ORIGINAL RESEARCH Evaluation of the Use of Industrial Wastes on the Encapsulation of Betalains Extracted from Red Pitaya Pulp (Hylocereus polyrhizus) by Spray Drying: Powder Stability and Application Michele Utpott 1 & Renato Queiroz Assis 1 & Carlos Henrique Pagno 1 & Sheila Pereira Krigger 1 & Eliseu Rodrigues 2 & Alessandro de Oliveira Rios 1 & Simone Hickmann Flôres 1 Received: 15 April 2020 /Accepted: 8 September 2020 # Springer Science+Business Media, LLC, part of Springer Nature 2020 Abstract Different encapsulating agents from agroindustrial waste were tested to encapsulate betalains from red pitaya for use as natural pigments. Mucilage, extracted from the fruit peel, and gelatin from nutraceutical capsules were tested in combination with maltodextrin, and the microencapsulation was done by the spray drying method. The powders were characterized by their physicochemical properties, encapsulation yield and efficiency, morphology, betalain content, and glass transition temperature. The storage stability and the application in a food model system were also evaluated. The capsules presented low moisture and water activity, which is adequate for their safety and application. The encapsulation yields (16–25%) obtained were due to the low solid contents presented, and the combination of both wall materials increased the betalains retention by 7% in relation to liquid extract. Results for efficiency of encapsulation (above 90%) and glass transition temperature (around 85 °C) were highly satisfactory, indicating that the compounds remain well protected inside the capsule and a good storage stability of the powders. The morphology image and the results of particle size prove the obtained microcapsules, and the powder with mucilage was highlighted in relation to its stability under the studied storage conditions, retaining more than 80% of the pigment in 50 days. The microcapsules when added in yogurts corroborate the stability results and indicate the great potential of mucilage as an encap- sulating agent for the food industry. Keywords Encapsulation . Mucilage . Pitaya . Pigment . Spray drying Introduction Consumer’s demand for more natural and healthy products has challenged the industry to search new sources of pigments in order to replace the artificial colorants. The occurrence of intolerance and allergenic responses in recent years has alerted consumers and manufacturers of the importance of using nat- ural ingredients like food dyes. However, the stability of nat- ural pigments compared to artificial ones needs to be over- come (Celli and Brooks 2017; Downham and Collins 2000). Thus, researches in this area are necessary and of great interest to the food industry. Studies on the use of betalains as a source of natural pig- ments in models of food systems are limited and essential to demonstrate their potentiality (Gengatharan et al. 2017). Cactus fruits with high contents of betalains, in contrast to red beets, can be used in food without causing a negative effect in flavor. Red-purple pitaya (Hylocereus polyrhizus) is native to Mexico, Central, and South America, and belongs to the family of Cactaceae (Leong et al. 2018). Betacyanins are responsible for its deep purple color, being betanin the most widely studied betacyanin, which has already shown several benefits to organism human (Choo et al. 2018). Betalains sta- bility is affected by many factors, such as temperature, * Michele Utpott michele.utpott@ufrgs.br * Simone Hickmann Flôres simone.flores@ufrgs.br 1 Bioactive Compounds Laboratory, Food Science and Technology Institute, Federal University of Rio Grande do Sul, Avenue Bento Gonçalves n° 9500, P. O. Box 15059, Porto Alegre, Rio Grande do Sul 91501-970, Brazil 2 Food Science and Technology Institute, Federal University of Rio Grande do Sul, Avenue Bento Gonçalves n° 9500, Porto Alegre, Rio Grande do Sul 91501-970, Brazil Food and Bioprocess Technology https://doi.org/10.1007/s11947-020-02529-3