Abstract A supercritical fluid extraction (SC-CO2) was used to extract high-quality oil from tomato skin by-products. The effects of pressure and extraction time on oil yield was investigated in the study. Lycopene and β-carotene content as well as p-coumaric acid, ferulic acid, caffeic acid, chlorogenic acid, vanillic acid, epicatechin, naringenin, catechin, quercetin and luteolin were estimated. The highest oil yield of 79.00% was obtained after 80 min with a pressure of 550 bar. The resulting oleoresin in carotenoids with lycopene and β-carotene content respectively of 0.86 and 1.5 mg/100 g, this oleoresin was found to be the richest. Naringenin was the most abundant flavonoid identified with a maximum content in oleoresin extracted at 550 bar (84.04 mg/kg DW) followed by caffeic acid (26.60 mg/kg DW). A moderate radical scavenging potential was further observed. Overall, results highlight that pressure is a key parameter for the extraction bioactive oleoresin from tomato skin by-products.

Resumo O processo de autoxidação da vitamina C no suco de laranja é a causa mais importante da perda de qualidade durante o seu armazenamento. O enriquecimento com diferentes concentrações de um extrato fenólico em um suco de laranja comercial foi avaliado para alguns parâmetros qualitativos, como conteúdo de vitamina C, compostos fenólicos e atividade antioxidante. A menor concentração de fenóis produziu o suco enriquecido mais estável. Em particular, foi observada uma correlação inversa entre a concentração fenólica e a retenção de vitamina C em sucos enriquecidos. Os resultados do ensaio DPPH confirmaram esta tendência, mais correlacionados com o efeito antioxidante da vitamina C. Os resultados da TEAC, ao invés disso, foram semelhantes para as diferentes amostras de suco, provavelmente influenciados pelo conteúdo fenólico. A aplicação deste estudo é na produção indústrial de novas bebidas funcionais, como sucos enriquecidos com ingredientes fenólicos, que mostram uma maior estabilidade comparativamente àqueles sem adição.

Abstract The autoxidation process of vitamin C in orange juice is the most important cause of quality loss during its storage. We evaluated the enrichment with different concentrations of a phenolic extract in a commercial orange juice for some qualitative parameters such as the content of vitamin C, phenolic compounds, and antioxidant activity. The lowest concentration of phenols produced the most stable enriched juice. In particular, we observed an inverse correlation between phenolic concentration and vitamin C retention in enriched juices. DPPH assay results confirmed this trend, correlated more to the vitamin antioxidant effect. TEAC results instead, were similar for the different juice samples, probably influenced by the phenolic content. The application of this study is the production for the industry of new functional drinks such as juices enriched with phenolic ingredients that show increased stability concerning those without addiction.