### Characteristics and Methods of Producing Snacks Based on Fruits and Vegetables
[PERSON] and [PERSON] [20],while examining the effect of convective and freeze-drying conditions of pumpkin and green pepper, concluded that the tested parameters of quality, such as colour and texture, indicated a much better quality of freeze-dried samples than that of convection-dried one. The freeze-drying process causes smaller colour changes as an effect of a slight and much smaller decomposition of chlorophyll and other pigments, and non-enzymatic reactions during convective drying. Another advantage of freeze-drying is that freeze-dried products are easy to reconstitute by rehydration, which is very important. [PERSON] et al. [21], examining the effect of the drying method on wild asparagus rehydration, showed that rehydration characteristics of the freeze-dried samples were significantly better than in the case of convective drying and the lower was freezing temperature the higher was rehydration ratio of freeze-dried material. Assessing the content of bioactive ingredients and antioxidant properties of freeze-dried powders delivered from plants, the freeze-drying method allows for obtaining products rich in bioactive compounds: vitamin C, polyphenols, including anthocyanins and carotenoids, characterised by high antioxidant activity. Due to the above advantages of the freeze-drying process, it may be used for producing food for special nutritional purposes, convenience food and dietary supplements. In addition, it is a suitable method for processing vegetables and fruit [5; 22; 23; 24; 25; 26]. Another group of snacks, quite popular and often consumed, are extruded products, such as corn crisps or puffs. Their main component is starch, which is the most important element in the extrusion method, as it is responsible for the formation of porous structure and brittleness typical of those products [27; 28; 29]. Due to the fact that corn crisps are quite poor in nutrients, they are more and more often enriched with other additives. The extrusion method allows for effective combination of raw cereal with aroma and oil fruit and vegetables, obtaining a product of good quality and durability [30]. [PERSON] et al. [28] examined the quality of corn crisps enriched with amaranth flour, Jerusalem artichoke and pumpkin pulp. They recommended the use of amaranth seeds flour, which increased quality indicators. The effects of Jerusalem artichoke and pumpkin on the structure of the corn snacks were adverse and the industrial application was excluded. [PERSON] et al. [31] conducted the analysis of the physical and functional properties of high-fibre cereal and vegetable snacks. Cereal-zucchini-broccoli and cereal-pumpkin crisps produced by the extrusion and expansion method were tested. The values of water content and activity were obtained ensuring microbiological stability. Moreover, based on the density and porosity of the products, it was found that they were characterised by a delicate, brittle texture. It was also concluded that those products had adequate digestibility. Producing fruit or vegetable bars is an innovative but not very popular method of obtaining a healthy snack. They may be single-layer or multi-layer ones. Hydrocolloids also have the ability to form gels, which maintain their shape and structure after water removal due to freeze-drying, and that allows to manufacture attractive for consumer products. Moreover, their ability to water binding and swelling capacity make them food components responsible for keeping the feeling of satiety for a long time. As was mentioned before, hydrocolloids are high molecular weight biopolymers that act in human's digestive system as dietary fibre. Thanks to referred properties of hydrocolloids, they are established as additives that can be used to create functional food [4; 32; 33]. [PERSON] et al. [34] investigated the quality attributes of bars made from papaya and tomatoes with the addition of hydrocolloids, such as pectin or starch.