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An orange-tangerine juice processed by pilot-scale UV-C light (390 mJ/cm2) assisted by mild heat (UV-C/H,50 °C) and enriched with yerba mate (YM) extract (UV-C/H + E) or encapsulated YM extract (UV-C/H + EE) is proposed. The inactivation of Escherichia coli, Lactiplantibacillus plantarum, and Saccharamyces cerevisiae was assessed. Juice samples were analysed for polyphenol content (TPC), total antioxidant activity (TAA), colour, turbidity, and °Brix along refrigerated storage (4 °C; 20 days). For the UV-C/H + E and UV-C/H + EE juices, dynamic consumer profiling studies were performed. According to the challenge study, UV-C/H induced high microbial inactivation (4.9–5.8 log-reductions). TPC (0.059 ± 0.002 mg GAE/mL) and TAA (6.3 ± 0.2 mg TroloxEq/mL) in the UV-C/H + EE juice were 2.1 and 1.6 times greater than the untreated ones, respectively. The UV-C/H + E juice displayed a slightly lower increase in TPC (0.045 ± 0.020 mgGAE/mL), but similar TAA (7.1 ± 0.3 mgTroloxEq/mL), compared to the UV-C/H + EE juice. Therefore, the encapsulation procedure prevented YM extract from TPC degradation. UV-C/H did not alter juice colour while YM addition increased its turbidity. Frequent consumers of YM tea showed a high willingness to try the juice. A cluster sensory analysis revealed that one group of consumers was interested in the sour and herbal aroma of the UV-C/H + E and UV-C/H + EE juices. The T-CATA question showed that the sweetness and herbal aroma of the UV-C/H + E juice were better perceived with sips; whereas, UV-C/H + EE juice perception shifted from fruity, herbal aroma, and sweet to intense taste, bitterness, and pleasant aroma. Thus, YM extract encapsulation also contributed to mask juice bitterness in the first sip while highlighting its sweetness. However, as juice intake proceeded, the panelists perceived juice bitterness more intensely. [ABSTRACT FROM AUTHOR]

The drying process used to obtain active food additives is critical to ensure its functionality. In this study, freeze- and spray-drying techniques were evaluated for encapsulation of extracts with antioxidant activity from yerba mate (Ilex paraguariensis), using maltodextrin (MD) as wall material. Additionally, the oxidative stability in a real food matrix (mayonnaise) was assessed. Both MD addition and drying methods affected the physical properties [moisture content, water activity (aW)] and oxidative stability. MD addition diminished moisture content and prevented polyphenol compounds from degradation. The spray-dried powders displayed the lowest moisture content (1.6 ± 0.3% bs), the highest polyphenol content (135.4 mg GAE/g pure extract), and oxidative stability than the freeze-dried samples. The antioxidant capacity of the encapsulated powder subjected to spray-drying increased the oxidative stability of the mayonnaise (258 ± 32 min) more than the other assayed system (165 ± 5 min). Therefore, a natural spray-dried antioxidant food additive was obtained with potential use in the food industry. [ABSTRACT FROM AUTHOR]

Advanced-stage gastrointestinal tumors have high mortality due to chemotherapy limitations. One of the causes of treatment failure is the presence of cancer stem cells (CSCs), which show resistance mechanisms against DNA damage, such as poly (adenosine diphosphate-ribose) polymerase 1 (PARP-1). However, little is known about the relevance of PARP-1 in these tumor cells. Our purpose is to analyze the expression of PARP-1 in cancer cells and CSCs from gastrointestinal tumors, its relationship with the DNA damage repair process and its modulation by cytotoxic and PARP-1 inhibitors. We used pancreatic, liver and colon cancer cell lines and isolated CSCs using Aldefluor technology to analyze PARP-1 expression. In addition, we examined the effect of classic cytotoxic drugs (Doxorubicin, Gemcitabine, Irinotecan and 5-Fluorouracil) and a PARP-1 inhibitor (Olaparib) in cultured cells and 3D tumorspheres. We demonstrated that PARP-1 is highly expressed in pancreatic, liver and colon tumor cells and that this expression was significantly higher in cell populations with CSC characteristics. In addition, Doxorubicin and Gemcitabine increased their cytotoxic effect when administered simultaneously with Olaparib, decreasing the formation of 3D tumorspheres. Our findings suggest that PARP-1 is a common and relevant resistance mechanism in CSCs from gastrointestinal tumors and that the use of PARP-1 inhibitors may be an adjuvant therapy to increase apoptosis in this type of cells which are responsible to cancer recurrence and metastasis. [ABSTRACT FROM AUTHOR]

