Susanna Buratti

Evaluation of the antioxidant power of honey, propolis and royal jelly by amperometric flow injection analysis.

In this paper is described the applicability of a flow injection system, operating with an amperometric detector, for measurement in rapid and simple way the antioxidant power of honey, propolis and royal jelly. The proposed method evaluates the reducing power of selected antioxidant compounds and does not require the use of free radicals or oxidants. Twelve honey, 12 propolis and 4 royal jelly samples of different botanical and geographical origin were evaluated by the electrochemical method and the data were compared with those obtained by the DPPH assay. Since a good correlation was found (R(2)=0.92) the proposed electrochemical method can be successfully employed for the direct, rapid and simple monitoring of the antioxidant power of honeybee products. Furthermore, the total phenolic content of samples was determined by the Folin-Ciocalteau procedure and the characteristic antioxidant activities showed a good correlation with phenolics (R(2)=0.96 for propolis and 0.90 for honey).

A New Method for the Evaluation of the ‘Antioxidant Power’ of Wines

Phenols present in wines are responsible for its antioxidant properties. Traditionally the antioxidant power of wines has been measured using in vitro tests principally based on the inhibition of human LDL oxidation and also using the ORAC assay with different reactive species. This work describes a new method to evaluate the antioxidant power of several red and white wines based on a FIA system with electrochemical detection. It represents a significant improvement over other previously reported methods since it is based on the chemical structure of polyphenols and does not require the use of reactive species.

Monitoring of alcoholic fermentation using near infrared and mid infrared spectroscopies combined with electronic nose and electronic tongue

Effective fermentation monitoring is a growing need due to the rapid pace of change in the wine industry, which calls for fast methods providing real time information in order to assure the quality of the final product. The objective of this work is to investigate the potential of non-destructive techniques associated with chemometric data analysis, to monitor time-related changes that occur during red wine fermentation. Eight micro-fermentation trials conducted in the Valtellina region (Northern Italy) during the 2009 vintage, were monitored by a FT-NIR and a FT-IR spectrometer and by an electronic nose and tongue. The spectroscopic technique was used to investigate molecular changes, while electronic nose and electronic tongue evaluated the evolution of the aroma and taste profile during the must-wine fermentation. Must-wine samples were also analysed by traditional chemical methods in order to determine sugars (glucose and fructose) consumption and alcohol (ethanol and glycerol) production. Principal Component Analysis was applied to spectral, electronic nose and electronic tongue data, as an exploratory tool, to uncover molecular, aroma and taste modifications during the fermentation process. Furthermore, the chemical data and the PC1 scores from spectral, electronic nose and electronic tongue data were modelled as a function of time to identify critical points during fermentation. The results showed that NIR and MIR spectroscopies are useful to investigate molecular changes involved in wine fermentation while electronic nose and electronic tongue can be applied to detect the evolution of taste and aroma profile. Moreover, as demonstrated through the modeling of NIR, MIR, electronic nose and electronic tongue data, these non destructive methods are suitable for the monitoring of must-wine fermentation giving crucial information about the quality of the final product in agreement with chemical parameters. Although in this study the measurements were carried out in off-line mode, in future these non destructive techniques could be valid and simple tools, able to provide in-time information about the fermentation process and to assure the quality of wine.

Diclofenac fast-dissolving film: suppression of bitterness by a taste-sensing system

Context: The selection of a proper taste-masking agent (TMA) is a critical issue in the development of fast‐dissolving films containing bitter drugs. Objective: This work is aimed to evaluate the suppression of the bitter taste of a maltodextrin fast-dissolving film loaded with 13.4 mg sodium diclofenac (DS) by adding TMAs. Methods: The films were prepared by casting and drying aqueous mixtures of maltodextrin (DE = 6), glycerin, sorbitan oleate, and DS. Films were characterized in terms of thickness, tensile properties, film disintegration time, and drug dissolution time. The bitterness intensity of DS and the masking effect of TMAs were evaluated by an electronic tongue. Results: The ‘mint’ and ‘licorice’ flavors and sucralose mixture resulted appropriate to mask DS bitterness as confirmed by a panel of volunteers. The addition of these TMAs did not significantly affect the film disintegration time (15–20 seconds) and DS dissolution rate (about 5 minutes). Conclusion: The electronic tongue was allowed to discriminate the effect of the TMA also in the presence of other hydrosoluble constituents of the film. Therefore, because of its simplicity and rapidity, this technique could assist or even replace the sensory evaluation in the development of fast‐dissolving films.

Amperometric detection of carbohydrates and thiols by using a glassy carbon electrode coated with Co oxide/multi-wall carbon nanotubes catalytic system.

