The grape juice by-product obtained from grape traditional press was extracted by Microwave Hydrodiffusion
and Gravity (MHG); a green extraction technique preliminarily optimized at 1 W/g. The MHG
extract (MHGE) was analyzed by HPLC for identification and quantification of anthocyanins and other
phenolic compounds. Then, MHGE was added to the natural juice (NJ) to produce an innovative grape
juice (IJ). These three juices were evaluated for their total polyphenol content (TPC), total anthocyanin
content (TAC) in addition to their sensorial characteristics. MHGE showed the highest values of TPC
(21.41 ± 0.04 mg GAE/g DW), TAC (4.49 ± 0.01 lg MVGE/g DW). Moreover, IJ (grape juice enriched with
MHGE) was richer in TPC (6.70 ± 0.01 mg GAE/g DW) and TAC (3.96 ± 0.01 lg MVGE/g DW) than NJ
(2.90 ± 0.02 mg GAE/g DW and 3.63 ± 0.06 lg MVGE/g DW, respectively).