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BACKGROUND: Although phenolic compounds have a role in the health benefits of fruit juice consumption, little is known about the effect of processing on their bioaccessibility. The release of phenolic compounds from the food matrix during digestion is an important pre-requisite for their effectiveness within the human body, and so it is fundamental to identify technological treatments able to preserve not only the concentration of phytochemicals, but also their bioaccessibility. In the present study, we investigated the impact of high-pressure homogenization (HPH), alone and in the presence of 100 g kg−1 trehalose or Lactobacillus salivarius, on the bioaccessibility of flavonoids in mandarin juice. In addition, digested mandarin juices were supplemented to liver cultured cells in basal and stressed conditions to evaluate their protective effect in a biological system. RESULTS: HPH reduced the concentration of total phenolics and main flavonoids but increased their bioaccessibility after in vitro digestion (P < 0.001). In the basal condition, supplementation with all digested juices significantly reduced intracellular reactive oxygen species (ROS) concentration (P < 0.001). Thiobarbituric acid reactive substances concentration in the medium was also reduced by supplementation with HPH-treated juices. Although pre-treatment with juices did not completely counteract the applied oxidative stress, it preserved cell viability, and cells pre-treated with juices submitted to HPH in the presence of probiotics showed the lowest ROS concentration. CONCLUSION: The present study represents an important step ahead in the evaluation of the impact of processing on the nutritional and functional value of food, which cannot simply be assessed based on chemical composition. © 2020 Society of Chemical Industry.

[EN] This study evaluates the effect of trehalose addition (10% or 20%, w/w) and/or sublethal homogenisation (25-150 MPa) on antioxidants content (vitamin C, total phenols and flavonoids) and activity (measured both by ABTS-TEAC and DPPH assays), as well as on microbial counts and survival to in vitro digestion of clementine juice inoculated with Lactobacillus salivarius spp. salivarius. Particle size, vacuum impregnation parameters and anti-Helicobacter pylori effect were also measured. Incubation with the probiotic improved the antioxidant properties of the juice. Homogenisation pressures below 100 MPa following incubation increased both the probiotic counts in the juice and its antioxidants bioaccesibility. Adding 10% (w/w) of trehalose to the juice was effective in preventing these bioactive compounds deterioration under adverse conditions. Once homogenised, liquids containing 10% (w/w) of trehalose became as able as those without trehalose to enter a food solid matrix. Inhibition of Helicobacter pylori growth was evident in all probiotic beverages., This research has been carried out with the financing granted by the Generalitat Valenciana for project GV/2015/066 "Improving the functional quality of a snack with probiotic effect and antioxidant properties through the incorporation of trehalose and the application of high homogenisation pressures".