Effect of high-pressure processing applied as pretreatment on carotenoids, flavonoids and vitamin C in juice of the sweet oranges 'Navel' and the red-fleshed 'Cara Cara'.

This work examines the effect of HPP at 200 MPa/25 °C/1 min (HPP-200) as pretreatment on whole-peeled orange fruits from ordinary 'Navel' and red-fleshed 'Cara Cara' sweet oranges before juicing with the aim to improve the extractability of carotenoids, flavonoids, vitamin C and hydrophilic antioxidant activity in the juices. Untreated and HPP-200 juices were subsequently processed at 400 MPa/40 °C/1 min (HPP-400 and HPP-200-400). HPP-200 and HPP-200-400 increased the concentration of hesperidin (25% and 16%), narirutin (27% and 9%), phytoene (40% and 97%) and phytofluene (9- and 12-fold) in Navel-juice and maintained the vitamin C content and the antioxidant activity compared to untreated freshly-prepared juice. However, these two HPP treatments in Cara Cara-juices preserved flavonoids and vitamin C concentration but decreased 16% total carotenoid content mainly lycopene due to its more exposed position in the food matrix. However, a single HPP-400 treatment applied on freshly-prepared orange juices reduced bioactive compounds, mainly in Navel-juices, perhaps due to the mechanical juicing procedure (jar-blender) used or/and with the pressure-induced activation of detrimental food enzymes. All the HP-treated Cara Cara-juices presented higher carotenoid content than the corresponding Navel-juices, and can be considered an excellent dietary source of these compounds. Therefore, HPP applied to whole peeled orange did not modified the profiling of bioactive compounds of Navel- and Cara Cara-juices and increased the concentration of total and individual carotenoids, flavonoids, vitamin C and antioxidant activity depending on the type of bioactive compounds, the orange fruit cultivar and the HPP conditions.

Evaluation of chemical and physical (high-pressure and temperature) treatments to improve the safety of minimally processed mung bean sprouts during refrigerated storage.

The objective of this study was to compare the effects of combined high hydrostatic pressure and temperature treatments with different chemical sanitation treatments (water, sodium hypochlorite, and hydrogen peroxide) on the microbiological properties of mung bean sprouts. In a first study, the raw product was subjected to several combined high-pressure and temperature treatments for calculating a mathematical model by a response surface methodology. The number of pressure-temperature (150 to 400 MPa; 20 to 40 degrees C) combinations was limited to 10. In addition, a model system consisting of mung bean sprout juice was inoculated with Listeria monocytogenes (CECT 4032). Microbial inactivation with this model system was also investigated by a response surface methodology. The highest aerobic mesophilic bacteria and L. monocytogenes inactivation was achieved at maximum pressure and temperature (5.5 and 1.8 log cycles, respectively). In a second study, the effect of five different processing lines on the microbial load reduction of minimally processed mung bean sprouts during refrigerated storage was studied. All treatments reduced the initial population of aerobic mesophilic bacteria and fecal coliforms, with the physical treatment of 400 MPa and 40 degrees C being the most effective, showing initial reductions of 5.8 and 7.8 log CFU/ g, respectively. Recovery of bacteria from sprouts treated under these conditions was not observed during storage. However, the sprouts that received washing treatments with water, sodium hypochlorite, and hydrogen peroxide exhibited increases in aerobic mesophilic and fecal coliform counts after 3 days of storage at 4 degrees C.

Intake of Mediterranean vegetable soup treated by pulsed electric fields affects plasma vitamin C and antioxidant biomarkers in humans.

The bioavailability of vitamin C from pulsed electric fields (PEF)-treated vegetable soup in comparison with freshly made (FM) vegetable soup-gazpacho-and its impact on 8-epiPGF(2alpha) and uric acid concentrations in a human population were assessed. For this purpose six subjects consumed 500 ml PEF-treated vegetable soup/day, and six subjects consumed 500 ml FM vegetable soup/day for 14 days. On the first day of the study, the subjects drank the vegetable soup in one dose (dose-response study), and on days 2-14 they consumed 250 ml in the morning and 250 ml in the afternoon (multiple-dose-response study). Blood was collected every hour for 6 h on the first day and again on days 7 and 14. All blood samples were analyzed for vitamin C, 8-epiPGF(2alpha), and uric acid. The maximum increase in plasma vitamin C occurred 3 h post-dose in both the PEF and the FM groups. Vitamin C remained significantly higher (P = 0.05) on days 7 and 14. The plasma 8-epiPGF(2alpha) concentration was significantly lower at the end of the study in both the PEF group (P = 0.002) and the FM group (P = 0.05). Plasma levels of vitamin C and 8-epiPGF(2alpha) were inversely correlated in both groups (r= -0.549, P = 0.018; and r = -0.743, P = 0.0004, respectively). To summarize, drinking two servings (500 ml) of PEF-treated or FM gazpacho daily increases plasma vitamin C and significantly decreases 8-epiPGF(2alpha) concentrations in healthy humans.