A Comparative Study between Beeswax and Glycerol Monostearate for Food-Grade Oleogels.

With the aim to produce solid fats with a high percentage of unsaturated fatty acids, oleogels based on olive and peanut oil with different concentrations of beeswax (BW) and glycerol monostearate (GMS) as oleogelators were studied and compared. The critical oleogelator concentration for both BW and GMS was 3%. Thermal properties of the developed GMS-based oleogels pointed to a polymorphic structure, confirmed by the presence of two exothermic and endothermic peaks. All developed oleogels released less than 4% of oil, highlighting their high oil binding capacity. A morphology evaluation of oleogels showed platelet-like crystals, characterized by a cross-sectional length of 50 µm in BW-based oleogels and irregular clusters of needle-like crystals with a higher diameter in GMS-based oleogels. BW-based oleogels showed a solid fat content ranging from 1.16% to 2.27%, and no solid fat content was found at 37 °C. GMS-based oleogels reached slightly higher values of SFC that ranged from 1.58% to 2.97% at 25 °C and from 1.00% to 1.75% at 37 °C. Olive oil-based oleogels with GMS showed higher firmness compared with BW-based ones. The stronger structure network in olive oil/GMS-based oleogels provided a real physical barrier to oxidants, showing a high oxidation stability.

Evaluation of the Content of Minerals, B-Group Vitamins, Tocols, and Carotenoids in Raw and In-House Cooked Wild Edible Plants.

Notwithstanding the increased interest in wild edible plants, little is known on how some domestic thermal processes can affect their content. The aim of this study was to investigate the amounts of minerals, B1 and B2 vitamins, tocols, and carotenoids in raw, boiled, and steamed wild edible plants, namely, Sonchus asper (L.) Hill s.l., Sonchus oleraceus L., Cichorium intybus L., and Beta vulgaris L. var cicla. All vegetables were confirmed as high sources of lutein (from 6 to 9 mg/100 g) and ß-carotene (from 2 to 5 mg/100 g). Quite high amounts of violaxanthin and neoxanthin were found. Alfa-tocopherol and γ-tocopherol were the main tocols, with same contents in raw and processed vegetables (about 2.5 mg/100 g). The most abundant macro element and trace element were, respectively, potassium and iron. B1 and B2 vitamins were found in low amounts in almost all plants, with the exception of thiamine in Beta vulgaris (about 1.6 mg/100 g). Boiling led to a significant loss of minerals (up to 60%) and B-group vitamins (up to 100%), while, among carotenoids, it only affected violaxanthin levels (up to 90%). Steamed vegetables showed only a slight reduction, about 20%, in ß-carotene and lutein, with a marked decrease in violaxanthin and neoxanthin. One hundred grams of all fresh and cooked plants can be claimed as a source of vitamin A and E.

High-Barrier, Biodegradable Films with Polyvinyl Alcohol/Polylactic Acid + Wax Double Coatings: Influence of Relative Humidity on Transport Properties and Suitability for Modified Atmosphere Packaging Applications.

Polyvinyl alcohol (PVOH) exhibits outstanding gas-barrier properties, which favor its use as a biodegradable, high-barrier coating on food-packaging films, possibly in combination with modified atmospheres. Nonetheless, its high sensitivity to water can result in a severe loss of barrier properties, significantly limiting its applications with fresh foods and in high-humidity conditions. In this work, the water vapor (PWV) and oxygen permeability (PO2) of high-barrier biodegradable films with PVOH/PLA + wax double coatings were extensively characterized in a wide range of relative humidity (from 30 to 90%), aimed at understanding the extent of the interaction of water with the wax and the polymer matrices and the impact of this on the permeation process. What is more, a mathematical model was applied to the PWV data set in order to assess its potential to predict the permeability of the multilayer films by varying storage/working relative humidity (RH) conditions. The carbon dioxide permeability (PCO2) of the films was further evaluated, and the corresponding permselectivity values were calculated. The study was finally augmented through modified atmosphere packaging (MAP) tests, which were carried out on double-coated films loaded with 0 and 5% wax, and UV-Vis analyses. The results pointed out the efficacy of the PLA + wax coating layer in hampering the permeation of water molecules, thus reducing PVOH swelling, as well as the UV-shielding ability of the multilayer structures. Moreover, the MAP tests underlined the suitability of the double-coated films for being used as a sustainable alternative for the preservation of foods under modified atmospheres.

Optimization of Hazelnut Spread Based on Total or Partial Substitution of Palm Oil.

