The influence of red grape pomace flour on the phytochemical characteristics of functional biscuits STURZA Rodica

Abstract

Grape pomace is the main by-product of winemaking, which consists mainly of grape skins and, in some cases, seeds and bunches. The valorization of these by-products through biorefining as a source of natural food additives represents a valuable alternative for the production of bio-ingredients with multiple practical applications, with a role in supporting the circular economy and protecting the environment. The purpose of experimental study consisted to elaborate functionals biscuits produced with mixt dried grape pomace (flour) of Cabernet Sauvignon and Rara Neagră red grapes pomace, determined the established of technology of classical biscuits and functionals products cookies. Under laboratory conditions at the Food Technology Department, 6 batches of functional biscuits with the addition of mixt dried red grape pomace (flour) in 1 % to 8 % proportions were developed. The study samples were examined at the level of physico-chemical and specific indices regarding the content of biologically active substances within the Oenological Research Center/Department of Oenology and Chemistry. The phytochemical composition and antioxidant activity of the obtained functional biscuits determine: Total monomeric anthocyanins (TMA) – 3.21 ± 0.05 mg C3G/g d.m.; Total polyphenols (TPC) – 40.28 ± 4.51mg GAE /g d.m.; Total flavonoids (TFC) – 12.83 ± 0.52 EC/g d.m.; Antioxidant activity (DPPH) (AA) – 62.11 ± 2.07 mmol TE/g d.m. and a degree of inhibition of 92.42 ± 0.65%. The results obtained confirm the bioactive potential of the mixt dried red grape pomace (flour), the content of bioactive compounds in the biscuits increasing proportionally to the concentration of the added powder. Thus, the addition of functional flour to the biscuit dough composition, at a concentration of 1% (w/w) (P-1) and 2% (w/w) (P-2), respectively, led to a clear increase in the anthocyanin concentration, from 5.24 mg C3G/100 g biscuits (P-1) to 9.54 mg C3G/100 g biscuits (P-2) and in the polyphenol content, from 132.62 mg GAE/100 g biscuits to 224.54 mg GAE/100 g biscuits, respectively. Regarding the overall appreciation, it was demonstrated that the addition of red pomace powder does not substantially influence the basic sensory characteristics (color, taste, aroma) of the biscuits.