375 CONTENT IN BIOACTIVE COMPOUNDS AND ANTIOXIDANT CAPACITY OF FLOURS OBTAINED FROM WINEMAKING BY- PRODUCTS Luminița CATANĂ, Monica-Alexandra LAZĂR 1 , Monica CATANĂ 1 , Anda-Grațiela BURNETE 1 , Răzvan Ionuț TEODORESCU 2 , Adrian Constantin ASĂNICĂ 2 , Anca Petronela ONACHE 3 , Dorin SUMEDREA 3 , Nastasia BELC 1 , Nicolae-Valentin VLĂDUȚ 4 1 National Research & Development Institute for Food Bioresources, 6 Dinu Vintila, District 2, Bucharest, Romania 2 University of Agronomic Sciences and Veterinary Medicine of Bucharest, 59 Marasti Blvd, District 1, Bucharest, Romania 3 National Research & Development Institute for Biotechnologies in Horticulture Ștefănești-Argeș, 37 Bucharest-Piteşti Road, Argeș County 4 National Institute of Research-Development for Machines and Installations Designed to Agriculture and Food Industry, 6 Ion Ionescu de la Brad Blvd, District 1, Bucharest, Romania Corresponding author email: mcatana1965@gmail.com Abstract Grape pomace is particularly noted for its content of fiber, phenolic compounds, unsaturated lipids and sterols, vitamins and antioxidants. In this paper are presented results of the performed research for determination of vitamin C, total polyphenol content and antioxidant capacity in case of flours (grape pomace flour, grape seed flour, grape skin flour) obtained from winemaking by-products. There were taken into the study, winemaking by-products from three grape varieties: Blauer Zweigelt, Burgund Mare and Fetească Regală. Vitamin C content of flours obtained from winemaking by-products varied in the range of 18.25-25.75 mg/100 g FW and total polyphenol content varied in the range of 57.45-258.75 mg gallic acid equivalent (GAE)/g FW. Due to the content in bioactive compounds, the obtained flours have an antioxidant capacity (9.98-46.12 mg trolox equivalent (TE)/g FW). The highest value of the antioxidant capacity was recorded in the case of grape seed flour, this one being followed by the grape pomace flour, on the last place being the grape peel flour. Due to the complex biochemical composition, the flours obtained from winemaking by- products, can be considered as functional ingredients. Key words: winemaking by-products, polyphenols, vitamin C, antioxidant capacity. INTRODUCTION Vinification is an important agro-industrial activity, in countries such as Italy, Spain and France, but also in Romania. Following the winemaking process, significant quantities of winemaking by-products (grape stalk, grape skins, grape seeds, traces of pulp) are produced. It is estimated that the production of 100 L of white wine results in about 30 kg of winemaking by-products (Mendes et al., 2013). Grape pomace represents a mixture of skins, seeds and traces of grape pulp, resulted after the wine is obtained. At the international level, there is a great interest for the increasing of the added value of industrial cultures, both for economic reasons and for the protection of the environment, associated with the tendency to obtain new food products and ingredients with nutritional and functional properties (García- Lomillo et al., 2017; Gil-Sánchez et al., 2018). Grape pomace is particularly noted for its content in fiber, phenolic compounds, unsaturated lipids and sterols, vitamins and antioxidants (Kalli et al., 2018). According to the international performed studies (Brenes et al., 2016), the content of bioactive compounds of grape pomace depends on the variety of grapes, the area where the culture is located, the conditions of fertilisation, the soil and the period of grape harvest. Also, research conducted by Cappa et al. (2015), showed that more than 70% of the phenolic compounds in grapes remain in the grape pomace. Therefore, Scientifc Papers. Series B, Horticulture. Vol. LXIV, No. 2, 2020 Print ISSN 2285-5653, CD-ROM ISSN 2285-5661, Online ISSN 2286-1580, ISSN-L 2285-5653