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An investigation of operational parameters of jet cutting method on the size of Ca‐alginate beads

Paulo, Bruna Barbon, Ramos, Fernanda de Melo, Prata, Ana Silvia
Journal of food process engineering 2017 v.40 no.6
biopolymers, calcium alginate, cost effectiveness, cutting, drugs, food industry, ingredients, microencapsulation, models, odors, physicochemical properties, prediction, proteins, sodium alginate, viscosity
A rarely used option for reduction the size of Ca‐alginate beads is the jet cutter, a rotating disk coupled to the output of the nozzle, and responsible for cutting the jet in smaller sizes. There are few systematic studies in the literature about this apparatus and its operational effects on the bead size. Therefore, this work aimed to investigate some operational parameters on the size of Ca‐alginate beads produced by dripping and jet cutting methods. First, physicochemical properties of different concentrations of sodium alginate solutions were determined, and the viscosity of 0.92 Pa s, corresponding to 2% (wt/wt), was found to be optimum for bead formation. For the dripping process, the highest flow rate of the alginate solution (49 mL/min) caused a limited reduction of bead size to 2 mm. This study on drop formation demonstrated that models developed for size prediction cannot be used as a tool for determination of size, due to the possible influences of the viscous forces. The jet cutter, adapted to a continuous jet regime, allowed to reduce from 5.2 mm to less than 1 mm in size with the increase of the rotation speed from 200 to 900 rpm. However, this increase resulted in higher tangential velocity of the beads, requiring larger collect recipients. This study developed the basis for broadening the application of the jet cutter to different biopolymers and ensures a better performance of this system. PRACTICAL APPLICATIONS: The technology of microencapsulation consists in the incorporation of a compound within a matrix, and it has been often used in the food industry by solving several limitations, allowing the immobilization, protection, controlled release of some ingredients, and changing of product properties. The use of biopolymers, such as sodium alginate, associated with the dripping method, enable the preservation even thermolabile compounds, such as drugs, organisms, proteins, and fragrances, since mild conditions are used. However, large beads are produced, which can limit their application. A rarely used and cost‐effective option for size reduction is the jet cutter, a cutting tool that, during its rotation, breaks the jet in smaller sizes, producing very small beads. The results of this study showed that the use of jet cutter was effective in the reduction of bead size and developed some basis for broadening its application for encapsulation using different materials.