Influence of Fermentation with Different Lactic Acid ... - ACS Publications

Mar 8, 2017 - This study describes the effect of fermentation and the impact of simulated gastrointestinal digestion (SGD) of four fermented pomegrana...
0 downloads 0 Views 753KB Size
Subscriber access provided by UB + Fachbibliothek Chemie | (FU-Bibliothekssystem)

Article

Influence of fermentation with different lactic acid bacteria and in vitro digestion on the biotransformation of phenolic compounds in fermented pomegranate juices Estefanía Valero-Cases, Nallely Nuncio-Jáuregui, and Maria Jose Frutos J. Agric. Food Chem., Just Accepted Manuscript • DOI: 10.1021/acs.jafc.6b04854 • Publication Date (Web): 08 Mar 2017 Downloaded from http://pubs.acs.org on March 10, 2017

Just Accepted “Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted online prior to technical editing, formatting for publication and author proofing. The American Chemical Society provides “Just Accepted” as a free service to the research community to expedite the dissemination of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully peer reviewed, but should not be considered the official version of record. They are accessible to all readers and citable by the Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore, the “Just Accepted” Web site may not include all articles that will be published in the journal. After a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web site and published as an ASAP article. Note that technical editing may introduce minor changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or consequences arising from the use of information contained in these “Just Accepted” manuscripts.

Journal of Agricultural and Food Chemistry is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Published by American Chemical Society. Copyright © American Chemical Society. However, no copyright claim is made to original U.S. Government works, or works produced by employees of any Commonwealth realm Crown government in the course of their duties.

Page 1 of 28

Journal of Agricultural and Food Chemistry

1

Influence of fermentation with different lactic acid bacteria and in vitro digestion on

2

the biotransformation of phenolic compounds in fermented pomegranate juices

3

Estefanía Valero-Casesa, Nallely Nuncio-Jáureguia, María José Frutosa*

4

Research Group on Food Quality and Safety. Food Technology Department, Miguel

5

Hernandez University. Ctra. Beniel, km 3.2, 03312-Orihuela, Alicante, Spain

6

*Corresponding author: María José Frutos. Tel.: +34966749744; Fax: +34966749677. E-

7

mail address: [email protected]

8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

ACS Paragon Plus Environment

Journal of Agricultural and Food Chemistry

25

ABSTRACT

26

This study describes the effect of fermentation and the impact of simulated gastrointestinal

27

digestion (SGD) of four fermented pomegranate juices with different lactic acid bacteria

28

(LAB) on the biotransformation of phenolic compounds. The changes of the antioxidant

29

capacity (AOC) and of LAB growth and survival in different fermented juices were also

30

studied. Two new phenolic derivatives (catechin and α-punicalagin) were identified only in

31

fermented juices. During SGD, the AOC increased together with the phenolic derivatives

32

concentration mainly in the juices fermented with Lactobacillus. These derivatives were

33

formed due to the LAB metabolism of the ellagitannins, epicatechin and catechin after

34

fermentation and during SGD. The FRAP assay performance might be associated with the

35

degradation and biotransformation of catechin. The fermented pomegranate juices with

36

these LABs increased the bioaccessibility of phenolic compounds ensuring the survival of

37

LAB after SGD, suggesting a possible prebiotic effect of phenolic compounds on LAB.

38 39

Keywords: Lactobacillus, Bifidobacterium, antioxidant capacity, probiotic, bioactive

40

compounds.

41 42 43 44 45 46 47 48

ACS Paragon Plus Environment

Page 2 of 28

Page 3 of 28

Journal of Agricultural and Food Chemistry

49

INTRODUCTION

50

The polyphenols are part of our diet and exert antioxidant properties; the main dietary

51

sources are wine, fruit, juices, leguminous and vegetables.1 The bioaccessibility of some

52

polyphenols is very low because of their degree of polymerization and glycosylation

53

pattern.2 Therefore, their physiological benefits depend on the quantity of phenolic

54

compounds that are available (bioavailability) to be absorbed in the intestine.3,

55

suggests that a large rate of phenolic compounds reaches the colon and due to the action of

56

gut microbiota, these compounds are transformed, leading to the production of metabolites

57

that can be absorbed producing a physiological effect.2, 5

58

Curiously, everybody has an individual microbiota composition, so that the bioavailability

59

of polyphenols for the production of microbial metabolites is subjected to inter-individual

60

variability. Therefore, the health effects are not the same for everyone.2, 6, 7

61

In recent years, pomegranate juice has been investigated due to its beneficial properties

62

because of its elevated concentration of polyphenols.8 Those polyphenols include mainly

63

anthocyanins, procyanidins, phenolic acids, flavonol glycosides and hydrolysable tannins

64

such as ellagitannins, gallotannins and punicalagins.9 However, humans cannot absorb

65

those hydrolysable tannins and therefore, these compounds are hydrolyzed to ellagic acid

66

that is also poorly absorbed being metabolized in the colon by the microbiota to produce

67

urolithins.10 The urolithins together with other phenolic metabolites are mainly responsible

68

for the health properties.9 The capacity of the lactic acid bacteria to metabolize the phenolic

69

compounds depends on the species or on the strain.11,

70

polyphenols can occur during a food fermentation process by lactic acid bacteria.12-14 Those

71

bacteria are the main source of probiotics which are “live microorganisms that, when

72

administered in adequate amounts confer health benefits on the host”.15 Although the health

12

ACS Paragon Plus Environment

4

This

The microbial conversion of

Journal of Agricultural and Food Chemistry

73

beneficial effects due to Lactobacillus and Bifidobacterium have been shown, their function

74

as antioxidants has not been fully investigated.16

75

The aim of this study was to investigate the biotransformation of the phenolic compounds

76

in pomegranate juices (a) after fermentation by four lactic acid bacteria and (b) during in

77

vitro digestion of unfermented and fermented juices. The antioxidant properties and the

78

LAB survival were also investigated in different fermented pomegranate juices to study the

79

influence of fermentation and in vitro digestion on the polyphenols biotransformations.

