Food Preservation Matters

The Chemistry Behind Home Food Preservation



By: Ms. Jessica,  Mr. Mike, and Ms. Lesley's 5th Grade 

December 2013


Written and Illustrated By: Two Rivers Public Charter School, 5th Grade 1

December 2013

The Problem

Cecile Jordan 

           Too many families are losing money due to wasting 25% of the food and beverages they buy a year.  Each year a four -person family would lose $2,200 to wasted food, yet they throw away food anyway.

            One way to preserve food is curing.  Curing is when you add salt to food.  The salt draws water and moisture towards itself and absorbs the water and moisture.  When you press hard on meat you will see that moisture comes out.  Curing is an example of dehydration.  Dehydrated food can last months.

            There are other methods, like canning, freezing, refrigeration, and natural preservatives, such as lemon juice.

            As you can see, food preservation would help people save money and food. It’s easy.



The States of Matter and How They Change

Alex Suggs 

     Chemistry is the study of matter and how it changes depending on temperature.  Matter is anything that takes up space and has mass.  There are four states of matter, which are solids, liquids, gasses, plasma.  Solids have a defined shape and only change when exposed to heat above 32 degrees Fahrenheit. Liquids have no defined shape and take the shape of any container they are put in.  They only boil at 212 degrees Fahrenheit.  When gases are hot and contained, they will take up space and won’t stop.  Plasma is the state of matter that has the least known about it but one thing is for sure… Plasma is really, really hot!

     The states of matter can also change based on temperature. If you lower the temperature of a gas it will turn to a liquid.  If you lower the temperature of a liquid it will turn to a solid.  But there is nothing after a solid… or is there? 


Physical and Chemical Changes in Food 

Ali Porchia 


      Chemical and physical changes happen when you prepare food.

       You know a chemical change is happening when you add heat and the results are color change or ash. The molecule of the item also changes. In food, chemical changes can’t be reversed. One example of a chemical change is when you cook grilled cheese sandwiches. When you add heat, the bread goes through a chemical change. You know when it goes through a chemical change because the bread changed color by blackening. Furthermore, you can not reverse the grilled cheese to bread, butter, and the solid cheese you had before.

       When you prepare food, it can also go through a physical change. You know a physical change is happening when motion, pressure, and temperature have been added to a substance. The results are a change in the state of matter or the molecules of the item splitting up into pieces. Physical changes can be reversed. One example of a physical change is when you make a salad. When you cut the lettuce, the lettuce goes through a physical change. You know it goes through a physical change because the lettuce has been split up into pieces by pressure. Furthermore, you can put the lettuce back to how it was before.

       As you can see, preparing food is a prime example of physical and chemical changes.



What is Chemistry?

Angel Silvers 

       Chemistry is the study of matter and how it changes. It impacts everyone’s life. Matter is anything that has mass takes up space. Products that are made of matter include laptops, clothes, and soda bottles. Materials that are not made of matter, heat, and energy. Most of the items we use in our daily life are created by chemistry.

         Chemistry impacts our life in many ways. For example, chocolate, Jell-o, sticky notes, and pencils and pencil lead. Pencil lead is made using chemistry. Pencils are a product we use everyday for writing in school and at work. According to the American Chemical Society, “Graphite and clay are crushed into fine powder in a rotating drum containing large rocks. These pencils are heated at a temperature of 1,800 degrees.” These are called chemical and physical changes. A chemical change is when the molecules of matter change. A physical change is when the state, size, or shape of an object changes without the molecules changing. When the pencils were heated to a temperature of 1800 degrees a physical change happened. Other products created by chemistry that impact our lives are chocolate, Jell-o, and even sticky notes. As you can see, chemistry has a big impact on our daily lives. 

Using Lemon Juice to Preserve

The Chemistry of Preserving with Lemon Juice

Ali Abdul-Hakim


          Preserving foods can be really easy with common household items. Acids, sugars, honey, syrup, lemon juice, and salt are common food ingredients for preservation. Although all of these ingredients work well, lemons are the best ingredient for home food preservation.

