Plums are rich in antioxidant polyphenols mainly found in the skin, and a considerable amount is retained in the pomace after juice processing. This study investigated the impact of combined ultrasound‐enzyme (UEZ) treatment (15–60 min) on antioxidant compounds recovery, quality, and extraction efficiency of plum‐juice, in comparison with single treatments. The result revealed that UEZ could shorten treatment time (up to four times), with significantly (p < .05) higher yield, bioactive compounds and antioxidant capacity compared to untreated, ultrasound‐ and enzyme‐treated juice samples, substantiating the effectiveness of combine‐treatment over single‐treatment. Moreover, clear juice obtained by UEZ (15 min), showed better and comparable physicochemical quality to juice from traditional enzymatic pretreatment (60 min). Furthermore, the antioxidant capacity of plum‐juice, estimated by various radical scavenging assays correlated strongly with high contents of coumaric, ferulic, and chlorogenic acids, rutin, and catechin released in plum‐juice. Overall, UEZ treatment expedited the production of clear plum‐juice rich in antioxidant compounds.
Practical Applications
The skin of plum constitutes about 70% of the beneficial phytochemicals of the fruit, with a majority retained in the pomace when the conventional squeezing method is employed to produce juice. To benefit from these nutrients, enzymatic pretreatment is used to produce clear juice, and also recover these compounds in juice. However, it is often time‐consuming. Hence, this study employed the combined use of ultrasound to intensify enzymatic extraction and facilitate the rapid recovery of beneficial phenolic compounds from the skin of plum into the extracted juice. The results obtained confirmed the synergistic impact of this technique in expediting clear juice production, with higher yields, antioxidant polyphenols, and better‐quality properties. Thus, provided a practical solution for the efficient production of clear plum juice with potential health benefits.