The thesis is dedicated to scientific rationale and development of technologies for nut and seed-based foods with balanced content of biologically valuable substances. The thesis contains an analysis of contemporary trends in production of wholesome foods based on plant products and emulsion-type products, identifies key methods for improvement and diversification of the range of healthy foods. The author dwells on the problem of the limited range of healthy foods with balanced content of polyunsaturated fatty acids, studies practices in production of emulsion-type products, such as non-alcoholic beverages and sauces, identifies key methods for production of emulsion-type plant-based products with balanced content of polyunsaturated fatty acids.
The author has proved viability of use of walnut kernels and chia seeds as a raw material for production of healthy foods for catering facilities, validated feasibility of development and use of multipurpose food base for production of nut-based non-alcoholic beverages and sauces, and performed a comprehensive research of the used raw material and end products.
By experiment the author has identified optimum wet heat treatment modes for further use of walnut kernels as a component in emulsion-type foods. The thesis contains an analysis of possibility of pre-processing nuts by a short-time high-temperature treatment and by a long-term water soaking method at an ambient temperature followed by wet heat treatment at a boiling water temperature. It has been established that at 200 °С fatty acid content of nuts deteriorates and optimum ratio of omega-3 and omega-6 polyunsaturated fatty acids changes.
The thesis proves that wet heat treatment has an effect on organoleptic and rheological properties of the product. Under the impact of long-term soaking of walnut kernels in water its structure becomes almost 18 times less strong, which has a positive effect on further crushing of nuts and extraction of soluble substances. Decrease of water duty down to 1:5 improves organoleptic properties of the suspension but the end product is too dense. By applying mathematical modelling of suspension production based on experimental data it has been established that optimum raw material/water ratio is 1:7 water duty.
It has been proved that in order to receive a nut-based product with necessary physicochemical and rheological properties it is feasible to make a colloid solution of walnut kernels by double crushing in water medium using a blender with power capacity of 900 W and more for 300 s with 30 minute long soaking in-between crushing phases at ambient temperature.
Chia seeds, widely popular among western nutrition experts, have been used in the study. Comparative analysis of the chemical composition, water absorption and water binding capacity of chia seeds and flaxseeds has been performed. It has been established that chia seeds outreach flaxseeds by far in terms of omega-3 fatty acids, vitamins and minerals content. Chia seeds have better water absorption capacity. When soaked, its weight grows 10 – 12 times, unlike flaxseeds, the weight of which grows only 3 – 4 times. Water binding capacity of chia seeds is due to a gel layer forming around each chia seed, which does not deteriorate during storage. According to data obtained, it is feasible to use chia seeds as a structure-forming agent. Use of chia seeds does not only improve nutrient, biological and physiological values of foods, but also enables to make products with specific rheological properties.
Based on theoretical and experimental studies a range of foods has been developed containing walnut suspension in water and solid residue remained after filtering thereof as a multipurpose base. The author has developed technologies and formulations of a nut-based beverage, 9 formulations of smoothies based on fruit, berries and vegetables, as well as a multipurpose base for making sauces and a green nut sauce for catering facilities. Such multipurpose bases enable to make foods with balanced fatty acid content complying with FAO/WHO guidelines to omega-3/omega-6 fatty acid ratio at the level of 1:4 units. Study of microbiological values of the beverage shows that it should be stored at 0 – 6 °С for 3 days maximum. Longer storage leads to development of moulds and yeasts. Viscosity and stability of the food system remain the same for 24 hours of storage. Nut and seed-based smoothies contain minimum 2,58 g polyunsaturated fatty acids in the end product and provide 30% of the required daily intake of these essential nutrients.
Paste-like fat base for making sauces has been developed, containing walnut kernels or solid residue remaining after making walnut-based beverage, i.e. processed raw material, chia seeds, water and olive oil. Depending on ingredient variety fat base contains 3,8 g protein, 27 g fats and 6,4 g carbohydrates, its energy value being 320 kcal. Fatty acid content of the multipurpose paste-l
