Optimization and characterization of chestnut shell pigment extract obtained microwave assisted extraction by response surface methodology.

The objective of this study is to find optimum conditions to valorize chestnut shell bioactive compounds with coloring pigments through microwave-assisted extraction. With this aim, response surface methodology with central composite design was used. Microwave power (800 W), extraction time (12 min) and solvent concentration (NaOH: 0.115 mol/L) were determined as the optimum conditions to maximize the responses like color value, total phenolic content and total antioxidant capacity. In the optimized extract (OE), characterization of brown melanin like pigments were assessed by Spectrophotometer, Fourier Transform Infrared Spectrometer and major phenolics were identified as; gallic acid, ellagic acid, protocatechuic acid, catechin, and epicatechin as 0.53, 0.48, 0.46, 0.46, 0.14 mg/g dried weight (dw) by High Performance Liquid Chromatography, respectively. In terms of antibacterial activity, OE inhibited the growth of Staphylococcus aureus. Consequently, chestnut shells were successfully processed into natural coloring agents that were possessing strong brown color properties as well as high bioactive potential.

A study of fortification of lemonade with herbal extracts

Abstract The aim of the present work was to design new beverages using lemonade and some herbal extracts (linden, heather, green tea, lemon verbena, clove, peppermint, ginger and mate) rich in vitamin C and flavonoids. The linden-added lemonade showed the highest value (597.9 mg/kg) for ascorbic acid content, whereas the lemon verbena-added lemonade showed the lowest value (486.04 mg/kg). The amount of saccharose was changed by 11.07-11.58%, the glucose by 1.11-1.62% and the fructose between 11.07-11.58% in the beverages. K, Na, Mg and P values in the lemonades were determined in the range of 178.83-210.98 mg/kg, 33.75-39.13 mg/kg, 22.37-27.89 mg/kg and 7.22-10.04 mg/kg, respectively. The total phenolic content in the samples changed between 315.11-397.57 mg GAE/100 g. When the samples were analyzed for antioxidant activity, FRAP (17.13-26.79 µmol trolox/mL) and ABTS (16.91-25.38 µmol trolox/mL) methods gave higher results than the DPPH (14.88-17.72 µmol trolox/mL) method. Linden-, ginger- and peppermint-added lemonades, which had been found to be rich in total phenolic compounds and ascorbic acid, showed higher antioxidant activity than the control sample. Overall, the most preferred lemonades were heather- and ginger-added beverages and the control sample. Mate-added lemonade was the least preferred.