Vinogradov V. Scientific and Technical Foundations of the Technology to Produce Grape Must and Wine Materials

The Thesis is concerned with the elaboration of theoretical and scientific foundations of grape must processing, cold treatment of wine materials and development of equipment to carry out these processes. A scientific concept of improvement and development of new technologies and equipment has been suggested based on physico-chemical quality characteristics of grape must and wine materials, which quality characteristics closely correlate with mechanical action on grape raw material to be processed. Significant characteristics of grape must and wine materials (mass proportion of suspended matter, mass concentrations of phenolic substances and their polymeric forms, potassium and tartaric acid) to be determined, new data to be obtained and regularities to be established referring to changes in quality characteristics as affected by the intensity of mechanical action. Further research has been made into improvement of continuous screw presses associated with the highest intensity of grating of grape raw material, which leads to deterioration in quality of the resulting must. The use of these devices enables manual labor inputs to be reduced and the probability of over-pressing into the pressure chamber which also leads to deterioration in quality of the must to be avoided. Research has been done into the possibility of using physical methods for grape crush treatment (microware heating, low-frequency vibration, use of auxiliary materials) which allow to intensify the process of juice recovery and to improve quality indices of the resulting must. The effect of different factors on the technological process of removal of coarse suspended matter during pre-filtration on screen filters has been investigated, and principal regularities have been established and expressed in the criterial form. Further research into grape must clarification has been undertaken. The possibility has been demonstrated to use the method of flotation clarification which is an alternative of settling and enables both an increased yield of the clarified portion of the must and high quality of the clarification process. For the first time, regularities governing changes in principal characteristics of ejection flotation of grape must suspended matter as affected by different factors have been established, and a design procedure of the flotation tank has been developed. Further research has been done with the aim to improve the technology of cold stabilization of wine materials versus crystal clouds, and the results obtained have enabled development and manufacturing application of new continuous and batch installations for accelerated treatment of wine and also heat exchange installations using an ecologically clean cooling agent. Data is provided referring to testing of results of research aimed at development of new technological equipment (a screw strainer and presses, a screen filter, grape processing lines and technologies of grape must pre-cleaning consisting of removal of coarse suspended matter and flotation clarification) and of acceptance trials of these research products at enterprises of the national wine industry, and benefits of manufacturing application thereof are stated. Social and practical importance of results arising from the research for the Doctorate has been determined.