Indus ial C ops & P oduc s 186 (2022) 115166
A ailable online 8 June 2022
0926-6690/© 2022 The Au ho (s). Published by Else ie B.V. This is an open access a icle unde he CC BY-NC-ND license (h p://c ea i ecommons.o g/licenses/by-
nc-nd/4.0/).
A echno-economic pe spec i e on a mic owa e ex ac ion p ocess o
e icien p o ein eco e y om ag i- ood was es
C is ina Ba ios
a
,
b
, Ma ina Fe n´
andez-Delgado
a
,
b
, Juan C. L´
opez-Lina es
a
,
b
,
Ma ía Te esa Ga cía-Cube o
a
,
b
, M´
onica Coca
a
,
b
, Susana Lucas
a
,
b
,
*
a
Ins i u e o Sus ainable P ocesses, D . Me gelina s/n, 47011 Valladolid, Spain
b
Depa men o Chemical Enginee ing and En i onmen al Technology, School o Indus ial Enginee ing, Uni e si y o Valladolid, D . Me gelina, s/n, 47011 Valladolid,
Spain
ARTICLE INFO
Keywo ds:
Ag i- ood was e
P o ein eco e y
Mic owa e-assis ed ex ac ion
Economic analysis
ABSTRACT
Di e en ag i- ood was es (b ewe ´s spen g ain (BSG), spen co ee g ound (SCG) and kale s ems) ha e been
p oposed as excellen sou ces o p o ein-en iched ex ac s wi h an an ioxidan capaci y. The op imiza ion o he
mic owa e-assis ed hyd o he mal and alkali ex ac ion has been compa ed in his s udy. F om a echnical and
economic poin o iew, he ex ac ion o BSG unde op imal condi ions (110 ºC, 10 min and 0.5 M NaOH)
p o ided he bes ex ac wi h a con en o 14.6 kg p o ein/100 kg BSG (d y ma e ), 13.8 g/L o o al suga s and
an an ioxidan ac i i y (DPPH me hod) o 17.1 mg olox equi alen s (TE)/g BSG. This ex ac had he lowes
p oduc ion cos (29.9
€
/kg) and a minimum selling p ice o 51.7
€
/kg, es ima ed o an ex ac ion pilo plan o
15 kg/h o BSG. The mic owa e-assis ed hyd o he mal ex ac ion o kale s ems, a no el was e in he bio e ine y
con ex , also p o ides bioac i e and g een ex ac s o comme cial in e es . The e is a need o speci ic esea ch
s udies ela ed o bio e ining o ag i- ood was es o p oduce p o eins o ood, con ibu ing o he de elopmen o
a u u e sus ainable and clima e-neu al ag icul u e. The p oposed echno-economic assessmen ep esen s an
impo an ad ance in esea ch and scaling-up o mic owa e-assis ed ex ac ion p ocesses o p o ein eco e y
om ag i- ood was es.
1. In oduc ion
Eno mous amoun s o ag i- ood was e (AFW) a e gene a ed in
a ious s ages o he en i e ag i- ood supply chain (including p ocessing)
(Bha , 2021). AFW is an excellen sou ce o bioac i e compounds o
exploi , including p o eins, suga s, lipids, and phenolics (Popo ic e al.,
2022). Acco ding o Ma i´
c e al. (2018), Eu ope gene a es abou 100
million onnes o was e each yea in he ood p ocessing indus y. The
concep o conside ing by-p oduc s as a aw ma e ial o he eco e y
and p oduc ion o se e al co-p oduc s using g een me hods wi hin he
in eg a ed bio e ine y model has g ea in e es and po en ial (Fie ascu
e al., 2020) conce ning he ci cula economy policies. In his con ex ,
b ewe s’ spen g ain (BSG) is he mos abundan by-p oduc in he bee
b ewing p ocess and is a ailable h oughou he yea (Pa chami e al.,
2021). This ma e ial consis s o he ba ley g ain husks ob ained as solid
esidue a e he p oduc ion o wo . I comp ises app oxima ely 85% o
he o al was e gene a ed in his indus y (Li e al., 2021); p oducing 0.2
kg we BSG pe li e o bee (Pa chami e al., 2021). In 2019, 38.2
million me ic ons o we BSG we e p oduced wo ldwide (Pa chami
e al., 2021). This esidue con ains a ela i ely la ge amoun o p o ein
(18–31% w/w) and ibe , suga s, and mine als. This was e is no mally
only used as animal eed o is di ec ly disca ded (Li e al., 2021).
Ano he in e es ing AFW is spen co ee g ounds (SCG). Co ee is one o
he mos consumed comme cial oods and he second mos expo ed
p oduc by eme ging coun ies (Ribei o e al., 2021). The co ee indus y
p oduces a la ge amoun o was e which, acco ding o Valdes e al.
(2020), may ep esen somewhe e o e 50% o he mass o all he co ee
beans in he p oducing coun ies. The wo ld p oduc ion o co ee in
2018 was a ound 9.5 million ons (de O ´
alo a e al., 2020) and
app oxima ely 0.91 g o SCG is p oduced o 1 g o co ee g ound (Tun
e al., 2020). SCG con ains signi ican p o ein con en (up o 12% w/w)
(Mussa o e al., 2011; Ribei o e al., 2021). On he o he hand, kale, a
ege able om he B assica genus, has been a ac ing a en ion o he
las ew decades due o i s high an ioxidan and die a y ibe con en
(Casajús e al., 2021). B assica genus c ops a e one o he en mos
economically essen ial ege ables in global ag icul u e and ma ke s. In
* Co espondence o: Depa men o Chemical Enginee ing and En i onmen al Technology, Uni e si y o Valladolid, D . Me gelina s/n, 47011 Valladolid, Spain.
E-mail add ess: [email p o ec ed] (S. Lucas).
Con en s lis s a ailable a ScienceDi ec
Indus ial C ops & P oduc s
jou nal homepage: www.else ie .com/loca e/indc op
h ps://doi.o g/10.1016/j.indc op.2022.115166
Recei ed 9 Feb ua y 2022; Recei ed in e ised o m 5 May 2022; Accep ed 28 May 2022
Indus ial C ops & P oduc s 186 (2022) 115166
2
2012, he global p oduc ion o B assica c ops was almos 92 million
me ic onnes, g own in 150 di e en coun ies and occupying 5.4
million hec a es. Spain, Mexico, I aly, F ance, and he USA p oduce o e
0.2 million me ic onnes pe yea . A ound 7% o his ege able is dis-
ca ded as was e (F ancisco e al., 2017). Acco ding o Megías-P´
e ez e al.
(2020), he a e age composi ion o kale is wa e (89%), ibe (4%),
p o eins (3%), lipids (1.5%), and low molecula weigh ca bohyd a es
(1%). So esh kale has mode a e le els o p o ein (1.6–5.9 g/100 g).
