Abstract A chromatographic method consisting of multi wavelength detection for identification of six phenolic acids, one stilbene and five flavonoids in grape and apple pomaces was proposed. Scavenging of DPPH (2,2-diphenyl-1-picrylhydrazyl), ABTS (2,2’-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid), reactive oxygen species and reduction of Fe3+ to Fe2+ using in vitro and HPLC-UV-ABTS on-line methods are herein presented. A reversed phase C18 coupled with an absorption detector operating at 280, 300, 320 and 360 nm for the benzoic acid derivatives and flavanols; stilbenes; cinnamic acid derivatives and flavonols, were respecctively used. The solvents water, methanol and acetonitrile acidified with acetic acid were evaluated as mobile phase. The optimized chromatographic method presented recoveries ranged from 68 to 130% and from 66 to 130% for grape and apple pomaces respectively. The determination coefficients (R2) of the 12 compounds were > 0.98. The extracts showed high total phenolic content and exhibits strong capacities to scavenge free radicals and reactive oxygen species. The results obtained by HPLC-ABTS on-line method suggest that pomaces of grape and apple are rich in bioactive compounds and that catechin and epicatechin contribute in a significantly way to the antioxidant activity in both agroindustrial pomaces.

Isolados e concentrados protéicos de soja são ingredientes largamente utilizados na indústria de panificação, confeitaria, bebidas e embutidos. As isoflavonas presentes na soja podem sofrer alterações em quantidade e perfil de distribuição dependendo das condições de processamento. O objetivo deste estudo foi verificar o balanço de massa de isoflavonas e proteína em processamento de isolados e de concentrados protéicos de soja (tratamento com ácido e com álcool). A maior parte das isoflavonas presentes na matéria-prima (farinha desengordurada de soja) é perdida nos sobrenadantes de processo (90% para extração com etanol 60%, 52% para processamento de isolado protéico e 47% para extração com ácido). O teor de isoflavonas nos produtos obtidos foi de 686µg/g base seca (b.s.) para isolado protéico, 871µ g/g b.s. para concentrado protéico obtido por tratamento ácido e apenas 153µg/g b.s. para concentrado protéico obtido por tratamento com álcool. Não foi observada alteração no perfil de distribuição das isoflavonas nesse último processo, enquanto que nos dois primeiros notou-se diminuição da quantidade das formas malonil glicosídeos e aumento da quantidade das formas beta-glicosiladas e gliconas.

Soy protein isolate (SPI) and soy protein concentrate (SPC) are largely used in bakery, confectionary, meat and beverage products. Isoflavones present in soybeans products can undergo changes in quantity and profile depending on the processing conditions. The objective of this work was to conduct mass balance studies of isoflavones and protein during the processing of SPI and SPC (acid and alcohol leach). The majority of isoflavones present in the raw material is lost in the supernatants (90% for SPC treated with alcohol, 52% for SPI and 47% for SPC treated with acid). Total concentration of isoflavones was 652µg/g for SPI, 838µg/g for SPC (acid leach), and only 147µg/g for SPC (alcohol leach). There were no changes in the profile of isoflavones in this last process, whereas in the previous two, the amount of malonyl glycosides decreased while the total amount of beta-glycosides and aglucones significantly increased.