PMID- 34885901
OWN - NLM
STAT- MEDLINE
DCOM- 20220208
LR  - 20220208
IS  - 1420-3049 (Electronic)
IS  - 1420-3049 (Linking)
VI  - 26
IP  - 23
DP  - 2021 Dec 2
TI  - Microwave-Assisted Extraction of Phenolic Compounds from Spent Coffee Grounds. 
      Process Optimization Applying Design of Experiments.
LID - 10.3390/molecules26237320 [doi]
LID - 7320
AB  - In this study, sustainable technology microwave-assisted extraction (MAE) in 
      association with green solvents was applied to recover phenolic compounds from 
      spent coffee grounds (SCGs). A design of experiments (DOE) was used for process 
      optimization. Initially, a 2(4-1) two level Fractional Factorial Design was used 
      and ratios "solvent to solute" and "ethanol to water" were identified as the 
      significant experimental factors. Consequently, Central Composite Design (CCD) 
      was applied to analyze the effects of the significant variables on the response 
      yield, total polyphenols content (TPC), and antioxidant activity (AA) by the DPPH 
      assay method, and quadratic surfaces to optimize those responses were generated. 
      The values of the significant factors of 16.7 (solvent/solute) and 68.9% 
      (ethanol/water) were optimized simultaneously the yield (%) at 6.98 +/- 0.27, TPC 
      (mg GAE/g) at 117.7 +/- 6.1, and AA (micromol TE/g) at 143.8 +/- 8.6 and were in 
      excellent agreement with those predicted from the CCD model. The variations of 
      the compositions of the lipids, caffeine, pentacyclic diterpenes, and FAME as a 
      function of the dominant factor % ethanol in the solvent mixture were analyzed by 
      applying NMR and GC-FID, and the results obtained confirmed their determinative 
      significance.
FAU - Coelho, Jose P
AU  - Coelho JP
AUID- ORCID: 0000-0001-8118-0864
AD  - Instituto Superior de Engenharia de Lisboa, Instituto Politecnico de Lisboa, Rua 
      Conselheiro Emidio Navarro 1, 1959-007 Lisboa, Portugal.
AD  - Centro de Quimica Estrutural, Instituto Superior Tecnico, Universidade de Lisboa, 
      Av. Rovisco Pais 1, 1049-001 Lisboa, Portugal.
FAU - Robalo, Maria P
AU  - Robalo MP
AUID- ORCID: 0000-0002-8200-6910
AD  - Instituto Superior de Engenharia de Lisboa, Instituto Politecnico de Lisboa, Rua 
      Conselheiro Emidio Navarro 1, 1959-007 Lisboa, Portugal.
AD  - Centro de Quimica Estrutural, Instituto Superior Tecnico, Universidade de Lisboa, 
      Av. Rovisco Pais 1, 1049-001 Lisboa, Portugal.
FAU - Boyadzhieva, Stanislava
AU  - Boyadzhieva S
AD  - Institute of Chemical Engineering, Bulgarian Academy of Sciences, Academic Georgi 
      Bontchev str., 1113 Sofia, Bulgaria.
FAU - Stateva, Roumiana P
AU  - Stateva RP
AUID- ORCID: 0000-0002-4834-8183
AD  - Institute of Chemical Engineering, Bulgarian Academy of Sciences, Academic Georgi 
      Bontchev str., 1113 Sofia, Bulgaria.
LA  - eng
GR  - UIDB/00100/2020/Fundacao para a Ciencia e Tecnologia/
GR  - 778168/European Union's Horizon 2020, Marie Sklodow-Curie/
GR  - DH 07/12/Ministry of Education and Science of Bulgaria/
PT  - Journal Article
DEP - 20211202
PL  - Switzerland
TA  - Molecules
JT  - Molecules (Basel, Switzerland)
JID - 100964009
RN  - 0 (Phenols)
RN  - 0 (Plant Extracts)
RN  - 0 (Solvents)
SB  - IM
MH  - Coffea/*chemistry
MH  - Microwaves
MH  - Phenols/analysis/*isolation & purification
MH  - Plant Extracts/analysis/*isolation & purification
MH  - Seeds/chemistry
MH  - Solvents
PMC - PMC8658841
OTO - NOTNLM
OT  - design of experiments
OT  - green technology
OT  - microwave extraction
OT  - spent coffee grounds
OT  - total polyphenols content
COIS- The authors declare no conflict of interest. The funders had no role in the 
      design of the study; in the collection, analyses, or interpretation of the data; 
      in the writing of the manuscript; or in the decision to publish the results.
EDAT- 2021/12/11 06:00
MHDA- 2022/02/09 06:00
PMCR- 2021/12/02
CRDT- 2021/12/10 01:08
PHST- 2021/10/28 00:00 [received]
PHST- 2021/11/28 00:00 [revised]
PHST- 2021/11/30 00:00 [accepted]
PHST- 2021/12/10 01:08 [entrez]
PHST- 2021/12/11 06:00 [pubmed]
PHST- 2022/02/09 06:00 [medline]
PHST- 2021/12/02 00:00 [pmc-release]
AID - molecules26237320 [pii]
AID - molecules-26-07320 [pii]
AID - 10.3390/molecules26237320 [doi]
PST - epublish
SO  - Molecules. 2021 Dec 2;26(23):7320. doi: 10.3390/molecules26237320.