80

MATERIALS AND METHODS

81

Activated bacterial strains and culture preparations

82

Lactobacillus acidophilus CECT 903 (LA), Lactobacillus plantarum CECT 220 (LP),

83

Bifidobacterium longum subsp. infantis CECT 4551 (BL), Bifidobacterium bifidum CECT

84

870 (BB), were purchased from the Spanish Type Culture Collection (CECT, Valencia,

85

Spain) in lyophilized form. To obtain the pre-inoculum, each strain was re-suspended in 10

86

mL of Man Rogosa Sharpe (MRS) broth (Oxoid; Madrid, Spain) at 37 °C during 24 hours

87

under aerobic conditions to Lactobacillus strains and 48 h under anaerobic conditions to

88

Bifidobacterium strains. After this time, to obtain an initial biomass of about 8 Log Colony

89

Forming Units per mL (CFU/mL), 1 mL of each pre-inoculum was inoculated in 100 mL of

90

MRS broth and incubated 24-48 h at 37 ºC. The cultures were separated by centrifugation

91

at 2000 × g for 10 min at 4 °C and washed twice with sterile phosphate buffer saline (PBS)

92

and stored with glycerol at -80 ºC until used.

93

Fermented pomegranate juices

94

Pomegranate juices in aseptic bags of 4.5 Kg were provided by Probelte Biotecnología,

95

S.L. (Murcia, Spain). According to the supplier´s certificate of analysis, the pomegranate

96

juice had 14.9% of soluble solids content, pH 3.7, an acidity of 0.31 g citric acid/100 mL,

ACS Paragon Plus Environment

Page 4 of 28

Page 5 of 28

Journal of Agricultural and Food Chemistry

97

as well as compliance with the microbiological criteria specified (total plate count, yeast

98

and mold, Salmonella sp. and Escherichia coli).

99

The pomegranate juices were put into sterile borosilicate glass bottles (250 mL) with

100

polypropylene screw caps. Each pomegranate juice bottle (250 mL) was inoculated with

101

1% (v/v) of individual LAB previously prepared and incubated at 37 °C for 24 h to obtain

102

four different fermented pomegranate juices (FPJ) with an initial concentration of 6 Log

103

CFU/mL: FPJ with Bifidobacterium bifidum (FPJBB), FPJ with Lactobacillus plantarum

104

(FPJLP), FPJ with Bifidobacterium longum subsp. infantis (FPJBL) and FPJ with

105

Lactobacillus acidophilus (FPJLA). The fermented juices were compared with two

106

different non-fermented controls: control juices with incubated at 37 ºC (CPJI) or stored

107

under refrigerated conditions at 4 ºC (CPJR). The fermented pomegranate juices were

108

analyzed after the incubation period together with the unfermented control juices.

109

Simulated gastrointestinal digestion

110

The in vitro digestion assay was carried out according to Valero-Cases and Frutos17 with

111

some modifications. For the assays, 100 mL of each juice was subjected to simulated

112

gastrointestinal digestion for 180 min at 37 °C under stirring. The simulated gastric juices

113

(SGJ) were prepared with 400 mL of PBS to pH 3 with 1M HCl (Panreac; Barcelona,

114

Spain) and pepsin was added to reach a concentration of 3 g/L (Oxoid; Madrid, Spain).

115

After the 60 min of gastric digestion, the simulated intestinal juices (SIJ) were prepared

116

increasing the pH to7 with 1 M NaHCO3 (Panreac; Barcelona, Spain) and adding 4.5 g/L of

117

bile salts and 1 g/L of pancreatin (Sigma; Madrid, Spain) and they were incubated during

118

120 min at 37 ºC. Samples were taken in each of the fermented and control juices after

119

incubation time and at the different stages of in vitro digestion: after 60 min of SGJ, after

120

60 min of SIJ (SIJ1) and after 120 min of SIJ (SIJ2).

ACS Paragon Plus Environment

Journal of Agricultural and Food Chemistry

121

Microbiological analysis

122

The growth and survival of LAB after fermentation and during in vitro digestion were

123

determined by plate count. Samples (10 mL) of each FPJ were taken after fermentation and

124

after different steps of in vitro digestion (SGJ, SIJ1 and SIJ2). Suitable dilutions (0.1 mL)

125

were spread in triplicate on MRS agar plates and incubated for 24-48 h at 37 ºC under

126

aerobic and anaerobic conditions depending on the LAB conditions. The results were

127

expressed as Log CFU/mL of fermented pomegranate juice or SGJ or SIJ.

128

Extract preparation

129

For the determination of the phenolic compounds and the antioxidant activity after the

130

incubation time, the pomegranate juices extracts were prepared as previously described by

131

Nuncio-Jáuregui, et al.18 with least modifications: all different juices (5 mL) were mixed

132

with 10 mL of MeOH/water (75:25 v/v) with 0.1 % HCl using an Utra-Turrax (T25, IKA,

133

China) for 5 min and centrifuged at 15000 x g for 15 min at 4 °C. The control samples

134

stored at 4 ºC followed the same extraction process. The supernatants were filtered

135

(0.45 µm, Millipore; Spain) and stored at -80 ºC until analysis. Samples from in vitro

136

gastrointestinal digestion (10 mL) were taken directly at every digestion step and

137

centrifuged and stored following the same procedure described above.

138

HPLC-DAD Analysis (Identification and quantification of phenolic compounds)

139

The identification and quantification of phenolic compounds was done following the

140

Robles-Sánchez, et al.19 method with some adaptations on the binary gradient elution

141

system. High performance liquid chromatography studies were performed using an Agilent

142

1200 series HPLC system (Agilent Technologies, Waldbronn, Germany) coupled with a

143

diode array detector (DAD) equipped with a reversed-phase column C18 Waters Spherisorb

144

ODS-1 (250 mm × 4.6 mm, 5 µm particle size, Mediterranea SEA18; Teknokroma S.C.L.,

ACS Paragon Plus Environment

Page 6 of 28

Page 7 of 28

Journal of Agricultural and Food Chemistry

145

Barcelona, Spain). A binary gradient elution system was composed of solvent A: deionized

146

water with 1% formic acid and solvent B: acetonitrile with 1% formic acid. The elution

147

profile was as follows: 95% (A) at 0 min, 87% (A) at 15 min, 85% (A) at 20 min, 70% (A)

148

at 25 min and continued isocratically for 3 min, then changing to 55% (A) at 32 min and

149

continued isocratically for 3 min, then changing to 10% (A) at 40 min and continued

150

isocratically for 5 min, changing to 95% (A) at 60 min. The flow rate was 1 mL/min with

151

an injection volume of 20 µL and the temperature of the column was kept at 30 °C.

