Study of preservation fruits methods and record of experiments on preservation fruits.
Preservation, "It means keeping perishable food in a consumable form for a certain period of time. Most food preservation practices are handed down from generation to generation and are derived from experience. Regardless of the scale of factory mass production, workshop-scale manual production, or ordinary households, the purpose of food preservation is to stop or slow down the propagation and activity of natural microorganisms or enzymes and to prevent food from spoiling." ( Grand Larousse(2021). Mi seon Kim (Ed.).Le Grand Larousse Gastronomique. Preservation. Citronmacaron )
Preservation methods include heat treatment such as 'heating and canning', saturation such as 'salting and addition of sugar', sterilization treatment such as 'addition of acids', and drying and addition of preservative. (Ryslett. K., personal communication,18th August)
Finished jam and pear canning
If we learn various food preservation methods based on this information, we can enjoy more flavors from one ingredient and longer. So today, I would like to tell you the detailed process of preventing oxidation of fruits, vegetables and berries and keeping them away from mold through some of the preservation methods introduced above, along with some tips and recipes.
Jam recipe
Raspberry jam
1kg raspberries
400-500 g of sugar
Jam preservatives
Approach
After washing the fruits to be made into jam, place them in a saucepan without water. Stir constantly to prevent sticking. When the fruit forms are crushed, add sugar and preservatives and stir until the moisture is evaporated and the jam consistency is achieved.
(Kriste, A. (1975). Fruit, berries and vegetables all year round. Oslo: Cappelen Forlag.)
Canning recipe
Sugar sauce
300-700 g of sugar
1 l of water
Canned pears
For 1 l glass
About 800 g reindeer pears
3-400 ml sugar sauce
Approach
-Sugar sauce : Heat the sugar and water until the sugar has dissolved, and let it boil for approx. 5 minutes. Foam if necessary.
-Canning : You need to peel and slice the fruit, but it is easy to brown during the process, so you need to put it in lemon water to prevent browning. Warm the berries or fruit carefully in the sugar sauce to 70-90 *C and the time that suits each type depending on how firm they are.
(Kriste, A. (1975). Fruit, berries and vegetables all year round. Oslo: Cappelen Forlag.)
Freshness
Before starting I like to say that the beginning of all this preservation process is to pick something fresh. If the condition of the food material is already poor before starting the preservation process, the preservation period will be significantly reduced. So, in my whole process, it starts with 'Choosing the fresh ingredients'. In the city of my hometown, Korea, it is not common to have a house with a yard where berries, fruits and vegetables are grown, so it is not as often as here to pick fruit and make jam or canning. That's why it's more meaningful to start by directly cultivating the ingredients in nature.
Picking the fruits from neighbor's yard : Photos by somin, Kim
Sterilization
Sterilization is a very important process that determines preservation failure. The purpose of sterilization is to remove bacteria and microbe with high temperature heat to keep them away from mold and to extend the preservation period. It is important that the temperature of the jar and lid is kept high until just before filling the jar. If you put it in the oven until right before use, you can fill the contents while it is hot. The temperature was about 220°C. ((Ryslett. K., personal communication,18th August) In addition, since the jar is in a vacuum state when the contents are filled and the lid is closed in a hot state, this also prevents the propagation of microorganisms.
: Photos by somin
Addition of sugar
Adding sugar in the process of making jam or canning is an important process that changes the fruit to a state to be able to preserve for a long time. If you use a preservative containing sugar here, you can make jam in good condition more easily. Usually, the amount of sugar is added at 40-50% of the total amount of fruit, and the amount of sugar can be adjusted within 10% according to the sweetness of the fruit. (Kriste, A. (1975). Fruit, berries and vegetables all year round. Oslo: Cappelen Forlag)
In canning, fruit is preserved by putting it in sugar syrup. Fruits boiled with sugar syrup are tossed with sugar at a high temperature, so microorganisms are removed, and at the same time, sugar saturation makes it possible to preserve for a long time. *JAM SYLTEPULVER 45G : sugar, gelling agent (pectin), preservative (sorbic acid), anti-caking agent (e341).
Adding sugar and preservatives
: Photos by somin, Kim
If the amount of sugar added is insufficient, the preservation period is shortened, so finding the right concentration increases the preservation period. After going through the process several times, when the jam has cooled slightly, the appropriate consistency is that the mark is left for a while when the bottom of the pot is scratched, In canning, the most appropriate time is when the fruit appears to have lost some moisture from the sugar syrup.
Check the finished status
: Photos by somin
Packing
One of the important preservation processes is to vacuum the can or bottle so that unnecessary microorganisms or bacteria do not breed until the lid is opened. And make sure to clear the mouth of the bottle so it doesn't interfere with the vacuum. (Ryslett. K., personal communication,18th August) It is best to fill the contents with as little air space as possible and use a funnel or tool that can cleanly put the contents.
And again, it should be noted that the packing process should be carried out while the bottle is warm so that it can be kept in a vacuum state after closing the lid. If there are many empty spaces other than those filled with contents, the vacuum cannot be maintained. After completing all the processes, if the lid does not make a sound and is not pressed when the lid is pressed, it can be confirmed that the vacuum is maintained.
Fill in the jar with tools : Photos by somin
If the lid is not opened after packing is complete, it can be stored at room temperature away from direct sunlight, but refrigeration after opening also helps to extend the shelf life.
Decorated finished products
As a side note, I made zucchini cakes and cookies and delivered them to two local residents who helped me pick fresh fruits with Kim. Making something to convey my gratitude was also very exciting and lovely. I hope they enjoyed our cakes.
Photo taken during gift delivery
Bibliography
-Grand Larousse(2021). Mi seon Kim (Ed.).Le Grand Larousse Gastronomique. Preservation . Citronmacaron
-Kriste, A. (1975). Fruit, berries and vegetables all year round. Oslo: Cappelen Forlag
-Matleveranser(2023).Jam syltepulver 45g freia. Matleveranser.
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