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Effects of the use of proteins on the barrier properties of particles produced by spray drying

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Bruna Barbon Paulo
Total Authors: 1
Document type: Doctoral Thesis
Press: Campinas, SP.
Institution: Universidade Estadual de Campinas (UNICAMP). Faculdade de Engenharia de Alimentos
Defense date:
Examining board members:
Ana Silvia Prata; Kaciane Andreola; Marcello Nitz; Paulo Henrique Mariano Marfil; Vania Regina Nicoletti
Advisor: Ana Silvia Prata; Izabela Dutra Alvim

Microencapsulation via spray drying is often applied successfully to flavors, pigments and edible oils to protect them against volatilization and oxidation. However, the retention of such compounds is usually evaluated on a case-by-case basis, without the necessary study of the protective barriers depending on the formulation components used. Therefore, this work aimed to investigate the influence of the hydrophobic active component, an unsaturated triglyceride (fish oil - FO) or a volatile oil (orange essential oil - OEO), and the wall materials, maltodextrin (MD) and surface-active compounds (SAC), on the barrier properties of particles produced by spray-drying. First, the effects of different concentrations (0.48 to 6 g/100 g emulsion) and type of SAC, gelatin (GE), whey protein isolate (WPI) or modified starch Capsul® were investigated on the formation and stabilization of emulsions (30 g solids/100 g emulsion and 1:4 oil:wall materials). GE behaved as a gelling agent and stabilized the emulsions by increasing the viscosity (> 42 mPa s) at concentrations above 3.6 % (w/w). In contrast, lower amounts of WPI (1.2 % w/w) e Capsul® (1.2 % e 3.6 % w/w for FO and OEO, respectively) were sufficient to stabilize the emulsions, which had lower viscosity (~ 14 mPa s) and oil droplet size (~2 µm) than GE-emulsions. Based on this study, the formulations that presented the highest emulsion stabilities at the lowest SAC concentrations were selected to be dried in the spray-dryer. All particles had similar physicochemical properties and morphology, but they showed different oxidation behaviors. The oxidative stability of the particles was evaluated by different techniques, including through a simple and low-cost and lab-scale apparatus developed in this work to measure the oxygen uptake. All methodologies presented similar results: the MD+Capsul® containing-particles presented higher oxygen consumption than those ones produced with MD+proteins (WPI or GE). However, MD+WPI containing-particles showed the highest encapsulation efficiency for both types of oil, followed by those ones with MD+Capsul® and MD+GE. Thus, the lower amount of total oil could result in less oxygen consumption, but the amount of surface oil is not necessarily related to oxidative stability. Although the pores in the dried matrices can contribute to the oxygen permeation, these were not sufficient to explain the different oxidation behaviors in this study, since they were similar for all particles. Thus, the interfacial membrane around the oil droplets is suggested as a determining factor to protect the active during storage. Additionally, the proteins showed potential for antioxidant activity, contributing to the higher oxidative stability observed (AU)

FAPESP's process: 17/14271-7 - Effects of the use of proteins on the barrier properties of particles produced by spray drying
Grantee:Bruna Barbon Paulo
Support type: Scholarships in Brazil - Doctorate