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Avocado leaves, typically considered as pruning residues, possess a significant amount of bioactive compounds. This research aimed to optimize the extraction of phenolic compounds from Hass avocado leaves using microwave-assisted extraction (MAE) and response surface method (RSM). The extraction yield and total phenolic content (TPC) were maximized by determining the optimal process conditions, which were found to be 47°C for 5 minutes and a solid/solvent ratio of 1.13 g dry leaf/100 mL, respectively. The predicted values of all models were found to be statistically significant (p <0.001). The aqueous extracts' antidiabetic and antioxidant activities were 64.59% and 235.6 mg TE/100 g, respectively. The amount of TPC was 591.76 μg GAE/g extract, and chlorogenic acid was the main phenolic component. These results indicated that MAE proved efficient with low energy consumption, yielding phenolic-rich avocado leaf extracts, which possess high antioxidant and antidiabetic activities. [ABSTRACT FROM AUTHOR]

This study covered the phenolic compounds extraction from tomato peels using microwave assisted extraction (MAE) system and their microencapsulation by spray drying technique. For this purpose, MAE conditions (microwave power: 250-500 W and extraction time: 1-60 min) for maximum recovery were optimized by response surface methodology. The highest values for total phenolic content (TPC) (3.58 mg GAE/g) and antioxidant capacity (29.85 mmol TE/g) were obtained at the point where the microwave power was 310 W and the extraction time was 35 min. Phenolic extracts produced under optimum conditions were mixed with maltodextrin (the ratio of soluble solids in the extracts to maltodextrin: 1/1 w/w) and converted into powder form using spray drying technique. The success of the microencapsulation process was confirmed by fourier transform infrared spectroscopy (FTIR). Powder yield, moisture content, water activity and solubility values for microcapsules were determined as 63.45%, 4.18, 0.19 and 92.34%, respectively. The antioxidant capacity of the final powder products was investigated by TFM (3.17 mg GAE/g), DPPH (23.10 mmol TE/g), ABTS (75.83 mmol TE/g) and FRAP (13.95 mmol TE/g) methods. The results show that it is not a reasonable approach to dispose of waste materials or use them in field with low economic value. On the contrary, they have the potential to transform value-added products. [ABSTRACT FROM AUTHOR]

In this study, bioactive compounds (phenolics) from carob pod were extracted by using microwave assisted extraction method. Spray drying technique was performed for the conversion of the resulting extract into powder form. Microwave assisted extraction and spray drying steps were optimized using response surface methodology. In the extraction stage, the effect of solvent temperature and extraction time on the total phenolic content was evaluated. Optimum extraction conditions (total phenolic content: 84.48 mg GAE/g) were determined as 55 °C and 26 min. For the final powder production, the maximum process yield (48.00%) was obtained at the point where the spray dryer inlet temperature was 184 °C and the flow rate was 8 mL/min. The presence of phenolic structures in final product was verified by FTIR spectroscopy. Total phenolic content (15.37 mg GAE/g) and antioxidative behavior (DPPH: 0.63 mmol TE/g, ABTS: 0.30 mmol TE/g, FRAP: 0.06 mmol TE/g, CUPRAC: 0.05 mmol TE)/g) of carob powders were evaluated. [ABSTRACT FROM AUTHOR]

In this study, phenolic compounds were extracted from hawthorn fruit using microwave (MAE) and ultrasound assisted extraction (UAE) methods. The MAE was applied at different solids ratios, different extraction times and different microwave powers. UAE was applied at different solids ratios and sonication times. The maceration method was used as the control group. Total phenolic content (TPC) and color values of the extracts were examined. The highest values of TPC were determined as 9.31, 5.34, and 3.00 mg GAE/g dry matter in MAE, UAE, and maceration methods, respectively. Based on these results, it was found that the TPC value of the MAE method was 1.7 and 3.1-fold more than those of UAE and maceration, respectively. In addition, it was observed that L* values of MAE samples were lowest among others. It was concluded that the MAE is the most suitable method for the extraction of phenolic compounds from hawthorn fruit. [ABSTRACT FROM AUTHOR]

In this study, components having antioxidant properties were extracted by microwave assisted homogenization process from artichoke leaves which are considered as a food waste. Antioxidant capacity, total phenolic and total flavonoid content analyzes were applied to the obtained extracts. Extraction yields were determined by proportioning the antioxidant capacity of the extract obtained as a result of the microwave assisted homogenization processes to the those which were obtained by Soxhlet extraction. To achieve the highest extraction yield for the microwave assisted homogenization, the optimum conditions were determined using D-optimal design by 'desirability' function approach. According to the optimization results, the highest extraction yield was predicted as 95.91% with an application of 17.13 minutes of homogenization time, 180 W of microwave power and 11200 rpm of homogenization rate. According to the verification tests, there was no statistical difference between the experimental (96.08±0.83%) and the estimated data (95.91%) (P>0.05). [ABSTRACT FROM AUTHOR]

Microwave-assisted extraction (MAE) is commonly used in recent years as an innovative approach to enhancing the quality of extracts while decreasing the extraction time and the solvent consumption in comparison to conventional techniques. In this study, the influence of microwave power, solid concentration and extraction time on total phenolic content (TPC), colour values and dielectric properties of Caucasian whortleberry were investigated. The process variables were optimized using response surface methodology. The highest TPC from Caucasian whortleberry was obtained at an extraction time of 3.5 min, a solid concentration of 15% and a microwave power of 360 W. The results showed that L* and a* values of the extracts were highly correlated with TPC by a second-order polynomial. Moreover, no significant difference was found in dielectric properties between the groups. [ABSTRACT FROM AUTHOR]

Extraction is an important method for analytical and industrial applications. The studies related to this subject mostly focus on the extraction of compounds such as anthocyanins, phenolic compounds which can be used for the production of functional foods. It is important to protect not only the extracted compounds from the adverse effects of extraction but also the environment by employing green extraction techniques. Hence, new technologies are being developed and studies are being conducted with different foods. Recently, it is aimed to reduce the solvent consumption and extraction time by employing new green extraction methods which are developed as alternatives to conventional methods. This article reviews the most commonly employed green extraction methods (microwave, ultrasound, high pressure, pulsed electric field, ohmic and supercritical fluid extraction) by focusing on the principals, advantages and applications of the new methods. [ABSTRACT FROM AUTHOR]