Soluble (SP), ionically bound (IBP) and covalently bound (CBP) peroxidases (POD) from artichoke leaves and heads have been characterized for the main biochemical parameters. The three PODs, in both ...leaves and heads, showed the major apparent catalytic efficiency (v.sub.max,app/K.sub.m,app) towards ferulic acid, even though, in some cases, they showed higher affinity (K.sub.m,app) for other substrates. In leaves, SP and IBP showed higher K.sub.m,app for ferulic and chlorogenic acids, and CBP for ferulic and caffeic acids. In heads, SP showed higher K.sub.m,app for chlorogenic acid, IBP for caffeic and ferulic acids, and CBP for ferulic acid. It was shown that pH optimum for PODs ranged between 5.0 and 6.0 in leaves. In heads, pH optimum for SP and IBP was 5.5, while CBP presented a very low activity in a wide pH range. All PODs showed high thermal stability but different ability to regenerate: the bound forms were more able to regenerate than the soluble one. The results obtained show that (i) CBP from heads is able to work under very different cellular conditions, (ii) all PODs, in both tissues, have a high apparent catalytic efficiency for ferulic acid, which could explain the effective involvement of POD in lignin biosynthesis, (iii) in heads, high K.sub.m,app of SP for chlorogenic acid, particularly abundant in artichoke, could justify the possible involvement of PODs in browning mechanism, and (iv) in heat-processed artichoke, the ability of PODs to regenerate could contribute to oxidation and loss of product quality. Key words: artichoke (Cynara cardunculus), soluble and bound peroxidases, characterization, thermostability, regeneration, browning
The strawberry tree (Arbustus unedo) is a medicinal plant and an important source of biocompounds, potentially useful for pharmaceutical and chemical applications to prevent or treat several human ...diseases. The strawberry tree fruits have usually been used to produce traditional products such as jams and jellies and to obtain fermented alcoholic drinks, representing the most valuable derivative products. Other fermented products are potentially interesting for their nutritional value; however, the fermentation process needs to be controlled and standardized to obtain high-quality products/ingredients. In this work, we investigated two different fermentative procedures, using strawberry tree whole fruit and fruit paste as matrices inoculated with a selected starter strain of Saccharomyces cerevisiae LI 180-7. The physical, chemical, microbiological and nutritional properties of fermented products were evaluated, as well as their antioxidant activity. The new obtained fermented products are enriched in organic acids (acetic acid varied from 39.58 and 57.21 mg/g DW and lactic acid from 85.33 to 114.1 mg/g DW) and have better nutritional traits showing a higher amount of total polyphenols (phenolic acids, flavonoids and anthocyanins) that ranged from 1852 mg GAE/100 g DW to 2682 mg GAE/100 g DW. Also, the amount of isoprenoid increased ranging from 155.5 μg/g DW to 164.61 μg/g DW. In this regard, the most promising strategy seemed to be the fermentation of the fruit paste preparation; while the extract of fermented whole fruits showed the most powerful antioxidant activity. Finally, a preliminary attempt to produce a food prototype enriched in fermented strawberry tree fruits suggested the whole fruit fermented sample as the most promising from a preliminary sensory analysis.
The oil industry produces large volume of waste, olive mill waste water (OMWW) and olive paste (OP), which represents a disposal and a potential environmental pollution problem. They are also ...promising sources of valuable compounds that can be recovered and used. The effects of OMWW and OP addition to bread and pasta, separately and combined, were studied. Both sensory and chemical properties as related to phenols content and antioxidant activity of raw materials, and fortified bread and pasta were evaluated. Results suggested that the enrichment of bread and pasta with OMWW slightly improved the chemical quality without compromising the sensory properties. While, foods enrichment with OP had considerably improved chemical quality, the sensory acceptability was worse due to the bitter and spicy taste of OP. To choose the best cereal food between bread and pasta to be enriched, a mathematical model, the whole quality index (WQI), was used. Bread was better than pasta for re-using olive oil by-products. Between OMWW and OP, the latter was more suitable for food fortification, despite the sensory problems of the enriched product. Also, when the two by-products were combined, the best product continued to be the bread.