Palm oil is widely used in the manufacturing of hazelnut-based spreads due to its unique fatty acid and triacylglycerol profile and, thus, its crystallization behaviour, which makes it suitable for use in fat-based spreadable products. An interesting solution that enables the replacement of palm oil is given by oleogels made with high nutritional quality oil. In this study, the influence of the replacement of palm oil with different glycerol monostearate/olive oil-based oleogels, as well as the influence of the different amounts of GMS employed in oleogel preparation, on the oil binding capacity, spreadability, and rheological and sensory parameters of hazelnut cocoa spreads was investigated. A design of experiment (DoE) approach, with the adoption of the D-optimal design, was used to plan the cocoa hazelnut spread formulations, with the aim being to identify the optimal formulation with desirable quality parameters in terms of Casson's viscosity, spreadability, and oil binding capacity. The resulting optimized formulation was identified in a spread characterized by a total replacement of palm oil with an oleogel made of 95% olive oil and 5% GMS.

Development and Characterization of Thermoformed Bilayer Trays of Paper and Renewable Succinic Acid Derived Biopolyester Blends and Their Application to Preserve Fresh Pasta.

The present study reports on the development by thermoforming of highly sustainable trays based on a bilayer structure composed of paper substrate and a film made of a blend of partially bio-based poly(butylene succinate) (PBS) and poly(butylene succinate-co-adipate) (PBSA). The incorporation of the renewable succinic acid derived biopolyester blend film slightly improved the thermal resistance and tensile strength of paper, whereas its flexural ductility and puncture resistance were notably enhanced. Furthermore, in terms of barrier properties, the incorporation of this biopolymer blend film reduced the water and aroma vapor permeances of paper by two orders of magnitude, while it endowed the paper structure with intermediate oxygen barrier properties. The resultant thermoformed bilayer trays were, thereafter, originally applied to preserve non-thermally treated Italian artisanal fresh pasta, "fusilli calabresi" type, which was stored under refrigeration conditions for 3 weeks. Shelf-life evaluation showed that the application of the PBS-PBSA film on the paper substrate delayed color changes and mold growth for 1 week, as well as reduced drying of fresh pasta, resulting in acceptable physicochemical quality parameters within 9 days of storage. Lastly, overall migration studies performed with two food simulants demonstrated that the newly developed paper/PBS-PBSA trays are safe since these successfully comply with current legislation on plastic materials and articles intended to come into contact with food.

Alginate Coating Charged by Hydroxyapatite Complexes with Lactoferrin and Quercetin Enhances the Pork Meat Shelf Life.

In this work, the effect of an alginate-based coating loaded with hydroxyapatite/lactoferrin/quercetin (HA/LACTO-QUE) complexes during the storage of pork meat was evaluated. FT-IR spectra of HA/LACTO-QUE complexes confirmed the adsorption of QUE and LACTO into HA crystals showing the characteristic peaks of both active compounds. The kinetic releases of QUE and LACTO from coatings in an aqueous medium pointed out a faster release of LACTO than QUE. The activated alginate-based coating showed a high capability to slow down the growth of total viable bacterial count, psychotropic bacteria count, Pseudomonas spp. and Enterobacteriaceae during 15 days at 4 °C, as well as the production of the total volatile basic nitrogen. Positive effects were found for maintaining the hardness and water-holding capacity of pork meat samples coated with the activated edible coatings. Sensory evaluation results demonstrated that the active alginate-based coating was effective to preserve the colour and odour of fresh pork meat with overall acceptability up to the end of storage time.

Olive Oil-Based Oleogel as Fat Replacer in a Sponge Cake: A Comparative Study and Optimization.

Oleogels (defined as structured solid-like materials with a high amount of oil entrapped within a three-dimensional network of gelator molecules) represent a healthy alternative to fats that are rich in saturated and trans fatty acids. Given its fatty acids composition (oleic, linoleic, and linolenic acids), olive oil is an excellent candidate for the use of oleogels in the food industry. In this study, a D-optimal mixture design was employed to optimize the replacement of butter with olive oil-based oleogel in a type of sponge cake formulation: the plum cake. In addition, emulsifiers and whey proteins were used as recipe ingredients to extend the product's shelf life by delaying staling phenomena and mold growth. In the experimental design, oleogel, emulsifier, and whey protein variables were set as the ingredients that change in specific ranges, while hardness, porosity, water activity, and moistness were used to characterize the obtained formulations. The experimental data of each response were fitted through polynomial regression models with the aim of identifying the best plum cake formulation. The results revealed that the best mixture was the formulation containing 76.98% olive oil-based oleogel, 7.28% emulsifier E471, and 15.73% whey protein. We stored the optimized plum cake for 3 months at room temperature and then checked for any hardness and moistness changes or mold spoilage.

