Fermentação láctica como estratégia de valorização de resíduos industriais de ketchup e integração em novas formulações

Abstract

In recent years, the increasingly unsustainable production and consumption patterns have led to an increase in the resources used, with an estimated annual waste of 1.3 billion tonnes, equivalent to a third of the world's food production for human consumption. The company Casa Mendes Gonçalves annually produces large quantities of ketchup with the inherent formation of industrial waste, called purges. Currently, its recovery goes through the production of biogas and fertilizers, but the solution found does not guarantee its full recovery, since part of the purges end up in landfill and represent a significant cost to the company. Thus, the present work aims to develop a strategy of valorization of the purges, through a fermentative process with lactic acid bacteria (LAB) and subsequent incorporation in ketchups. To this end, two purges were collected from the company's production unit, one without preservatives and the other with potassium sorbate, which did not present any significant differences (p > 0.05) in the physicochemical parameters compared to ketchups, confirming their relevance of valorization. The microbiological analyses performed demonstrated that the purges have adequate parameters for the reprocessing of these flows. The purges proved to be a medium with unfavorable conditions for the development of LAB, so a dilution of factor 6 (D6) was performed to decrease acetic acidity and °Brix and increase pH. In the purge without preservatives the most promising inoculums, which fermented in just 7 days, were Leuconostoc mesenteroides, individually and in consortium with Lactobacillus plantarum, with D6 and 1.5% salt. Also in this dilution, the association of Debaryomyces hansenii with the consortium of 4 LAB with 0.4% salt fermented after one week. The consortium of the 4 LAB also stood out in the purges with dilution factor of 3 (D3) with fermentative activity in 7 days. In the purge with preservatives, the consortium of the 4 bacteria under study with D6 and 0.4% NaCl, as well as with D3 and 1.5% salt showed the highest lactic acid production. The four preservative-free purge fermentations with the best results were selected for the development of ketchups with different percentages of incorporation of each one of the four fermented purges. The ketchup without preservatives that led to the formation of the purges was used as a standard and, in general, there were no significant differences (p > 0.05) in the physicochemical parameters between the developed samples and the standard. The sensory analysis allowed to select the ketchups with the incorporation of 40.9% of fermented purge with the consortium of 4 LAB, with D3 and 1.5% of salt and the ketchup with the incorporation of 39.2% of fermented purge with Lactobacillus plantarum and Leuconostoc mesenteroides, with D6 and 1.5% of salt. The nutritional analysis of these samples showed the nutritional improvement of ketchups with the inclusion of fermented purge, which has higher protein content as well as a superior content of ash and dietary fiber. In the future, it is essential to analyze the fermentations using HPLC to identify and quantify the organic acids produced and the sugar content throughout the fermentation in order to correlate with the pH and acidity results obtained in the fermentation tests performed.

Date of Award	10 Nov 2023
Original language	Portuguese
Awarding Institution	Universidade Católica Portuguesa
Supervisor	Conceição Hogg (Supervisor)