Fruit & Vegetable Products

Fruits and vegetables provide a substantial and cheap source of vitamins, minerals, and fibre. While vegetables are often used as accompaniments to main meals, fruits are often eaten as appetizers and used for desserts. Both fruits and vegetables can also be used as raw material for a great variety of products such as juices, jams, dairy products and frozen, dried or canned food.

 


The differentiation between fruits and vegetables is ambiguous. Usually, fruits are derived from perennial plants while vegetables originate from one-year-old plants. Fruits have much higher contents of sugar and are usually more acidic. Vegetables are less acidic and for that reason are classified as 'low acid' products. These properties have a big influence e.g. on the type of microorganisms that are able to grow in corresponding products and thus on the type of processing.

A major product made out of fruits is marmalade / jam. Marmalade is a fruit preserve made from the juice and peel of citrus fruits boiled with sugar and water. It can be produced from lemons, limes, grapefruits, mandarins, sweet oranges, bergamots and other citrus fruits, or any combination thereof. In contrast, jams are usually made from pulp and juice of one fruit, rather than a combination of several fruits. Berries and other small fruits are most frequently used, though larger fruits such as apricots, peaches, or plums cut into small pieces or crushed are also used for jams.

The processing steps for producing marmalade are the preparation of the raw material (washing), followed by the extraction (e.g. by pressing/pulping),straining andthe addition of other ingredients (sugar, pectin) and process control (pH, temperature, measurement of the proportions of ingredients, sugar content). After a boiling step, which is the most important step regarding texturizing and preservation, the finished marmalade is filled into the packaging and ready to be delivered to the supermarkets.

Frozen foods are an important product made from vegetables. Frozen spinach, peas or whole meals containing a variety of different types of vegetables are very popular products. Those products have two big advantages: since the vegetablesare deep frozen directly after harvesting, they usually contain higher contents of important vitamins and secondary plant compounds than commonly stored vegetables. In addition, their shelf-life is greatly extended.

Altogether, fruits, vegetables and their products are foods which provide nearly all nutrients we need. Appropriate processes allow the production of well tasting foods with longer shelf-life, which can be found in nearly every meal – from breakfast over lunch to dinner.

 


This text was prepared by Björn Surowsky of the Department of Food Biotechnology and Food Process Engineering, Berlin Institute of Technology (Technische Universität Berlin), Berlin, Germany.

For further questions please refer to: bjoern.surowsky@tu-berlin.de


 

 


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