In this study, a thermal treatment (T, 85 °C) assisted by short-wave ultraviolet C light (UV-C, 1060 mJ/cm2) under vacuum conditions (400 mmHg) (TV-UVC) is proposed for milk processing, intended to improve some yogurt quality aspects during refrigerated storage (4 °C). In addition, thermal treatment (T) and UV-C light assisted by T without using vacuum (T-UVC) were evaluated for comparison purposes. The TV-UVC treatment was the most effective one, eliminating coliforms and effectively reducing mesophilic counts (4 log-reductions). The effect of the proposed TV-UVC treatment on physicochemical properties, texture, and sensory characteristics of yogurt was studied during storage. TV-UVC yogurt showed 60% less syneresis and highest white index, while exhibiting similar mechanical properties compared to T yogurt during 21-day refrigerated storage. Non-significant changes among all treatments were determined on all evaluated physicochemical parameters during storage (soluble solids, pH, and titratable acidity). Cluster analysis revealed that a group of consumers was very interested in the product; however, some improvements in vanilla and sour taste should be introduced in order to increase overall acceptability. These results suggest that UV-C light assisted by heat and vacuum would represent a promissory alternative for milk processing aimed at yogurt manufacturing. [ABSTRACT FROM AUTHOR]

The susceptibility of Escherichia coli, Salmonella enteritidis, Saccharomyces cerevisiae, and Zygosaccharomyces bailii to binary and ternary mixtures of potassium sorbate (KS), vanillin (V), and citral (C) was evaluated according to the Berenbaum experimental design, in laboratory media. For some V/C combinations, KS inhibitory concentrations were determined in agarized melon and mango purées by the spiral gradient endpoint (SGE) method. In laboratory media, inhibitory antimicrobial combinations were generally additives. For the yeasts, some synergistic effects were observed. All Berenbaum mixtures which resulted inhibitory in laboratory media were confirmed in the fruit purées. When the SGE method was used, several inhibitory ternary mixtures were found. The lowest inhibitory KS concentrations, estimated for a given V/C combination, corresponded to the bacteria assayed in melon purée. Z. bailii was not inhibited at any condition. Some synergistic antimicrobial combinations (595 ppm V + 251 ppm C + 8 ppm KS in melon and 280 ppm V + 123 ppm C + 8 ppm KS in mango purées) could be useful to achieve a desired inhibitory effect in fruit purées while reducing their concentrations. [ABSTRACT FROM AUTHOR]

The effect of steam blanching (90 or 150 s) on linear viscoelastic and compression properties, sensory texture, and micro- and ultrastructure of cut apple was analyzed. All apple samples showed a solid behavior (storage modulus G′ > loss modulus G″) dominating the viscoelastic response, but both dynamic modules were reduced due to processing. For blanched tissues, the instantaneous elastic compliance J and the retarded compliances J and J increased and the steady-state viscosity decreased. Values of mechanical parameters and texture attributes (except cohesiveness) decreased for blanched tissues. Partial least squares regression analysis (PLS) technique was used to study how texture characteristics (dependent variables) were related to rheological properties (independent variables) of untreated and blanched apples. Sensory hardness and crispness were negatively related to J, J, and J and positively correlated to G′ at intermediate and high frequencies ( ω) and G″ at low frequencies. Sensory fracturability was positively correlated with G′ at ω = 0.1 1/s and G″ at ω = 100 1/s. Juiciness and sensory fracturability were positively correlated to instrumental hardness and area 1, and crispness and sensory hardness were positively related to instrumental fracturability. Structure differences (rupture of membranes, decrease in cell-to-cell contact, degradation of cell walls, changes in microfibril arrangements) could explain some changes observed in rheological properties and texture of blanched apples. [ABSTRACT FROM AUTHOR]

This work analyzed the pulsed light (PL) (0.0-71.6 J/cm)-induced damage on Saccharomyces cerevisiae KE162 cells in peptone water (pH 3.5 or 5.6) and apple juice (pH 3.5) by applying flow cytometry (FCM) and transmission electronic microscopy. Cells were labeled with fluorescein diacetate (FDA) for detecting membrane integrity and esterase activity and with propidium iodide (PI) for monitoring membrane integrity. S. cerevisiae inactivation curves reached 6-7 log reductions (peptone water systems) and 3.9 log reductions (apple juice) after 60 s (71.6 J/cm) of PL exposure. FCM revealed the same damage pattern (although at different doses) in all media: at low doses, there was an increase in population in PI−FDA quadrant, while at high doses, most of the population was located at quadrant PI-FDA, indicating that PL provoked rupture of the cytoplasm membrane allowing PI to penetrate cells and there was progressive loss of esterase activity. Comparison of conventional culture technique with FCM revealed the occurrence of certain cell subpopulations in peptone water with pH 3.5 which were stressed and lost their ability to grow in agar but still showed metabolic activity. Transmission electron microphotographs of PL-treated cells clearly indicated that various cell structures other than plasma membranes were altered and/or destroyed in a different degree depending on exposure time and type of medium. [ABSTRACT FROM AUTHOR]

