Foeniculum vulgare Mill. as a natural ingredient to improve cottage cheese antioxidant properties

Food industry is focused on the development of novel functional foods containing health promoting natural ingredients. Natural antioxidants present important health benefits like the prevention of several diseases related to oxidative stress [1,2]. Foeniculum vulgare Mill. (fennel) is a source of those compounds with proved antioxidant potential [3]. Herein, after evaluation of 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity and reducing power of fennel (provided by Américo Duarte Paixão Lda.) decoction, we propose its incorporation into cottage cheese (produced by Queijos Casa Matias Lda.). Three groups of cottage cheese samples were prepared: control; samples with fennel decoction (incorporated at EC25 value=0.35 mg/mL, previously determined by DPPH assay); and samples with fennel powder (incorporated at 1.75 mg/mL, considering the decoction yield=20%). The samples were submitted to an evaluation of DPPH scavenging activity and reducing power immediately after the incorporations, and after 7 and 14 days of storage, at 4 ºC. The incorporation of fennel improved the antioxidant activity of cottage cheese. Samples incorporated with plant powder revealed higher antioxidant properties than samples incorporated with decoction, either in 0 or 7 days of storage. After 14 days, cottage cheese incorporated with fennel decoction gave the highest DPPH scavenging activity (46.72±0.09 mg/mL). A decrease in the antioxidant potential of the cottage cheese with fennel was observed along the shelf life. Nevertheless, it is important to highlight that the samples still display antioxidant properties. Studies regarding the effects of the incorporation of these natural ingredients on nutritional and chemical composition of cottage cheese are in course

Optimization of microwave-assisted extraction of hydrophilic and lipophilic antioxidants from a surplus tomato crop by response surface methodology

Tomato is the second most important vegetable crop worldwide and a rich source of industrially interesting antioxidants. Hence, the microwave-assisted extraction of hydrophilic (H) and lipophilic (L) antioxidants from a surplus tomato crop was optimized using response surface methodology. The relevant independent variables were temperature (T), extraction time (t), ethanol concentration (Et) and solid/liquid ratio (S/L). The concentration-time response methods of crocin and β-carotene bleaching were applied, since they are suitable in vitro assays to evaluate the antioxidant activity of H and L matrices, respectively. The optimum operating conditions that maximized the extraction were as follows: t, 2.25 min; T, 149.2 ºC; Et, 99.1 %; and S/L, 45.0 g/L for H antioxidants; and t, 15.4 min; T, 60.0 ºC; Et, 33.0 %; and S/L, 15.0 g/L for L antioxidants. This industrial approach indicated that surplus tomatoes possess a high content of antioxidants, offering an alternative source for obtaining natural value-added compounds. Additionally, by testing the relationship between the polarity of the extraction solvent and the antioxidant activity of the extracts in H and L media (polarity-activity relationship), useful information for the study of complex natural extracts containing components with variable degrees of polarity was obtained.