How is juice made?
The interview was conducted with prof. dr hab. Witold Płocharski from the Institute of Horticulture.
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1. Professor, please tell us what are the types of juices?
There are several criteria for determining the types of juices. One of the basic criteria is the type of raw material from which the juice was made. The name of the juice is specified in the recipes. We distinguish here fruit, vegetable and fruit and vegetable juices.
The second criterion are additives, which must be always natural in juices. So these will be, for example, minerals and vitamins. The criterion of additives allows us to distinguish two types of juices - 100 percent. and juices. Juices 100% they must not contain any, even these natural additives. They only consist of the fruit or vegetables from which they are produced. On the other hand, juices to which you can add natural additives include e.g. tomato juice and tomato juice reconstituted from tomato concentrated juice. You can add salt and aromatic spices to them. There is no EU legislation on vegetable juices other than tomato juices; natural additives may be added to them in line with general EU legislation.
The third criterion is the consistency of juices - we distinguish pure juices, clear juices and cloudy juices. Purée juices are obtained by rubbing whole or peeled vegetables or fruits. Clear juices are characterized by the fact that as a result of filtration and clarification they are free from clouding and insoluble parts. On the other hand, cloudy juices - as the name suggests - do not undergo the process of clarification and filtration, which means that they contain natural turbidity. Few people know that the orange and grapefruit juices in cartons available in stores are cloudy juices.
The fourth criterion that we adopt is the criterion of thermal treatment to which the juices are subjected. Juices that are not subjected to any thermal treatment are the so-called unpasteurized juices. They have a short shelf-life (usually 1 to 3 days) and require uninterrupted cooling conditions. The second type in this criterion is pasteurized juices. Depending on the temperature of pasteurization, these juices will remain usable for several weeks to several months, and their storage does not require refrigeration.
The last criterion is the type of semi-finished products from which the juices are made. We have two types of juices here: direct, so-called NFC - Not From Concentrate and reconstituted from juice or concentrated puree.
2. Professor, what does it mean that the juice has been reconstituted from concentrated juice?
Let's start with the fact that concentrated juice is usually produced in the season when fruit and vegetables have the most vitamins. This is very important because fruit and vegetables lose their nutrients as summer and autumn progress. Producing concentrated juice in the period when the products contain the most vitamins ensures that these juices also have a maximum of them.
Concentrated juice is the juice obtained from fruit or vegetables, which is then concentrated under reduced pressure and temperature by evaporating water from this juice. The aroma is also separated during this process. When the producer wants to recreate the juice from such a juice, the concentrated juice is replenished with drinking water in the amount that has been evaporated from it. Contrary to popular belief, the juice produced from concentrated juice cannot be more diluted than the juice obtained directly from the raw material. Thanks to this process, the content of ingredients such as vitamins, minerals, acids and sugars will be similar to those in juices obtained directly from fruits or vegetables. When reconstituting the juice, we also add back the natural aroma that was previously separated, and sometimes also the flesh and fruit particles. Juices made from concentrated juice have a high nutritional value. For their production - as with all other types of juices - you must not use any artificial substances that improve the taste or color, or preservatives.
3. What is the pasteurization process?
Pasteurization is a natural method of preserving juices by heating them, usually from 80 to 95 degrees Celsius, and then cooling them quickly. In this way, we can only preserve acid-containing products, e.g. fruit juices. During this process, which in industrial conditions lasts only several to several dozen seconds, bacteria and other microorganisms that, if left in the juice, would lead to a natural spoilage process, are destroyed. Thanks to advanced technical solutions, pasteurization takes place very quickly, many times faster than when preparing homemade preserves for the winter. Before bottling, the juice is pasteurized in the flow also at a similar temperature (on average from 15 to 30 seconds). As a rule, after a rapid increase in temperature to the pasteurization temperature, and a very short hold, the juices are quickly cooled and then poured under sterile conditions into packaging such as cardboard boxes, plastic bottles or "bag in box" packaging. The appropriate combination of pasteurization time and temperature is selected individually, matching the type of fruit or vegetables from which the juice is made.
4. Does the pasteurization process reduce the nutritional value of juices?
Pasteurized juices, like all juices, are natural products, rich in vitamins and nutrients. As I mentioned, nowadays the pasteurization process is so refined that the possible loss of nutrients in the juice is really minimal.In fact, a noticeable loss only applies to vitamin C, which oxidizes quickly, not only at high temperatures. In an orange or grapefruit that came to Poland from Africa, the vitamin C content will also be lower than in the product right after picking it from the bush. Still, a glass of pasteurized orange juice covers about 70 percent. the daily requirement for this vitamin. It is worth emphasizing that the lycopene contained in tomato juice, thermally processed during the preparation of the juice, is better absorbed by humans than that derived from raw tomatoes. So it seems that if we want lycopene, it's much better to reach for pasteurized tomato juice than raw tomato.
5. What about the fiber and pectin content in pasteurized juices?
In general, juices should be treated as a source of vitamins, micro and macro elements; they also contain small amounts of naturally occurring carbohydrates in fruits and vegetables. Purée juices (especially vegetable and fruit and vegetable juices as well as cloudy juices, e.g. from citrus fruits, but also from apples and other fruits) contain fiber. I would like to mention that a little-known curiosity is the fact that the heat treatment process has a positive effect on the content of soluble fiber, which plays a very positive role in our body. The cloudy apple juice contains a similar amount to that of apples. That is why puree and cloudy juices perfectly regulate metabolism, lower cholesterol and blood pressure.
6. Why is it worth reaching for a glass of juice a day?
Juices are a source of vitamins, minerals, and antioxidants (antioxidants), including polyphenols and pectins. This applies to all types of juices - day and fresh juices, as well as pasteurized ones with a longer shelf life. According to the law in force throughout the European Union, and thus in Poland, a product called juice must be a completely natural product. Therefore, pasteurized juices with a longer shelf life, also made from concentrated juice or the so-called direct (not from concentrated juice - NFC) are a good source of ingredients present in vegetables and fruits. The World Health Organization recommends that you consume min. 400 g vegetables and fruit, five portions. A glass of juice, approx. 200 ml, can be one of these portions.
The program is financed by the Fruit and Vegetable Promotion Fund. Organizer National Union of Juice Producers Association.
Information material of the National Union of Juice Producers Association
The program is financed by the Fruit and Vegetable Promotion Fund