In ecen yea s, he ood indus y has ocused on s udying he an-
si ion om he use o animal p o eins o plan -based p o eins (Yang and
Sagis, 2021). This de elopmen is due o he en i onmen al aspec s o
mea p oduc ion and he need o new p o ein sou ces o he highe
global popula ion (Pa chami e al., 2021). Ex ac ed p o eins ha e
p ope ies ha a e bo h bio unc ional (nu i ional p ope ies o appli-
ca ion in eed/ ood and pha maceu ical sec o s) and echno- unc ional
(s uc u es echnical applica ions such as packaging wi h solubili y o
ne wo k o ma ion and iscosi y) (Yada e al., 2020). So i is necessa y
o ind an al e na i e, less esou ce-in ensi e sou ce o p o ein o ood,
as well as o o he applica ions.
The con en ional p o ein ex ac ion me hod has some d awbacks,
such as he ac ha i equi es a la ge amoun o wa e and ene gy, he
p o ein ex ac ion yield dec eases when high pu i y p o ein ex ac s a e
ob ained, o he p ocess may al e he p o ein s uc u e (Yang and Sagis,
2021). The p oblem o ex ac ing p o ein in his ype o was e wi h high
yields is ha se e al componen s, such as cellulose and lignin, o m a
complex ne wo k and ap he p o ein inside (Li e al., 2021). The e o e,
chemical ea men s ha e been applied. Con en ional alkali ex ac ion
has been p o ed o be an app op ia e p o ein ex ac ion me hod, bu i
also has he disad an age o a long ex ac ion ime (Li e al., 2021). Fo
his eason, physical me hods a e gene ally used oge he wi h he
chemical me hod o o e come he abo emen ioned disad an ages.
Mic owa e-assis ed ex ac ion (MAE) could be a cos -e ec i e, e icien
and s aigh o wa d me hod o assis in p o ein ex ac ion. Mic owa e
echnology has been conside ed a g een and eco- iendly me hod o
dis up he cell wall wi h ela i ely low ene gy inpu , a apid ea men
ime and he a oidance o he u iliza ion o haza dous subs ances. Mi-
c owa es in e ac selec i ely wi h pola molecules and induce in a-
cellula hea ing. This hea and p essu e loca ed in he cell walls lead o
cell dis up ion allowing and imp o ing he ex ac ion o in acellula
p o eins. MAE was hus applied o enhance he e icacy o p o ein
ex ac ion and he co-ex ac ion o phenolic compounds om se e al
AFW, such as BSG, SCG, and kale s ems.
The p esen wo k a emp s o s udy he use o se e al was es om he
ood and be e age indus y (BSG, SCG, and kale s ems) o achie e
bioac i e p o ein-en iched ex ac s wi h an ioxidan ac i i y. In his
con ex , he MAE p ocess was p oposed, in which he in luence o h ee
pa ame e s ( empe a u e, ime, and NaOH concen a ion), as well as he
compa ison o alkali and hyd o he mal ex ac ion, a e e alua ed using
he esponse su ace me hodology. The e alua ed maximizing esponse
was he p o ein eco e y. On he o he hand, he o al phenolic con en
(TPC), o al la onoid con en (TFC), and an ioxidan ac i i y (DPPH
me hod) we e measu ed a he op imum alue o each scena io e alu-
a ed. In addi ion, a p elimina y economic s udy was ca ied ou o
compa e he op imal scena ios o p o ein ex ac ion om AFW. Fo his
pu pose, he o al cos s o he ex ac ion and a e sa ile plan wi h a
capaci y o 15 kg/h o ag o-was e o p o ein eco e y om AFW, along
wi h he ma ke alue o he p o ein ha could be heo e ically p o-
duced, we e es ima ed.
This esea ch s udy ep esen s a signi ican ad ance in he de el-
opmen o new s a egies o he p oduc ion, ex ac ion, p ocessing and
ma ke ing o new al e na i e p o eins om new sou ces ha could be
conside ed o animal eed and di ec human consump ion. I is wo h
men ioning ha his s udy is he i s o compa e, om a echnical and
economic poin o iew, he mic owa e-assis ed hyd o he mal and al-
kali ex ac ion o p o ein om a ious AFW. Mo eo e , a ew e e ences
we e ound ela ed o p o ein ex ac ion om BSG and SCG, bu none
abou kale was e o i s alo iza ion.
2. Ma e ials and me hods
2.1. Raw ma e ials
In his case, AFW was used, namely BSG, SCG, and kale s ems. The
SCG was p o ided by PROSOL P oduc os Solubles (Ven a de Ba˜
nos,
Spain), he BSG was dona ed by he B ewe y Mahou San Miguel (Bu gos,
Spain), and he kale s ems we e supplied by Na u Snacks (Ped ajas de
San Es eban, Spain). The h ee aw ma e ials we e d ied a 60 ◦C in an
o en and milled using a co ee g inde (Tau us A oma ic, 150 W). In his
way, a pa icle size lowe han 1 mm and mois u e con en lowe han
3% o he h ee cases was achie ed.
2.2. Mic owa e-assis ed alkali ex ac ion
A mul iwa e PRO SOLV eac o 50 Hz wi h Ro o ype 16HF100
(An on Paa GmbH, Aus ia, Eu ope) was used o ex ac he p o ein
om he AFW, wi h a solid o liquid a io o 10% (w/ ). I is ope a ed
wi h con inuous empe a u e con ol o he applied mic owa e ene gy
( o mo e de ails, see L´
opez-Lina es e al., 2019).
The aw ma e ials and sol en we e mixed (5 g d y weigh aw
ma e ial and 50 mL o sol en ) in each o he p essu e essels o he
mul iwa e eac o . The eac o wa med up and he ex ac ion ime was
ini ia ed when each un a ained he equi ed empe a u e. When he
expe imen al uns we e inished, he mic owa e equipmen cooled he
p essu e essels o he eac o down o a empe a u e o 50 ◦C. The
slu y was acuum il e ed (when he sol en was wa e ), o cen i uged
a 10,000 pm o 10 min (in he case o alkali sol en ), o sepa a e he
solid and liquid phases. In addi ion, he solid phase was washed wi h
dis illed wa e and d ied a 50 ºC o 48 h. The solid was hen weighed o
de e mine he solid eco e y (SR) (g solid ac ion/100 g d y aw ma-
e ial). The TPC, TFC, DPPH, and o al suga con en we e de e mined in
he liquid phase. Finally, he p o ein in he solid phase was analyzed.