Rapid Detection of Deoxynivalenol in Dry Pasta Using a Label-Free Immunosensor.

This work focused on the development and optimization of an impedimetric label-free immunosensor for detecting deoxynivalenol (DON). A monoclonal antibody for DON detection was immobilized on a modified gold electrode with a cysteamine layer and polyamidoamine (PAMAM) dendrimers. Cyclic voltammetry and electrochemical impedance spectroscopy techniques were used to monitor the layer-by-layer development of the immunosensor design, while electrochemical impedance spectroscopy and differential pulse voltammetry were employed to investigate the antigen/antibody interaction. The PAMAM dendrimers, allowing to immobilize a large number of monoclonal antibodies, permitted reaching, through the DPV technique, a high sensitivity and a low limit of detection equal to 1 ppb. The evaluation of the possible reuse of the immunosensors highlighted a decrease in the analytical performances of the regenerated immunosensors. After evaluating the matrix effect, the developed immunosensor was used to quantify DON in pasta samples spiked with a known mycotoxin concentration. Taking into consideration the DON extraction procedure used for the pasta samples and the matrix effect related to the sample, the proposed immunosensor showed a limit of detection of 50 ppb, which is lower than the maximum residual limit imposed by European Regulation for DON in dry pasta (750 ppb).

Lactoferrin, Quercetin, and Hydroxyapatite Act Synergistically against Pseudomonas fluorescens.

Pseudomonas fluorescens is an opportunistic, psychotropic pathogen that can live in different environments, such as plant, soil, or water surfaces, and it is associated with food spoilage. Bioactive compounds can be used as antimicrobials and can be added into packaging systems. Quercetin and lactoferrin are the best candidates for the development of a complex of the two molecules absorbed on bio combability structure as hydroxyapatite. The minimum inhibiting concentration (MIC) of single components and of the complex dropped down the single MIC value against Pseudomonas fluorescens. Characterization analysis of the complex was performed by means SEM and zeta-potential analysis. Then, the synergistic activity (Csyn) of single components and the complex was calculated. Finally, the synergistic activity was confirmed, testing in vitro its anti-inflammatory activity on U937 macrophage-like human cell line. In conclusion, the peculiarity of our study consists of optimizing the specific propriety of each component: the affinity of lactoferrin for LPS; that of quercetin for the bacterial membrane. These proprieties make the complex a good candidate in food industry as antimicrobial compounds, and as functional food.

A novel impedimetric biosensor based on the antimicrobial activity of the peptide nisin for the detection of Salmonella spp.

Nisin is an antimicrobial peptide with bacterial, fungicidal, virucidal properties, attacking bacteria and destroying the cell membranes. Thanks to its stability to hard conditions, it is a candidate for the use as molecular recognition elements in biosensing platform. In this work, the use of nisin as a biological molecule for the development of a sensitive biosensor for bacteria detection is reported: nisin molecules were immobilised on gold electrodes and Electrochemical Impedance Spectroscopy was to investigate the electrochemical responses after the exposure of the biosensor to different bacteria. The biosensor was able to detect all bacterium tested with different impedimetric responses; the singular impedimetric behaviours recorded after the exposure to pathogenic and non - pathogenic Salmonella strains, highlighted the possibility of the proposed biosensor to detect selectively Salmonella cells with a low limit of detection of 1.5 * 101 CFU/mL. Finally, the developed biosensor was used to detect Salmonella in milk.

Sensitive Detection of Escherichia coli O157:H7 in Food Products by Impedimetric Immunosensors.

In this work, the development of an impedimetric label-free immunosensor for the detection of Escherichia coli O157:H7 is reported. Different immobilization techniques of monoclonal anti-E. coli were tested, in order to reach the very low limit of detections. The comparison between the immobilization procedures underlined the advantages of the oriented procedure and the use of a dendrimer, which allowed for immobilizing a higher number of antibody units, reaching a very high sensitivity. However, the use of activated ferrocene as electron-transferring mediator, which improved the electrical properties of the system, resulted in a very low limit of detection equal to 3 cfu/mL. This immunosensor was used to analyze milk and meat samples obtaining a good agreement with the results of the ELISA methods.

Fabrication of SrTiO3 Layer on Pt Electrode for Label-Free Capacitive Biosensors.

