Selecting optimal parameters for obtaining the extract of red grape pomace

Abstract

Due to the industrial processing of grapes, large amounts of by-products are produced. The main varieties of by-products are pomace, which is comprised of skins, seeds and any other solid remaining after pressing process and sediments. It is necessary to implement new effective ways of processing to minimize these residues. This problem is relevant for all the wine-producing countries, including Georgia. It is well-known fact that pomace is an important source of phenolic compounds, which are characterized by high antioxidant activity and possess healing-prophylactic properties. It is also worth mentioning that pomace is an easily spoiled product, and without the proper processing, it cannot be stored for a long time. Thus, this research aimed to obtain optimal parameters for extraction, preserving the antioxidant characteristics. The optimal range of the following parameters for extraction was determined: the temperature for drying 45-50 °C, grinding level 1.5 mm, diluent concentration 70% ethanol/water solvent, extraction module 1:20, extraction temperature 50-55 °C, and duration 2 h. This determination of technological parameters of extraction was done according to the best physical-chemical measures and antioxidant activity level. The physical-chemical tests were performed according to the European Union standards. These parameters can produce an extract with distinct antioxidant characteristics that can be used in the food industry as a natural antioxidant. The extract with distinct antioxidant properties was obtained, which can be used in the food industry as a natural antioxidant.