2.3. Expe imen al design
In o de o selec he op imal condi ions o p o ein ex ac ion using
mic owa e-assis ed (alkali o hyd o he mal) ea men om he h ee
chosen aw ma e ials, a cen al composi e expe imen al design was
used. The ac o s we e empe a u e, ime, and sodium hyd oxide con-
cen a ion. Acco ding o li e a u e (Qin e al., 2018; Con e as e al.,
2019; Du e al., 2020; Samsalee and So ho n i , 2021; Ribei o e al.,
2021), highe p o ein ex ac ion yields we e achie ed ope a ing in a
basic medium, being NaOH he mos widely employed sol en . Sol en
concen a ions used a e usually less han 1 M and ex ac ion empe a-
u es below 120ºC in o de o a oid possible p o ein dena u a ion,
deg ada ion o p ecipi a ion p ocesses. Sho ex ac ion imes a e
equi ed using mic owa e echnology (<15 min). Table 1 shows he
coded and uncoded alues o ac o s in he expe imen al designs whose
da a we e p ocessed and analyzed wi h he so wa e S a g aphics
Cen u ion XVIII.
2.4. Analy ical me hods
2.4.1. Raw ma e ial composi ion
The composi ion o he p oposed aw ma e ials, i.e., ex ac i es,
s uc u al ca bohyd a es (cellulose and hemicellulose), lignin, and ash
con en we e measu ed using he analy ical me hodology o he Na ional
Renewable Ene gy Labo a o y (NREL) (Slui e e al., 2005, 2008, 2011).
The expe imen s we e ca ied ou in iplica e and he a e ages o he
esul s a e shown.
The o al p o ein con en o he aw ma e ial and ex ac ed solids was
analyzed by he Kjeldahl acid diges ion me hod o P abhuzan ye e al.
(2019). The SR om he ex ac ions was de e mined acco ding o
C. Ba ios e al.
Indus ial C ops & P oduc s 186 (2022) 115166
3
L´
opez-Lina es e al. (2021).
2.4.2. Chemical cha ac e iza ion o he liquid ex ac s
The o al suga concen a ion was de e mined by he Phenol-Sul u ic
Acid Me hod, a colo ime ic me hod ha uses D-glucose as s anda d
(Nielsen, 2017). The esul s a e exp essed as g o o al suga L
−1
o he
liquid ex ac .
The Folin-Ciocal eu me hod (Single on and Rossi, 1965) was used o
analyze he TPC. This me hod uses gallic acid as s anda d, and he e-
sul s a e exp essed as mg gallic acid equi alen s (GAE) g
−1
o he d y
aw ma e ial.
On he o he hand, o analyze he TFC, he colo ime ic me hod
desc ibed by Zhishen e al., (1999) was employed, using ca echin as
s anda d. The TFC is exp essed as mg o ca echin equi alen s (CE) g
−1
o
he d y aw ma e ial.
In o de o measu e he an ioxidan capaci y o he liquid ex ac s
ob ained om he ea men wi h mic owa es, he DPPH adical sca -
enging me hod desc ibed by B and-Williams e al. (1995) was used. The
s anda d used was T olox (6-hyd oxy-2, 5,7,8- e ame hylch ome-2-ca -
boxylic acid), and he esul s a e shown as mg o T olox equi alen s (TE)
g-1 o he d y aw ma e ial.
The analy ical de e mina ions we e ca ied ou in iplica e, and he
a e age esul s we e indica ed. Rela i e s anda d de ia ions we e below
2%.
2.4.3. Calcula ion o p o ein ex ac ion yield
The p o ein ex ac ion yield was calcula ed as he a io o he
ex ac ed p o ein o he ini ial p o ein in he aw ma e ial (RM), using
Eq. (1).
P o ein ex ac ion yield (%) = Ini ial p o ein in RM −solid p o ein
Ini ial p o ein in RM ⋅100
(1)
2.5. De ini ion o scena ios
The p o ein ex ac ion p ocess om AFW has wo s ages: he i s is a
solid-liquid MAE, ob aining a slu y s eam. The nex s age sepa a es he
liquid and solid phases o ob ain wo s eams; he liquid s eam being
ich in p o eins and phenols, while solid s eam is was e.
Fou scena ios ha e been conside ed o e alua e he bes ope a ing
condi ions o p o ein ex ac ion. In addi ion, an economic e alua ion
was ca ied ou . Scena io 1 (BSG-NaOH), Scena io 2 (SCG-NaOH), and
Scena io 3 (kale-NaOH) consis in a MAE using an alkali solu ion as he
sol en . Scena io 4 (kale-H
2
O) comp ises a MAE using wa e as he
sol en . A e ex ac ion, all ou scena ios conside a liquid and solid
phase sepa a ion s age.
The ope a ing condi ions o he MAE we e selec ed based on p e i-
ously published esul s and p e ious expe imen al esul s (da a no
shown). Two esponse a iables ha e been compa ed: he p o ein
Table 1
Expe imen al design o he ou scena ios p oposed.
Run Tempe a u e
(◦C)
Time (min) NaOH concen a ion
(M)
Run Tempe a u e
(◦C)
Time (min) NaOH concen a ion
(M)
Coded Real Coded Real Coded Real Coded Real Coded Real Coded Real
(A) (B)
Scena io 1
(BSG-NaOH)
1 0 90 0 6.25 0 0.3 Scena io 2
(SCG-NaOH)
1 0 90 0 10 1.682 1.31
2 1 110 -1 2.50 1 0.5 2 -1 70 1 15 1 1
3 0 90 0 6.25 1.682 0.64 3 0 90 1.682 18.41 0 0.55
4 -1.682 56 0 6.25 0 0.3 4 1 110 1 15 -1 0.1
5 -1 70 1 10.00 -1 0.1 5 1.682 124 0 10 0 0.55
6 0 90 0 6.25 0 0.3 6 0 90 0 10 -1.682 0
7 -1 70 -1 2.50 1 0.5 7 1 110 1 15 1 1
8 1 110 -1 2.50 -1 0.1 8 -1 70 1 15 -1 0.1
9 0 90 0 6.25 0 0.3 9 0 90 0 10 0 0.55
10 0 90 -1.682 0.00 0 0.3 10 -1 70 -1 5 -1 0.1
11 1 110 1 10.00 1 0.5 11 1 110 -1 5 -1 0.1
12 0 90 0 6.25 0 0.3 12 -1 70 -1 5 1 1
13 -1 70 -1 2.50 -1 0.1 13 1 110 -1 5 1 1
14 0 90 1.682 12.56 0 0.3 14 -1.682 56 0 10 0 0.55
15 -1 70 1 10.00 1 0.5 15 0 90 0 10 0 0.55
16 0 90 0 6.25 0 0.3 16 0 90 -1.682 1.59 0 0.55
17 1 110 1 10.00 -1 0.1
18 0 90 0 6.25 0 0.3
19 0 90 0 6.25 -1.682 0
20 1.682 124 0 6.25 0 0.3
Run Tempe a u e
(◦C)
Time (min) NaOH concen a ion
(M)
Run Tempe a u e
(◦C)
Time (min) NaOH concen a ion
(M)
Coded Real Coded Real Coded Real Coded Real Coded Real Coded Real
(C) (D) 1 -1.414 62 0 10 – 0
Scena io 3
(kale-NaOH)
1 0 90 0 10 0 1 Scena io 4
(kale-wa e )
