Food preservation requires a method and some knowledge of the effects on nutrients. There are natural preservatives, chemical preservatives, and processes such as dryingand vacuum packaging. One goal for all of these proposals, is to keep food fresh and nutrient-rich.
Why are foods perishable?
Over time, the enzymes The food contained in the food digests the cells that harbor it and begins its decomposition. In addition, most food products are rich in water and sugars, two components that promote the spread of microorganisms (bacteriamushrooms yeasts, for example). Finally, the oxygen in the air can attack the food: the fruits turn black and the fat becomes rancid.
Therefore, conservation has several goals, such as reducing the water content of food, and neutralizing it enzymes As well as microorganisms and prevent the work of oxygen.
The three types of food preservation
All foods have a limited shelf life. Industrial products must display an expiration date on their packaging. A distinction is made between foods for short, medium and long storage.
The Short shelf life Relates to perishable food items with a shelf life of one day to a maximum of two weeks; This is the case for meats, cold cuts, milk and dairy products, eggs, cheese, and fresh fruits and vegetables. Most of it should be put in the refrigerator. Certain foods should be eaten on the same day, such as fish, shredded carrots, and ground meat. Some of them can be frozen, which makes it possible to extend the shelf life.
The average memorization It relates to fresh foods that can be kept in a basement or basement, such as some fruits and vegetables or cured and dried meats. It is necessary that the cellar be cool, dry and well ventilated. For potatoes, the storage place should be dark to avoid greening (associated with the formation of solanine, a toxic substance) and germination.
long shelf life
products long shelf life These are dry foods, canned foods, and frozen foods. Dried products such as vegetables, dried fruits, pasta and rice are highly resistant. Practically insensitive to temperature changes, it can be stored for a year or more. It should be placed away from moisture.
Cans are sterilized at a temperature of at least 100 ° C in metal or glass containers. Its validity period is at least one year. Glass containers should be stored protected from light.
|Removing air (and therefore oxygen) from the package containing food prevents oxidation and prevents the growth of many bacteria. We distinguish conservation under the void and save under normal atmosphere (Oxygen is replaced by another gas such as nitrogen). These methods are used in addition to cold or heat treatment or irradiation. Mainly related to cold meats and ready meals.|