The Arbuscular Mycorrhizal Fungus Glomus viscosum Improves the Tolerance to Verticillium Wilt in Artichoke by Modulating the Antioxidant Defense Systems.

Verticillium wilt, caused by the fungal pathogen Verticillium dahliae, is the most severe disease that threatens artichoke (Cynara scolymus L.) plants. Arbuscular mycorrhizal fungi (AMF) may represent a useful biological control strategy against this pathogen attack, replacing chemical compounds that, up to now, have been not very effective. In this study, we evaluated the effect of the AMF Glomus viscosum Nicolson in enhancing the plant tolerance towards the pathogen V. dahliae. The role of the ascorbate-glutathione (ASC-GSH) cycle and other antioxidant systems involved in the complex network of the pathogen-fungi-plant interaction have been investigated. The results obtained showed that the AMF G. viscosum is able to enhance the defense antioxidant systems in artichoke plants affected by V. dahliae, alleviating the oxidative stress symptoms. AMF-inoculated plants exhibited significant increases in ascorbate peroxidase (APX), monodehydroascorbate reductase (MDHAR), and superoxide dismutase (SOD) activities, a higher content of ascorbate (ASC) and glutathione (GSH), and a decrease in the levels of lipid peroxidation and hydrogen peroxide (H2O2). Hence, G. viscosum may represent an effective strategy for mitigating V. dahliae pathogenicity in artichokes, enhancing the plant defense systems, and improving the nutritional values and benefit to human health.

Effect of nitrogen fertilisation on the overall quality of minimally processed globe artichoke heads.

BACKGROUND: Although nitrogen (N) fertilisation is essential for promoting crop yield, it may also affect the produce quality. Here, the influence of three N fertiliser rates (0 kg ha-1 as a control, 200 kg ha-1 and 400 kg ha-1 referred to as N0 , N200 and N400, respectively) on the overall quality of minimally processed globe artichoke heads was investigated during refrigerated storage for 12 days. RESULTS: Throughout the storage time, N fertilised samples had higher inulin contents than those unfertilised. In addition, the respiratory quotient of N200 and N400 samples was 2-fold and 2.5-fold lower than N0 ones, whose values were close to the normal range for vegetables. All the samples reported good microbiological standards, although N200 and N400 achieved lower mesophilic and psychotropic counts than N0 throughout the storage time. After 8 and 12 days of refrigerated storage, the N200 samples showed the highest scores of positive sensory descriptors. CONCLUSION: A fertiliser level of 200 kg N ha-1 is suitable for obtaining minimally processed globe artichoke heads with good nutritional, sensory and microbiological quality, characterised by low endogenous oxidase activities. Proper packaging systems and procedures are, however, crucial for extending the product shelf-life and, thus, promoting its exportation on a wider scale. © 2016 Society of Chemical Industry.

Effect of high-pressure homogenization on different matrices of food supplements.

There is a growing demand for food supplements containing high amounts of vitamins, phenolic compounds and mineral content that provide health benefits. Those functional compounds have different solubility properties, and the maintenance of their compounds and the guarantee of their homogenic properties need the application of novel technologies. The quality of different drinkable functional foods after thermal processing (0.1 MPa) or high-pressure homogenization under two different conditions (80 MPa, 33 ℃ and 120 MPa, 43 ℃) was studied. Physicochemical characteristics and sensory qualities were evaluated throughout the six months of accelerated storage at 40 ℃ and 75% relative humidity (RH). Aroma and color were better maintained in high-pressure homogenization-treated samples than the thermally treated ones, which contributed significantly to extending their shelf life. The small particle size obtained after high-pressure homogenization treatments caused differences in turbidity and viscosity with respect to heat-treated samples. The use of high-pressure homogenization, more specifically, 120 MPa, provided active ingredient homogeneity to ensure uniform content in functional food supplements. Although the effect of high-pressure homogenization can be affected by the food matrix, high-pressure homogenization can be implemented as an alternative to conventional heat treatments in a commercial setting within the functional food supplement or pharmaceutical industry.

Establishment of fungal entomopathogens Beauveria bassiana and Bionectria ochroleuca (Ascomycota: Hypocreales) as endophytes on artichoke Cynara scolymus.

