The influence of actively/passively encapsulated oleuropein on DPPC liposomes thermal and structural properties, and its antioxidant capacity against lipid peroxidation were investigated. Also, an ...oleuropein-rich olive leaf extract was encapsulated in soy phosphatidylcholine (PL-90 g) and incorporated in model and commercial drinks. Oleuropein induced a concentration-dependent broadening and splitting of the gel-to-liquid phase transition temperature. Fluorescence measurements revealed a fluidizing effect on liposomes below their gel-to-liquid phase transition temperature, and a higher lipid ordering above, especially to active encapsulation. Oleuropein also showed an antioxidant effect against lipid peroxidation in PL-90 g liposomes. PL-90 g Liposomes with olive leaf extract showed a mean diameter of 405 ± 4 nm and oleuropein encapsulation efficiency of 34% and delayed oleuropein degradation at pH 2.0 and 2.8 model drinks. In conclusion, greater effects were observed on the structure and fluidity of DPPC liposomes when oleuropein was actively encapsulated, while its incorporation into acidic foods in encapsulated form could enhance its stability.
There is increasing concern for reduction of the ecological impacts of industrial waste caused by fruits and vegetables. To reduce costs of onion waste disposal while obtaining value-added products, ...onion skin can be used to extract quercetin, a natural flavonoid with antioxidant, anti-inflammatory and anti-cancer effects. The aim was to optimize quercetin extraction from brown onion (
L.) skin through investigation of the effects of different parameters on quercetin yield. Operational parameters for conventional maceration extraction and for ultrasound-assisted extraction were compared: solvent type, mass-to-liquid ratio, extraction time and temperature. Antioxidant capacity was determined using DPPH· radical scavenging assays and quercetin yield using HPLC/DAD. Anti-α-amylase activity of onion skin extracts was investigated using α-amylase inhibition assays. Optimal extraction conditions of quercetin from onion skin were obtained with maceration extraction, 50% ethanol, 1:100 mass-to-liquid ratio, 25 °C, for 15 min. Under these conditions, the antioxidant capacity (expressed as quercetin equivalents) was 18.7 mg/g and the mass fraction of quercetin was 7.96 mg/g. The onion skin extracts showed a dose-dependent relationship between dry extract concentration and α-amylase inhibition, which confirms that this onion skin extract can be considered as an anti-diabetes agent.
Adverse environmental conditions are severely limiting the use of microorganisms in food systems, such as probiotic delivery, where low pH causes a rapid decrease in the survival of ingested ...bacteria, and mixed-culture fermentation, where stepwise changes and/or metabolites of individual microbial groups can hinder overall growth and production. In our study, model probiotic lactic acid bacteria (
ATCC 8014,
GG) and yeasts native to dairy mixed cultures (
ZIM 1868) were entrapped in an optimized (cell, alginate and hardening solution concentration, electrostatic working parameters) Ca-alginate system. Encapsulated cultures were examined for short-term survival in the absence of nutrients (lactic acid bacteria) and long-term performance in acidified conditions (yeasts). In particular, the use of encapsulated yeasts in these conditions has not been previously examined. Electrostatic manufacturing allowed for the preparation of well-defined alginate microbeads (180-260 µm diameter), high cell-entrapment (95%) and viability (90%), and uniform distribution of the encapsulated cells throughout the hydrogel matrix. The entrapped
maintained improved viabilities during 180 min at pH 2.0 (19% higher when compared to the free culture), whereas,
appeared to be less robust. The encapsulated
exhibited double product yields in lactose- and lactic acid-modified MRS growth media (compared to an unfavorable growth environment for freely suspended cells). Even within a conventional encapsulation system, the pH responsive features of alginate provided superior protection and production of encapsulated yeasts, allowing several applications in lacto-fermented or acidified growth environments, further options for process optimization, and novel carrier design strategies based on inhibitor charge expulsion.
Pomegranate fruit is an ancient fruit that is used not only because of its deep-red color and tasty arils but also due to the health benefits of its extracts. Pomegranate is a valuable source of ...bioactive compounds, including colorful anthocyanins and other polyphenols. The main objective of the present study was to gain comprehensive knowledge of the phenolic composition and antioxidative activity of a new pomegranate cultivar, grown in Northwest Istria, a part of the North Adriatic coastal area. Various parts of the pomegranate fruit parts were extracted in 70% ethanol or water. Total phenolic content and antioxidative capacity were respectively determined with Folin–Ciocalteu reagent and ABTS radical. Phenolics were examined and analyzed with TLC, LC-MS, and HPLC. Pomegranate juice was prepared from red arils and after thermal treatment, the stability of anthocyanins was monitored for several months to understand the effect of storage. The highest total phenolics were determined in ethanol pomegranate peel extracts (30.5 ± 0.6 mg GAE/g DM), and water peel extracts exhibited the highest antioxidative activity (128 ± 2 µg TE/g DM). After five months of storage of thermally treated pomegranate juice, 50–60 percentage points increase in anthocyanin degradation was observed. Pomegranate peel was further tested as a sustainable inedible food source for papermaking. Due to the low content of cellulose and the high percentage of extractives, as well as a distinguished texture and appearance, the paper made from pomegranate peel is best suited for the production of specialty papers, making it particularly interesting for bioactives recovery, followed by material restructuring.
