Combination effects of ultrasound and hyperbranched poly-L-lysine on quality preservation of fresh‑cut carrots during storage

Abstract

During the handling and preservation of fresh-cut fruits and vegetables, challenges such as moisture loss, color fading, and softening frequently arise, substantially affecting their quality and storage duration. This study investigated the impact of the combined application of ultrasound (US) and hyperbranched poly-L-lysine (HBPL) on the storage quality of fresh-cut carrots. The results demonstrated that the combined treatment of US and HBPL, particularly the post-cut US-HBPL (POUS-HBPL) treatment, significantly enhanced the storage quality, maintaining superior quality even after 15 days of storage. After 15 days, the weight loss rate, hardness, whiteness index, and total number of colonies in the POUS-HBPL group were 0.88%, 8.39, 41.55, and 5.09 logCFU/g, respectively, all of which were all notably lower compared to those in other treatment groups (p < 0.05). Additionally, the levels of reducing sugar, soluble protein, vitamin C, total phenols, and carotenoids in POUS-HBPL group were 1.99 mg/g, 0.2515 mg/g, 8.32 mg/g, 0.0628 mg/g, and 0.71 mg/g, which were considerably higher compared to other treatment groups (p < 0.05). Furthermore, the combined US and HBPL treatment effectively inhibited the accumulation of malondialdehyde (MDA), reduced relative electrolyte leakage, and significantly increased the activities of catalase (CAT), superoxide dismutase (SOD), and phenylalnine ammonialyase (PAL), while significantly inhibiting polyphenol oxidase (PPO) activity. In summary, the combined treatment of US and HBPL, particularly POUS-HBPL, adequately maintained the quality characteristics and nutritional value of freshly cut carrots, improved their antioxidant capacity, and prolonged their shelf life.