2 0 90 0 10 – 0
2 0 90 0 10 0 1 3 0 90 0 10 – 0
3 1.682 124 0 10 0 1 4 -1 70 1 15 – 0
4 -1.682 56 0 10 0 1 5 1 110 1 15 – 0
5 1 110 -1 5 -1 0.5 6 -1 70 -1 5 – 0
6 -1 70 -1 5 1 1.5 7 0 90 -1.414 2.93 – 0
7 0 90 0 10 1.682 1.84 8 1.414 118 0 10 – 0
8 0 90 1.682 18.41 0 1 9 1 110 -1 5 – 0
9 1 110 1 15 1 1.5 10 0 90 1.414 17.07 – 0
10 -1 70 -1 5 -1 0.5
11 0 90 -1.682 1.59 0 1
12 -1 70 1 15 -1 0.5
13 1 110 1 15 -1 0.5
14 -1 70 1 15 1 1.5
15 1 110 -1 5 1 1.5
16 0 90 0 10 -1.682 0.16
C. Ba ios e al.
Indus ial C ops & P oduc s 186 (2022) 115166
4
eco e y in o he was es (ag o-indus ial and ui / ege able was es)
and he sol en used (alkali ex ac ion o wa e ). The p ocess low
conside ed is p esen ed in Fig. 1.
2.6. Economic e alua ion
A p elimina y and compa a i e economic s udy o an indus ial plan
o p o ein ex ac ion-pu i ica ion om di e en AFW was ca ied ou . A
plan wi h a p oduc ion capaci y o 15 kg/h o aw ma e ial (BSG, SCG,
and kale s ems) and a humidi y o 20% w/w was selec ed as he basis o
he economic analysis. This low a e was chosen based on he lowes
p oduc ion o he h ee aw ma e ials in Cas ile & Le´
on (Spain) o ensu e
con inuous yea - ound p oduc ion. In his case, only 280 o kale we e
p oduced in his egion in 2020 (MAPA, 2021). In o de o es ima e he
minimum selling p ice o p o ein, wo s ages ha e been conside ed.
Fi s , he ups eam (ex ac ion +cen i uga ion) has been igo ously
designed based on he labo a o y da a using he op imal condi ions o
each scena io; he ela ed equipmen cos s we e also calcula ed. Second,
he cos o he pu i ica ion sec ion (p ecipi a ion and sp ay-d ying) was
es ima ed. The downs eam p ocesses a e he mos expensi e pa o he
p o ein ex ac ion-pu i ica ion p ocess, and hei associa ed cos can be
a ound 70% o he o al plan cos s (K uschi z and Nide zky, 2020;
Łojewska e al., 2016). The heo e ical p o ein p oduc ion was calcu-
la ed on his basis, conside ing ha he o al p ecipi a ed p o ein was
70% o he heo e ical. The ma ke alue o he bioac i e p o ein ex ac
was es ima ed in o de o e i y whe he he p ocess could become
economically iable and i he selling p ice could be compe i i e.
The Lang ac o s me hod, ex ensi ely used in indus ial enginee ing
o calcula e he di e en plan cos s, was applied o his p elimina y
economic s udy. A comple e me hod is desc ibed in he li e a u e
(Sinno , 2005). Fi s , he ups eam equipmen was designed and he
associa ed equipmen cos (PCE) was es ima ed using he CAPCOST
so wa e. To calcula e he o al plan PCE, he ups eam PCE was di ided
by 0.3 in o de o be able o apply he Lang Fac o me hod o calcula e
he To al In es men Cos (TIC) o he whole p ocess. A e ha , he TIC
was calcula ed using he solid-liquid c i e ia o he Lang ac o me hod.
Eqs. (2)–(4) we e used o es ima e he plan cos s.
Physical Plan Cos (PPC) =PCE * 3⋅15 (2)
Fixed Capi al Cos (FCC) =PPC * 1⋅40 (3)
TIC =FCC * 1⋅05 (4)
The cos s o he p oposed aw ma e ials we e es ima ed om he
li e a u e: p ocess wa e : 3.16
€
/m
3
(Aqua all, 2017), and NaOH: 4
€
/kg
(Sinno , 2005). The a e age cos conside ed o he AFW was 20
€
/
because he ange o he BSG cos was 20 – 35
€
/ (Fe n´
andez-Delgado
e al., 2019), while he SCG cos was a ound 20–60 $/ (A abani e al.,
2019, Kamil e al., 2019), hough no da a we e ound o kale.
The ollowing assump ions we e necessa y o es ima e he plan
p o i s and he minimum selling p ice o he p o ein ex ac . All sce-
na ios and equipmen amo iza ion had a plan li e ime o 10 yea s. The
annual p oduc ion cos s pe kg o p o ein we e es ima ed conside ing
ha he plan wo ks 8000 h/y. Finally, he minimum sale p ice could be
calcula ed, conside ing a ne p esen alue (NPV) o he plan o 0
€
and
an in e nal a e o e u n (IRR) o 10% (Fe n´
andez-Delgado e al., 2022).
Fig. 1. Flow diag am o he p oposed scena ios. Flow diag ams elabo a ed acco ding o UNE ISO 10628:2015.
C. Ba ios e al.
Indus ial C ops & P oduc s 186 (2022) 115166
5
3. Resul s and discussion
3.1. Cha ac e iza ion o ag i- ood was es
Fi s ly, he composi ion achie ed o SCG was he ollowing (% w/w
d y ma e ): cellulose, 16.3 ±0.1; hemicellulose, 27.7 ±0.7, acid-
insoluble lignin (AIL), 38.5 ±0.7; acid-soluble lignin (ASL), 0.7 ±0.1;
ex ac i es, 12.4 ±0.4 (glucose in ex ac i es, 0.0 ±0.0); ash, 0.1
±0.0; ace yl g oups, 0.4 ±0.0 and p o ein, 12.1 ±0.4 (Lopez-Lina es
e al., 2021). On he o he hand, he composi ion was (% w/w d y
ma e ) o BSG: cellulose, 32.6 ±0.6; hemicellulose, 23.2 ±0.1, AIL,
13.0 ±0.5 ASL, 1.3 ±0.0; ex ac i es, 14.2 ±0.3 (glucose in ex ac-
i es, 0.8 ±0.0); ash, 13.0 ±0.1; ace yl g oups, 0.8 ±0.0; and p o ein,
22.04 ±0.2. Finally, he composi ion o kale s ems was (% w/w d y
ma e ): cellulose, 15.0 ±0.0; hemicellulose, 13.0 ±0.1, AIL, 2.1 ±0.3;
ASL, 1.8 ±0.0; ex ac i es, 46.9 ±0.7 (glucose in ex ac i es, 7.5
±0.6); ash, 19.3 ±0.1; ace yl g oups, 0.3 ±0.0; and p o ein, 15.7
±0.2.