A glassy carbon electrode coated with cobalt oxide/multi-wall carbon nanotubes (MWCNT) system was used for the detection of carbohydrates and thiols. The modification of the glassy carbon electrode increased the anodic current response of these organic compounds and decreased their overvoltage. The amperometric responses were extremely stable with no loss of sensitivity over many days of storage. Such attractive performance characteristics indicate great promise for using this new catalytic system for monitoring in fast and simple way compounds of great interest for food industry, biotechnology and clinical diagnostics.

Characterization and differentiation of Italian Parma, San Daniele and Toscano dry-cured hams: a multi-disciplinary approach.

This study aimed at characterizing the sensory quality of Italian PDO dry-cured Parma, San Daniele and Toscano hams, applying a multi-disciplinary approach. Ham sensory profile as well as physico-chemical, aromatic, morphological and textural characteristics was investigated. There was a great difference between Toscano ham and Parma and San Daniele hams, which were more similar even though differentiated. Toscano ham showed higher scores for pork-meat odor, saltiness, dryness, fibrousness and hardness; accordingly, this ham was described by a high NaCl content and by high values of instrumental hardness, cohesiveness, gumminess and chewiness. Parma ham was characterized by a cured flavor, whereas San Daniele ham showed a wider fatty area and higher pH values. Parma and San Daniele hams were also described by higher values of sweetness, RGB color values and water activity. Sensory characteristics evaluated by trained assessors were correlated to instrumental measures, indicating that instrumental devices can be effectively applied for dry-cured ham characterization.

Application of electronic senses to characterize espresso coffees brewed with different thermal profiles

Electronic senses were applied in order to evaluate the effect of brewing temperature on the sensorial properties of espresso coffees (ECs) produced by a bar machine of the latest generation able to work with constant, increasing and decreasing water temperature profiles. The obtained ECs were analyzed by e-nose, e-tongue and e-eye to depict their aroma and taste fingerprint and to evaluate the visual characteristics of foam. Physicochemical analyses were carried out to determine the extraction rate of typical EC components and to evaluate their antioxidant activity. The electronic devices coupled with multivariate statistical analysis demonstrated a good ability to discriminate and characterize coffee samples on the basis of their sensorial properties in relation to the brewing temperature. According to these results, electronic senses can be applied to assess the influence of the percolation parameters on the sensory attributes of ECs, thus resulting useful tools for the optimization of processing conditions.

Determination of ascorbyl 6-palmitate in food matrices by amperometric flow injection analysis

In this paper a rapid method based on a FIA (flow injection analysis) system with amperometric detection for the evaluation of ascorbyl 6-palmitate in foods is described. The selectivity of the proposed method is related to the low anodic potential applied to the working glassy carbon electrode (+0.1 V vs. Ag/AgCl) that leaves out interferences from ascorbic acid and phenolic compounds. By flow injection analysis, under optimised conditions, the calibration curve was linear in the range 0-20 mg l(-1) and the detection limit was 0.2 mg l(-1).

Discriminative capacities of infrared spectroscopy and e-nose on Turkish olive oils

The potentials of Fourier transform (FT) near- (NIR) and mid-infrared (IR) spectroscopy, and electronic nose (e-nose) on varietal classification of Turkish olive oils were demonstrated. A total of 63 samples were analyzed, comprising Ayvalik, Memecik, and Erkence oils. Spectra were pretreated with standard normal variate and second derivative. Classification models were built with orthogonal partial least square-discriminant analysis (OPLS-DA), considering the single data sets and also the combined FT-NIR-IR spectra. OPLS-DA models were validated both by cross validation and external prediction. All the models gave good results, being the average correct classification percentages in prediction higher than 90% for spectroscopic data and equal to 82% for e-nose data. The combined FT-NIR-IR data set gave the best results in terms of coefficients of determination (0.95 and 0.67). Different e-nose sensors discriminated Ayvalik, Memecik, and Erkence oils, explaining their distinct aromatic profiles.

Application of the electronic nose in olive oil analyses

Publisher Summary It is possible to differentiate and classify extra virgin olive oil (EVOOs) from different geographical areas by using a commercial electronic nose and by applying multidimensional chemometric techniques. There is a growing emphasis and consensus that intelligent sensor arrays or electronic noses are most effective in the quality control of raw and manufactured products—for example, for determination of food freshness and maturity monitoring, shelf-life investigations, authenticity assessments of products and even microbial pathogen detection and environmental control. This application area is particularly important because the e-nose can be trained to recognize hazardous chemicals as well as odors. Furthermore, with respect to the human nose, the e-nose does not fatigue as easily, is less costly, and can travel easily into outer space. It also holds the promise of being much cheaper, smaller and easier to use and maintain than a mass spectrometer.