Falciano, Aniello (2023) The Neapolitan Pizza: processing, distribution, innovation and environmental aspects. [Tesi di dottorato]

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Abstract

Not only is the Neapolitan pizza one of the most popular and well-known products of the Italian gastronomy, but also is one of the pillars of the food service and catering industry. Recently, its Disciplinary of Production which defines the standards for raw materials and technology parameters was encoded by the Official Journal of the Italian Republic n. 56/2010. In addition, the importance of the ‘art’ of Neapolitan pizza making has been inscribed in the List of Intangible Cultural Heritage of Humanity (Jeju, South Corea, 7 December 2017). The typicality of Neapolitan pizza essentially lies in the technology used in the preparation of leavened dough, raw materials used to garnish and its rapid cooking in a wood-fired oven. Despite its worldwide popularity and economic relevance, Neapolitan pizza is a topic that has attracted little interest from the scientific community. While from a scientific point of view Neapolitan pizza is a neglected topic, from the media point of view there is growing attention towards the potential impact of the consumption of pizzas made according to the traditional technology on human health. The information generally disclosed, even if unsupported by scientific evidence, has negative economic effects. The introduction of some innovations in the Neapolitan pizza production process, such as the use of sourdough, alternative flours, medium-long shelf-life ready-to-use dough balls, new pizza service systems, as well as a scientific analysis of the phenomena occurring during the Neapolitan pizza baking in traditional wood-burning ovens, might improve the qualitative aspects of the Neapolitan pizza, develop alternative baking systems, and achieve a circular economy to slash food waste formation. Therefore, the purpose of this doctoral thesis was to investigate the different aspects of the Neapolitan pizza production process, as reported below. In order to develop and characterize a liquid sourdough to be used in the Neapolitan pizza production process, it was investigated the effect of refreshment on the growth of endogenous microorganisms during the preparation of liquid mother yeast (DY 200) incubated for 6 days using wheat flours from two different geographical locations (i.e., Italian and Mexican flours), and their effects on physicochemical properties. The results showed that there is no need for refreshment during the first 6 days of incubation. The use of jujube powder as alternative flour was evaluated. The idea was to exploit the beneficial properties of jujube powder by using it to make composite flours in the development of a functional pizza base, produced in the Neapolitan style. The total phenolic and antioxidant properties of the pizza base, texture and color analysis of the samples were assessed. The results demonstrated that jujube powder could be considered as a potential healthy functional ingredient, without promoting adverse effects on the physical and sensory characteristics of pizza. The possibility of developing ready-to-use dough balls with a medium-high shelf life using low refrigeration temperatures was investigated. The samples were evaluated as a function of the leavening time, and after 28 days of storage. The chemical-physical and microbiological parameters did not show any significant differences, and the dough balls with a longer leavening time (16 h) showed characteristics similar to the fresh one and good rolling properties. The operation of a pilot-scale wood-fired pizza oven from its start-up phase to firing was characterized to evaluate its thermal efficiency. To manage the firing of the bricks, the oven was lit at a wood flow rate (Qfw) of 3 kg/h for just 1 hour on the 1st day, for 2 hours on the 2nd day, for 4 hours on the 3rd day and for about 8 hours on 4. Regardless of how often it was fired, after 4-6 hours the temperature of the vault or the floor of the furnace approached an equilibrium value of 546 ± 53 °C or 453 ± 32 °C, respectively. The initial temperature gradient of the kiln floor was found to be linearly related to Qfw, while the maximum floor temperature tended to an asymptotic value of 629 ± 43 °C at Qfw=9 kg/h. The known water boiling test has been adapted to evaluate the heat absorbed by a predetermined quantity of water when the pizza oven was operating in pseudo-stationary conditions at Qfw=3 kg/h. The thermal efficiency of this oven was 13 ± 4%, a value further confirmed by other baking tests with four different white and tomato pizza products. The combustion reaction of the oak logs of a wood-burning oven on a pilot scale and maintained in quasi-stationary conditions was modelled, and the composition of the fumes was measured. The