Gabriella Giovanelli

Variation in antioxidant components of tomato during vine and post-harvest ripening

The variation in the antioxidant content (lycopene, β-carotene, ascorbic acid and total phenolics) was evaluated on two tomato genotypes during vine and post-harvest ripening. Tomatoes were sampled and analysed at seven ripening stages according to the colour value. The data indicate that ripening conditions affected both the antioxidant accumulation kinetics and the final content, which was higher in post-harvest-ripened fruits. In particular, lycopene mainly accumulated in the very last period of ripening and its content was not linearly related to colour changes. Antioxidant accumulation and other ripening indexes were not significantly different in the two tomato genotypes. © 1999 Society of Chemical Industry

Water sorption, drying and antioxidant properties of dried tomato products

Abstract This work is focused on some properties of various dried tomato products (tomato pulp, tomato halves and insoluble solids-rich tomato), useful to optimize drying processes. Adsorption and desorption isotherms at 20°C of these products were measured and modelled by the Guggenheim–Anderson–de Boer (GAB) equation. Insoluble solids-rich tomato was the least hygroscopic of all tomato products. Tomato products were air-dried in a pilot plant and the drying kinetics was modelled. The mass transfer equation for drying of thin slabs, modified to include shrinkage of samples during drying, was successfully applied to experimental data. Apparent water diffusivity values ranged from 2.3×10−9 to 9.1×10 −9 m 2 /s as a function of the structure of tomato products. The lycopene and ascorbic content and the antioxidant activity of hydrophilic and lipophilic extracts were measured both on fresh and dried tomato products. Interesting properties of insoluble solids-rich tomato were evidenced: it had the highest lycopene content (ca. 12,000 mg/kg dm) and lipophilic antioxidant activity (ca. 400I 50 , μg dm ) of all tomato products.

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.

Effects of Baking Temperature on Crumb-Staling Kinetics

ABSTRACT This study evaluated the effects of bread baking temperature on the staling kinetics of crumb. Bread dough was leavened and baked in sealed molds. Cooking trials were performed at various temperatures ranging from 90 to 110°C. The crumb samples were then stored at 20°C at constant moisture, and staling was evaluated by measuring crumb elastic modulus (using an Instron dynamometer) and starch retrogradation degree (using differential scanning calorimetry). Results show that the cooking temperature greatly influences bread staling. The lower the cooking temperature, the lower the staling rate, both in terms of crumb hardening and of starch retrogradation. Starch and protein solubility was evaluated on crumb cooked at 90 and 110°C. An increase in cooking temperature resulted in an increase in protein insolubilization and starch granule disruption.

Modelling the effects of thermal sterilization on the quality of tomato puree

Abstract The aim of this work was to study and to model the effects of time-temperature conditions for sterilization on the overall quality of tomato puree. Tomato puree was produced from raw tomatoes in a pilot plant. Three sterilization tests were carried out at 90, 95 and 100 °C to obtain kinetic constants of quality properties. Heat and oxidative damage was observed in samples throughout sterilization. The furosine content increased, both the ascorbic acid content and the antioxidant activity of the hydrophilic fraction decreased, and a variation in colour (ΔE) occurred. No significant variations were found in the lycopene content, antioxidant activity of lipophilic fraction and sensory descriptors. Data were processed to obtain the relevant reaction kinetic constants, and a mathematical model was set up, which was able to predict quality variations in tomato puree during sterilization both under isothermal and non-isothermal conditions. The model was applied as a chart for optimization of sterilization.

Design and setting up of a water vapour pressure capacitance manometer for measurement of water activity

Abstract Water activity (a w ) plays an essential role in food science and technology in optimizing processes (i.e. drying) and evaluating the microbiological, chemical and physical stability of foods. Accurate and precise measurement of a w is also required in view of the new trend to minimal processing of foods. A thermostated vapour pressure capacitance manometer (VPM) apparatus, based on the theory of Benado and Rizvi, was designed and built. It consisted of two flasks, one for sample and another for desiccant (CaSO 4 ), connected by means of two solenoid valves to a tubing manifold, connected to a pressure transducer, and to a vacuum pump by means of a solenoid valve. Reference samples (i.e. pure water, saturated salt solutions and microcrystalline cellulose at different moisture contents) were used to validate the VPM at 25 °C. Results showed an accuracy of ±0.01 a w and a standard deviation of ±0.01 a w . Based on this study, the evacuation time and the time of sample equilibrium after evacuation were identified as the two critical points of the VPM for accurate measurements.

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.

E-nose, e-tongue and e-eye for edible olive oil characterization and shelf life assessment: A powerful data fusion approach

The aim of this work was to investigate the applicability of e-senses (electronic nose, electronic tongue and electronic eye) for the characterization of edible olive oils (extra virgin, olive and pomace) and for the assessment of extra virgin olive oil and olive oil quality decay during storage at different temperatures. In order to obtain a complete description of oil samples, physico-chemical analyses on quality and nutritional parameters were also performed. Data were processed by PCA and a targeted data processing flow-sheet has been applied to physico-chemical and e-senses dataset starting from data pre-processing introducing an innovative normalization method, called t0 centering. On e-senses data a powerful mid-level data fusion approach has been employed to extract relevant information from different analytical sources combining their individual contributions. On physico-chemical data, an alternative approach for grouping extra virgin olive oil and olive oil samples on the basis of their freshness was applied and two classes were identified: fresh and oxidized. A k-NN classification rule was developed to test the performance of e-senses to classify samples in the two classes of freshness and the average value of correctly classified samples was 94%. Results demonstrated that the combined application of e-senses and the innovative data processing strategy allows to characterize edible olive oils of different categories on the basis of their sensorial properties and also to follow the evolution during storage of extra-virgin olive oil and olive oil sensorial properties thus assessing the quality decay of oils.

Evolution of physicochemical, morphological and aromatic characteristics of Italian PDO dry-cured hams during processing

Abstract The aim of this work was to follow the evolution of physicochemical (dry matter, NaCl concentration, pH, water activity), morphological (image analysis) and aromatic (e-nose) characteristics of the three main Italian PDOs during processing, from slaughtering to end of ripening. Main phenomena distinguishing the PDOs are NaCl concentration increase, which is higher in Toscano than in Parma and San Daniele hams, starting from the salting phase. Water activity values decrease during processing, and the lowest values are detected in Toscano ham. Changes in morphological parameters (area, shape) and in color progressively occur during processing and are more pronounced in Toscano ham. A clear evolution of aroma of the three PDOs has been observed by e-nose, and the complexity of the aromatic profile of the ripened hams is clearly highlighted.