            When you taste a lemon, it is really sour. The sour taste is the acid that helps preserve your food. Lemon juice is highly acidic. When food spoils, it is because oxygen causes enzymes to start a reaction. This process is called oxidation. You know food has spoiled when you see color changes. The acid in lemons slows down the enzyme reaction and breaks down bacteria. Your lemon juice will stop the browning and make your food last longer.

            Preserving with lemons is very simple.  Get a lemon that is really ripe. Cut the lemon in half. After that get one of the halves and squeeze it on the food you want to preserve. The lemon will last for about twenty minutes. 

Fruit Salad with Lemon

Jalynn Roberts


            When you put lemon juice on foods it makes the food last longer. Lemon juice will really work on white foods and fruits like apples and bananas. The trick to using lemon juice is to put it on when you first cut up the fruit. Here is a recipe that uses lemon to preserve a fruit salad!



  • ½ cup of sugar
  • 1 lemon
  • 1 cup of sliced apples
  • 1 cup of sliced oranges
  • 1 cup of sliced strawberries
  • 1 cup of grapes


First, get a cutting board and slice the fruit.

Next, put the cut up fruit in a big bowl and pour the sugar in the bowl.

Then, cut one lemon in half and squeeze it on the fruit.

Finally, mix the fruit up and Enjoy! 

Freezing and Refrigerating Foods 

How to Refrigerate and Freeze Foods Like a Pro

Nyah Barrett 


        Refrigerating and freezing food is easy to do and make many foods last longer.  The temperature of you refrigerator should be 40 degrees Fahrenheit or below and the freezer should be at 0 degrees Fahrenheit or below.  Refrigerating cooked meat or poultry should last three to four days, while lunch meats and egg, tuna, or macaroni salads may last three to days.  Store foods in the best fitting, shallow containers.  Glass storage containers have some benefits.  It is easy to check the contents, they may be microwavable, and they are more eco-friendly. 

          When freezing food keep food in airtight packages to prevent freezer burn.  Freezer burn degrades the quality of your food.  You should learn how to wrap your meat like a pro for freezing.  Use good quality freezer paper, fold the paper over the meat, and crease.  Then continue folding and pressing the air out.

          If you freeze and refrigerate food you can save money and your food will last longer. 


Chemistry of Freezing 

Quinton Tobler-Cunningham 


      When you freeze food chemistry is involved.

      Food goes bad because of enzymes and microorganisms. Enzymes are in most of the food we eat. When you cut food, enzymes react with oxygen in the air. This is a chemical change. Another reason food could go bad is because microorganisms grow on them. Microorganisms grow when food is exposed to air or moisture. Temperature can also cause the growth of microorganisms on food. Between 40 degrees and 140 degrees farhenheit miro-organisms grow best.

     Using the freezer can slow these problems. A freezer changes the texture of food by making it harder. When you put food in the freezer the temperature is lower than if left out at room temperature or in the fridge. Therefore, the food undergoes a physical change. The reason you put food in the freezer is to preserve it. The freezer slows the growth of microorganisms because freezers usually have a temperature between 320 and -100f. At these temperatures most microorganisms stop growing, although some still grow.

     As you can see there is a physical change when you freeze foods. An understanding of this chemistry can teach you about freezing foods. 


Pros and Cons of Freezing Food

Beydi Castro


            Have you ever wondered what you could do with all of the food you throw away? You should try to freeze the food! There are more pros than cons when freezing food. Frozen food lasts longer than fresh food. You can use a variety of materials when packaging food to freeze, and the materials are cheap and easy to find. The packing containers are re-usable and easy to stack, so the frozen food does not take up much room in your freezer.