152

Different pure standards: ellagic acid, α–punicalagin, β-punicalagin, punicalin, catechin,

153

epicatechin and galic acid (Sigma; Madrid, Spain) were used to prepare different

154

calibration curves. The standards were dissolved in MeOH/water (75:25 v/v) and acidified

155

with 1 % HCl. The chromatograms were carried out simultaneously at 260, 280, 320, 360

156

or 520 nm. The identification of phenolic compounds was carried out by comparing the

157

retention time and UV absorption spectra with those of the standards, and quantified using

158

calibration curves of the standards. The microbial metabolites such as ellagic acid

159

derivative, ɑ-punicalagin derivative and catechin derivative were identified according to the

160

literature20,

161

tentatively quantified using the calibration curves of ellagic acid, ɑ-punicalagin and

162

catechin. All determinations were made in triplicate and the results were expressed as

163

mg/100 mL.

164

Antioxidant capacity determined by 2,2-Diphenyl-1-picrylhydrazyl (DPPH) free

165

radical scavenging method

166

The free radical scavenging activity was determined using the DPPH (radical 2,2-diphenyl-

167

1-picrylhydrazyl) method adopted from Brand-Williams, et al.22 Each supernatant (10 µL)

168

was mixed with 40 µL of MeOH and added to 950 µL of DPPH solution. The mixture was

21

by comparing the UV absorption spectrum with those of the standardsand

ACS Paragon Plus Environment

Journal of Agricultural and Food Chemistry

Page 8 of 28

169

shaken and kept during 10 min in a dark room. The absorbance decrease was measured at

170

515 nm in an UV–Vis Uvikon XS spectrophotometer (Bio-Tek Instruments, Saint Quentin

171

Yvelines, France). The calibration curve was of the form y = 0.2443x + 0.0047 (R2 = 0.999)

172

and was made using Trolox as standard solution in the range 0.01-5.00 mmol/ L. The

173

analyses were run in three replications and the results were expressed as mmol Trolox/ L of

174

juice.

175

Antioxidant capacity determined by ferric reducing antioxidant power (FRAP)

176

method

177

The ferric reducing antioxidant power (FRAP) method was employed adopted fromBenzie

178

and Strain.23 Briefly, the FRAP reagent was prepared fresh daily by mixing 300 mmol/L

179

acetate buffer (pH 3.6), 10 mmol/L TPTZ solution, in 40 mmol/L HCl and 20 mmol/L

180

FeCl3·6H2O solution in a volume ratio of 10:1:1, respectively. For the assays, 10 µL of

181

each extract was mixed with 990 µL of FRAP and kept in a dark room for 10 min at 37 ºC.

182

Then, the absorbance was measured at 593 nm. The calibration curve was of the form y =

183

0.4043x + 0.0626 (R2 = 0.998) using Trolox as standard solution in the range 0.01-5.00

184

mmol/ L. The analyses were run in three replications and results were expressed as mmol

185

Trolox/ L of juice.

186

Antioxidant

187

ethylbenzothiazoline-6-sulphonic acid) scavenging method

188

The

189

method was measured adopted from the method developed by Re, et al.24 Briefly, the

190

ABTS

191

allowed to react for 12-16 h in the dark at room temperature. The solution was then diluted

192

with PBS at pH 7.4 to an absorbance of 0.70 + 0.02 at 734 nm. For the assays, 10 µL of

capacity

determined

by

the

ABTS

radical

ABTS[2,2´-azino-bis-(3-ethylbenzothiazoline-6-sulphonic

+

acid)]

2,2´-azino-bis-(3-

radical

cation

was prepared mixing ABTS 7 mM with K2S2O8 2.45 mM and this mixture was

ACS Paragon Plus Environment

Page 9 of 28

Journal of Agricultural and Food Chemistry

193

each extract was mixed with 990 µL of ABTS and kept in a dark room for 10 min. The

194

calibration curve was of the form y = 0.2238x + 0.0322 (R2 = 0.991) using Trolox as

195

standard solution in the range 0.01-5.00 mmol/ L. The analyses were run in three

196

replications and the results were expressed as mmol Trolox/ L of juice.

197

Statistical analysis

198

All the experiments and analyses were performed in triplicate. The results were expressed

199

as mean ± standard deviation. The mean comparison was performed via SPSS v 21.0

200

software package (SPSS Inc., Chicago-Illinois-USA) using analysis of variance (ANOVA)

201

followed by a Tukey multiple range test to evaluate the significant differences (p < 0.05).

202

RESULTS AND DISCUSSION

203

Biotransformation of phenolic compounds in fermented pomegranate juices after 24

204

hours of incubation

205

Figure 1 and 2 shows the biotransformation of phenolic compounds by different lactic acid

206

bacteria in pomegranate juices in relation with the control juices (CPJR and CPJI). In the

207

control juices stored at different temperatures (4 ºC and 37 ºC), 8 different phenolic

208

compounds were identified, catechin, α and β punicalagin, punicalin, epicatechin, gallic

209

acid, ellagic acid derivative and ellagic acid. To our knowledge, all these phenolic

210

compounds have been reported in pomegranate juices in previous studies.21, 25-27 Most of

211

the initial phenolic compound values did not show significant differences between the

212

control samples stored at different temperatures (4 and 37 ºC, CPJR and CPJI,

213

respectively). However, it seems that when the control juices were stored at 37 ºC, the

214

catechin content was lower with respect to the initial concentration in control juices stored

215

at 4 ºC (130.87 vs 173.42 mg/100 mL, respectively) (Figure 1). At the same time, the

216

microbial fermentation had an increase in the levels of the phenolic compounds; in the

ACS Paragon Plus Environment

Journal of Agricultural and Food Chemistry

217

different experimental fermented juices, a total of 9 compounds were identified in this

218

study after fermentation (37 ºC during 24 h). Eight of the phenolic compounds were the

219

same as the control juices. However, a new compound was found only in fermented

220

pomegranate juices. This new phenolic metabolite was a new catechin derivative identified

221

after the fermentation (by comparison of the spectral data with the standard) with respect to

222

the control juices (Figure 1). Epicatechin was almost completely metabolized (only traces

223

were obtained) by BB, LP & LA and in a lesser extent by BL (3.59 mg/100 mL) (Figure 1).

