There are many effective preservation methods that have evolved over the years,? to prevent spoilage. The principle of food preservation is to prevent spoilage while maintaining quality and nutritional properties. It’s needless to say that fresh fruits always yield juices of higher quality.
However, this is a very temporary product that has a limited shelf life of hours or days, even in the best of circumstances. Let’s view some effective preservation techniques used by manufacturing companies, for the preservation of fruit juices:-
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Heat treatment is one of the most common ways to store an preserve fruit juices. Pasteurization is the process of heating juice to 100 degree celsius or slightly below, for a certain amount of time in order to kill the spoilage causing microorganisms.
Generally, fruit juices are pasteurized between 75-88 degree celsius. The length of the time of the? pasteurization can be from 30 seconds to? 30 minutes, depending on the type of heating system, and the nature of the juice or the size of the container.
Various companies like ROETELL, which specialise in manufacturing sterilized glass jars and containers, which can be used for storage. You can opt for a ?glass jar dollar tree, which is a special kind of glass jar bottle product of ROETELL.
?Here are a few types of pasteurisation:-
In this method, the prepared juices are poured into sterilized glass jars, with adequate headspace, after which they are sealed airtight. Then they are pasteurized,? however, this method does not apply for commercial-scale products.
Pasteurization by Overflow
In this method, the juices are filled into an autoclaved container to the edge, heated to about 2.5 degrees above the pasteurization temperature, and sealed inside sterilized bottles. Care must be taken in maintaining the temperature during filling and sealing operations.
Sealed bottles are processed into boiling water for a certain period of time, then these bottles are cooled. When cooled, the juice shrinks, leaving a small space at the head of the bottle. This method is commercially practiced in the food industry while storing all types of juices.
In this process, the juices are heated for a short period of time at a temperature of about 5.5 degrees above the pasteurization temperature, and then sealed into a container airtight.?
The sealing is done through a cover of steam, which sterilizes the seal. This process is generally known as the HTST (High Temperature Short Time) method.
Rapid pasteurization can minimize flavor loss, better retention of vitamins, and also minimises the cooked taste of the juice.
Aseptic Processing and Packaging
Aseptic processing and packaging can be referred to the process by which commercial juice products are packaged in sterile containers in an aseptic environment.?
The system uses high temperature short time (HTST) sterilization over a temperature range of 90- 110 degree celcius for acidic products (pH <4.6) and ultra high temperature (UHT) sterilization over 121 degree celcius for mildly acidic foods (pH>4.6).
Aseptic processing improves the retention of vitamins and results in products with superior organoleptic quality. Apple, lychee or pineapple beverages contained in commercial packaging are generally processed using aseptic processing and packaging systems.
Preservation Using Chemicals
Various fruit juices like pulp, squash, kodi, syrup, RTS drinks, etc. are stored with chemical preservatives. The two most commonly used chemical preservatives for the storage of fruit juices are:
Benzoic acid is an effective agent, but it has a high solubility in water, which is why it’s sodium salt is used. Benzoic acid is relatively more effective against yeast than mold. However, it does not stop fermentations from lactic acid and acetic acid.? The amount of sodium benzoate required depends on the characteristics of the juice, and the type of microbes present in the juice.
Potassium meta-bi-sulaphate is generally used as the source of sulphur dioxide.It functions as an antioxidant or a bleach, which helps in the maintenance of ascorbic acid, carotene, and other oxidizing compounds. It also delays non-enzymatic browning or discoloration of the product.
However, sulphur dioxide cannot be used for colored juices such as pulsar, advice, pomegranate and strawberry juice due to it’s bleaching properties
Preservation By Sugar
Fruit juices containing 66% sugar are usually not fermented. High in total solids (more than 65%) fruit syrup or sharbats have very low water activity, which prevents the microbes from multiplying. Sugar acts as a preservative by osmosis, which does not allow the growth of microorganisms, in fruit beverages.
Preservation By Freezing
Properly frozen juices retain their freshness, color, taste and aroma for a longer period of time. In this process, de-aerated juices are transferred to a container and sealed , after which they are frozen. It doesn’t sterilize the fruit juices, instead it just lowers the temperature to the point where microbes can’t multiply properly and chemical changes occur at a very slow rate.
Small ice crystals are formed when the juices are freezed rapidly, and the amount of coagulation of the colloidal material is reduced. When you freeze a juice to -18 degrees, it practically turns it into solids, except for the slightly thick syrup in the center of the container.
Preservation By Filtration
Fruit juices which are refined in this way (especially apples and grapes) are passed through a special filter that can retain yeast and bacteria.? This method is generally used for soft drinks, fruit juices and wines.
Preservation by Carbonation
In this method,the fruit juices are pressured under carbon dioxide and then sealed. This also gives them a characteristic flavor. However, the commercially used amount is? relatively lower than the required amount that is required to completely suppress microbial growth (14.6 g per liter), but it is important to complement the lethal effects of pathogenic bacterial acids.?
Carbonation also helps air removal, which creates an anaerobic condition and reduces the oxidation of ascorbic acid. Molds and yeast need oxygen to grow, so the presence of carbon dioxide makes them ineffective
Fruit juices are made from fruits, so it maintains the physicochemical and nutritional properties of the fruits. Therefore, their intake must also contribute to maintaining good health as the fruit itself.?
The health benefits of fruit juices contribute to many biologically active compounds present in such foods. Therefore, following proper preservation protocols are extremely necessary, in order to retain its nutritional values. Eat healthy and stay Safe!