Due to their interesting ferroelectric, conductive and dielectric properties, in recent years, perovskite-structured materials have begun to attract increasing interest in the biosensing field. In this study, a strontium titanate perovskite layer (SrTiO3) has been synthesized on a platinum electrode and exploited for the development of an impedimetric label-free immunosensor for Escherichia coli O157:H7 detection. The electrochemical characterization of the perovskite-modified electrode during the construction of the immunosensor, as well as after the interaction with different E. coli O157:H7 concentrations, showed a reproducible decrease of the total capacitance of the system that was used for the analytical characterization of the immunosensor. Under optimized conditions, the capacitive immunosensor showed a linear relationship from to 1 to 7 log cfu/mL with a low detection limit of 1 log cfu/mL. Moreover, the atomic force microscopy (AFM) technique underlined the increase in roughness of the SrTiO3-modified electrode surface after antibody immobilization, as well as the effective presence of cells with the typical size of E. coli.

Impedimetric Label-Free Immunosensor on Disposable Modified Screen-Printed Electrodes for Ochratoxin A.

An impedimetric label-free immunosensor on disposable screen-printed carbon electrodes (SPCE) for quantitative determination of Ochratoxin A (OTA) has been developed. After modification of the SPCE surface with gold nanoparticles (AuNPs), the anti-OTA was immobilized on the working electrode through a cysteamine layer. After each coating step, the modified surfaces were characterized by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The capacitance was chosen as the best parameter that describes the reproducible change in electrical properties of the electrode surface at different OTA concentrations and it was used to investigate the analytical parameters of the developed immunosensor. Under optimized conditions, the immunosensor showed a linear relationship between 0.3 and 20 ng/mL with a low detection limit of 0.25 ng/mL, making it suitable to control OTA content in many common food products. Lastly, the immunosensor was used to measure OTA in red wine samples and the results were compared with those registered with a competitive ELISA kit. The immunosensor was sensitive to OTA lower than 2 µg/kg, which represents the lower acceptable limit of OTA established by European legislation for common food products.

A highly sensitive impedimetric label free immunosensor for Ochratoxin measurement in cocoa beans.

In this work the development and optimization of an impedimetric label free immunosensor for the detection of Ochratoxin A (OTA) is reported. Two antibody immobilization methods (oriented and not oriented) were compared highlighting a lower limit of detection (5pg/ml) for the not oriented immobilization but a closer linear range in contrast to oriented anti-OTA immunosensors which showed linearity in the range of 0.01-5ng/mL OTA. The analysis of the Atomic Force Microscopy (AFM) images showed two different nanostructures indicating that the use of oriented immobilization created a more ordered and highly dense antibody surface. Finally the oriented immunosensor was used to quantify OTA in spiked cocoa bean samples and the results were compared with those registered with competitive ELISA kit. The immunosensor was sensitive to OTA lower than 2µg/kg that represents the lower acceptable limit of OTA established by European legislation for the common food products.

A doped polyaniline modified electrode amperometric biosensor for gluconic acid determination in grapes.

In winemaking gluconic acid is an important marker for quantitative evaluation of grape infection by Botrytis cinerea. A screen-printed amperometric bienzymatic sensor for the determination of gluconic acid based on gluconate kinase (GK) and 6-phospho-D-gluconate dehydrogenase (6PGDH) coimmobilized onto polyaniline/poly (2-acrylamido-2-methyl-1-propanesulfonic acid; PANI-PAAMPSA) is reported in this study. The conductive polymer electrodeposed on the working electrode surface allowed the detection of NADH at low potential (0.1 V) with a linear range from 4 × 10(-3) to 1 mM (R2 = 0.99) and a sensitivity of 419.44 nA∙mM(-1). The bienzymatic sensor has been optimized with regard to GK/6PGDH enzymatic unit ratio and ATP/NADP+ molar ratio which resulted equal to 0.33 and 1.2, respectively. Under these conditions a sensitivity of 255.2 nA∙mM(-1), a limit of detection of 5 µM and a Relative Standard Deviation (RSD) of 4.2% (n = 5) have been observed. Finally, the biosensor has been applied for gluconic acid measurements in must grape samples and the matrix effect has been taken into consideration. The results have been compared with those obtained on the same samples with a commercial kit based on a spectrophotometric enzyme assay and were in good agreement, showing the capability of the bienzymatic PANI-PAAMPSA biosensor for gluconic acid measurements and thus for the evaluation of Botrytis cinerea infection in grapes.