external temperatures of the wall and floor of the oven were thermographically scanned, so that it was possible to verify the material and energy balances and therefore evaluate that the heat loss rates through the fumes and insulated kiln chamber were respectively equal to 46 % and 26% of the energy supplied by the combustion of wood. The enthalpy accumulation rate in the internal chamber of the oven was approximately 3.4 kW, sufficient to keep the vault and floor temperatures of the oven almost constant, but also to cook one or two pizzas at the same time. This speed was predicted by contemplating the simultaneous heat transfer mechanisms of radiation and convection between the furnace vault and floor surfaces. The effectiveness of the semi-empirical modeling developed here was further verified by reconstructing quite accurately the time course of water heating in aluminum pans with a diameter close to that of a typical Neapolitan pizza. The heat flow from the furnace roof to the water tank was approximately 73% to 15% radiative and convective, while the remaining 12% was conductive from the furnace floor. The phenomena that occur during the cooking of the Neapolitan pizza in a wood-burning oven on a pilot scale operating in almost stationary conditions such as: the rise of the rim, the heat and mass transfer, and the degree of browning and the apparence of burning spots of pizza samples garnished in different ways were studied since the heat transfer during the cooking of the pizza is not at all uniform and is particularly complex. Regardless of the garnish ingredients used, the rim height increased from 0.8 ± 0.1 cm to 2.3 ± 0.3 cm in just 80 s of cooking. During the cooking of the pizza, the temperature of the oven floor remained practically constant (439 ± 3 °C), while that under each pizza decreased the faster the greater the mass of the pizza placed on it. The maximum temperature of the bottom of the pizza was 100 ± 9 °C, while that of the top side of the pizza varied according to the type of topping and the different humidity content and emissivity of the ingredients. The overall weight loss was about 10 g in all types of pizza examined. Thanks to the use of the IRIS electronic eye, it was possible to quantify the brown or black areas. The upper area had higher degrees of browning and blackening than the lower one, whose maximum values of about 26 and 8% are observed respectively in the white pizza as it is. These results are needed to develop an accurate modeling and control strategy to reduce variability and maximize quality attributes of Neapolitan pizza. The cradle-to-grave carbon footprint of the different versions of the True Neapolitan Pizza was estimated in accordance with the PAS 2050 standard method. By assuming the same specific greenhouse gas emissions associated to some life cycle phases in the case of a typical Neapolitan pizzeria (i.e., energy consumption, refrigerant gas leakage, detergent production and wastewater treatment), the Marinara and Margherita pizza carbon footprint was about 4 and 5.1 kg CO2e/kg, respectively. By garnishing the latter with buffalo mozzarella cheese, its footprint would increase up to ~8.4 kg CO2e/kg. Such difference in their environmental impacts mainly derives from the use of condiments of only vegetable or even animal origin, these varying the protein and lipid contents and consequently the energy value of each pizza type. Finally, it was evaluated how the material and sensory properties change over time from the moment the pizza is taken out of the oven and placed in a cardboard box and when it is eaten at home. Furthermore, to avoid having to dispose of the unused balls of leavened dough at the end of the daily work activity in the pizzeria, the feasibility of a new take-away pizza service was evaluated with the final aim of improving the sensorial quality of the pizza perceived at home. These balls of dough were transformed into pizzas, cooked in a wood-burning oven, quickly frozen, packaged, stored in a freezer until sold, transported or delivered to your home, and finally heated in a domestic oven. The sensory acceptability of frozen pizza samples was compared to that of freshly baked pizza samples, as such, after queuing on a plate for only 5 minutes or being stored in cardboard boxes for 10, 20 or 30 minutes. These boxes slowed down the cooling of the pizza but improved its gumminess as the storage time lengthened. While panelists generally preferred freshly baked pizza, the frozen pizza samples were the far favorites over all of the other samples examined here. The cradle-to-grave carbon footprint and cost of frozen pizza were also assessed to show how such a food product, which would have been wasted, could be profitably converted into a high-quality alternative take-away pizza service.

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