The objective of this work was to evaluate and correlate rheological properties (small-scale dynamic oscillatory and creep/recovery measurements and large-scale compression force-deformation testing), texture (sensory evaluation by trained panel) and structure (optical and transmission electronic microscopy observations) of apples osmotically dehydrated to water activity ( a) 0.97 with glucose, with or without previous blanching. All apple samples showed a solid behavior ( G′ > G″) dominating the viscoelastic response, but both dynamic moduli were reduced due to processing. The instantaneous elastic compliance ( J) and the retarded compliances ( J and J) increased for treated tissues and the steady-state viscosity ( η) was approximately 15% to 29% of the value of fresh apple. In general, compression parameters decreased for all treated tissues. Changes in structural features were mainly evidenced in heated samples. Partial least squares regression analysis regression models revealed that texture could be well predicted by rheological properties (compression and creep parameters). Juiciness, crispness and sensory hardness were negatively correlated to J, J and J, and η was negatively correlated to sensory fracturability. Some mechanical parameters (fracturability, hardness 2, area 2, modulus of deformability and cohesiveness) were positively related to sensory fracturability, crispness and sensory hardness; and juiciness was negatively correlated to hardness. Compression and creep parameters showed ability to evidence structure differences (rupture of membranes, swelling of cells and degradation of cell walls) and to explain texture of treated apples. [ABSTRACT FROM AUTHOR]

Novel technologies that involve non-thermal processes have been investigated in the last two decades as full or partial alternatives to conventional heat treatment. The main objective of this study was to evaluate the survival of single or strain cocktail of Escherichia coli, Saccharomyces cerevisiae, and a yeast cocktail in orange (pH 3.5; 9° Brix) and/or apple (pH 3.1; 12° Brix) juices and in 0.1% w/ w peptone water processed by two non-thermal techniques: high-intensity ultrasound (USc) and/or short-wave ultraviolet radiation (UV-C). USc treatments (20 kHz, 95 µm-wave amplitude) were performed using a stainless steel continuous flow cell with a 13-mm probe (0.2 L/min; 40°C). The UV-C device consisted of a 90-cm long UV-C-lamp (100 W) placed inside a glass tube leaving an annular flow space (0.2 L/min; 40°C). Inoculated systems were recirculated through simultaneous or consecutive USc and UV-C devices and samples were taken at preset time intervals. Microbial populations were monitored by plate count technique. In peptone water and apple juice, UV-C radiation provoked higher E. coli ATCC 35218 inactivation than USc treatment. E. coli ATCC 35218 and its cocktail were more sensitive than S. cerevisiae KE162 and the cocktail of yeasts. UV-C efficiency was highly dependent on media nature. The poor single effect of UV-C light in orange juice was enhanced by the combination with USc. Combined treatment was more effective in simultaneous rather than in a series of USc − UV-C arrangement. [ABSTRACT FROM AUTHOR]

The response of Listeria innocua (surrogate for Listeria monocytogenes) to combined treatments involving moderate temperatures (57 to 61 °C) and the addition of different levels of citral (0 to 75 ppm) was assessed to obtain a minimally processed orange juice. The presence of citral notoriously increased the bactericidal effect of mild heating treatment. This effect did not depend on the amount of added citral at all assayed temperatures. In a second stage, combinations of two natural antimicrobials (vanillin and citral) were assessed in order to find the most effective inactivation treatment in orange juice. Vanillin (900–1,100 ppm) and citral (25 ppm) combined with mild heating treatment (52 or 57 °C) were tested against L. innocua in orange juice. The addition of 900 ppm vanillin and 25 ppm citral halved or more the time required to achieve five logarithmic cycles of reduction at both temperatures with respect to thermal treatment without antimicrobial addition. The increase in the maximum growth rate calculated from the modified Gompertz model properly correlated with the increasing vanillin level for a given citral concentration. Complementary information was obtained from successfully fitting a Weibullian model to the nonlinear semilogarithmic survival curves: The addition of vanillin and citral significantly increased the bactericidal effect of mild thermal treatment, changing the distribution of inactivation times and obtaining narrower frequency shapes with lower variance and mode values. The combination of vanillin and citral with mild heating treatment resulted in an innovative alternative to minimize detrimental effects caused by thermal processing of fruit juices. In addition, a consumer panel evaluated them with an acceptable overall pleasantness. [ABSTRACT FROM AUTHOR]

