1,720,964 research outputs found
Antimicrobial and antibiofilm activities of pomegranate peel phenolic compounds: Varietal screening through a multivariate approach
No full textPomegranates are rich in phenolic compounds and known for their antioxidant, anti-inflammatory, and anticancer properties. The highest concentration of these compounds is found in the peel (exocarp and mesocarp), which constitutes about 50% of the whole fresh fruit. These bioactive phytochemicals exhibit a broad spectrum of antimicrobial effects against both Gram-negative and Gram-positive bacteria, as well as fungi. In the present paper, the chemical composition and antimicrobial activity of the peel (exocarp and mesocarp) from seven Punica granatum varieties (Wonderful, Mollar de Elche, Primosole, Sassari 1, Sassari 2, Sassari 3, and Arbara Druci) grown in Sardinia (Italy) were evaluated. Polar phenols, flavonoids, condensed tannins, and anthocyanin contents were evaluated by extraction with water at 20 and 40 °C. Orthogonal projections to latent structures discriminant analysis (OPLS-DA) was used to characterize each variety according to the chemical composition of the pomegranate peel extracts (PPEs). The antimicrobial and antibiofilm activities of each PPE were further tested in vitro against Staphyloccocus aureus, Listeria monocytogenes, Salmonella bongori, Escherichia coli, Lacticaseibacillus casei and Limosilactobacillus reuteri. Gram-positive species were more sensitive than Gram-negative to the extracts tested. Antimicrobial activity was shown against S. aureus and L. monocytogenes strains, whereas less, even no activity was found against S. bongori and E. coli strains. The PPEs from Mollar de Elche, Primosole, and Sassari 3 showed the highest antimicrobial activities at concentrations that varied from 0.19 to 1.50 mg/mL, with biofilm activity being reduced by more than 70%. These activities were positively related to the punicalagin, flavonoid, and chlorogenic acid content of the extracts. Finally, regarding the pro-technological bacterial strains, La. casei and Li. reuteri showed very low, even no sensitivity to the used of the specific PPEs with high concentrations. This study proposes a formulation of pomegranate peel extract that valorizes agro-industrial waste in the context of sustainability and circular economy. Pomegranate extracts should be considered potential sources of natural, plant-derived antimicrobials, providing an alternative to artificial antimicrobial products
Evolution of monovarietal virgin olive oils as a function of chemical composition and oxidation status
No full textVirgin Olive Oil (VOO) shelf life is determined by the varietal-specific chemical composition and principally by the of phenolic composition. The aim of this study was to investigate the changes in fatty acid profile, phenolic composition, and quality parameters of nine Italian monovarietal VOOs obtained under the same pedoclimatic, agronomic and technological conditions and stored for 12 months at 15 degrees C in the dark. The varieties with medium-high concentrations of secoiridoids and balanced values between the individual molecules were those with the highest stability. Orthogonal Projections to Latent Structures (OPLS) regression revealed that oleuropein derivatives and phenolic alcohols had the highest antioxidant activity. OPLS discriminant analysis separated well fresh and stored oils. PV, K270, tyrosol, hydroxytyrosol, and oxidated oleacein were the most effective indicators of VOO ageing. Oleacein and oleocanthal decreased after storage, phenolic alcohols, oleacein and ligstroside aglycon increased.[GRAPHICS]
In vitro studies on the effect of methanol and dimethyl sulfoxide on the growth and sporification of Penicillium expansum and Botritis cinerea.
No full textPenicillium expansum and B.cinerea are among the pathogens most frequently affecting apples and grapes respectively after harvest. We studied the behaviour of theses moulds when subjected to different concentrations of methanol (MeOH) and dimethyl sulfoxide (DMSO) as a possible alternative method to fungicides in controlling postharvest decay of horticultural products.
The experiments were performed with 5 cm Petri dishes containing PDA amended with 0, 5, 10, 20, 30, 40 or 50 L/mL of each of the two tested chemicals. Freshly prepared conidia (50 conidia/plate in 50 L) of P.expansum and B. cinerea were sown onto the media and then kept into an incubation chamber at 21 °C up to 6 and 3 days, respectively. daily, the formed colonies (cfu), the colony diameter and the degree of sporification was monitored. Additionally, Scanning Electron Microscopy (SEM) observations were performed in order to shed light on the effect of these chemicals on P. expansum and B. cinerea growth. Compared to the control, both chemicals affected the growth rate of the two pathogens. The cfu value of P. expansum and B. cinerea was not inhibited significantly but the colony diameter and the degree of sporification decreased as concentration was raised. B. cinerea cultured on DMSO showed a significant drop of sporification up to the tested concentration of 10 L/mL, and a complete inhibition of cfu when the concentrations was higher than 20 L/mL. SEM observations evidenced changes in the pathogen growth behaviour and structure. The importance to fasten or inhibit the sporification will be discussed and data of preliminary in vivo experiments will be presented
Combined effect of curing followed by acetic acid vapour treatments improves postharvest control of Penicillium digitatum on mandarins
No full text
Postharvest decay reduction of fig fruit (Ficus carica) by hot water sodium carbonate solutions dip.
No full textTreatments with GRAS compounds to keep fig fruit (Ficus carica L.) quality control during cold storage
No full text
Application of proximal and remote sensing on precision viticulture in Sardinia (Italy) – Preliminary results
No full textThe anthocyanin content of colored grapes is a useful tool when making decisions in viticulture. The optical portable sensor Multiplex3® (FORCE-A, Paris, France) is a rapid and non-destructive method for screening the colored component of grapes. It is based on the transmission of fruit chlorophyll fluorescence, based on the anthocyanin content of the intact berry skin. As a result it creates some indices to describe this phenomenon. These are ANTH_RG (Anthocyanin excitation in Red-Green fluorescence) and FERARI (Fluorescence Excitation Ratio Anthocyanin Relative Index). The aim of this study is to use wet chemistry analysis to calibrate FERARI and ANTH_RG indices in relation to total anthocyanin content (mg/100g skin). The trial was carried out in two Cagnulari vineyards in Northern Sardinia (Alghero, Sennori). The ANTH_RG and FERARI indices were monitored in the field on bunches of grapes during the 2015 season, from veraison to harvest. The FERARI index showed that there was a good correlation with the anthocyanin concentration derived from spectrophotometric analysis in both samples (Alghero ρ=0.69, Sennori ρ=0.66). The equation obtained for this index is a logarithmic curve. The ANTH_RG index showed a weak inverse correlation with the anthocyanins measured (Alghero ρ=-0.24, Sennori ρ=-0.23). An exponential curve gave the best possible fit.
In conclusion, in this first part of the research, we found that the FERARI index may help in making decisions in precision viticulture. Further studies are being carried out to confirm these preliminary results
Oxidative enzymes and PAL activity in Ficus carica and Citrus fruit following UV-C treatments alone or with hot water: fruit quality and resistance considerations
No full text- …