3.2. E ec o ope a ion condi ions on p o ein ex ac ion yield
In o de o e alua e he e ec o he ope a ing condi ions on he
p o ein ex ac ion yield, he esul s o scena ios 1, 2, and 3 we e
analyzed. The cen al composi e expe imen al designs analyzed he e -
ec s o h ee ac o s: namely empe a u e, ime, and he NaOH con-
cen a ion. Table 2 shows he expe imen al esul s ob ained o he
con en o solid p o ein a e he MAE and he p o ein ex ac ion yield
esponses o each expe imen al un and each scena io.
As can be app ecia ed in Table 2, he p o ein ex ac ion yield anged
be ween 14.1% ( un 19) and 93.7% ( un 11) o BSG, be ween 9.6% ( un
6) and 60.3% ( un 7) o SCG, and be ween 69.4% ( un 16) and 95.4%
( un 15) o kale. A ound he cen al poin o each scena io (Scena io 1:
90ºC, 6.25 min and 0.3 M NaOH ( uns 1, 6, 9, 10, 12, 16 and 18); sce-
na io 2: 90ºC, 10 min and 0.55 M NaOH ( uns 9 and 15); and scena io 3:
90ºC, 10 min and 1 M NaOH ( uns 1 and 2)), an a e age p o ein
ex ac ion yield o 71.7%, 32.3%, and 90.5% was measu ed o scena ios
1, 2, and 3, espec i ely.
Second-o de polynomial equa ions adjus ed he p o ein ex ac ion
yield esponses (Eq. (5) o scena io 1, Eq. (6) o scena io 2, and Eq. (7)
o scena io 3):
P o ein ex ac ion yield = − 175.737 +3.959 T+0.633
+198.404 C−0.021 T2+0.646 TC
−225.692 C2
(R2=0.993;R2adjus =0.986)(5)
P o ein ex ac ion yield =56.668 −0.866 T−19.379 C
+0.501 TC
(R2=0.983;R2adjus =0.957)(6)
P o ein ex ac ion yield = − 7.823 +1.185 T+0.164 +50.523 C
−0.004 T2−14.602 C2
(R2=0.963;R2adjus =0.907)(7)
whe e "T" is he empe a u e (ºC), " " is he ime (min), and "C" is he
NaOH concen a ion (M).
In all he modeling, he alues o R
2
and adjus ed R
2
(Eqs. (1)−(3)),
as well as he con idence le els (90%, p <0.05), show a easonable
adjus men be ween he expe imen al and p edic ed da a.
As obse ed in Eqs. (5)–(7) and Table 2, he mos signi ican e ec is
he NaOH concen a ion in he h ee scena ios, his e ec being posi i e
o scena ios 1 and 3, and nega i e o scena io 2. In he case o BSG and
kale (scena ios 1 and 3), in o de o impo ance, he empe a u e and
ime we e also posi i e e ec s, bu he e was a big di e ence be ween
hese and he NaOH concen a ion e ec (and e en mo e o BSG). Thus,
high alues o NaOH concen a ion could lead o an inc ease in he
p o ein ex ac ion yield o BSG and kale. The ime e ec was insigni -
ican in SCG (scena io 2).
On he o he hand, conce ning he in e ac ions be ween he di e en
ac o s (Eqs. (5)–(7) and Fig. 2), a sligh posi i e in e ac ion be ween he
empe a u e and he NaOH concen a ion ac o s can be obse ed in
scena ios 1 and 2 (BSG and SCG).
This end can also be obse ed in he Deleu e al. (2019) s udy,
indica ing ha he alkali ex ac ion condi ions gene ally inc ease he
p o ein ex ac ion yield by b eaking down he ma ix in which p o eins
a e p esen and making he p o ein o ce eals and pseudo-ce eals mo e
soluble. In his way, p o eins om ba ley we e also ex ac ed using he
alkaline ex ac ion (23ºC, 0.5 M NaOH and 2 h), achie ing 57.1% o
p o ein eco e y yield, wi h a p o ein con en o 33 g/100 g aw ma e-
ial (Houde e al., 2018). Li e al. (2021) demons a ed ha ul asound
alkali ex ac ion imp o es he p o ein yield om BSG e sus con en-
ional alkali ex ac ion (86.16 s. 45.71%), a a concen a ion o
110 mM NaOH and 1:15 (w/ ) solid o liquid a io o 20 min unde
ul asound ea men . Acco ding o Pa chami e al. (2021), 48% o he
ini ial p o ein in BSG was solubilized using a hyd o he mal p e ea men
(180 ℃ and 30 min), which is a lowe alue han ha men ioned be o e
using alkalis. In his con ex , Con e as e al. (2019) also obse ed a
signi ican posi i e e ec when NaOH was added as a sol en , wi h
concen a ions up o 0.4 M; poin ing ou ha he solid- o-liquid a io,
ex ac ion ime, pH, empe a u e, and alkali concen a ion a e c ucial
condi ions, wi h he absolu e amoun o applied alkali being he c i ical
ac o .
3.3. E ec o sol en ype on ex ac ion yield
In his case, o e alua e he e ec o he sol en ype on he p o ein
ex ac ion yield, he expe imen al esul s o scena ios 3 and 4 we e
analyzed. The p o ein concen a ion and p o ein ex ac ion yield e-
sponses o each expe imen and scena io a e shown in Table 2.
As can be seen in Table 2, and compa ing he expe imen al alues o
scena ios 3 and 4, he p o ein ex ac ion yield anged be ween 69.4%
( un 16) and 95.4% ( un 15) o alkali ex ac ion and be ween 68.6%
Table 2
P o ein composi ion o ex ac ed solids and ex ac ion yields.