            When fresh food is spoiling, you will have to throw it away and that will be a waste of your money. If you freeze food, it will last longer and you will not be wasting money. There are many materials, like freezer bags, flexible bags, and collapsible cover boxes that you can use to package fresh food before freezing. You can find these materials in any grocery store. Many people don’t have a lot of money so it is a good option for them. Many people also don’t have a lot of extra space to store large or specialized equipment, but everyone has a freezer!

            There are some negatives to freezing food like freezer burn and bad odors. It is negative because it it can make the food and freezer smell bad. Freezer burn could make the food feel and taste different. Another negative is that you can only use certain materials for long term storage. Some people might not have those materials for long-term storage. They also might be more expensive and hard to find.

            There are some cons to freezing like freezer burn and bad odors, but I still believe there are more positives than negatives when it comes to freezing food. 

Seasoned, Breaded Porkchops 

Ashley Jenkins 

         When you freeze food, it lasts longer than food that is not frozen. Many people buy big package of meat when they are on sale. Sometimes they cant use all of it and it goes bad and gets thrown away. If you pat meat in a Ziploc bag, press all the air out of the bag and seal the bag. You can store it in the freezer for up to 6 weeks. Here is a recipe you could use if you buy a big package of pork chops!



  • 4 large eggs
  • 1 tablespoon and 2 teaspoons of Dijon Mustard
  • 1 tablespoon and 2 teaspoons of finely chopped fresh sage
  • 8 tablespoons unsalted butter, melted
  • ¼ cups vegetable oil


         Put eggs, mustard, and sage in a medium bowl. Mix it together and let set for 15 minutes. Spread breadcrumbs on the rim of a baking sheet and season the porkchop with salt and black pepper. Then, pour the egg mixture onto the rim of a baking sheet. Put the seasoning, pepper, and egg mixture on the porkchop.

        Next, layer the porkchops between sheets of freezer paper and transfer to two 1 gallon freezer bags. Press out or seal bag and freeze flat. Store in the freezer for up to six weeks.                When you want to reheat porkchops you have to place a baking sheet under the broiler to heat it up. Use 1 ½ tablespoons of melted butter and 1 ½ teaspoons of oil to brush both sides. Put the porkchops on a baking sheet until both sides are brown. flip in 10-15 minutes. 

Dehydrating Foods 

How to Dehydrate Fruits, Vegetables, and Other Foods Using Heat  

Vanilla Murray

        Drying or dehydrating food is easy to do at home. There are many ways you can dehydrate your food. For example, you could dry in the sun, dry over a campfire, dry in the oven, or dry in a microwave.

         First, you will need to rinse whatever fruit, vegetable, or other food you want to dehydrate. If you don’t know what you can dehydrate then search for it on the web.

         Next, slice the fruit, vegetable, or other food into long strips. Let a parent do the slicing.

         Then, add heat to your fruit, vegetable, or other food.

         Finally, enjoy your dehydrated fruits, vegetables, or other foods.




Helpful Tip


4-5 hours

Leave the door open a few inches while drying


2-3 hours

Don’t go over the time


1-2 minutes, add ½-1 minute if it does not look done

Only add the time if the food doesn’t look dehydrated

Sun Dry

Several Hours

Check every hour until dry

Camp Fire

Leave until dry (2-3 hours)

Don’t put too close to flame



Chemistry of Dehydrating with Heat 

Londyn Griggs 

        Chemistry is involved within the steps of dehydrating food. Chemistry is the study of matter and how it changes. Everything is made of matter, even food! If food is changed it would be chemistry. There are two types of changes matter undergoes, chemical and physical.

         Heat is the main factor in the dehydration process. That heat can come from a dehydrator, oven, the sun, or fire. For example, apple chips are crispy. At first the apple is soft, but when put in to the oven the heat evaporates and the moisture and water out of the apple. It makes the food dry. This would be a chemical change.

         Dehydration can also be used for meat. Beef or ham can spoil very easily because the enzymes in the flesh react with air and often frown mold. When the meat is dehydrated the moisture is taken out so it can be preserved longer.

