RESUMO
Yacon is a tuber known as a healthy food due to its effects as an antidiabetic, anti-inflammatory, anticancer, and prebiotic agent; it is rich in fructooligosaccharides (FOS) and antioxidants, and due to its sweet taste and low-calorie content, it is used as a substitute for ordinary sugar. This research aimed to evaluate the influence of the composition of the feed and the microencapsulation process by spray drying (SD) on the properties of a yacon powder mixture (YP). Response surface methodology with a central composite design with a face-centered composition (α = 1) was used, considering the independent variables: inulin (IN) (3-5% w/w), maltodextrin (MD) (3-5% w/w), air inlet temperature (AIT) (140-160 °C), air outlet temperature (AOT) (75-85 °C) and atomizer disc speed (ADS) (18000-22000 rpm), and the dependent variables: moisture (Xw), water activity (aw), hygroscopicity (Hy), solubility (S), particle size (percentile D10, D50, and D90), total phenols (TP), antioxidant capacity (ABTS and DPPH), color (CIE-Lab*) and yield (Yi). The suspension formulation contained xanthan gum (0.167 %) and a mixture of ascorbic and citric acids (0.3 %). The aw and Xw values of the YP guarantee its microbiological stability; however, the process formulation produces a complex matrix (FOS- sugars- MD - IN) with high affinity for water, which favors adsorption phenomena (hygroscopic material) and high reconstitution (high solubility). The independent variables that best fit the experimental optimization criteria were: IN = 3.0 %, MD = 5.0 %, AIT = 143.7 °C, AOT = 80.1 °C, ADS = 22000 rpm, where Yi = 84.2 %, and the quality of the YP: Xw = 2.4 %, a w = 0.220, Hy = 23.0 %, S = 96.9 %, D10 = 10.6 µm, D50 = 23.4 µm and D90 = 169.3 µm, TP = 1228.2 mg gallic acid equivalent/100 g, ABTS = 2295.9 mg Trolox equivalent (TE)/100 g, DPPH = 5192.3 mg TE/100 g, L* = 80.5, a* = 5.1 and b* = 17.4. SD is an effective technology that positively impacts the development of new food products. In addition, the YP could have multipurpose applications for the industry, generating value in this agri-chain.
RESUMO
Antecedentes: En Colombia, el fruto de la uchuva (Physalis peruviana) está identificado como un fruto promisorio de exportación, por lo que la mejora de su procesamiento representa contribuir a una mayor competitividad de la cadena. Objetivos: el objetivo de este trabajo fue optimizar en función de parámetros fisicoquímicos y reológicos la formulación de una suspensión a base de pulpa de uchuva mezclada con los aditivos maltodextrina (MD) y goma arábiga (GA) con fines de ser utilizada en secado por atomización. Métodos: La optimización se realizó aplicando un diseño experimental central compuesto mediante superficie de respuesta con dos factores (MD y GA) y variables de respuesta (densidad, ºBrix, aw, pH, y parámetros reológicos). Resultados: La caracterización reológica de las suspensiones mostró un comportamiento tipo adelgazante con esfuerzo de cedencia (Modelo de Hershel-Bulkley). La suspensión que mejor se ajustó a los criterios de optimización para fines de secado por atomización fue para la formulación basada en MD (24%) y GA (0%) con caracterización reológica de Herschel-Bulkley tipo adelgazante con índice de consistencia (K= 0,119±0,017 Pa.sn), índice de potencia (n=0,75±0,03) y esfuerzo de cedencia (τo= 0,092±0,069 Pa). Los resultados para las propiedades fisicoquímicas en el punto optimizado fueron densidad = 1,167±0,005 g/mL, °Brix = 35,5±0,5, aw = 0,974±0,002. El pH y τo no fueron estadísticamente significativos (p>0,05) en la formulación de las suspensiones. Conclusiones: La optimización experimental representa una herramienta importante que permitió obtener una formulación de uchuva con MD y GA apta para secado por aspersión, representando un ahorro en tiempo y dinero para el investigador y la industria.
Background: In Colombia, the Cape gooseberry fruit (Physalis peruviana) is identified as a promising export fruit, so improving its processing is contributing to greater competitiveness of the chain. Objectives: The aim of this study was to optimize suspension of cape gooseberry pulp mixed with gum arabic (GA) and maltodextrin (MD) with the purpose of being used in spray drying. Methods: The optimization was performed using a central composite design with response surface of two factors (MD and GA) and response variables (density, ° Brix, water activity (aw), pH, and rheological parameters). Results: The rheological characterization of the suspensions showed a shear thinning behavior with yield stress (Herschel-Bulkley Model). The results indicated that best suspension to be used in spray drying would be formulated with MD (24%) and GA (0%) showing a rheological response of Herschel-Bulkley fluid with consistency index (K=0.119±0.017 Pa-sn), power index (n=0.75±0.03) and yield stress (τo=0,092±0,069 Pa). To the optimized condition, the results for the physicochemical properties were density (1.167 ± 0.005 g/mL), °Brix (35.5±0.5), aw (0.974±0.002). Additionally, the pH and τo of Herschel Bulkley model was not statistically significant (p>0.05) in the suspension formulation. Conclusions: The experimental optimization is an important tool that allowed us to obtain a formulation of gooseberry with MD and GA suitable for spray drying, representing a saving in time and money for research and industry.