Premise

The regional fish supply chain, unlike the agricultural one and that deriving from animal breeding, is a very short supply chain characterized mainly by the marketing of fresh products as is and by some products with low service content. As such, it suffers from some critical issues that limit its development and do not allow it to fully exploit its potential. Among these: the high perishability of the product, the low service content, the uncertainty about the origin of the catch.

In fact, almost all fish species are highly perishable and to preserve their commercial quality in the phases following fishing it is necessary to resort to the cold chain and rapid delivery to sorting points. These measures, however, are not always suitable for guaranteeing the consumer an adequate and expected level of quality and freshness of the product. The dynamics of supply and demand, then, do not always develop synchronously and sometimes the times and methods of conservation in storage sites cause deterioration of the product and are incompatible with market demand. Hence the need to develop new technologies capable of improving the conservation process, both on board fishing boats and in storage cells, which allow the shelf life of fish products to be extended in a manner suited to needs.

In some cases, a solution that is practiced to extend the preservation times of the catch is freezing it. This practice, commonly used to preserve products caught in areas far from the marketing points, while on the one hand prevents the phenomena of biological degradation, is however to the detriment of their sensorial quality. The formation of ice crystals causes a strong reduction in the WHC (structural water holding capacity) of animal tissues which exude when thawed, losing turgidity, negatively modifying the texture and nutritional properties. Even in this area, there is room for improvement by exploring new technologies capable of lowering the temperature to stop the development of deteriorative biological processes but at the same time prevent the qualitative alterations of the catch associated with the reduction of temperatures and tempering.

Regarding the extension of primary and secondary shelf life, encouraging progress has been achieved through various mild technologies, in particular mainly applied to products of plant origin.

These techniques allow interference through physical interaction with many of the biological reactions responsible for the degradation of the sensorial and commercial quality of various products and suggest the possibility of use also in the case of fish products.

The project is divided into investigative work packages whose objective is to preserve the quality and food safety of fish from the coasts of Campania through the study of technologies aimed at prolonging the primary and secondary shelf-life that can be easily implemented by operators in the sector (fishing boats , general markets and retail outlets).

Correspondence between the objectives of the project proposal and the institutional activities of the Centre

CAISIAL (Center for Innovation and Development in the Food Industry) was established with DR 4770 on December 27, 2004. The Center is a service center that aims to optimize and use the resources and skills of the Federico II University of Naples in development and innovation activities in the food field.

In particular, CAISIAL’s activity focuses on the collection of data relating to innovations in the food field of shelf-life, food transformations and technological transfer to companies in the sector. To carry out its institutional activities, the Center is equipped with:

1. a) an Observatory for the development of market surveys aimed at defining the needs and expectations of consumers;
2. b) modern laboratories for sensory, chemical and rheological analyses,
3. c) pilot plants for the production of food and drinks
4. d) a specific section of aquaculture and processing of fish products.

Over the years, the Center has carried out numerous projects in the field of fishing and aquaculture financed by national and community bodies (Mipaf, EU, Campania Region) and by private entities, developing new products and assisting numerous national and local companies in the development of their business plans as well as consultancy regarding research and development of innovative food processes and products.

The Center is directed by Professor Paolo Masi, professor of Food Technologies at Federico II, supported by a Board of Directors, an administrative secretariat and technical staff. CAISIAL partners include the Chamber of Commerce, Industry and Crafts of Naples, Coldiretti Campania, STOÀ and the Eubeo Consortium.

Description of the project activities

Process innovation in fish conservation

This line of research is divided into two distinct WPs, the first intended for the development of an objective method for evaluating the freshness of the catch and the kinetics of its decay in the post-capture phase, the second intended for the application of different technologies conservation of fish products as such or processed.

WP1: Evaluation of the freshness of Campania fish

The freshness evaluation involves the development and optimization of the “Quality Index Method” (QIM) for Mediterranean fish species. In fact, the QIM approach varies depending on the species, and is currently used in Northern European countries for the examination of a limited number of fish species, mainly oceanic. The sheets currently available are almost exclusively published in English in scientific journals; therefore, they are not easily usable by operators in the sector. This method is based on the evaluation of certain sensory attributes relating to appearance, odor and consistency of fishery products as such or manipulated, through the use of a demerit score system from 0 to 3. The scores obtained from each sensory attribute are added to obtain a total score which represents the Quality Index of the product. Since the Quality Index has been shown to be linearly related to the ice storage time of fresh fish, an estimate of the remaining shelf life can also be obtained in this way.

Both sector operators (fishing and marketing workers) and regular consumers purchasing fish products will be involved in the development of the research.

The data obtained from the sensorial analysis will be correlated to physical-chemical and microbiological analytical indices.

The three categories of sensory attributes, evaluated with the QIM, will, in fact, also be measured in parallel using instrumental methods, in particular: appearance using the IRIS electronic eye; the smell with the help of the electronic nose; consistency using texture analyzer.