224

Catechin was completely degraded by BB and LA (only traces were obtained) and LP and

225

BL in a lesser extent (15.30 and 90.28 mg/100 mL were obtained, respectively). However,

226

in control juices (CPJR and CPJI), the amount of epicatechin and catechin was higher than

227

in the fermented juices (ca. 48 and 130 mg/100 mL, respectively) (Figure 1). Therefore, this

228

microbial-derived catechin could be synthesized from the metabolism of other phenolic

229

compounds (epicatechin and catechin) during bacterial fermentation, due to the different

230

concentrations in relation with the control samples. These results are in agreement with

231

Alberto, Gómez-Cordovés and Manca de Nadra20 who reported the identification of

232

intermediate metabolites from catechin due to Lactobacillus hilgardii fermentation.

233

Otherwise, a decrease of ca. 40% in the ellagic acid derivative in FPJBB, FPJLB and

234

FPJLP was observed with respect to the control juices (Figure 2). Nevertheless, in FPJLA

235

the decrease was 70% higher with respect to the unfermented juices.

236

On the other hand, with respect to the β-punicalagin and α-punicalagin

237

concentrations, in the pomegranate juices fermented by Lactobacillus (FPJLP and FPJLA)

238

the concentrations of β and α-punicalagin were lower than in the juices fermented by

239

Bifidobacterium strains (FPJBB and FPJBL) (Figure 2). However, the punicalin remained

240

without significant differences between all fermented juices while the gallic acid

ACS Paragon Plus Environment

Page 10 of 28

Page 11 of 28

Journal of Agricultural and Food Chemistry

241

concentrations in FPJBL were the lowest (12.94 mg/100 mL). The free ellagic acid

242

concentrations in control and fermented juices did not change during incubation time and

243

hence did not present significant differences between juices (Figure 2). The low

244

biotransformation of ellagic acid in this step might be due to its insolubility in aqueous

245

media especially at low pH.28,

246

fermented only by different Lactobacillus strains also showed the biotransformation of

247

phenolic compounds during fermentation.12

29

Previous studies with cherry juice and broccoli puree

248

At the same time, the number of viable cells was determined (Table 1) to study the

249

relationship between the viable cells concentration and the biotransformation of phenolic

250

compounds. In spite of pomegranate juices being a hostile ecosystem (pH, buffering

251

capacity) and needing a long time for fermentation for the growth of LAB,13 in the present

252

study all strains increased from 6 Log CFU/mL to 7.26-7.78 Log CFU/mL without

253

significant differences (p > 0.05) among the LAB used. This growth increase could be in

254

relation with the metabolism of most of the pomegranate phenolic compounds in a greater

255

or lesser extent, depending on the strain as stated before. Previous studies in pomegranate

256

juice fermented by LAB showed the same increase after 120 h at 30 ºC (from ca. 7.0 to 7.3

257

Log CFU/mL) and a higher one (8 Log CFU/mL) after 72 h at 37 ºC.21-30 Hence, in this

258

study a good growth was observed with different LAB and lower fermentation times (24 h

259

at 37 ºC).

260

Metabolism and biotransformation of phenolic compounds in fermented pomegranate

261

juices after gastric digestion

262

The phenolic compounds concentrations were measured with the aim of testing their

263

stability after 60 minutes in SGJ in the different juices (Figure 1 and 2). The SGJ

264

conditions promoted the degradation of the epicatechin in the control juices with an

ACS Paragon Plus Environment

Journal of Agricultural and Food Chemistry

265

increase (ca. 30%) in the catechin concentration in these juices (Figure 1). With respect to

266

the fermented juices, the α- and β-punicalagins concentrations increased (ca. 25% and 30%,

267

respectively) in the juices fermented by Lactobacillus (FPJLA and FPJLP), and only in

268

FPJLA it was found that the gallic acid was fully metabolized by LA after gastric digestion.

269

The FPJBB presented the lowest concentrations of these compounds (56.00 and 60.92

270

mg/100 mL respectively). A decrease in the concentration of ellagic acid (ca. 30%) in the

271

juices fermented by Bifidobacterium (FPJBB and FPJBL) was also observed (Figure 2). At

272

the same time, the survival in Bifidobacterium FPJs was higher than in the juices fermented

273

by Lactobacillus, with concentrations of 7.40 and 7.18 Log CFU/mL for BB and BL,

274

respectively (Table 1). These survival differences could be due to a higher metabolism of

275

phenolic compounds by Bifidobacterium strains during SGJ (Figure 1 and 2). In other

276

studies with apples and blackberries phenolic compounds such as flavonoids, lignans and

277

phenolic acids were stable to the gastric conditions.31,

278

dried figs and pomegranate extracts, a slight decrease in such compounds was observed.5, 33

279

It has to be pointed out that none of the previous studies was performed with fermented

280

food matrices.

281

Metabolism and biotransformation of phenolic compounds in fermented pomegranate

282

juices during and after intestinal digestion

283

The different phenolic compounds were measured in all juices after 60 min (SIJ1) and after

284

120 min of intestinal digestion (SIJ2) to study and compare their metabolism and stability

285

with AF and SGJ (Figure 1 and 2). After SIJ1 an increase of ellagic acid in all juices was

286

observed, with amounts three times higher than those found after gastric digestion (Figure

287

2). The SIJ conditions (neutral pH, presence of pancreatic enzymes and bile salts) could

288

promote the transformation of ɑ- and β-punicalagins into ellagic acid.34 Consequently, a

32

However, in other studies with

ACS Paragon Plus Environment

Page 12 of 28

Page 13 of 28

Journal of Agricultural and Food Chemistry

289

decrease was observed in those phenolic compounds (ɑ- and β-punicalagin), with a higher

290

decrease (ca. 40%) of ɑ-punicalagin content in the fermented juices with respect to the

291

control juices (ca. 14%) (Figure 2). This decrease could be related to the generation of a

292

new ɑ-punicalagin derivative that was only detected in fermented juices as a possible

293

metabolite of the microbial transformations. The concentrations in fermented juices with

294

BB, LP y LA were between 30-31 mg/100 mL, while the FPJBL presented lower

295

concentrations (25.07 mg/100 mL).