         Heat is the main factor in dehydrating food. Dehydration is a chemical change because molecules can’t changed back once the change has occurred. Therefore, an understanding of chemistry can really help you be an expert at dehydrating. 



Chemistry of Dehydrating with Salt

Clayton Wrinn 


            There is chemistry involves in salting to dehydrate food. Let’s say you sprinkle salt on an apple, the salt absorbs the moisture and leaves the apple with no tears, and lots of salt.

         When the salt sucks the moisture, it changes the amount of water molecules and creates a chemical change. A chemical change is when there is a change in the molecular structure of a substance.

         Also, when you salt food it changes the chance of micro-organisms and yeast. This is true because micro-organisms and yeast need water and moisture to grow. Therefore, when you sprinkle salt on your food, you are preventing the growth of micro-organisms and yeast, thus you are preserving your food.

         As you can see, there is chemistry involved in salting to dehydrate your foods.


Pros and Cons of Dehydration

Marcus Butler


            There are more pros and cons when you dehydrate foods. When foods are dehydrated they get preserved, which means that the foods go through the process of changing chemical and physical properties in order to prevent the growth of micro-organisms. When foods are preserved, they have a longer shelf life than fresh foods.

            Dehydrated foods also have low levels of moisture because the water molecules in the foods evaporate. Dehydrated foods do not spoil easily, because there isn’t any water and the water cant react to the enzymes found inside of most fresh food. Dehydrated foods are also very lightweight, since there isn’t any moisture.

            Some of the cons of dehydrating foods are that foods sometimes need water to prepare. Another con is that some foods loose taste after reconstitution. The last con is that the dehydration process can affect nutritional value by evaporating the nutrients.

            The reason why the pros out weigh the cons is because sometimes people need water to prepare the foods, but people have easy access to water. Also the foods sometimes loose their taste, but the food is still healthy. Finally, the dehydration process can affect the nutritional value of the food, but people can just drink water with the food and supplement with other healthy foods.

            As you can see, there are more pros than cons when you use the food preservation method of dehydrating. 

Smoked, Cured Salmon

Braxton Crumpton

         Curing makes food last longer. When you cure meat, you use salt and/or sugar. Salt and sugar take the moisture out of the meat and make the microorganisms stop growing or make them grow slower. Curing is a chemical change because the color of the food changes and the change can not be reversed. Raw salmon is pinkish/brownish and cured salmon is dark pinkish brownish. The cured salmon can’t be reversed, because you can’t make dehydrated salmon back into raw salmon. Don’t forget to read the recipe below so you can make your very own smoked salmon.



  • Fresh salmon (at least 1 pound, cut into 2 equal pieces)
  • ¼ cup of brown sugar (per pound of fish)
  • 2 tablespoons Kosher salt
  • 1 tablespoon of smoked salt (per pound of fish)
  • 1 tablespoon of fresh cracked black pepper (per pound of fish)



  • 1 large glass bowl
  • 1 small glass bowl
  • 1 large dinner plate
  • plastic wrap
  • knife
  • needle pliers (potentially)

 Combine Salt Cure Ingredients

         First, start by combining the two salts, pepper, and sugar in a small bowl. Combine thoroughly and make sure that the sugar is evenly distributed amongst the salt granules.


Check for Pin Bones

         Even if your nearest butcher should have the bones and the scales off, it doesn’t mean there won’t be more left. Feel your fish to see if it still has bones or if they are all gone. Use tweezers to remove any stragglers.


Lay out Plastic

         Lay out two lengths of salmon side by side and slightly intersecting on your countertop, about three feet in length. You will want to cover the fish completely with the salt and sugar mixture. The goal is to be able to flip the two pieces on top of each other while they rest. Leave an inch between and don’t worry about applying the mixture to the skin side.

         Now, fold the fish on top of each other. Wrap the fish in plastic wrap and keep the salt and sugar in. Don’t wrap it too tight.

