter
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Kosher: right and proper
Based on the religious ritual of the Jewish faith
Animals must be killed by a rabbi or specially
trained repersenative
Methods and time by which the meat must be
sold are based on ritual that relates to concern
for sanitation
Meat must be consumed quickly and neither
packers or retailers can hold kosher meat for
more than 216 hours (9 days)
Washing of the meat is required every 72 hours
Major Cuts of Meat
Different areas of the animal are useful for
different purposes
 See fig 33-22, 33-23, 33-24
 Quizzes
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Learn the Major cuts of meat for beef, pork
and lamb
Use the worksheets and this book to help you
study
Quiz 1 will be on the beef on January 30
Quiz 2 will be on the lamb on February 6
Quiz 3 will be on the pork on February 13
By-Products
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All parts of the animal are not edible
Dressing percentage is a term used to indcate the
percentage or yeild of hot carcass weight to the
weight of the animal on foot
Offal is removed from the live animal to arrive
that the dressing percentage
Formula: hot carcass weight divided by the live
weight of the animal
For example: HCW= 900 lbs LW= 1500
900/1500= 0.6 or 60% DP
What happens to the offal?XXXX
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Accounts for many products that are used daily and can be
divided into 12 categories
Hides
Fats
Variety Meats
Hair
Horns and Hooves
Blood
Meat Scraps
Bones
Intestines and Bladders
Glands
Collagen
Contents of Stomach
Hides
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Leather products
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Shoes
Harnesses
Saddles
Belts
Clothes
Sporting Equipment
Hats
Gloves
Fats
Oleomargarien
 Soaps
 Animal feeds
 Lubricants
 Leather dressing
 Candles
 fertilizers
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Variety Meats
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Heart, liver, brains, kidneys, tongue,
cheek meat, tail, feet, sweetbreads
(thymus and pancreatic glands), tripe
(pickled rumen) are sold over the counter
as variety or fancy meats
Hair
Artists brushed
 Toothbrushes
 Paint brushes
 Mattresses
 Upholstery
 Air filters
 Baseball mits
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Horns and Hooves
Carving medium
 Fashioned into decorative knives, umbrella
handles, goblets, combs and buttons
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Blood
Used in refining sugar
 Stock feed
 Shoe polish
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Meat Scraps and Muscle Tissue
Meat meal
 Tankage
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Dried animal residue used in feed and fertilizer
Bones
Some put the same uses as horns and
hooves
 Stock feed
 Fertilizer
 Glue
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Intestines and Bladders
Sausage
 Lard
 Cheese
 Snuff
 Strings for musical instruments
 Tennis rackets
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Glands
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Medical drugs
Collagen
Glues
 Gelatin
 Used in various forms in the industries of
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Furniture
Photography
Medical
Baking
Stomach Contents
Feed
 Fertilizers
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New Food Products on the Horizon
New foods and new versions of familiar
things arrive daily
 Scientist and technology are striving to
make what we eat better for us and also
working to keep food cost low
 Convenience foods are on the rise and will
continue to become more important to us
in the future
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