296

On the other hand, after SIJ1 a decrease of catechin and epicatechin in the control

297

juices was observed (ca. 45% and 64%, respectively) (Figure 1). The decrease in control

298

juices could be due to the instability of the catechin at neutral pH.35-37 In this digestion step,

299

these compounds (catechin and epicatechin) were not detected in fermented juices because

300

of a previous biotransformation of these compounds due to the LAB metabolism. The

301

catechin derivative was only detected in fermented juices with respect to the control juices,

302

and it was present in higher concentrations (4.37 mg/100 mL) in FPJLA, while the other

303

fermented juices only presented trace amounts of these compounds after SIJ1 (Figure 1).

304

In different studies with green and black tea, an important decrease was also observed in

305

catechin after intestinal digestion.35, 37

306

After 120 min of SIJ, following the same pattern as in SIJ1, the phenolic compound

307

metabolism observed in fermented juices was higher than in the control juices, probably

308

because of the longer time in intestinal juices with the microorganisms. The catechin

309

derivative (detected only in fermented juices), increased significantly in FPJLP, FPJBL and

310

FPJLA (from trace amounts to 19.22, 6.47 and 9.45 mg/100 mL, respectively) while in

311

FPJBB only trace amounts were detected (Figure 1). However, the ɑ-punicalagin

312

derivative concentration in SPJ1 was stable during this same period (Figure 2). This fact

ACS Paragon Plus Environment

Journal of Agricultural and Food Chemistry

313

may suggest that the bacterial metabolism of ellagitannins, catechin and epicatechin occurs

314

during all the steps of the in vitro digestion, predominantly during the intestinal step.

315

Generally, the decrease in phenolic compounds for this period was higher for the fermented

316

juices with Bifidobacterium (FPJBB and FPJBL). At the same time, when the cell

317

concentration was compared between the LAB strains, it can be observed that the

318

concentrations of the Bifidobacterium strains were higher than the Lactobacillus ones. The

319

FPJBL presented the highest cell concentration at the end of in vitro digestion. This fact

320

could be related to the higher metabolism of most of the phenolic compounds in these

321

fermented juices with respect to the other fermented ones (Table 1). Regarding the cell

322

concentration, our results showed that although the LAB survival in SIJ2 was lower than in

323

the other digestion steps, the cell concentrations were high (>106 CFU/mL) after all the in

324

vitro digestion period. However, the lowest cell survival was observed for FPJLP and the

325

phenolic compound concentration in these juices was higher than in the other FPJs (Table

326

1). The relationship observed in fermented juices between the phenolic compounds and cell

327

concentrations suggests the possible prebiotic effect of phenolic compounds on the LAB.

328

The metabolites excreted by the LABs could produce health benefits through

329

bioaccessibility or bioactivity even though they are not absorbed in the gut.3 This is a

330

preliminary study, thus it could be considered as a basis for future studies to reinforce this

331

hypothesis.

332

Effect of fermentation and in vitro digestion on the antioxidant capacity of

333

pomegranate juices

334

During the fermentation and gastrointestinal digestion, different transformations

335

(epimerization, degradation, oxidation and hydrolysis) may occur to the phenolic

336

constituents of the pomegranate juices that could change the pattern (structure and levels)

ACS Paragon Plus Environment

Page 14 of 28

Page 15 of 28

Journal of Agricultural and Food Chemistry

337

of their metabolites.21, 35 Therefore, it is necessary to use different methods for providing an

338

estimate of the in vitro antioxidant capacity. In this study, three methods were used to

339

evaluate the changes in the antioxidant capacity after fermentation and during in vitro

340

digestion. After fermentation, it was observed that the antioxidant capacity was higher in

341

the fermented samples for the three methods, depending on the AOC method used and on

342

the bacterial strain (Table 2). Therefore, the DPPH scavenging activity of fermented juices

343

with BL and LA was higher (p < 0.05) than the control samples, while the ABTS

344

scavenging activity of fermented samples did not change with respect to the control juices.

345

The FRAP values of FPJLA and FPJBB were higher (p < 0.05) than the control samples

346

values. However, a continuous increase in the antioxidant capacity was observed in

347

fermented samples during the gastric digestion period, only for the DPPH and ABTS

348

assays. This increase in AOC for these assays could be due to the gastric conditions, with

349

low pH and pepsin activity that led to an improvement in the release of bioactive

350

compounds such as epicatechin, catechin and ɑ-punicalagin (Figure 1 and 2) increasing

351

their bioaccessibility, and thus the interaction with LABs. Huang, et al.,38 found the same

352

results after chemical extraction and in vitro digestion in Chinese bayberry. These results

353

are in agreement with those of Gullon, Pintado, Fernández-López, Pérez-Álvarez and

354

Viuda-Martos21 where the gastric digestion increased the inhibition values of the DPPH and

355

of the ABTS in the pomegranate peel.

356

In the intestinal digestion, the increase observed in the AOC during the SGJ for the

357

ABTS and DPPH methods, remained without significant changes during the two hours of

358

intestinal digestion for all FPJs (Table 2). At the end of the in vitro digestion, the

359

antioxidant capacity for the DPPH and ABTS method was in most of the FPJs, higher than

360

in the control ones. Several authors have reported that the in vitro digestion has a high

ACS Paragon Plus Environment

Journal of Agricultural and Food Chemistry

361

impact on the AOC measured with these methods, as can be demonstrated in the studies

362

performed in 33 fruit types, where the inhibition of DPPH radical increased after in vitro

363

digestion.39 The results are also in agreement with those reported by Chandrasekara and

364

Shahidi4 and Wootton-Beard, et al.40 who found an increase in the ABTS values after in

365

vitro digestion for millet grain and for 23 vegetable juices, respectively.

366

Nevertheless, during in vitro digestion, the FRAP assay values, in contrast to the

367

DPPH and ABTS assay, showed a decrease in AOC for all juices after the gastrointestinal

368

step. However, this initial decrease in fermented samples was higher (p ≥ 0.05) after 60 min

369

under intestinal conditions. These values obtained after SIJ1 remained stable at the end of

370

SIJ2 with values between 10.7 and 8.4 mmol Trolox/ L. According to a previous study,41

371

the FRAP assay values of the control , fermented

372

conditions can be enhanced by the electron transfer reaction under acid pH conditions.

