In this case study, we will examine the characterization of industrial wastewaters from a blanching (blanching) process in which legumes are treated during the production cycle of soups, to identify the potential for reuse and valorization of these waters.
The project fits perfectly within a circular model and green economy context. The dual aim of companies today is to provide eco-sustainable processes and products and to gain advantages in terms of productivity and cost reduction due to waste disposal.
Starting Situation and Final Objective
The project was commissioned to I.T.P. by a major multinational in the agri-food sector.
This confirms the strong interest and growing awareness of industrial realities regarding themes such as eco-sustainability, environmental protection, and waste reduction.
The client requested a study aimed at valorizing wastewater from their bean blanching processes, the phase preceding canning and subsequent sterilization.
Our work was primarily based on the chemical-physical characterization of blanching waters with different dissolved solids concentrations and on the identification of their potential as fermentative substrates.
The objectives were:
- Determine the functional properties of the supplied blanching waters, with a view to potential reuse as emulsifying and antioxidant additives;
- Verify the possibility to further enhance these properties through a lactic fermentation process.
Strategy Adopted
Three different types of blanching waters were subjected to chemical-physical analyses, collected at three different stages of the process, to determine their nutritional and functional profiles, particularly:
- Determination of total protein content;
- Determination of simple sugars concentration (glucose, fructose, sucrose) and oligosaccharides;
- Determination of starch content;
- Determination of total polyphenols and flavonoids content (antioxidant compounds);
- Determination of saponins content (substances with high foaming and emulsifying capacity);
- Evaluation of antioxidant, emulsifying, and foaming activities.
At the end of the preliminary characterization, the samples were subjected to a 24-hour lactic fermentation process. We used a batch fermentation apparatus equipped with a temperature control system and a pH probe throughout the process.
The fermentation process was characterized in terms of:
- Microbial load evaluation;
- Production trend of lactic acid and pH during the process;
The impact of fermentation on the main functional properties previously examined was then studied through a chemical-physical characterization of the fermented samples, to assess their potential as a valid functionalization technology.
Results Obtained
The wastewaters examined, corresponding to three different dissolved solids concentrations, proved to be excellent fermentation substrates, despite the low nutrient content (simple sugars and starch).
In all samples, fermentation led to an increase in total polyphenols and flavonoids, with a consequent increase in antioxidant capacity. The emulsifying and foaming activities and related stability indices were also higher at the end of the process.
Furthermore, for the sample with the lowest dissolved solids concentration, a marked proteolytic activity by the microorganism was evident, leading to an enrichment of the solution in simple peptides and amino acids and consequently to an improvement of the nutritional profile of the fermented waters.
Conclusions
The objective we set with the client, to determine the potential of blanching waters for their valorization and inclusion in other production applications, was achieved successfully.
Our team, based on the knowledge and experience acquired over the years in analytical techniques and fermentation processes, suggested to the client the concrete possibility of considering fermentation as an effective valorization technology and thus using the waste as raw material to obtain functional pre- and postbiotic ingredients and/or production of emulsifying and antioxidant additives.
Finally, we are proud that the client, in the following months, deemed our suggestion valid and started the project to implement a new industrial process based on what is described in this case study.