A number of studies have reported that heavy metals are not only toxic for the organism but they may modulate immune responses. In the current study, the effect of 4-week administration of 200 ppm of PbAc2, using different routes of administration (orally and intraperitoneal injection), on lymphatic organs was evaluated. In the thymus, the number of lymphocyte cells and the cellularity diminished significantly for both routes of treatment. Regarding the submaxillary lymph nodes, no significant variations took place. Cell-mediated immune response is commonly evaluated by cell proliferation assays. Mitogens are known to induce a vigorous proliferative response in lymphoid cells from mammals. An increase in the proliferation of T lymphocytes stimulated by concanavalin A and the proliferation of B lymphocytes stimulated with lipopolysaccharides was found in thymus for both routes of administration, whereas in the lymph nodes, there was a decrease in proliferation of T lymphocytes. Furthermore, lead administration by intraperitoneal route caused an effect on B and T lymphocyte subpopulations. Thus, there was an increase in B+ cells and a decrease in T+ cells. Regarding CD4+ and CD8+ T cells, there were only variations, concretely a drop in both subpopulations, in lymph nodes when lead was administered intraperitoneally. It is important to emphasize that an increase in apoptosis was found in this tissue. At the histological level, evident alterations were described in thymus both for the oral and for the intraperitoneal route. Therefore, it is possible to show that lead administered by both routes generated effects on an immunological level. [ABSTRACT FROM AUTHOR]

Ultraviolet energy at a wavelength of 253.7 nm (UV-C) was investigated for its microbicidal effects on pear slices with and without peel. Effectiveness of UV-C light against Listeria innocua ATCC 33090, Listeria monocytogenes ATCC 19114 D, Escherichia coli ATCC 11229, and Zygosaccharomyces bailli NRRL 7256 individual strains was tested in both types of pear slices. In a second experiment, strain cocktails of Listeria (L. innocua ATCC 33090; L. innocua CIP 8011 and L. welshimeri BE 313/01), L. monocytogenes (L. monocytogenes ATCC 19114 D, L. monocytogenes ATCC 7644), and yeasts (Z. bailii NRRL 7256, Zygosaccharomyces rouxii ATCC 52519, and Debaryomyces hansenii NRRL 7268) were also used as inocula and compared with single-strain responses. Inoculated pear slices were exposed to a UV-C dose range between 0 and 87 kJ/m² and enumerated to determine log reductions of microbial populations. Overall, as UV-C dose was increased (increasing the time of exposure), more inactivation was observed for all species assayed. UV-C irradiation appeared to improve microbial inactivation in pear slices without peel. In most experiments, great log reduction rates were observed at doses between 0 and 15 kJ/m². Inactivation kinetics was successfully fitted using a Weibullian distribution of resistances model. Narrow frequency shapes strongly skewed to the right were obtained. This model offers improved tools for designing and implementing UV-C light treatment and assessing the impact of some microorganisms' disease. [ABSTRACT FROM AUTHOR]

Samples of four different species of seaweed were collected monthly between October 2000 and March 2001 from the coast of the Strait of Magellan, Chile to establish baseline levels of trace metals (silver, total mercury, nickel, lead, antimony, vanadium and zinc) and to compare the accumulation capacity among species. The algae included in the study were Adenocystis utricularis (n = 15); Enteromorpha sp . (n = 11), Mazzaella laminarioides (n = 12) and Porphyra columbina (n = 6). The concentration range of each metal in μg g−1 dry weight varied as follows: Ag = ND-0.3, Hg = ND-0.02, Ni = ND-12.6, Pb = ND-11.2, Sb = ND-1.97, V = ND-11.34 and Zn = 14.10-79. Results showed that levels of Ag, Hg, Ni, Pb, Sb, V and Zn for all species were similar to those found in other studies for non-contaminated areas with very little influence from anthropogenic activity. Also among the four species studied macroalgae Enteromorpha sp. had the highest capacity for metal accumulation and could therefore be considered as a biomonitor for future studies in the area. [ABSTRACT FROM AUTHOR]

A correction to the article "Intra-specific variation in nitrate tolerance in tadpoles of the Natterjack toad" that was published online on June 1, 2011 is presented.