From this point of view, research has been developed by the working group which has allowed the development of protocols for image acquisition (IRIS electronic eye) and analysis which allow the detection of:

• modifications of the colorimetric properties and tonality of the eye, to be used as freshness indices during refrigerated storage;
• morphological parameters, to be used as indicators of authenticity.

Furthermore, protocols have been developed for texture evaluation (texture analyzer and dynamometer), which allow the measurement of structural changes in the fish from Campania during cold storage.

Previous research will be implemented through analytical investigations to identify markers of freshness through the degradation of muscle proteins that occur post-mortem; variation of freshness indices such as TVB-N (Total volatile basic nitrogen) and TMA (Trimethylamine) on crustaceans and fish during refrigeration and development of biosensors for the determination of quality indices such as TMA and histamine through immobilization of trimethylamine oxidase and amine oxidase . NIR-FTR technology will also be implemented for the development of a rapid method of evaluating the freshness and quality of the products on some of the fishing products characteristic of the Campania navy.

WP2: Process innovation in the conservation/refrigeration of fish

Fish products are highly perishable foods characterized by a short shelf-life, so it is a priority to better manage their conservation from the first stages after fishing to slow down deterioration phenomena as much as possible and guarantee consumers a safe and high-quality product. quality. To guarantee a shelf-life of 5-7 days, fish products must be stored at temperatures close to zero and the cold chain must be guaranteed during all phases of distribution and sale. The main deterioration mechanisms that cause the loss of quality of fish products are due to the growth of spoilage microorganisms, hydrolysis of proteins, and oxidation of lipids.

Consumers are increasingly demanding in requesting foods free of chemical preservatives, so in recent years research has focused more on emerging technologies capable of preserving the quality of foods, without compromising their safety of use.

Among these, interesting for the specific application are sanitization technologies through washing with electrified water, the application of active coatings based on biopolymers to preserve the safety and quality of the products during storage and the application of static electric fields and ozone during the conservation of the product in refrigeration cells. To increase their effectiveness in preserving the quality of food, minimizing the impact on the safety of use of the product, a possible strategy is to couple the different technologies to extend the shelf-life of the product as much as possible.

To this end, the project intends to study the effect of electrified water, active coatings and static electric fields and ozone alone and in combination on the quality of different categories of fish products (at least two). The experimentation therefore includes a first phase for the optimization of the conditions of use of the individual technologies and a second phase for the application of the three technologies in combination and the quantification of the impact on the quality of the product.

Electrified water can be prepared acidic, basic and neutral. The type of water will be selected following an in-depth bibliographic research relating to the specific application. The experimental hypothesis is that electrified water, thanks to its bactericidal power, can guarantee a better microbiological quality of the product compared to preservation in ice made with non-electrified water. Then, a type of electrified water will be used to produce ice to be used for preserving fish products immediately after fishing. To this end, it is planned to store the product in the presence and absence of ice obtained with electrified water and to evaluate the microbiological quality of the samples at different storage times during storage at 4°C. The ice will be prepared by varying the process conditions of the electrified water in order to select the process parameters that guarantee the minimum growth of specific indicator microorganisms.

Active coatings based on biopolymers are a preservation technology based on the control of material flows between the food and the conservation environment and on the controlled release of natural antimicrobial or antioxidant substances. The first part of the work involves in-depth bibliographic research to select the biopolymers and the active substance to be used for the composition of the coating.

Subsequently, the physical and antimicrobial or antioxidant properties of the coating will be studied to optimize the relationship between the components and the optimal concentration of active substance.

Finally, the coating will be applied to the food product before the storage phase in the cell and the quality of the product with and without coating will be studied at different storage times to quantify the impact of the coating on the alteration kinetics of the food.

Static electric fields will be applied in storage cells at 4°C using DEMBA+ technology. The production of the electric fields will be carried out in a single process condition, so the objective of the study is to evaluate the effectiveness of the technology on the quality of the product during conservation. The product stored in the absence of electric fields will be used as a control sample.

The second phase of the experimentation involves using the three technologies in combination to study their impact on the quality of the product during storage in the refrigeration cell. To this end, the fish product will first be covered with the active coating and then stored in ice made with electrified water inside cells in which static electric fields are produced thanks to DEMBA+ technology. The study plans to quantify the evolution of product quality during conservation in order to quantify the impact of the combination of technologies on the quality and freshness indicators of the product. During the tests, a thermal study of the cooling dynamics of the product will also be carried out using thermoscanners.

WP3: Dissemination and technology transfer activities

Results of the research will obviously be scientific publications in referenced journals. Since the objective of the project is above all to illustrate to operators in the sector the potential of the innovative solutions that will be developed to stimulate their interest and encourage their adoption, it is planned to carry out dissemination activities both through the development of a dissemination manual intended to operators in the fish supply chain, both dissemination operations on IT media such as social media and the project website, and through a conference event during which the results obtained in the research will be presented.

Duration of the project

The activities relating to the proposed research began upon the signing of the Agreement (ex article 15, Law 7 August 1990, n. 241) on 12/12/2022 and will end on 30 October 2023.