         Take a big glass bowl and put the small glass bowl upside down in the center of the big glass bowl. Put the fish on the small bowl. To put pressure on the fish, put a plate on the fish. Put more plastic wrap on the large bowl so your fridge won’t smell like fish.


         You have to put your fish in the fridge for 5 days. Everyday you flip the fish and replace the plate. After 5 days are over then you take the salt and sugar out of the skin and flesh.

         Use your longest blade to cute the layers of your fish. Eat with eggs, bagels, cucumber, or even plain. 

Canning Food 

How to Can Foods 

Kaliah Smith 


         Canning food should only be used by advanced food preservers because it has a lot of steps and it can be deadly. There are 12 steps, from examining the can to letting the jars cool. There is a risk of botulism, which is food poisoning, if you don’t can food correctly.

         First, check the jars, lids, and bands for cracks, nicks, and uneven edges. Then, clean the jars and fill a pot half full with hot water. Pick fresh fruits or vegetables and boil them. There are many fruits and vegetables, and even meat that you can can!

         After that, cut out the core of the fruit or vegetable. Then, put them into the jar and leave ½ of an inch of air at the top. Slide a non-metal spatula in between the jars to get out air bubbles. Next, clean edges and threads of the jar with a clean, damp cloth. Then, as each jar is fillet, set it onto the rack in the boiling water. Finally, when the processing time is done turn off the heat. Last, after jars have cooled check the lids for a seal by pressing on the center of the can.

Chemistry of Canning

Kaimyah Booker


            Canning food is a helpful thing to do. When canning, you kill harmful bacteria and seal the can or jar to prevent any new bacteria from getting inside the can or jar. It’s good to can, but you need to learn how to can properly. An understanding of chemistry can help you be an expert canner.

            When canning fruits or vegetables, you have to add some lemon juice, vinegar, or citric acid. Acid is needed in your fruit and vegetable recipes because it kills harmful bacteria that could make you sick. Make sure you add a good amount of acid to your recipe.

            All fruits and vegetables also have micro-organisms growing them. Micro-organisms wont harm us, but if you don’t check your fruits and vegetables for spoiling before canning them, the yeasts, molds, and bacteria will grow, change, and multiply to poisonous or even toxic levels.

            When the jar is cooling down to room temperature, the pressure inside the jar drops. The pressure outside the jar gets higher, which pushed the lid down. The seal is now forming. When you seal, no outside air can get inside to re-contaminate the food.

            As you can tell, canning is helpful to do. However, you need to have an understanding of chemistry, because it can help you become an expert canner. 


Why You Should Can Food at Home

Daniel Voss 

        Canning foods is a good idea. I say this because of various reasons. First of all, it is a good thing to do with family, and creates lifelong memories. Also, if you buy locally you can get good deals on the foods you will can. Canning also saves money because it causes the food to have a longer shelf life than regular foods and you wont need to throw them out since they wont spoil as quickly. You wont have to replace them, therefore saving money. Also, since you wont throw canned foods out, you will not pollute the world as much.

         You may or may not be thinking, “Why should I can my own foods when I can just pop down to the store and get a can of Spam?” Well, commercially canned foods, like Spam, are found to be high in salt and artificial chemicals, which have been found to contribute to the obesity epidemic, and other health problems later in life. If you can your own food, you can make sure that the ingredients are organic and healthy!

         Make a healthy and helpful choice today. Start canning food.

Cons of Canning Food 

Asia Elliot 


           Canning food is not easy. A lot of time is spent preparing and shopping. Also, you have to follow guide lines for canning food, or you could kill a while family in one meal.

            If you can food incorrectly, botulism can form. Botulism is a rare, and sometimes fatal, paralytic illness. It forms when canned foods are in an environment with no oxygen. Botulism can be prevented if the can has the correct amount of head space and heating.

