Liquid nitrogen–assisted juicing coupled with high hydrostatic pressure: A non-thermal strategy to improve the quality of NFC mandarin juice

This study investigated liquid nitrogen-assisted juicing (LNJ) combined with high-pressure processing (LHPP, 400 MPa, 5 min) as a non-thermal processing approach under laboratory-scale conditions for improving the quality of NFC citrus juice. The effects of LHPP were compared with conventional room-temperature juicing followed by pasteurization (CP), liquid nitrogen-assisted juicing followed by pasteurization (LP), and conventional room-temperature juicing combined with high-pressure processing (CHPP). Compared with thermally pasteurized juice, LHPP-treated juice enhanced retention of characteristic citrus aroma compounds, as evidenced by electronic nose, electronic tongue, and GC-IMS analyses. Compared with fresh NFC juice (CK), LHPP showed relatively higher relative signal intensities of key citrus-related volatile compounds, such as ( R / S )-linalool and 1-penten-3-ol, suggesting a lower extent of flavor loss typically associated with thermal processing. In addition, LHPP effectively inhibited browning development, reduced particle size, and increased zeta potential, indicating potential improvements in turbidity stability. The contents of total phenolics, total flavonoids, and carotenoids were better retained in LHPP-treated juice than in thermally processed counterparts. The combined application of LNJ and HPP showed effects on flavor retention, physicochemical stability, and bioactive compound preservation, providing preliminary insights into process interactions in NFC citrus juice systems at the laboratory scale.