Entomopathogenic fungi (EPF) are commonly found in diverse habitats and are known to cause mycoses in many different taxa of arthropods. Various unexpected roles have been recently reported for fungal entomopathogens, including their presence as fungal endophytes, plant disease antagonists, rhizosphere colonizers and plant growth promoting fungi. In Tunisia, a wide range of indigenous EPF isolates from different species, such as Beauveria bassiana and Bionectria ochroleuca, were found to occur in the soil, and to be pathogenic against the artichoke aphid Capitophorus elaeagni (Hemiptera: Aphididae). Since endophytic fungi are recently regarded as plant-defending mutualists and their presence in internal plant tissue has been discussed as an adaptive protection against insects, we were interested on elucidating the possible endophytic behavior of B. bassiana and B. ochroleuca on artichoke, Cynara scolymus, after foliar spraying tehcnique. The leaf spray inoculation method was effective in introducing the inoculated fungi into the plant tissues and showed, then, an endophytic activity on artichoke even 10 days later. According S-N-K test, there was significant differences between the two fungal treatments, B. ochroleuca (84% a) and B. bassiana (78% a), and controls (0% b). Likewise, the inoculated entomopathogenic fungi were also isolated from new leaves even though with significant differences respectively between controls (0% c), B. bassiana (56% b) and B. ochroleuca (78% a). These results reveals significant new data on the interaction of inoculated fungi with artichoke plant as ecological roles that can be exploited for the protection of plants.

Bioprotection of ready-to-eat probiotic artichokes processed with Lactobacillus paracasei LMGP22043 against foodborne pathogens.

The survival of 3 pathogens Listeria monocytogenes ATCC19115, Salmonella enterica subsp. enterica ATCC13311, and Escherichia coli ATCC8739 was evaluated over time in ready-to-eat (RTE) artichoke products processed or not with the probiotic strain Lactobacillus paracasei LMGP22043. Both probiotic and standard products (final pH about 4.0; aw = 0.98) dressed with oil and packaged in modified atmosphere were inoculated with pathogens at a level of about 3 log CFU/g and stored at 4 ºC for 45 d. Pathogens decreased in the probiotic product in 2 descent phases, without shoulder and/or tailing as observed by fitting the models available in the GInaFit software to the experimental data. S. enterica subsp. enterica was completely inactivated after 14 and 28 d in probiotic and standard products, respectively; E. coli was inhibited in the probiotic food at day 4 (count

Polyphenol metabolite profile of artichoke is modulated by agronomical practices and cooking method.

In this paper artichoke phenolic pattern was characterized using an Orbitrap Exactive Mass Spectrometer at high mass accuracy and conventional HPLC MS/MS. Twenty four phenolic acids and 40 flavonoids were identified, many of them not previously reported in artichoke. Variations in phenolic compounds were investigated in relation to mycorrhization: results showed that inoculation with mycorrhizae greatly influences metabolite profile proving to be a good strategy to enhance the biosynthesis of secondary metabolites in this plant. This practice also caused a different distribution of the main phenolic compounds within head parts. Both steaming and microwaving cooking treatments caused an increase in antioxidant activity: the lower the initial concentration the higher the effect. A similar trend was observed looking at the phenolic compounds concentration: it increased because of cooking treatments the lower the initial content, the highest the increase. Steamed artichoke showed higher phenols content than microwaved ones.

Randomised clinical trial: efficacy of Lactobacillus paracasei-enriched artichokes in the treatment of patients with functional constipation--a double-blind, controlled, crossover study.

BACKGROUND: The role of probiotics in the management of constipation is uncertain. AIMS: To evaluate the effects of probiotic-enriched artichokes on treatment preference, symptom profile and short-chain fatty acid (SCFA) production in constipated subjects when compared with ordinary artichokes. METHODS: Twenty constipated patients (3M/17F; 38.8 ± 14.4 years) were studied using a double-blind method and a computer-generated randomisation list. Each patient consumed 180 g per day of ordinary artichokes or artichokes enriched with Lactobacillus paracasei IMPC 2.1 for 15 days (daily dose of 2 × 10(10) CFU). Relief of symptoms was evaluated using a visual analogue scale. The stool consistency and symptom profile of patients were investigated using the Bristol stool form chart and the Gastrointestinal Symptom Rating Scale questionnaire (GSRS). SCFA production in faecal samples was evaluated using HPLC. RESULTS: Eighty per cent of patients preferred probiotic-enriched artichokes to ordinary ones (P = 0.011). Satisfactory relief of symptoms was significantly higher (P = 0.0014) during the probiotic-enriched artichoke period. Bristol chart cluster scores were significantly higher (3.3 ± 1.2, 2.9 ± 1.3 2.2 ± 1.2, baseline, ordinary artichokes and probiotic-enriched ones, respectively; P = 0.009) and GSRS constipation was significantly lower (13.9 ± 0.9, 10.2 ± 0.8, 8.3 ± 0.9; P = 0.032) in the probiotic group compared with the baseline. As for SCFA production, propionic acid was significantly higher (2.2 ± 1.4, 2.1 ± 1.53, 1.5 ± 1.2; P = 0.035) in the probiotic group compared with baseline. CONCLUSION: This trial shows a positive effect on symptoms in constipated patients after intake of probiotic-enriched artichokes.