The hyperthermophilic archaeon Aeropyrum pernix has adapted to optimal growth under high temperatures in saline environments and under oxidizing conditions. In the present study, we focused on the ...antioxidative activity of proteins from A. pernix K1. Following high temperature methanol and water extractions of the protein from the biomass of A. pernix K1, the total sulphydryl groups and radical scavenging activities were investigated. The total protein in the methanolic extract was 36% lower and showed 10% fewer sulphydryl groups than that from the water extract. However, the radical scavenging activity of the water extract was four-fold greater than for the methanolic extract. The proteins of both of these extracts were separated by two-dimensional electrophoresis, and selected proteins were identified using mass spectrometry. The majority of these identified proteins were intracellular proteins, such as those involved in oxidative stress responses and osmotic stress responses, and proteins with hydrolase and dehydrogenase activities. These proteins are also common to most organisms, and included putative uncharacterized proteins.
Knotweed is a flowering plant that is native to temperate and subtropical regions in the northern hemisphere. We evaluated Japanese (
Houtt.) and Bohemian (
) knotweed rhizome and flower ethanol ...extracts and compared them in terms of their biological activities. The specific polyphenols were identified and quantified using HPLC/DAD, and the antioxidant activity was determined using 2,2-diphenly-1-picrylhydrazyl (DPPH) and cellular antioxidant capacity assays. The anticancer activity was evaluated as the difference between the cytotoxicity to cancer cells compared with control cells. The antimicrobial activity was determined using bacteria and yeast. The antidiabetic activity was tested as the ability of the extracts to inhibit α-amylase. Both rhizome extracts were sources of polyphenols, particularly polydatin and (-)-epicatechin; however, the cellular assay showed the highest antioxidant capacity in the flower extract of
. The PaTu cell line was the least sensitive toward all knotweed extracts. The flower extracts of both species were less toxic than the rhizomes. However, the activity of the tested extracts was not specific for cancer cells, indicating a rather toxic mode of action. Furthermore, all used extracts decreased the α-amylase activity, and the rhizome extracts were more effective than the flower extracts. None of the extracts inhibited bacterial growth; however, they inhibited yeast growth. The results confirmed that rhizomes of
Houtt. could become a new source of bioactive compounds, which could be used for the co-treatment of diabetes and as antifungal agents.
Lutein is a challenging compound to incorporate into food, as it is poorly soluble and unstable in aqueous solutions. In this study, the aim was to prepare stable encapsulates of lutein and lutein ...esters using feasible and straightforward techniques. Fine suspensions based on polyoxyethylene sorbitan monooleate and medium-chain triglyceride oil micelle-like units with 3.45% lutein esters or 1.9% lutein equivalents provided high encapsulation efficiencies of 79% and 83%, respectively. Lutein encapsulated in fine suspensions showed superior stability, as 86% was retained within the formulation over 250 days at 25 °C in the dark. Under the same storage conditions, only 38% of lutein remained in corresponding formulations. Higher encapsulation efficiencies were achieved with lecithin emulsions, at up to 99.3% for formulations with lutein, and up to 91.4% with lutein esters. In lecithin emulsions that were stored for 250 days, 17% and 80% of lutein and lutein esters, respectively, were retained within the formulations.
Jujube (
Mill.) has favourable horticultural properties including adaptation to arid conditions, abiotic and biotic stresses, as well as positive impact on human health. The present study describes ...the characterization of genetic diversity of the germplasm of jujube from the Istrian peninsula, the determination of important chemical compounds, antioxidative properties in relation to antibacterial and antifungal activities of jujube fruit extracts, and the determination of nutritional properties of jujube fruit. The results of the genetic analysis showed that most of the samples from the Istrian peninsula belong to two recently introduced varieties, 'Li' and 'Lang', and the most widespread local variety 'Navadna žižola'. The local variety has smaller fruit than the 'Li' and 'Lang' varieties, with thick and fleshy mesocarp. Chemical analysis indicated that fruits of the local variety contained a valuable source of dietary fibre ((9.7±0.6) g/100 g) and were rich in minerals such as (in g/100 g dry mass): potassium (829±51), calcium (177±11) and phosphorus (129±19). Aqueous extracts showed slight antibacterial activity, while ethanol extracts had higher mass fractions of phenolic compounds (expressed as gallic acid equivalents (GAE), 5.8-8.7 mg/g) than the aqueous extracts, but did not show antimicrobial activity. Compounds other than phenolic compounds in jujube fruit may be more biologically active. Based on the results of these analyses, the local Istrian jujube variety is a promising candidate for cultivation potential.
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