Table olives are one of the most known fruit consumed as fermented food, being a fundamental component of the Mediterranean diet. Their production and consumption continue to increase globally and ...represent an important economic source for the producing countries. One of the most stimulating challenges for the future is the modernization of olive fermentation process. Besides the demand for more reproducible and safer production methods that could be able to reduce product losses and potential risks, producers and consumers are increasingly attracted by the final product characteristics and properties on human health.
In this study, the contribution of microbial starters to table olives was fully described in terms of specific enzymatic and microbiological profiles, nutrient components, fermentation-derived compounds, and content of bioactive compounds. The use of microbial starters from different sources was tested considering their technological features and potential ability to improve the functional traits of fermented black table olives.
For each fermentation assay, the effects of controlled temperature (kept at 20 °C constantly) versus not controlled environmental conditions (oscillating between 7 and 17 °C), as well as the consequences of the pasteurization treatment were tested on the final products. Starter-driven fermentation strategies seemed to increase both total phenolic content and total antioxidant activity. Herein, among all the tested microbial starters, we provide data indicating that two bacterial strains (Leuconostoc mesenteroides KT 5-1 and Lactiplantibacillus plantarum BC T3-35), and two yeast strains (Saccharomyces cerevisiae 10A and Debaryomyces hansenii A15-44) were the better ones related to enzyme activities, total phenolic content and antioxidant activity. We also demonstrated that the fermentation of black table olives under not controlled environmental temperature conditions was more promising than the controlled level of 20 °C constantly in terms of technological and functional properties considered in this study. Moreover, we confirmed that the pasteurization process had a role in enhancing the levels of antioxidant compounds.
•Microbial starters characterization for table olives functional traits improvement.•Effect of different fermentation temperatures on table olives production.•Effect of the heat treatment on fermented table olives.
•Apulian table olive polyphenols were positively affected by autochthonous starters.•Cellina di Nardò fermented with starters showed the highest antioxidant effect.•Polyphenols from fermented table ...olives were highly in vitro bioaccessible.•Fermented table olives are 8 times richer of bioactive compounds than olive oil.
The effects of fermentation by autochthonous microbial starters on phenolics composition of Apulian table olives, Bella di Cerignola (BDC), Termite di Bitetto (TDB) and Cellina di Nardò (CEL) were studied, highlighting also the cultivars influence. In BDC with starter, polyphenols amount doubled compared with commercial sample, while in TDB and CEL, phenolics remain almost unchanged. The main phenolics were hydroxytyrosol, tyrosol, verbascoside and luteolin, followed by hydroxytyrosol-acetate detected in BDC and cyanidine-3-glucoside and quercetin in CEL. Scavenger capacity in both DPPH and CAA assays, assessed the highest antioxidant effect for CEL with starters (21.7 mg Trolox eq/g FW; 8.5 μmol hydroxytyrosol eq/100 g FW). The polyphenols were highly in vitro bioaccessible (>60%), although modifications in their profile, probably for combined effect of environment and microorganisms, were noted. Finally, fermented table olives are excellent source of health promoting compounds, since hydroxytyrosol and tyrosol are almost 8 times more than in olive oil.
Previously we presented the purification, biochemical characterization, and cloning of a cationic peroxidase isoenzyme (CysPrx) from artichoke (Cynara cardunculus subsp scolymus (L.) Hegi) leaves. ...The protein was shown to have some interesting properties, suggesting that CysPrx could be a considered as a potential candidate for industrial application. In addition, from the CysPrx sequence, two full-lengh cDNAs: CysPrx1 and CysPrx2, differing for three amino acids, were isolated. A three-dimensional model was predicted from CysPrx1 by homology modeling, using two different computational tools. Herein we discuss the roles of particular amino acid residues and structural motifs or regions of both deduced sequences with the aim to find new understandings between the new plant peroxidase isoenzymes and their physiological substrates. Additionally, the obtained information may lead to new methods for improving the stability of the enzyme in several processes of biotechnological interest for peroxidase applications.
