Rosa Palmeri

An alkaline β-glucosidase isolated from an olive brine strain of Wickerhamomyces anomalus.

An efficient β-glucosidase (βG)-producing strain, Wickerhamomyces anomalus BS81, was isolated from naturally fermented olive brine and identified based on PCR/restriction fragment length polymorphism of the rDNA internal transcribed spacer and sequence analysis of the D1/D2 region of the 26S rRNA gene. The hydrolytic activity of the βG had an optimum pH of 8.5 and an optimum temperature of 35 °C. The enzyme had high substrate specificity and high catalytic efficiency (K(m) 0.99 mM, V(max) 14 U g(-1) of cells) for p-nitrophenyl-β-d-glucopyranoside. The enzyme was activated by increasing concentrations of NaCl, with maximum activity at 150 g L(-1) NaCl. Although βGs have been purified and characterized from several other sources, the W. anomalusβG is unique among βGs because its relative maximum activity occurs at alkaline pH and 35 °C. Moreover, the yeast strain has esterase activity that acts synergistically with βG to degrade oleuropein to debitter table olives and olive oil.

Partial sequencing of the β-glucosidase-encoding gene of yeast strains isolated from musts and wines

The aim of the present work was the identification of the gene encoding for β-glucosidase and its partial sequencing in the strainsPichia anomala AL112,Hanseniaspora uvarum Y8 andSaccharomyces cerevisiae AL41. To this aim degenerated primers, designed on the basis of aminoacid similarities of four known yeast β-glucosidases, have been used in PCR amplifications. An expected fragment of about 200 bp was amplified from all the DNAs, cloned and sequenced. Sequence homology demonstrated for the first time the presence of a β-glucosidase encoding gene inHanseniaspora uvarum andSaccharomyces cerevisiae.

Inexpensive isolation of β-d-glucopyranosidase from α-l-arabinofuranosidase, α-l-rhamnopyranosidase, and o-acetylesterase

Abstractβ-d-Glucopyranosidase (βG, EC 3.2.1.21) has been isolated from some collateral activities, α-l-arabinofuranosidase (Ara, EC3.2.1.55), α-l-rhamnopyranosidase (Rha, EC 3.2.1.40), and o-acetylesterase (Est, EC 3.1.1.53), using a commercial enzyme preparation and a simple method economically sustainable for the food industry. The procedure comprises precipitation of extraneous substances by adding ethanol and CaCl2, ultrafiltration, and adsorption, first on bentonite and then on chitosan. The results obtained were the complete isolation of βG from the above-mentioned activities, a drastic reduction in extraneous compounds, such as brown substances and polysaccharides, and a slight increase in purification.

Olive Leaf Extract from Sicilian Cultivar Reduced Lipid Accumulation by Inducing Thermogenic Pathway during Adipogenesis

Olive leaves contain a wide variety of phenolic compounds belonging to phenolic acids, phenolic alcohols, flavonoids, and secoiridoids, and include also many other pharmacological active compounds. They could play an important role in human diet and health because of their ability to lower blood pressure, increase coronary arteries blood flow and decrease the risk of cardiovascular diseases. The aim of this study was to investigate the effect of olive leaf extract (OLE) from Sicilian cultivar on adipogenic differentiation of human adipose derived mesenchymal stem cells and its impact on lipid metabolism. We showed that OLE treatment during adipogenic differentiation reduces inflammation, lipid accumulation and induces thermogenesis by activation of uncoupling protein uncoupling protein 1, sirtuin 1, peroxisome proliferator-activated receptor alpha, and coactivator 1 alpha. Furthermore, OLE significantly decreases the expression of molecules involved in adipogenesis and upregulates the expression of mediators involved in thermogenesis and lipid metabolism. Taken together, our results suggest that OLE may promote the brown remodeling of white adipose tissue inducing thermogenesis and improving metabolic homeostasis.

Bioactivity Improvement of Olea europaea Leaf Extract Biotransformed by Wickerhamomyces anomalus Enzymes

Olive leaves represent a quantitatively significant by-product of agroindustry. They are rich in phenols, mainly oleuropein, which can be hydrolyzed into several bioactive compounds, including hydroxytyrosol. In this study, water extract from olive leaves ‘Biancolilla’ was analyzed for polyphenol profile, DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging activity and protective effect on differentiated Caco-2 cells. The efficacy of two enzymatic treatments in promoting the release of bioactive phenols was investigated: a) enzymatic extract from Wickerhamomyces anomalus, characterized by β-glucosidase and esterase activities; b) commercial β-glucosidase. Composition and bioactivity of the resulting extracts were compared. The results showed that the yeast-treated extract presented hydroxytyrosol content and DPPH radical scavenging activity comparable to those obtained using commercial β-glucosidase; however, it was showed the additional presence of hydroxycinnamic acids. In experiments on Caco-2 cells, the leaf extracts promoted the recovery of cell membrane barrier at different minimum effective concentrations. The high specificity of W. anomalus enzymatic extract may represent an effective tool for the release of bioactive phenols from olive by-products.