Role of the probiotic strain Lactobacillus paracasei LMGP22043 carried by artichokes in influencing faecal bacteria and biochemical parameters in human subjects.

AIMS: To evaluate the positive influence of the probiotic strain Lactobacillus paracasei LMGP22043 carried by artichokes into the human gut with special reference to faecal bacterial balance, short-chain fatty acid concentrations and enzyme activities in a randomized, double-blind human trial in comparison with probiotic-free artichokes (control). METHODS: Twenty subjects were randomized into two groups, which consumed daily 180 g of the artichoke product (probiotic or control) during two 15-day study periods (periods 1 and 2) separated by a 15-day washout in a crossover manner. Faecal samples were subjected to microbiological and biochemical analyses, and a strain-specific PCR was performed to monitor the probiotic strain. RESULTS: The probiotic strain, transported by the vegetable matrix, transiently colonized the gut of 17/20 subjects (median 6·87 log CFU g⁻¹ faeces), antagonized Escherichia coli and Clostridium spp. and increased the genetic diversity of lactic population based on REP-PCR profiles, mainly after period 1. CONCLUSIONS: The probiotic L. paracasei LMGP22043 successfully colonized the human gut and positively influenced faecal bacteria and biochemical parameters. SIGNIFICANCE AND IMPACT OF THE STUDY: The association of the probiotic L. paracasei with a food carrier rich in fibre can represent a new strategy for favouring a daily supply of probiotics and attracting more consumers to vegetable food fortified with probiotic strains.

Effects of probiotic Lactobacillus paracasei-enriched artichokes on constipated patients: a pilot study.

GOALS: To determine whether the consumption of artichokes enriched with a probiotic Lactobacillus paracasei strain affects fecal microbiota composition, fecal enzyme activity, and short-chain fatty acids production and symptom profile in patients suffering from constipation. BACKGROUND: Constipation is a common gastrointestinal disorder often related to the food diet. The beneficial effects of probiotics and prebiotics on human health are under investigation. Moreover, recent studies assessed the suitability of some vegetables, particularly olives and artichokes, to vehicle probiotic strains into the gastrointestinal tract. STUDY: For 15 days, 8 volunteers (3M/5F age 40+/-14 y) integrated their normal diet with artichokes (180 gr) enriched with 20 billions of L. paracasei LMGP22043. Faecal samples were subjected to microbiologic and biochemical analyses. Besides, investigations on symptom profile of the volunteers and stool consistency were carried out by using a validated questionnaire (Gastrointestinal Symptom Rating Scale) and the Bristol stool form chart. RESULTS: The gut of all volunteers resulted to be colonized by the probiotic strain after 15 days feeding. No significant differences in the microbiological counts throughout the experimental period were registered, whereas a significant increase of butyric and valeric acids with a concomitant decrease of lactic acid was registered. At the same time, the fecal beta-glucuronidase activity was significantly reduced. Finally, the analysis of symptom profile indicated a marked reduction in abdominal distension and feeling of incomplete evacuation. CONCLUSIONS: These preliminary data suggest that novel approaches for treating constipation can come through ingestion of probiotic vegetable products that, acting as symbiotics, can ameliorate this common disorder.

Evaluación fermentativa del ensilado del subproducto de alcachofa (Cynara scolymus L. ) en tres niveles de un microsilo / Fermentative evaluation of the artichoke (Cynara scolymus L. ) by-product ensilage on three levels of microsilo

Se ha estudiado la evolución de indicadores fermentativos durante 50 días de ensilaje en el subproductoagroindustrial de alcachofa (Cynara scolymus, L). Las muestras se analizaron a intervalos regulares de tiempo(1, 2, 3, 4, 8, 12, 24 y 50 días), en tres fracciones del microsilo (inferior, medio y superior). El pH se estabilizóen los primeros 12 días de fermentación. El contenido de ácido láctico y acético fue diferente entre los días defermentación (p<0,001), pero las diferencias entre fracciones no fue significativa. El contenido de hidratos de carbono solubles fue diferente solo entre los diferentes días de ensilaje (p<0,001). Los resultados demuestran que no existen cambios estadísticamente signifi cativos entre las fracciones evaluadas demostrando un buen nivel fermentativo del ensilaje. Se puede concluir que el subproducto crudo de alcachofa es un material muy idóneo para ser conservado mediante ensilaje