373

Previous results obtained for catechin instability at neutral pH in control juices and by the

374

metabolism of the LAB in fermented juices (Figure 1 and 2), could be of some relation

375

with the results of the FRAP assay after SIJ1 (Table 2). A possible explanation could be

376

related to the metal-chelating properties of catechin and epicatechin with an important

377

contribution to the antioxidant activity of the juices.42 Therefore, the degradation of

378

catechin and epicatechin in control juices and the formation of the catechin microbial

379

metabolite through LAB metabolism in fermented juices, could be associated with the

380

reduction of the chelating activity resulting in a lower antioxidant activity in the FRAP

381

assay.

and digested juices under gastric

382

In conclusion, the results of the present study showed that the fermentation of

383

pomegranate juices improves the antioxidant capacity evaluated by the DPPH and ABTS

384

assays and modifies the type and amount of phenolic compounds with respect to the

ACS Paragon Plus Environment

Page 16 of 28

Page 17 of 28

Journal of Agricultural and Food Chemistry

385

unfermented ones. Through the biotransformation of these compounds by lactic acid

386

bacteria, two new phenolic derivatives were obtained (catechin and α-punicalagin). The in

387

vitro digestion improved the antioxidant capacity for the ABTS and DPPH assays.

388

However, the FRAP assay was significantly influenced by the degradation and

389

biotransformation of the catechin and epicatechin. At the same time, the pomegranate juices

390

were a good food matrix to ensure a high viability (≥106 CFU/mL) of all lactic acid bacteria

391

used in this study after in vitro digestion. Therefore, the lactic acid bacteria used in this

392

study can transform the phenolic compounds present in pomegranate juices, suggesting a

393

possible prebiotic effect of phenolic compounds.

394

Microbial metabolites derived from the fermentation of pomegranate juices and the high

395

viability of microorganisms reaching the colon, may contribute to the maintenance of gut

396

health. Further research is needed to understand the mechanisms of action of phenolic

397

microbial metabolites in humans. Acknowledgments

398

The authors acknowledge Mr. Graham Arnold for his assistance during the preparation of

399

the manuscript and Probelte Biotecnología, S.L. (Murcia, Spain) for the donation of the

400

pomegranate juices

401

Supporting information

402

Additional figures. Representative HPLC chromatograms of fermented pomegranate juices

403

and fermented pomegranate juices after gastrointestinal in vitro digestion.

404 405 406 407 408 409 410 411

ABBREVIATIONS AOC Antioxidant capacity LAB Lactic acid bacteria CFU Colony Forming Units PBS Phosphate Buffer Saline CPJI Control Pomegranate Juices with Incubation CPJR Control Pomegranate Juices with Refrigeration FPJBB Fermented Pomegranate Juice with Bifidobacterium bifidum

ACS Paragon Plus Environment

Journal of Agricultural and Food Chemistry

412 413 414 415 416 417 418 419 420 421 422 423

FPJLP FPJBL FPJLA SGD SGJ SIJ SIJ1 SIJ2 AI

Fermented Pomegranate Juice with Lactobacillus plantarum Fermented Pomegranate Juice with Bifidobacterium longum subsp. Infantis Fermented Pomegranate Juice with Lactobacillus acidophilus Simulated Gastrointestinal Human Digestion Simulated Gastric Juice Simulated Intestinal Juices Simulated Intestinal Juices after 60 min Simulated Intestinal Juices after 120 min After Incubation

424

1. Lewandowska, U.; Szewczyk, K.; Hrabec, E.; Janecka, A.; Gorlach, S. Overview of

425

metabolism and bioavailability enhancement of polyphenols. J. Agric. Food Chem. 2013,

426

61, 12183-99.

427

2. Etxeberria, U.; Fernandez-Quintela, A.; Milagro, F. I.; Aguirre, L.; Martinez, J. A.;

428

Portillo, M. P. Impact of polyphenols and polyphenol-rich dietary sources on gut

429

microbiota composition. J. Agric. Food Chem. 2013, 61, 9517-33.

430

3. Fernandez-Garcia, E.; Carvajal-Lerida, I.; Perez-Galvez, A. In vitro bioaccessibility

431

assessment as a prediction tool of nutritional efficiency. Nutr. Res. 2009, 29, 751-60.

432

4. Chandrasekara, A.; Shahidi, F. Bioaccessibility and antioxidant potential of millet grain

433

phenolics as affected by simulated in vitro digestion and microbial fermentation. J. Funct.

434

Foods 2012, 4, 226-237.

435

5. Mosele, J. I.; Macià, A.; Romero, M.-P.; Motilva, M.-J.; Rubió, L. Application of in vitro

436

gastrointestinal digestion and colonic fermentation models to pomegranate products (juice,

437

pulp and peel extract) to study the stability and catabolism of phenolic compounds. J.

438

Funct. Foods 2015, 14, 529-540.

439

6. Moco, S.; Martin, F. P.; Rezzi, S. Metabolomics view on gut microbiome modulation by

440

polyphenol-rich foods. J. Proteome Res. 2012, 11, 4781-90.

441

7. Pandareesh, M. D.; Mythri, R. B.; Srinivas Bharath, M. M. Bioavailability of dietary

442

polyphenols: Factors contributing to their clinical application in CNS diseases. Neurochem.

443

Int. 2015, 89, 198-208.

REFERENCES

ACS Paragon Plus Environment

Page 18 of 28

Page 19 of 28

Journal of Agricultural and Food Chemistry

444

8. Viuda-Martos, M.; Fernández-López, J.; Pérez-Álvarez, J. A. Pomegranate and its Many

445

Functional Components as Related to Human Health: A Review. Compr. Rev. Food Sci.

446

Food Saf. 2010, 9, 635-654.

447

9. Gomez-Caravaca, A. M.; Verardo, V.; Toselli, M.; Segura-Carretero, A.; Fernandez-

448

Gutierrez, A.; Caboni, M. F. Determination of the major phenolic compounds in

449

pomegranate juices by HPLC-DAD-ESI-MS. J. Agric. Food Chem.2013, 61, 5328-37.