            While artificial preservatives added during commercial canning may increase the shelf life of vegetables, they are not advisable for everyone. Another disadvantage of canned vegetables is that they tend to have lower nutritional value than fresh and frozen foods. Many canned foods also contain high levels of heavy syrup and sodium, which are not healthy to eat all of the time.

            As you can see, there are a lot of disadvantages to canning food. 

Chile Tomato Salsa Recipe

Ellen Curtis 


The United States grows 12,526,070 tons of tomatoes each year. Also of people buy tomatoes, and when they don’t use them they go bad. People should use the chile salsa recipe for their almost spoiled tomatoes so they can save money. Canning proves a shelf life typically ranging from one to five years. This chile salsa recipe is a good recipe to use when your tomatoes are about to go bad.



  • 5 lbs. tomatoes
  • 2 lbs. child peppers
  • 1 lb. onions
  • 1 cup vinegar



         Peel the child peppers to make tomato sauce. Clean the tomatoes very well and then dip them in boiling water for 30 to 60 seconds. Take the tomatoes out of the pot and place them in cold water. Remove the skin and cores. Dice tomatoes, onions, chili pepper and remaining ingredients and put them in a sauce pan. Cook until it boils and then let it simmer for 10 minutes. Fill your jars up and make sure you leave ½ inch of head space. Adjust the lids and boil for 15 minutes. 

You Have Options 

Kari Pelletiere


            Food preservation is worth your time.  When you throw away spoiled food, not only are you wasting money, but you are throwing away food that people have put a lot of work into growing and bringing to you.  In addition, the food that you waste goes in to a landfill.  The more food you throw away, the more landfills we create. This means that green spaces that could be a nice park, turn in to disgusting mounds of trash.

            One reason why you should preserve you food is that when you throw out spoiled food, you are wasting money.  “Americans waste up to 34 million tons of food per year, according to the environmental protection agency, tossing millions of dollars of food in the trash.”  This means that if you are throwing out food because it is spoiled you  might be adding to the millions of dollars of wasted food every year.  Food preservation is when your food goes through the process of changing the chemical and physical peroperties so that micro-organisms do not grow on the food. For example, lets say you go to the super market and you want to buy fresh blueberries that are usually $3.99 per pound.  If you buy the blueberries on sale, you may be able to get them at a price of 3 for $4.99. However, you might not be able to use them before they go bad. If you froze two and kept one to eat fresh, you would save about $2-$3.

            Another reason why you should use your time to preserve food is that you are making green spaces into landfills by wasting food you could preserve. Which would you rather have in your backyard, a stink, disgusting mound of trash or a lush, green park to come to on a beautiful, sunny day?

            We hope you look into preserving your food, remember you can save money, green spaces, time, and effort. You are also honoring the people that work to grow and bring your food to you. 


Ammar Mohamed, Parris Allen, and Jy'Quan Thompson 


Atom: The small building blocks of matter.  They are kinda like the legos you use to build a lego person.


Chemist: A scientist who studies chemistry.  Similar to how a mathematician who studies mathematics.


Chemistry: The study of matter and how it changes


Compound: A substance that is made up of two or more parts that can not be separated.


Electrons: One of the particles that make up an atom. They have a negative charge.


Element: Substances that cant possibly be broken down into anything simpler by a chemical reaction 

Energy: The force of power and energy made of power. It makes things work.


Heat: Heat makes molecules move faster.  Heat makes energy which causes the molecules to move faster.


Matter: Anything that has mass and takes up space


Molecule: Two or more atoms combined.


Nucleus: The center of an atom that contains protons and neutrons.


Neutron: a particle, similar to a proton, that is smaller than an atom. It has a neutral charge.


Physical Change: The size and shape of a substance but the molecules remain the same.  Temperature, motion, or pressure are used to change the molecules.


Proton: Small particles that are in an atom. They have a positive charge.


States of Matter: The forms of anything that is made of atoms. For example, solids, liquids, and gases are states of matter.