The fermentative indicators evolution has been studied during 50 days of silage in the agro-industrial artichokeby-product (Cynara scolymus, L). The samples were analyzed at different sampling days (1, 2, 3, 4, 8,12, 24 and 50), in three fractions of the microsilo (botton, medium and top). The pH stabilized in the first 12 days. The lactic and acetic acids content was different between the sampling days (p<0.001), but the differences between fractions were not significatives. Water soluble carbohydrates content was different between the different ensiling days (p<0.001). No changes on pH have found and lactic or acetic acids and water solublecarbohydrates between the fractions evaluated. We can conclude that crude artichoke by-product will be suitableto be conserved by ensilage

In vitro and in vivo survival and transit tolerance of potentially probiotic strains carried by artichokes in the gastrointestinal tract.

The ability of potentially probiotic strains of Lactobacillus plantarum and Lactobacillus paracasei to survive on artichokes for at least 90 days was shown. The anchorage of bacterial strains to artichokes improved their survival in simulated gastrointestinal digestion. L. paracasei IMPC2.1 was further used in an artichoke human feeding study involving four volunteers, and it was shown that the organism could be recovered from stools.

Survival and growth of Listeria monocytogenes and enterohemorrhagic Escherichia coli O157:H7 in minimally processed artichokes.

The ability of Listeria monocytogenes and Escherichia coli O157:H7 inoculated by immersion (at 4.6 and 5.5 log CFU/ g, respectively) to survive on artichokes during various stages of preparation was determined. Peeling, cutting, and disinfecting operations (immersion in 50 ppm of a free chlorine solution at 4 degrees C for 5 min) reduced populations of L. monocytogenes and E. coli O157:H7 by only 1.6 and 0.8 log units, respectively. An organic acid rinse (0.02% citric acid and 0.2% ascorbic acid) was more effective than a tap water rinse in removing these pathogens. Given the possibility of both pathogens being present on artichokes at the packaging stage, their behavior during the storage of minimally processed artichokes was investigated. For this purpose, batches of artichokes inoculated with L. monocytogenes or E. coli O157:H7 (at 5.5 and 5.2 log CFU/g, respectively) were packaged in P-Plus film bags and stored at 4 degrees C for 16 days. During this period, the equilibrium atmosphere composition and natural background microflora (mesophiles, psychrotrophs, anaerobes, and fecal coliforms) were also analyzed. For the two studied pathogens, the inoculum did not have any effect on the final atmospheric composition (10% O2, 13% CO2) or on the survival of the natural background microflora of the artichokes. L. monocytogenes was able to survive during the entire storage period in the inoculated batches, while the E. coli O157:H7 level increased by 1.5 log units in the inoculated batch during the storage period. The modified atmosphere was unable to control the behavior of either pathogen.

Effectiveness of chlorine washing disinfection and effects on the appearance of artichoke and borage.

AIM: Optimal conditions for chlorine application to obtain a reasonable decrease in the microbial counts without damaging the appearance of artichoke and borage have been established. METHODS AND RESULTS: The influence of chlorine concentration (0-200 mg l(-1)), pH, addition of organic acids, contact time and presence of protective structures on the microflora and vegetal appearance were studied. When pH was not controlled the effect of chlorine depended on its concentration until the pH increase caused by addition of chlorine reached 8.8. Any further increase in chlorine concentration was nullified by the pH increase. When pH was adjusted to 4.5 with acetic acid, the effectiveness increased with concentration. However, the use of citric acid to control pH caused a sharp decrease in effectiveness at concentration about 250 mg l(-1). The higher effectiveness of chlorine on homogenized plant extracts compared with the whole plant showed the impact of the vegetal structures on the resistance of the microorganisms. For artichoke, a relationship between the effectiveness of chlorine disinfection and its structures was also found. Extended washing times did not affect the total counts. However, in both vegetables, the appearance was affected by the extended contact times. CONCLUSIONS: The solutions rendering the highest microbial reduction with minimum damages were: 50 mg l(-1) free chlorine without pH control for artichoke and 100 mg l(-1) free chlorine at pH 7.0 for borage. SIGNIFICANCE AND IMPACT OF THE STUDY: Specific conditions for chlorine disinfection of artichoke and borage were determined to reduce the microorganisms in minimally processed artichoke and borage without damaging their appearance.