Establishment of Acid Hydrolysis by Box–Behnken Methodology as Pretreatment to Obtain Reducing Sugars from Tiger Nut Byproducts
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Razola Díaz, María del Carmen; Verardo, Vito; Martín-García, Beatriz; Díaz-de-Cerio, Elixabet; García Villanova Ruiz, Belén; Guerra Hernández, Eduardo JesúsEditorial
MDPI
Materia
Surface response methodology Horchata byproducts Glucose Xylose Chemical hydrolysis Schoorl method
Date
2020-03Referencia bibliográfica
Razola-Díaz, M. D. C., Verardo, V., Martín-García, B., Díaz-de-Cerio, E., García-Villanova, B., & Guerra-Hernández, E. J. (2020). Establishment of Acid Hydrolysis by Box–Behnken Methodology as Pretreatment to Obtain Reducing Sugars from Tiger Nut Byproducts. Agronomy, 10(4), 477. [doi:10.3390/agronomy10040477]
Sponsorship
This study is part of ERA-Net SUSFOOD2 project SUSPUFA, ID 145, funding provided by Spanish Ministry of Science, Education and Universities/ Spanish State Research Agency (PCI2018-093178) and co-funding by the European Union’s Horizon 2020 research and innovation program.Abstract
Carbohydrate-rich byproducts may be used as a growth substrate for microalgae. The tiger
nut, compared to other tubers, has higher carbohydrate content, which mostly remain in the byproduct
after the production of tiger nut milk (“Horchata”). The aim of this study is the optimization of a
hydrolysis pre-treatment in tiger nut byproduct to obtain reducing sugars, objective framed in the
European SUSPUFA (Sustainable production of health-promoting n-3 LC-PUFA using agro-food
industry by-products through microalgae) Project. Two experimental 4-factor Box–Behnken designs
(acid concentration (N), temperature (◦C), time (min) and ratio acid/sample) were carried out with
27 experiments to optimize chemical hydrolysis conditions with H2SO4 and H3PO4 in duplicate.
The sugars were determined by the Schoorl method and the extracts obtained by the optimal conditions
were analyzed by high-performance liquid chromatography (HPLC). Protected designation of origin
(PDO) and non-protected designation of origin (n-PDO) tiger nut byproducts were characterized
by physicochemical methods. The validity of the experimental designs was confirmed by ANOVA.
The optimum sugar values were obtained with H2SO4 2 N at 85 ◦C, 60 min and ratio 60 and H3PO4
21 N at 90 ◦C, 60 min and ratio 60. Glucose and xylose were the sugars detected in the hydrolyzed
samples. In conclusion, almost 50% of the total carbohydrates present in the tiger nut byproduct were
hydrolyzed to reducing sugars.