Microencapsulação de ferro por coacervação complexa para fortificação de bebida láctea fermentada

Abstract

Malnutrition is a serious public health issue, especially in children and in less developed countries. Current data from the World Health Organization indicate that approximately 150 million children suffer from malnutrition. Micronutrient deficiency is a form of malnutrition, with iron deficiency being one of the most prevalent worldwide. In this context, food fortification becomes a viable alternative to address the iron deficiency in the population, through microencapsulation to be added to various food matrices, including dairy products. Microencapsulated iron, due to its high reactivity, has proven to be an attractive option for food fortification purposes. Thus, this research aimed to microencapsulate and characterize heptahydrated ferrous sulfate (Fe2+) to fortify a dairy beverage. Fe2+ was encapsulated in whey protein isolate (WPI) and gum arabic (GA) through the complex coacervation method, in a double emulsion process, followed by cooling and freeze-drying. The data showed that the iron content in the microcapsules ranged from 1.29 ± 0.02 to 1.32 ± 0.01 (mg/g). The morphology of the microcapsules was characterized as irregular, with sizes ranging from 0.48 ± 0.43 to 5.13 ± 2.10 µm. Regarding process efficiency and yield, the values ranged from 44.62 ± 9.45 to 61.1 ± 9.3 and 50.39 ± 0.64 to 55.78 ± 3.24 (%), respectively. The presence of O – H and C – O functional groups, observed in the FTIR spectra, indicates the presence of WPI-GA and Fe2+. Thermogravimetric analysis revealed five decomposition events, with the major mass loss occurring in the 2nd stage at a temperature of 331.57 ºC. Exploratory calorimetric analysis showed a glass transition temperature and a melting temperature of 30 and 130 ºC, respectively. These data demonstrate that the encapsulation process was successful and that the microcapsules exhibit good stability, making them suitable for incorporation into various food matrices, both in wet and powder forms. Dairy beverages were fortified with free iron (BLFL) and microencapsulated iron (BLFM), and their iron levels were evaluated after 7 and 21 days of storage. The iron content (mg/100mL) in BLFL was 0.19 and 0.14, and in BLFM it was 2.29 and 2.47, at 7 and 21 days, respectively. At the end of 21 days, the iron content in BLFM was equivalent to 22% of the maximum recommended daily intake for children aged 0 to 5 years, classifying it as a fortified food. These findings suggest that the microencapsulation process is an effective alternative to protect and stabilize Fe2+ in the fortification of fermented dairy beverages.