Póster presentado en: 17th European Meeting on Supercritical Fluids. 2019, 8-11 de abril, Ciudad RealJCyL and ERDF for financial support of project BU301P18. To Hiperbaric, S.A. for financial support of Project BIOLIGNO

Alonso Riaño, Patricia

English

Repositorio Institucional de la Universidad de Burgos

Brewer’s spent grain (BSG) • Is the most abundant brewing industry by-products (85 % of the total generated1)  • Is a lignocellulosic material, source of different biocompounds. Subcritical water fractionation (SWF) • Semicontinuous bed reactor • Flow rate of 4 mL/min  • Operating pressure of 50 bar •  Different temperatures.  Effluents were periodically collected and analyzed in terms of: • Total proteins • Free amino acids • Polyphenols   BSG has a wide range of possible applications as a valuable source of bioactive products as it has been shown in this work. Furthermore, BSG, as lignocellulosic biomass, is also a source for sugars production such as xylose, arabinose and glucose. High protein content of BSG (17.8 %wt.) makes it very interesting for application in the human diet. The results obtained in this work suggest that subcritical water fractionation of BSG is suitable to recover the main protein fraction and the total polyphenol content. The highest temperature in the range investigated, shows the best results related with bioactivity. CHARACTERIZATION 1. K. M. Lynch, E. J. Steffen, E. K. J. Inst. Brew. 2016,122, 553–568.  2. M. Santos, JJ. Jiménez, B. Bartolomé, C. Gómez-Cordovés, M. J. Del Nozal, Food Chem. 2003, 80, 17–21.  3. LAP-002. NREL Determination Analytical Procedure. 2004.  4. I. Sereewatthanawut, S. Prapintip, K. Watchiraruji, M. Goto, M. Sasaki, A. Shotipruk, Bioresour. Technol. 2008, 99, 555–561.  5. J.R. Vergara-Salinas, J. Cuevas-Valenzuela, J.R. Pérez-Correa, Biotechnol. of Bioactive Comp. 2015–101.  CONCLUSIONS REFERENCES Chart 1. Effect of temperature on (SWF) of BSG at 50 bars and different temperatures (125ºC,145ºC, 160 ºC and 185ºC). (a) % Protein  (b) Free Amino acids as mg amino acid/g BSG. Table 1.  Chemical composition of BSG. *Glucan in BSG is mainly cellulose but residual amounts of starch and β-glucan are also present.  Chart 2. Total polyphenol compound at 50 bars and different temperatures (125ºC,145ºC, 160 ºC and 185ºC).  Figure 3. BSG extracts obtained by SFW at 185 ºC and different times. Compound % w/w AX 22.3 Glucan* 26.7 ASL 5.3 KL 11.5 Ashes 1.4 Protein 17.8 Lipids 5.9 Extractives 15.2 TOC 47.5 Charts 1a and 1b show the proteins and amino acid yields at different operating temperatures, in the range from 125 to 185 ºC.   A temperature increase led to an increase of the extraction yield. The highest protein and amino acids yield were obtained at 160ºC: being a protein content of 11.44% w/w with respect to dried raw material and 16,69 mg amino acid/g BSG accumulated after 240 minutes of extraction, respectively.   These results could be due to an increase of the protein solubility at high temperature, but also to an increase of the ionization constant of water (Kw) with temperature at subcritical water condition. In the presence of hydronium and hydroxide ions, peptide bonds are broken down into smaller molecules of soluble protein or amino acids4. In any case, amino acids yield is not high due to stability of the peptide bond. Proteins and amino acids could start to be degraded at temperatures over 160ºC.,due to the high residence time.  Chart 2 shows the total polyphenol compounds (TPC) extraction curve in the temperature range from 125 to 185ºC. TPC extraction yield increases with increasing temperature, in the experimental range investigated, the highest quantity being found at 185ºC. At 160 and 185ºC, the TPC obtained in the extract is even higher than the TPC obtained after acid hydrolysis, (18.1 mg /g BSG dry).   Maillard reactions being favored by high temperatures. This can be visually observed in the color of the extracts from BSG since they become darker at higher temperatures with toasty aroma (Figure 3). Additionally, this can be also related to the increase of antioxidant activity with temperature since Maillard-reaction products may reinforce the antioxidant activity of PLE extracts from different raw materials, including BSG5.  POLYPHENOL EXTRACTION 051015202530350 30 60 90 120 150 180 210 240mg GAE/ g BSG TIME (MINUTES) 051015200 30 60 90 120 150 180 210 240 mg AMINOACID / g BSG  TIME (MINUTES) (b) 024681012140 30 60 90 120 150 180 210 240% PROTEIN TIME (MINUTES) (a) Subcritical Water Fractionation of bioactive compounds from Brewer’s Spent Grain (BGS) Patricia Alonso-Riaño*, Esther Trigueros, María Teresa Sanz, Rodrigo Melgosa, Óscar Benito-Román and Sagrario Beltrán Universidad de Burgos, Biotechnology and Food Science Dept. Chemical Engineering Division  Pza. Misael Bañuelos s/n 09001 Burgos (Spain) UNIVERSIDAD  DE BURGOS PROTEIN EXTRACTION AND HYDROLYSIS Figure 1. Brewer´s spent grain. Figure 2. Continuous pressurized liquid extraction. BSG composition can vary due to several factors2. Biomass characterization has been carried out according to the NRLE protocols3 (Table 1).  Acknowledgements • To JCyL and ERDF for financial support of project BU301P18 • To Hiperbaric, S.A. for financial support of Project BIOLIGNO • To JCyL and ESF for E. Trigueros predoctoral contract and for the contracts of P. Alonso-Riaño, Sarai del Rio Melgosa and Maria Berzal Lorenzo and Davinia Benito Bedoya through the YEI program EUROPEAN REGIONAL DEVELOPMENT FUND EUROPEAN SOCIAL FUND 

Subcritical Water Fractionation of bioactive compounds from Brewer’s Spent Grain (BGS)

https://riubu.ubu.es/bitstream/10259/5167/1/Subcritical_water_fractionation.pdf

Subcritical Water Fractionation of bioactive compounds from Brewer’s Spent Grain (BGS)

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