The Use of Thermal Analysis and Photoacoustic Spectroscopy in the Evaluation of Maltodextrin Microencapsulation of Anthocyanins from Juçara Palm Fruit (Euterpe edulis Mart.) and Their Application in Food

Ana Paula da Silva dos Passos¹, Grasiele Scaramal Madrona¹, Vanessa Aparecida Marcolino², Mauro Luciano Baesso³ and Graciette Matioli¹*


¹Postgraduate Program in Food Science, State University of Maringá (UEM), Avenida Colombo 5790, CEP 87020-900, Maringá
  PR, Brazil
²Food Technology Department, Federal Institute for Education, Science and Technology of Paraná (IFPR), R. José Felipe
  Tequinha 1400, 87703-536, Paranavaí PR, Brazil
³Physics Department, State University of Maringá (UEM), Avenida Colombo 5790, CEP 87020-900, Maringá PR, Brazil





Article history:
Received May 15, 2014
Accepted: June 19, 2015





Key words:
anthocyanins, natural colourants, lyophilisation, microencapsulation, juçara palm




Summary:
Anthocyanins extracted from the pulp of the fruit of juçara palm (Euterpe edulis Mart.) were microencapsulated with maltodextrin in order to stabilise them. Photoacoustic spectroscopy was used to investigate the photostability of the microencapsulated samples. Complementary differential scanning calorimetry and scanning electron microscopy measurements were also performed. Lyophilised extract had 14 340.2 mg/L of total anthocyanins, and the microencapsulation efficiency of 93.6 %. Temperature analysis showed that maltodextrin conferred protection up to 70 °C for 120 min. Scanning electron microscopy showed that the microencapsulated particles had a flake-like morphology with a smooth surface, characteristic of lyophilisation processes. In addition, when added to yogurt, a red colourant was predominant in the samples at pH from 1.5 up to 5.0. Thermal analysis showed a weak interaction between the sample and the encapsulating agent, and photoacoustic data indicated the photostability of the matrix when exposed to light. Yogurts containing microencapsulated anthocyanins showed a more intense pink colour than yogurts treated with pure dye, and sensory analysis demonstrated that they can have good acceptance on the market. Microencapsulation enabled the innovative application of anthocyanins from juçara palm fruit, and complementary techniques allied to the photoacoustic spectroscopy were effective tools for its evaluation.






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