Run Scena io 1 (BSG-
NaOH)
Scena io 2 (SCG-
NaOH)
Scena io 3
(kale-NaOH)
Scena io 4
(kale-H
2
O)
g/kg
RM
Yield
(%)
g/kg
RM
Yield
(%)
g/kg
RM
Yield
(%)
g/kg
RM
Yield
(%)
1 10.6 69.9 9.9 48.9 1.9 92.4 7.9 68.7
2 3.6 89.7 13.7 29.3 2.9 88.5 7.1 71.7
3 3.6 89.9 12.2 36.8 1.5 94.1 7.0 72.2
4 22.3 36.7 13.8 28.8 5.6 77.8 7.3 71.0
5 27.1 23.1 9.4 51.5 4.0 83.9 6.8 73.0
6 10.2 71.1 17.5 9.6 4.3 82.9 7.9 68.6
7 12.2 65.4 7.7 60.3 2.1 91.8 7.7 69.4
8 24.9 29.5 16.0 17.0 1.9 92.5 7.2 71.3
9 8.4 76.1 12.3 36.1 1.5 94.0 7.4 70.5
10 10.1 71.3 15.4 20.1 6.6 73.6 7.0 72.0
11 2.2 93.7 14.3 26.1 2.9 88.3
12 10.2 71.1 13.6 29.7 7.4 70.6
13 27.6 21.9 9.1 52.7 3.0 87.9
14 8.8 75.0 14.6 24.3 2.9 88.5
15 7.5 78.8 13.8 28.6 1.1 95.4
16 9.4 73.4 13.8 28.3 7.7 69.4
17 23.3 34.0
18 11.1 68.5
19 30.3 14.1
20 2.6 92.6
C. Ba ios e al.

Indus ial C ops & P oduc s 186 (2022) 115166
6
( un 6) and 73.0% ( un 5) o aqueous ex ac ion. The a e age p o ein
ex ac ion yield a ound he cen al poin (scena io 3: 90ºC, 10 min and
1 M NaOH ( uns 1 and 2); and scena io 4: 90ºC and 10 min ( uns 2 and
3)), was 90.5% o alkali ex ac ion (scena io 3) and 71.9% o wa e
ex ac ion (scena io 4).
The p o ein ex ac ion yield esponses we e also adjus ed by he
second-o de polynomial equa ion (Eq. (8) o scena io 4):
P o ein ex ac ion yield =46.039 +0.437 T+0.594 −0.002 T2
(R2=0.962;R2adjus =0.917)(8)
whe e "T" is he empe a u e (ºC), and " " is he ime (min). The alues o
R
2
and adjus ed R
2
(Eq. (4)), as well as he con idence le els (90%,
p<0.05), also show a easonable adjus men be ween he expe imen al
and p edic ed da a in his case.
As men ioned abo e and looking a he equa ions (Eqs. (7) and (8))
and Table 2, he mos signi ican posi i e e ec in he case o alkaline
ex ac ion is he NaOH concen a ion, and e y sligh ly he empe a u e
and ime. On he o he hand, in aqueous ex ac ion, he mos signi ican
posi i e e ec is he ime, ollowed by he empe a u e (bo h e y
simila ), while e y low e ec s we e ound by compa ing wi h he NaOH
concen a ion e ec obse ed o alkaline ex ac ion. This beha io can
also be seen in Fig. 2(C-D), espec i ely. This is due o he NaOH ac ing
as a acili a ing agen in he ex ac ion p ocess when alkalis a e used. In
con as , he e ec is compensa ed o e ime in aqueous ex ac ion,
acco ding o Con e as e al. (2019), which indica es ha alkaline
ex ac ion gene ally shows highe yields han acid o hyd o he mal
ex ac ion. Mo eo e , i is wo h highligh ing ha , by compa ing wi h
con en ional ex ac ion me hods, mic owa e-assis ed ex ac ion is able
o inc ease he p o ein ex ac ion yield by up o 1.54 imes (Con e as
e al., 2019).
3.4. Op imiza ion o ex ac ion condi ions
The MAE op imiza ion om h ee AFW (BSG, SCG, and kale) was
ca ied ou , maximizing he p o ein ex ac ion yield as he s udied
esponse. Thus, he op imal expe imen al condi ions ound by he model
o he ou scena ios ( empe a u e, ime, and NaOH concen a ion in
he case o alkali ex ac ion) a e included in Table 3.
The model was alida ed by pe o ming a con i ma o y expe imen al
un in op imal condi ions. As can be obse ed in Table 3, a easonable
adjus men o he model was ound o he ou scena ios, since he
de ia ions be ween he p edic ed and expe imen al alues we e less
han 3% in all ou cases. By compa ing he h ee AFW (BSG, SCG and
kale), i can be obse ed ha he bes p o ein ex ac ion yields (92–95%)
we e achie ed o BSG and kale when he mic owa e assis ed alkaline
ex ac ion was ca ied ou . Howe e , a p o ein ex ac ion yield lowe
han 59% was ob ained o SCG using he same alkaline ex ac ion
me hod. On he o he hand, by compa ing bo h he hyd o he mal and
alkaline ex ac ion me hods o kale, bo h assis ed by he mic owa e
echnique; an inc ease in he p o ein ex ac ion yield o up o 22.64%
was a ained h ough he alkaline ex ac ion echnique. As desc ibed
p e iously, alkaline ex ac ion gene ally shows highe p o ein ex ac-
ion yields han acid o hyd o he mal ex ac ion (Con e as e al., 2019).
In addi ion, unde hese op imal ex ac ion condi ions, he TPC, TFC,
Fig. 2. Su ace esponses o he mos signi ican pa ame e s o each scena io.
C. Ba ios e al.
Indus ial C ops & P oduc s 186 (2022) 115166
7
an ioxidan capaci y, and o al suga con en we e de e mined (Table 3).
As can be app ecia ed, excep o SCG, abou 14–15 g/L o al suga s can
be ob ained o bo h BSG and kale aw ma e ials, independen ly o he
ca alys (wa e o alkalis) used. Rega ding TPC, simila concen a ions
(abou 48–52 mg GAE/g RM) we e a ained o BSG and SCG, while
lowe alues we e ob ained o kale (<34 mg GAE/g RM), using bo h
hyd o he mal and alkaline ex ac ion echniques. Ne e heless, SCG
was he AFW wi h he highes TFC (15.95 mg CE/ g RM), ollowed by
BSG and kale (8.68 and 0.98–2.46 mg CE/ g RM, espec i ely). Con-
ce ning he an ioxidan ac i i y (DPPH), up o 7.6 and 17.1 mg TE/g RM
could be go om BSG and kale by mic owa e-assis ed alkaline ex ac-
ion. The e o e, in conclusion, by compa ing he h ee AFW used, BSG
could be an in e es ing aw ma e ial o p o ein p oduc ion, as well as
o al suga s and phenolic and an ioxidan compounds.
On he o he hand, conce ning bo h he hyd o he mal and alkaline
ex ac ion me hods pe o med wi h kale, he esul s o o al suga s, TPC,
TFC and an ioxidan compounds ob ained (Table 3) show ha hyd o-
he mal ex ac ion was able o ge be e esul s o TPC (34.32 s.
20.87 mg GAE/g RM) and TFC (2.46 s. 0.98 mg CE/g RM), as happened
o he p o ein ex ac ion yield desc ibed be o e, bu wi h much lowe
DPPH alues (1.71 s. 7.57 mg TE/g RM). The o al suga con en was
simila (abou 15 g/L) o bo h ex ac ion echniques.