450

10. Tomas-Barberan, F. A.; Garcia-Villalba, R.; Gonzalez-Sarrias, A.; Selma, M. V.; Espin,

451

J. C. Ellagic acid metabolism by human gut microbiota: consistent observation of three

452

urolithin phenotypes in intervention trials, independent of food source, age, and health

453

status. J. Agric. Food Chem. 2014, 62, 6535-8.

454

11. Cueva, C.; Moreno-Arribas, M. V.; Martin-Alvarez, P. J.; Bills, G.; Vicente, M. F.;

455

Basilio, A.; Rivas, C. L.; Requena, T.; Rodriguez, J. M.; Bartolome, B. Antimicrobial

456

activity of phenolic acids against commensal, probiotic and pathogenic bacteria. Res.

457

Microbiol. 2010, 161, 372-82.

458

12. Filannino, P.; Bai, Y.; Di Cagno, R.; Gobbetti, M.; Ganzle, M. G. Metabolism of

459

phenolic compounds by Lactobacillus spp. during fermentation of cherry juice and broccoli

460

puree. Food Microbiol. 2015, 46, 272-9.

461

13. Filannino, P.; Azzi, L.; Cavoski, I.; Vincentini, O.; Rizzello, C. G.; Gobbetti, M.; Di

462

Cagno, R. Exploitation of the health-promoting and sensory properties of organic

463

pomegranate (Punica granatum L.) juice through lactic acid fermentation. Int. J. Food

464

Microbiol. 2013, 163, 184-92.

465

14. Svensson, L.; Sekwati-Monang, B.; Lutz, D. L.; Schieber, A.; Ganzle, M. G. Phenolic

466

acids and flavonoids in nonfermented and fermented red sorghum (Sorghum bicolor (L.)

467

Moench). J. Agric. Food Chem. 2010, 58, 9214-20.

468

15. FAO/WHO, Working Group Report on Drafting Guidelines for the Evaluation of

469

Probiotics in Food In FAO/WHO, Ed. London, Ontario, Canada 2002.

470

16. Mishra, V.; Shah, C.; Mokashe, N.; Chavan, R.; Yadav, H.; Prajapati, J. Probiotics as

471

potential antioxidants: a systematic review. J. Agric. Food Chem.2015, 63, 3615-26.

472

17. Valero-Cases, E.; Frutos, M. J. Effect of different types of encapsulation on the survival

473

of Lactobacillus plantarum during storage with inulin and in vitro digestion. LWT - Food

474

Sci. Technol. 2015, 64, 824-828.

ACS Paragon Plus Environment

Journal of Agricultural and Food Chemistry

475

18. Nuncio-Jáuregui, N.; Nowicka, P.; Munera-Picazo, S.; Hernández, F.; Carbonell-

476

Barrachina, Á. A. Wojdyło, A., Identification and quantification of major derivatives of

477

ellagic acid and antioxidant properties of thinning and ripe Spanish pomegranates. J. Funct.

478

Foods 2015, 12, 354-364.

479

19. Robles-Sánchez, R. M.; Rojas-Graü, M. A.; Odriozola-Serrano, I.; González-Aguilar,

480

G. A.; Martín-Belloso, O. Effect of minimal processing on bioactive compounds and

481

antioxidant activity of fresh-cut ‘Kent’ mango (Mangifera indica L.). Postharvest Biol.

482

Technol. 2009, 51, 384-390.

483

20. Alberto, M., R.,; Gómez-Cordovés, C.; Manca de Nadra, M. Metabolism of Gallic Acid

484

and Catechin by Lactobacillus hilgardii from Wine. J. Agric. Food Chem. 2004, 52, 6465-

485

6469.

486

21. Gullon, B.; Pintado, M. E.; Fernández-López, J.; Pérez-Álvarez, J. A.; Viuda-Martos,

487

M. In vitro gastrointestinal digestion of pomegranate peel (Punica granatum) flour obtained

488

from co-products: Changes in the antioxidant potential and bioactive compounds stability.

489

J. Funct. Foods 2015, 19, 617-628.

490

22. Brand-Williams, W.; Cuvelier, M. E.; Berset, C. Use of a Free Radical Method to

491

Evaluate Antioxidant Activity. J. Food Sci. Technol. 1995, 28, 25-30.

492

23. Benzie, I. F. F.; Strain, J. J. The Ferric Reducing Ability of Plasma (FRAP) as a

493

Measure of "Antioxidant Power'':The FRAP Assay. Anal. Biochem. 1996, 239, 70-76.

494

24. Re, R.; Pellegrini, N.; Proteggente, A.; Pannala, A.; Yang, M.; Rice-Evans, C.

495

Antioxidant activity applying an improved ABTS radical cation decolorization assay. Free

496

Radic. Biol. Med. 1999, 26, 1231-1237.

497

25. Herceg, Z.; Kovacevic, D. B.; Kljusuric, J. G.; Jambrak, A. R.; Zoric, Z.; Dragovic-

498

Uzelac, V. Gas phase plasma impact on phenolic compounds in pomegranate juice. Food

499

Chem. 2016, 190, 665-72.

500

26. Mena, P.; Vegara, S.; Marti, N.; Garcia-Viguera, C.; Saura, D.; Valero, M. Changes on

501

indigenous microbiota, colour, bioactive compounds and antioxidant activity of pasteurised

502

pomegranate juice. Food Chem. 2013, 141, 2122-9.

503

27. Onsekizoglu, P. Production of high quality clarified pomegranate juice concentrate by

504

membrane processes. J. Memb. Sci. 2013, 442, 264-271.

ACS Paragon Plus Environment

Page 20 of 28

Page 21 of 28

Journal of Agricultural and Food Chemistry

505

28. Bala, I.; Bhardwaj, V.; Hariharan, S.; Kumar, M. N. Analytical methods for assay of

506

ellagic acid and its solubility studies. J. Pharm Biomed. Anal 2006, 40, 206-10.

507

29. González-Sarrías, A.; García-Villalba, R.; Núñez-Sánchez, M. Á.; Tomé-Carneiro, J.;

508

Zafrilla, P.; Mulero, J.; Tomás-Barberán, F. A.; Espín, J. C. Identifying the limits for

509

ellagic acid bioavailability: A crossover pharmacokinetic study in healthy volunteers after

510

consumption of pomegranate extracts. J. Funct. Foods 2015, 19, 225-235.