Soluble peroxidases (SP), and ionically (IBP) and covalently (CBP) bound peroxidases were extracted from leaves and edible part of artichoke heads (heart). The peroxidase (POD) forms showed a ...characteristic electrophoretic pattern; in particular SP and IBP forms showed nearly the same pattern, while CBP was quite different. Several basic and acid POD isoforms were present in SP and CBP forms, whereas in IBP only basic components were found. The thermal stability of different POD forms was tested at different temperatures (70, 80, 90 and 100 degree C). The leaf POD forms showed greater heat stability compared to the head ones. The heat sensitivity of three POD forms was different: the bound forms were characterized by a greater heat stability than the soluble form. A series-type mathematical model has been developed to describe the inactivation kinetics of artichoke POD. The activation energies for the three POD forms of artichoke leaves and hearts were estimated by an Arrhenius-type relationship. The second step of the inactivation requires more energy to be carried out in all POD forms, especially in SP and IBP.
The aim of this work was to recover and identify the phenolic compounds from olive mill wastewater (OMWW) samples belonging to two Italian (Cellina and Coratina) and three Greek (Asprolia, Lianolia ...and Koroneiki) olive cultivars. The OMWWs were processed using membrane technologies to obtain three fractions: microfiltrate (MF), ultrafiltrate (UF) and nanofiltrate (NF). These steps allowed purifying the OMWWs in order to achieve fractions with different profile and concentrations of polyphenols. In particular, the amount of polyphenols ranged from 2456μg/mL to 5284μg/mL in MF; from 1404μg/mL to 3065μg/mL in UF and from 373μg/mL to 1583μg/mL in NF. Among the cultivars analyzed Coratina followed by Lianolia showed the highest amount of verbascoside (VB) (308μg/mL in Coratina versus 145μg/mL in Lianolia, respectively) in UF fractions.
Furthermore, UF fractions that showed adequate purification degree and polyphenol enrichments, were used for the identification of the phenolic compounds by liquid chromatography/diode array detection/electrospray ion trap tandem mass spectrometry (LC/DAD/ESI–MSn) analysis. Twenty three compounds, belonging to the following classes of constituents: secoiridoids and their derivatives, phenyl alcohols, phenolic acid and derivatives, and flavonoids, were identified in almost all the UF fractions of the different cultivars. Finally, differences were observed among the cultivars regarding the presence of elenolic acid derivatives, hydroxytyrosol glucoside, and β-hydroxyverbascoside diastereoisomers. The results obtained showed that OMWW can be considered as raw material for the isolation of valuable bioactive compounds able to be used in food, cosmetic and pharmaceutical industry.
•OMWWs were processed using membrane technologies with filters at different porosity.•The ultrafiltrate fraction gave good purification degree and polyphenol enrichment.•The most abundant compound is HT followed by Tyr.•Identification of phenols from OMWW from Italian and Greek olive cultivars showed differences.•OMWW, a raw material for use in food, cosmetic and pharmaceutical industry
Olive quick decline syndrome (OQDS) causes severe damages to the olive trees in Salento (Apulia, Italy) and poses a severe threat for the agriculture of Mediterranean countries. DNA-based typing ...methods have pointed out that OQDS is caused by a single outbreak strain of Xylella fastidiosa subsp. pauca referred to as CoDiRO or ST53. Since no effective control measures are currently available, the objective of this study was to evaluate in vitro antimicrobial activities of different classes of compounds against Salento-1 isolated by an OQDS affected plant and classified as ST53. A bioassay based on agar disk diffusion method revealed that 17 out of the 32 tested antibiotics did not affect bacterial growth at a dose of 5 μg disk-1. When we assayed micro-, ultra- and nano-filtered fractions of olive mill wastewaters, we found that the micro-filtered fraction resulted to be the most effective against the bacterium. Moreover, some phenolics (4-methylcathecol, cathecol, veratric acid, caffeic acid, oleuropein) were active in their pure form. Noteworthy, also some fungal extracts and fungal toxins showed inhibitory effects on bacterial growth. Some of these compounds can be further explored as potential candidate in future applications for curative/preventive treating OQDS-affected or at-risk olive plants.
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