Effect of High-Pressure Processing on Storage Quality, Bioactive Compounds, and Flavor Profile of Selenium-Sand Melon...

This study systematically evaluated the effects of high-pressure processing (HPP, 500 MPa, 10 min) on the comprehensive quality of selenium-sand melon juice (SSJ) over a 35-day refrigerated storage period (4 °C). To simulate extreme contamination scenarios, samples were inoculated with Escherichia coli (6.886 log₁₀ CFU/mL) and Aspergillus sclerotioniger (5.011 log₁₀ spores/mL). Five treatment groups were established, including HPP-treated (inoculated and uninoculated) and low-temperature long-time (LTLT, 65 °C for 30 min) pasteurized (inoculated and uninoculated) groups. HPP treatment completely inactivated the inoculated microorganisms, with no regrowth detected during storage, whereas regrowth was observed in the LTLT groups after day 7. HPP-treated samples exhibited superior color stability (ΔE ≤ 1.58) and compounds, and maintained a higher final pH (5.76 vs. 5.39 in LTLT) at the end of storage, with significantly better retention of lycopene and total phenolic compounds compared to LTLT-treated samples. OPLS-DA analysis of volatile compounds showed that the HPP-M group had only four discriminating compounds (VIP ≥ 1), all characteristic C9 aldehydes and alcohols, while the LTLT-M group showed significant acetic acid accumulation, likely due to residual microbial metabolism. This study demonstrates that HPP is superior to LTLT pasteurization for ensuring microbial safety, preserving nutritional quality, and maintaining the characteristic flavor of SSJ during cold storage.