Análise do desempenho de filtração de gelatina utilizando terras diatomáceas e perlitas no pré-revestimento

Abstract

Gelatine is a product with wide application in the food industry, whether as a clarifying agent, stabilizer and protective coating material, especially in the composition of desserts, sweets, baked goods, frozen meat, ice cream, dairy products and others. Regardless of the process applied for the extraction, it is necessary to control some quality parameters during its manufacture, in order to add value to gelatin. Some of these parameters are: bloom, viscosity, turbidity, color and odor. It is exactly in the clarification stage that turbidity and color are controlled. At this stage, the processes involved are applied in order to separate particulate materials present in the gelatin solution after its extraction. In it’s turn, pre-coating filtration (using diatomaceous earth, perlite, charcoal and cellulose as a filtering aid) stands out for presenting advantages in relation to its high efficiency, low energy demand and gelatin organoleptic characteristics preservation. As a result, this work aimed to analyze the different filtering aids performance from mixtures of diatomaceous earth and perlite, regarding the clarification capacity of gelatin, in order to verify the best configuration for this operation. For such a purpose, experimental tests were carried out in which gelatin was filtered in a vacuum kitassate system using different blends of diatomaceous earth and perlite, in which the performance was investigated in terms of permeate flux, permeability, porosity, filtration resistance and final quality permeate correlating them with the granulometry of the coating and its chemical composition. The results provided led to the conclusion that perlite is a less porous filter aid, however it is promising when mixed with fine-grained flux-calcined diatomaceous earth, proving to be ideal for gelatin filtration. Thus, the most efficient blend was composed of 75% perlite and 25% diatomaceous earth, with an average permeate flux of 4.409 L/m2 s and turbidity removal efficiency and 450 nm color increase above 50%. The filtering characteristic of each filter aid studied was demonstrated. The present study could also provide an efficient experimental basis for optimizing precoat filtration processes, as it offers an efficient methodology for testing permeability, porosity, percolation resistance and gelatin physicochemical analysis.