Economic importance: The conversion of agricultural products in the seasons when the product is abundant and cheap causes the product to be offered at a reasonable price in the market by processing the product and variety, and products that are processed hygienically and packaged. Optimal can also compete for export in the global market.
Political importance: Food supply and conversion and storage of agricultural products by preventing waste can lead to self-sufficiency of the country and thus independence from other countries. Due to the lack of industrial facilities and advanced factories in the production area and due to the problems discussed in the first article, we will try to explain simple food preservation methods under the traditional methods of preserving agricultural products.
The most common of these methods are:
A) Storage by drying using solar heat:
Using solar heat is one of the most simple, old and cheap methods that is used for most agricultural products. One of the most important advantages is the low cost and ease of packaging and transportation.
Tips to follow in this case:
The fruits that are selected for drying should be of the best and best quality, the fruits should be selected fleshy, sweet, large and uniform. The fruit drying operation should be done on the same day as the harvest and the crop should be harvested early in the morning. The air should be dry enough and a sunny and warm day is the best time for this, but the drying operation should be done in a canopy and in indirect light. Aeration around the fruits should be done well and the product should be turned upside down two to three times a day. The trays should be covered with a clean cloth to ensure that the product dries, it should be weighed, whenever it weighs between 60 80% reduced, completely dry. After drying, place the nuts in a dark, dry place away from dust and insects and visit them from time to time.
B) Storage using cold:
Using cold is one of the best and most common ways to store food, which is done in various ways, including the use of simple home refrigerators or freezers.
Tips to follow in this regard:
The temperature of the bottom of the refrigerator is about 4 degrees Celsius, and at this temperature a large number of microbes are active and can easily spoil food. Therefore, perishable materials can not be stored in the refrigerator for a long time. Instead, it is better to use a cup or freezer for long storage. The temperature is always below zero degrees.
Foods such as vegetables should be heated before freezing, which kills germs that cause unwanted changes in the food.
When the food comes out of the freezing state of the extract, it is better to add it again to the food.
Avoid putting large amounts of food in the freezer at once. Place home refrigerators and freezers in a completely dry, cool, level environment.
Store different foods in sealed containers with the date and type label on the refrigerator. Foods that contain vegetable oil should not be frozen because they taste spicy and unpleasant. The faster the food freezes, the less unpleasant changes occur due to freezing.
The best way to get out of the freezing mode is to gradually increase the temperature, so take the products out of a place first and put them in the bottom of the refrigerator, and getting out of the freezing mode with hot water, sun and direct heat is not appropriate.
C) Preservation by boiling and concentrating:
Some agricultural products can be stored for a while by boiling and concentrating. Lavashka and all kinds of pastes are of this type.
Tips to follow in this case:
To do this, use perfectly ripe and healthy fruits and make sure that the fruits are not moldy. To increase the shelf life of the paste, use 2 to 5% of unripe tomatoes in its preparation.
To store the paste, be sure to use glass containers and boil the containers and lids in water for 15 minutes before filling, and after drying, pour the paste into it hot, and in the last step, add oil to it and the glass. Hold upside down for a few seconds.
Sour fruits are more suitable for preparing lavashka. From the combination of several fruits, you can prepare desserts with different flavors and colors. Adding a small amount of salt and sugar helps the dish taste good and last longer.
D) Storage by vinegar:
One of the most common ways in cities and villages is to preserve fruits and vegetables using vinegar and pickles. The following points are very important in pickling:
Never use copper, brass, iron or plastic utensils for this purpose. The ingredients for making pickles should not have any moisture. The best vinegar is for preparing grape pickles. Boil glass jars and lids in boiling water for 15 minutes and fill them after drying. Store the jars in a cool, dark place.
R) storage by salt:
Many vegetables and fruits can be stored for a short time using water, salt and vinegar. (Salt)
In preparing the salt, pay attention to the following points:
The salt water used to prepare the brine must be boiled and contain 4 to 7% salt. Prevent air from entering the containers containing salt for at least 20 days, so it is better to solder in a container of salt or take it with dough. Once opened, it should be stored in the refrigerator. In preparing the types of salt, make sure that all the waste materials attached to fruits and vegetables are completely separated. Because the presence of these substances probably causes mold and softening of the salt. If cucumber is used in the preparation of salt, cucumbers should be healthy and eaten at the time of consumption. Spices such as angelica, or vegetables such as tarragon can be used to flavor the salt and pickle.
G) Maintenance using suitable warehouses:
Another very important and common method is to store food in storage. Warehouses that are built in a correct and scientific way and are equipped with the necessary equipment. These warehouses must meet the following conditions:
Be impermeable to moisture.
They are impermeable to heat. Its doors and windows should have wire mesh to prevent insects from infiltrating.
Have enough light (indirect light) and be well ventilated.
They are shelved and have the necessary equipment to control the temperature and humidity.
To prevent spoilage of food, they should not be stacked, but should be placed in appropriate categories.
Note that the sacks and bags of food are placed on top of each other or next to each other at a certain distance.
And prevent the accumulation of food, especially those that breathe, such as grains, legumes and vegetables because it damages their quality.
Q) Storage using sugar:
By adding syrup or sugar to the vegetable fruit and cooking and bringing it to a certain concentration, jam or marmalade of that fruit can be prepared. In preparing jam and marmalade, it is necessary to pay attention to the following points:
When cooking jam, the dish should be open so that its color does not change. Except for the jam, which must be closed in the container.
Do not use crushed and fully ripe fruits for this purpose. The concentration of jam and its juice should be sufficiently consistent. (To do this, pour some jam syrup in a glass of cold water. If a drop is placed at the bottom of the glass, the jam will thicken). Jams made from sweet fruits should be after consistency
He added a little lemon juice to it. Sugaring the jam indicates that the jam is overcooked and moldy indicates that the jam is not thick enough. Pour the jam hot into a glass jar and then turn the jar upside down so that if the air under the lid is contaminated, it will probably be destroyed by heat contamination.
In order for the jam to thicken sooner, it is better for 2% of the fruits used to be unripe.
It is better to use glazed dishes to prepare jam. Another way to store products using sugar is to prepare compote, which seems important to pay attention to the following points. When chopping fruits, to prevent them from changing color, pour the fruit in a dilute solution of salt water or use a solution of diluted lemon juice. After taking it out, wash it in cold water and soak it in boiling water for three minutes. This will preserve the aroma, color and taste of the fruits.
Pour the fruits into glass jars that have tightly closed lids and then add the prepared syrup to the fruits. Boil the jars containing the prepared ingredients in boiling water for 20 minutes.