Microwave radiation extraction of polyphenols from apple peel

The extraction of apple-polyphenols from apple peel was studied. The extraction effects of different solvents were compared,and the technological conditions of microwave radiation extraction of polyphenols were investigated by the single factor and orthogonal experiments. The influence of solvent concentration,microwave power,microwave treatment time and solid-to-liquid ratio on the extraction was studied,and comparison was made between conventional extraction and microwave radiation extraction. The results indicated that alcohol was the appropriate solvent if extraction effect and food safety were taken into consideration. The optimum technological conditions of microwave radiation extraction were determined as follows: alcohol concentration 70%,microwave power 210W,microwave extraction time 25s and solid-to-liquid ratio 1 : 5. The content of proanthocyanidin was 0.3668 mg/ml with microwave radiation extraction, and 0.2552 mg/ml with the conventional method, which showed that the former was superior to the latter.