Application of prickly pear fruit extract to improve domestic shelf life, quality and microbial safety of sliced beef

The research aimed to expand the knowledge on the use of natural bioactive compounds for food preservation. First-crop fruit of prickly pear were subjected to water extraction and evaluated for total polyphenol content, antioxidant activity, in vitro antimicrobial performance against food spoilage and pathogenic bacteria, and betacyanin and betaxanthin content. The extract was then applied by dipping technique to packed sliced beef, to evaluate its effect on physical and chemical parameters, color and texture maintenance, as well as on microbial growth during shelf life at domestic storage conditions. The in vitro antimicrobial assay of prickly pear fruit extract evidenced a wide spectrum activity, since it inhibited the growth of all Gram positive and negative targeted strains. In vivo application of extract effectively reduced microbial growth during refrigerated storage; total mesophilic count was maintained below the limit established by Commission Regulation (EC) No 2073/2005 of 5 × 106 log CFU/g of beef up to 8 d, in comparison to control sample that reached the mentioned limit after 4 d. Moreover, extract addition preserved beef color and texture over the considered storage period, supporting the potential prospect to utilize the extract to improve overall quality and to prolong domestic shelf life of sliced beef.

The effects of olive leaf extract from a Sicilian cultivar in an experimental model of hepatic steatosis

AbstractOlive oil is a well-known product for its health benefit, but the leaf has also been used as a traditional medicine in the Mediterranean for centuries. Olive leaves contain a great variety of chemical substances belonging to phenolic acids, phenolic alcohols, flavonoids and secoiridoids, and many other pharmacological active compounds with an important antioxidant effects such as oleuropein (OE), hydroxytyrosol (HT), tyrosol, cumaric acid, ferulic acid, caffeic acid, vanillic acid, rutin, verbascoside, luteolin, quercetin, dimethyloleuropein and ligstroside. Characterization of these compounds demonstrated that they can play an important role in human health, because of their ability to improve glucose homeostasis, ameliorate dyslipidemia and reduce inflammatory cytokine. The aim of this study was to investigate the effect of olive leaf extract (OLE) from Sicilian cultivar in an in vitro model of hepatic steatosis to evaluate the protective effects again free fatty acids accumulation in hepatocytes. We report here that OLE treatment ameliorated the lipid metabolism, and this effect was coupled with a parallel decrease in number of lipid droplets and a concomitant increase in FABP-4, SIRT-1 and HO-1 expression. Furthermore, OLE treatment induced a significantly reduction of the inflammatory cytokines IL-1β and TNF-α.

Preliminary study of employ of an olive leaf extract on bakery products

Most baking processes in the food manufacturing sector involve use of gas-fired ovens. Only about one-third of the total energy used in these ovens adds value to the final product. The remaining two-thirds is discharged with the exhaust gases at 150-250o C and thus represents an opportunity for heat recovery. However, the low temperature range, fouling and presence of corrosive materials in the exhaust streams make heat recovery technically challenging and uneconomical. The existing low grade heat recovery technolgies mostly use gas to liquid heat transfer to produce hot water for use in other areas of the manufacturing plant. The performance of these systems is governed by hot water demand in the factory and is therefore not recommended if there are frequent fluctuations in demand or if a more efficient technology, such as combined heat and power, is already in place. This study involves design, manufacturing and testing of a novel low-temperature gas to gas heat recovery system using an array of heat pipe heat exchangers, for industrial-scale baking ovens at a large confectionary manufacturing plant. Unlike gas to liquid heat transfer, a gas to gas heat transfer system provides direct savings in oven fuel consumption, independent of the hot water and other energy demands elsewhere in the plant. The heat recovery potential of the system is estimated using a thermodynamic model developed based on energy and mass balance for the ovens. The design enables recovery of up to 50% of the energy available through the exhaust stack, increasing the energy efficiency of the overall process to 60% and reducing food manufacturing costs by one third.