Finally, by compa ing he esul s ob ained in his wo k (Table 3) wi h
he li e a u e, conside ing BSG o ins ance, simila esul s (90–95%)
we e a ained by Qin e al. (2018) using dilu e acid (11,400 mg H
2
SO
4
/g
BSG, 121 ◦C o 1 h), o sequen ial alkaline (110 mM NaOH, 1:20 w/ ,
50 ◦C and 200 pm) and dilu e acid (1 M H
2
SO
4
, 25 ◦C, 250 pm o 1 h,
ollowed by au ocla ing a 121 ◦C o 1 h) ex ac ion, bu lowe alues
(64–66%) by hyd o he mal ex ac ion (2.5% w/ , 60ºC, 24 h). A much
lowe p o ein ex ac ion yield (48%) and concen a ion (27 g/L) was
also achie ed by Pa chami e al. (2021) using hyd o he mal ex ac ion
(180 ℃ and 30 min). Du e al. (2020) also ob ained a low p o ein
ex ac ion yield (21.4%, 6.8% and 7.2%) using h ee di e en ex ac ion
me hods: alkaline (40ºC, 120 min and 0.1 M NaOH), aqueous (40ºC and
120 min), and subc i ical wa e ex ac ion (200ºC and 20 min).
Wi h ega d o SCG, simila esul s o p o ein ex ac ion yields
(abou 59%) o hose ob ained in his wo k (61%, Table 3) we e ach-
ie ed by an acid ex ac ion p ocess (using 0.1 M HCl and 0.1 M NaCl, a
1:12, w/ ) a 4 ºC o 12 h (Ribei o e al., 2021). Mo eo e , he p esence
o phenolic (1755.76 µmol GAE/g) and an ioxidan compounds (ABTS:
441 µmol TE/g SCG; FRAP: 611 µmol TE/g SCG) was also de ec ed. This
he e o e means ha he p o ein ex ac ion can be sui ably ca ied ou
using alkali and acid, which may be due o he s uc u e o he SCG.
Samsalee and So ho n i (2021) go a lowe p o ein con en (34%) by
ul asonic-assis ed ex ac ion (40% ampli ude, 20 min and pH 11 using
0.7 M Na
3
PO
4
). Howe e , much highe TPC and DPPH alues
(304.81 mg GAE/g RM and 933.92 mM TE/g RM) we e ob ained.
As poin ed ou abo e, simila o ela i ely highe p o ein ex ac ion
yields a e achie ed in his s udy. Howe e , he bioac i e liquid ex ac s
ob ained in his wo k a e cha ac e ized by con aining an app eciable
amoun o an ioxidan compounds and ca bohyd a es, gi ing hem
g ea e added alue o hei possible comme cial applica ion in he
ood, pha maceu ical and cosme ic indus ies.
3.5. Economic e alua ion
3.5.1. In es men and p oduc ion cos s
A p elimina y economic s udy compa ed he op imal p o ein e-
co e y s a egies om BSG, SCG, and kale was es. Table 4 summa izes
he esul s o he Lang Fac o me hod o he ou p oposed scena ios.
The o al cos o he equipmen o scena ios 1, 2, and 3, based on
NaOH-ex ac ion, is iden ical (153,000
€
), ega dless o he aw ma e ial
used because he necessa y equipmen is he same in hese scena ios.
Howe e , he cos o scena io 4, which uses wa e as a sol en , is lowe
(150,000
€
), because he sol en s o age ank does no equi e co osion-
esis an cons uc ion ma e ials, and his scena io does no ha e he
NaOH sol en p epa a ion s age be o e MAE.
This cos di ec ly a ec s he TIC, 690,000
€
(scena io 4) o 710,000
€
(scena ios 1, 2, and 3). On he o he hand, he de e mining ac o o
es ima e p oduc ion cos s is he aw ma e ial, mainly he amoun o
NaOH equi ed in each scena io. Achie ing he lowes cos o he aw
ma e ial and he lowes annual p oduc ion cos equi ed, he p oduc ion
cos o he p o ein ex ac may hus be educed. So, as shown in Table 4,
scena io 4 had he lowes p oduc ion cos (438,000
€
/y ) as he
ex ac ion is only pe o med wi h wa e . I he NaOH-ex ac ion sce-
na ios a e compa ed, scena io 1 had a lowe p oduc ion cos (524,000
€
/y ) in compa ison o scena ios 2 and 3 (647,000
€
/y ), since scena io 1
needs a lowe concen a ion o NaOH (0.5 M) in con as o scena ios 2
and 3, which use almos 3- imes mo e o NaOH du ing he ex ac ion
(1.3 M). O he wise, he p oduc ion cos pe kg o p o ein was associa ed
wi h he ini ial p o ein concen a ion o he AFW and wi h he ex ac ion
yield achie ed unde op imum ope a ing condi ions. So, scena io 1,
whose yield was highe han scena ios 2 and 3, had he lowes p o-
duc ion cos s pe kg o p o ein (29.9
€
/kg e sus 51.1 –104.6
€
/kg). On
he o he hand, compa ing he kale-ex ac ion scena ios (3 and 4), he
p oduc ion cos depends p incipally on he sol en used. In his case,
scena io 4, using wa e as a sol en , had a lowe p oduc ion cos (45.5
€
/kg) e sus scena io 3 wi h NaOH sol en (51.1
€
/kg).
Finally, he minimum selling p ice o he p o ein, shown in Table 4,
is he selling p ice om which he plan would begin o be p o i able. As
can be seen, he lowes selling p ice o he p o ein ob ained is associ-
a ed wi h scena io 1, wi h 51.7
€
/kg co esponding o he BSG-NaOH
ex ac ion p ocess and a highe yield (14.6 kg p o ein/100 kg DM). In
compa ison, he highes p ice was eached in scena io 2 (SCG-NaOH),
wi h a selling p ice o 168.6
€
/kg, whose o e all ex ac ion yield is he
lowes (5.2 kg p o ein/100 kg DM). In any case, hese p ices a e abo e
he es ima ed p ices o he sale o p o ein ound in he li e a u e,
indica ing ha he p oposed p ocesses a e no p o i able. The ma ke
p ice depends on he aw ma e ial and he p o ein p ope ies (Bake and
Cha l on, 2020). Fo example, Munee e al. (2021) es ima ed ha he
p o ein ma ke p ice a ied om 2 o 15
€
/kg. Howe e , his p ocess
could p o e p o i able i no only he p ecipi a ed p o ein is aken in o
accoun . The ex ac s ob ained a e ex ac ion con ain signi ican
Table 3
Cha ac e iza ion o op imal ex ac s.
