| Abstract [eng] |
By-products from food production often have a variety of useful functional properties that could be used in the production of functional foods. One of the manufacturing sectors where food by products are produced is the beverage sector. Berries, such as black currants or cranberries, are one of the most commonly used raw materials for the production of beverages. The by-products obtained from such raw materials are characterized by a high content of fibrous materials and contain various biologically active components. The latter can be adapted to create value-added foods. Therefore, the aim of this final master's project is to evaluate the modification and application of dry berry pulp for the production of yoghurt drinks. The initial chemical composition, color, particle size and polyphenolic content of blackcurrant and cranberry cake powder were evaluated. The properties of the powder, i.e. swelling, water holding, oil retention capacity, solubility, foaming and stability, were also evaluated. Based on the obtained initial data, the chemical composition of berry pulp powder and its properties before powder modification were summarized. Innovative berry pulp modification technology using encapsulation of insoluble particles and spray drying was used to create a functional berry pulp powder. The following capsule shell variations were selected for encapsulation: whey protein, mixtures of maltodextrin and gum arabic, and maltodextrin and whey protein. Particle size was found to be a key factor limiting the encapsulation of berry cake powder (to form a stable suspension) and drying (due to the small diameter of the spray head). The use of polysaccharide coatings (a mixture of maltodextrin and gum arabic) significantly reduces the amount of fiber in the powder after drying. It has been found that most of the sprayed suspension does not dry out and settles in the drying chamber under the action of the air stream, making this variation of the dowel unsuitable. Meanwhile, a suitable modification obtained using capsules from whey protein. After studies and comparison with the initial data, a suitable functional berry pulp powder (sufficient amount of fiber, suitable color and good solubility) was developed. Developed drinking yoghurts without and with modified pulp powder. Sensory and physico chemical tests were performed to determine the pH and viscosity values and sensory evaluation parameters of yoghurt drinks. Yoghurts with unmodified pulp powder had a brighter color, but an unpleasant "sandy" taste. When using a modified powder, the color remains lighter, but the taste properties are particularly improved. According to sensory evaluation, drinking yogurt with modified black currant cake powder was rated as the most acceptable. These studies have shown that modified berry pulp powder could be used in the production of other functional dairy products in the future. |
