Effect of high-pressure processing on bioactive compounds in pomegranate juice

Abstract:

What observers of the juice industry have noticed is a growing gap between consumer demand for fresh-like, nutrient-rich beverages and the shelf-life constraints of cold-pressed products. High-pressure processing (HPP) can bridge this gap by inactivating microorganisms at ambient temperature, but its impact on pomegranate’s signature bioactives—anthocyanins, ellagitannins, and vitamin C—remains incompletely characterised. This research treated freshly extracted pomegranate juice (cv. Bhagwa) at 200, 300, 400, 500, and 600 MPa for 5 min at 25 °C and evaluated the effects on total phenolic content, anthocyanins, vitamin C, DPPH radical scavenging, colour, microbial load, and storage stability (28 days, 4 °C). The work was carried out at the Department of Food Science and Technology, Ege University, Bornova, İzmir, during July-November 2023. At 400 MPa, the juice retained 95.6% TPC, 94.1% anthocyanins, and 90.3% vitamin C while achieving a 2.9-log reduction in total plate count. Treatments at 500-600 MPa gave greater microbial kill (3.6-4.2 log) but caused 10-21% losses in vitamin C. Colour stability during storage was markedly better in HPP-treated juice than in untreated controls. HPP at 400 MPa offers the best balance of safety and bioactive retention for pomegranate juice.