Scena io 1
(BSG-
NaOH)
Scena io 2
(SCG-
NaOH)
Scena io 3
(kale-
NaOH)
Scena io 4
(kale-H
2
O)
Tempe a u e (ºC) 110 113 109 102
Time (min) 9.98 3.33 14.93 15.30
NaOH concen a ion
(M)
0.50 1.30 1.29 0.00
P o ein ex ac ion
yield (%)
93.99 61.17 96.55 72.78
Con i ma o y
expe imen al
p o ein ex ac ion
yield (%)
92.05 58.99 95.23 72.59
To al suga s (g/L) 13.84 5.50 14.96 15.20
TPC (mg GAE/g RM) 48.42 52.08 34.32 20.87
TFC (mg CE/ g RM) 8.68 15.95 2.46 0.98
DPPH (mg TE/g RM) 17.10 2.09 1.71 7.57
C. Ba ios e al.
Indus ial C ops & P oduc s 186 (2022) 115166
8
amoun s o suga s and an ioxidan compounds, demons a ing an
adequa e an ioxidan capaci y. Fo example, he ex ac om scena io 1
has a suga con en o 13.84 g/L, a TPC o 48.42 mg GAE/g RM, a TFC o
8.68 mg CE/g RM, and a DPPH an ioxidan capaci y o 17.10 mg TE/g
RM. These concen a ions would posi i ely a ec he selling p ice o he
bioac i e ex ac s ob ained. In his way, he p o i abili y o he p ocess
would be signi ican ly imp o ed.
3.5.2. Sensi i i y analysis
Based on he economic e alua ion, a sensi i i y analysis was pe -
o med o analyze he in luence o he mos c i ical pa ame e s ha
could a ec he NPV (Fig. 3). Fo he e alua ed scena ios, he key pa-
ame e s ha signi ican ly a ec he NPV a e he p o ein selling p ice
and he o al di ec cos s.
Among he aw ma e ials cos s, hose o he AFW and wa e a e
insigni ican in he NPV a ia ion in he scena ios e alua ed (Fig. 3). On
he con a y, he a ia ion in he cos o NaOH a ec s scena ios 1, 2, and
3 (NaOH-ex ac ion). The NPV can a y by up o 360,000
€
when he
cos o he NaOH changes by 50% (inc emen al and dec emen al)
(Fig. 3. C). On he o he hand, scena io 1 (BSG-NaOH) is he leas
a ec ed by he a ia ion in he cos o he NaOH, since he NPV only
dec eases o 140,000
€
when he cos o he NaOH inc eases by 50%.
Conce ning he plan p o i s, he only income is gene a ed om
selling he p o ein, while he sensi i i y analysis demons a es ha he
NPV alue is suscep ible o changes in his p ice. Fo example, a 50%
inc ease in he p o ein sale p ice can inc ease he NPV by 1280,000
€
o
1675,000
€
(Fig. 3. B-D). Howe e , he inc emen in he p o ein p ice is
un easible om an economic poin o iew, and i is necessa y o educe
he selling p ice in o de o be compe i i e. Fo example, in he case o
scena io 1 (BSG-NaOH), which has he lowes selling p ice (51.7
€
/kg)
(Table 4), he sensi i i y analysis shows ha i he p o ein we e o be
sold wi h a compe i i e p ice (15
€
/kg), he plan losses would be abo e
2100 k
€
.
Some esea che s ha e demons a ed he economic iabili y o he
MAE echnology o o he applica ions (Zhang e al., 2014; Fe n´
an-
dez-Delgado e al., 2022). The e o e, an al e na i e o ob aining a iable
and compe i i e ex ac ion p ocess could be o op imize he MAE p o-
cess o ob ain ex ac s en iched no only in p o eins, bu also in o he
bioac i e compounds o in e es o ood and biomedical applica ions.
As seen be o e, hese ex ac s con ain a signi ican suga concen a ion
and an ioxidan compounds, p o ing a sui able an ioxidan capaci y. In
his way, he p oduc ion cos s could dec ease signi ican ly and he
selling p ice o he whole p ocess could be compe i i e in he ood and
pha maceu ical ma ke .
Table 4
Economic e alua ion o he p oposed scena ios.
P ecipi a ed P o ein PCE TIC P oduc ion Cos Minimum Selling P ice
Yield Flow
Uni s kg/100 kg DM kg/h
€ € €
/yea
€
/kg
€
/kg
Scena io 1
(BSG-NaOH)
14.6 2.2 153,000 710,000 524,000 29.9 51.7
Scena io 2
(SCG-NaOH)
5.2 0.8 153,000 710,000 647,000 104.6 168.6
Scena io 3
(kale-NaOH)
10.6 1.6 153,000 710,000 647,000 51.1 82.3
Scena io 4
(kale-H
2
O)
8.0 1.2 150,000 690,000 438,000 45.5 82.9
Fig. 3. Sensi i i y analysis o he p oposed scena ios. (A) Scena io 1: BSG +NaOH; (B) Scena io 2: SCG +NaOH; (C) Scena io 3: kale +NaOH; (D) Scena io 4:
kale +H
2
O.
C. Ba ios e al.
Indus ial C ops & P oduc s 186 (2022) 115166
9
4. Conclusions
This s udy con i ms ha mic owa e-assis ed hyd o he mal and al-
kali ex ac ion is a sui able echnology o he e icien eco e y o
bioac i e compounds om he ag i- ood was es es ed (BSG, SCG and
kale s ems). Technically and economically, mic owa e-NaOH ex ac ion
om BSG p o ides he bes al e na i e o ob aining ex ac s o com-
me cial in e es en iched in p o ein (p o ein eco e y yield o 94%),
o al suga s and an ioxidan compounds. Howe e , hyd o he mal mi-
c owa e ex ac ion om kale s ems could become a p omising p ocess
ha combines a no el was e in a bio e ine y con ex , which con ains an
app eciable p o ein concen a ion (15.7% w/w) wi h a wa e -based
cleane sol en ope a ing unde mild p ocess condi ions.
CRediT au ho ship con ibu ion s a emen
C is ina Ba ios: In es iga ion, Me hodology, W i ing −o iginal
d a . Ma ina Fe n´
andez Delgado: In es iga ion, Me hodology,
W i ing −o iginal d a . Juan C. L´
opez-Lina es: In es iga ion, Me h-
odology, W i ing −o iginal d a , Supe ision. Ma ía Te esa Ga cía-
Cube o: Concep ualiza ion, Supe ision, W i ing −o iginal d a .
M´
onica Coca: Concep ualiza ion, Fo mal analysis, Supe ision. Susana
Lucas: Concep ualiza ion, W i ing − e iew & edi ing, P ojec
adminis a ion.
Decla a ion o Compe ing In e es
The au ho s decla e ha hey ha e no known compe ing inancial
in e es s o pe sonal ela ionships ha could ha e appea ed o in luence
he wo k epo ed in his pape .
Acknowledgmen s
The au ho s acknowledge he inancial suppo om he Spanish
Minis y o Science and Inno a ion (p ojec PID2020–115110RB-I00/
AEI/10.13039/501100011033), and he Jun a de Cas illa y Le´
on (UIC
320, VAG028G19, CLU 2017–2109, CL-EI-2021–07).
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