511

30. Mousavi, Z. E.; Mousavi, S. M.; Razavi, S. H.; Emam-Djomeh, Z.; Kiani, H.

512

Fermentation of pomegranate juice by probiotic lactic acid bacteria. World J. Microbiol

513

Biotechnol 2010, 27, 123-128.

514

31. Bouayed, J.; Deußer, H.; Hoffmann, L.; Bohn, T. Bioaccessible and dialysable

515

polyphenols in selected apple varieties following in vitro digestion vs. their native patterns.

516

Food Chem. 2012, 131, 1466-1472.

517

32. Correa-Betanzo, J.; Allen-Vercoe, E.; McDonald, J.; Schroeter, K.; Corredig, M.;

518

Paliyath, G. Stability and biological activity of wild blueberry (Vaccinium angustifolium)

519

polyphenols during simulated in vitro gastrointestinal digestion. Food Chem. 2014, 165,

520

522-31.

521

33. Kamiloglu, S.; Capanoglu, E. Investigating the in vitro bioaccessibility of polyphenols

522

in fresh and sun-dried figs (Ficus caricaL.). Int. J. Food Sci. Technol. 2013, 48, 2621-2629.

523

34. Larrosa, M.; Garcia-Conesa, M. T.; Espin, J. C.; Tomas-Barberan, F. A., Ellagitannins,

524

ellagic acid and vascular health. Mol. Aspects of Med. 2010, 31, 513-39.

525

35. Jilani, H.; Cilla, A.; Barberá, R.; Hamdi, M. Biosorption of green and black tea

526

polyphenols into Saccharomyces cerevisiae improves their bioaccessibility. J. Funct. Foods

527

2015, 17, 11-21.

528

36. Krook, M. A.; Hagerman, A. E. Stability of Polyphenols Epigallocatechin Gallate and

529

Pentagalloyl Glucose in a Simulated Digestive System. Food Res. Int. 2012, 49, 112-116.

530

37. Marchese, A.; Coppo, E.; Sobolev, A. P.; Rossi, D.; Mannina, L.; Daglia, M. Influence

531

of in vitro simulated gastroduodenal digestion on the antibacterial activity, metabolic

532

profiling and polyphenols content of green tea (Camellia sinensis). Food Res. Int. 2014, 63,

533

182-191.

ACS Paragon Plus Environment

Journal of Agricultural and Food Chemistry

534

38. Huang, H.; Sun, Y.; Lou, S.; Li, H.; Ye, X. In vitro digestion combined with cellular

535

assay to determine the antioxidant activity in Chinese bayberry (Myrica rubra Sieb. et

536

Zucc.) fruits: a comparison with traditional methods. Food Chem. 2014, 146, 363-70.

537

39. Chen, G.-L.; Chen, S.-G.; Zhao, Y.-Y.; Luo, C.-X.; Li, J.; Gao, Y.-Q. Total phenolic

538

contents of 33 fruits and their antioxidant capacities before and after in vitro digestion. Ind.

539

Crops Prod. 2014, 57, 150-157.

540

40. Wootton-Beard, P. C.; Moran, A.; Ryan, L. Stability of the total antioxidant capacity

541

and total polyphenol content of 23 commercially available vegetable juices before and after

542

in vitro digestion measured by FRAP, DPPH, ABTS and Folin–Ciocalteu methods. Food

543

Res. Int. 2011, 44, 217-224.

544

41. Dejian Huang; Boxin Ou; Prior, R. L. The Chemistry behind Antioxidant Capacity

545

Assays. J. Agric. Food Chem. 2005, 53, 1841-1856.

546

42. Braicu, C.; Ladomery, M. R.; Chedea, V. S.; Irimie, A.; Berindan-Neagoe, I. The

547

relationship between the structure and biological actions of green tea catechins. Food

548

Chem. 2013, 141, 3282-9.

549

43. Argyri, K.; Komaitis, M.; Kapsokefalou, M. Iron decreases the antioxidant capacity of

550

red wine under conditions of in vitro digestion. Food Chem. 2006, 96, 281-289.

551

44. Kim, Y.; Brecht, J. K.; Talcott, S. T. Antioxidant phytochemical and fruit quality

552

changes in mango (Mangifera indica L.) following hot water immersion and controlled

553

atmosphere storage. Food Chem. 2007, 105, 1327-1334.

554

45. Xia, E. Q.; Deng, G. F.; Guo, Y. J.; Li, H. B. Biological activities of polyphenols from

555

grapes. Int. J. Mol. Sci 2010, 11, 622-46.

556

ACS Paragon Plus Environment

Page 22 of 28

Page 23 of 28

Journal of Agricultural and Food Chemistry

Table 1. Growth of different lactic acid bacteria in pomegranate juices after incubation period and their survival during the different steps of the in vitro digestion.

Period AI SGJ SIJ1 SIJ2

FPJBB 7.78 ±0.05D a 7.40±0.01Cc 7.09±0.01Bc 6.79±0.15Ab

FPJBL Log CFU/mL 7.33±0.02Ca 7.67±0.02Da Ba 6.83±0.04 7.18±0.01Cb ABa 6.73±0.02 7.11±0.01Bc Aa 6.71±0.02 6.99±0.02Ac

FPJLP

FPJLA 7.26±0.07Ba 6.93±0.02Aa 6.88±0.01Ab 6.82±0.01Ab

Values are the mean of 3 replications (± standard error). Capital letters refer to the evolution of each period: After Incubation (AI), Simulated Gastric Juice (SGJ), Simulated Intestinal Juices after 60 min (SIJ1) and Simulated Intestinal Juices after 120 min (SIJ2). Lowercase letters are the comparison among Fermented Pomegranate

Juices

with:

Bifidobacterium

bifidum (FPJBB),

Lactobacillus plantarum

(FPJLP),

Bifidobacterium longum subsp. Infantis (FPJBL) and Lactobacillus acidophilus (FPJLA). Values followed by the same letter within the same column or row were not statistically different according to Tukey’s multiple range test (p < 0.05).

ACS Paragon Plus Environment

Journal of Agricultural and Food Chemistry

Page 24 of 28

Table 2. Antioxidant Capacity of pomegranate juice after incubation period and during the different steps of the in vitro digestion.

Period

DPPH

ABTS

FRAP

AI SGJ SIJ1 SIJ2 AI SGJ SIJ1 SIJ2 AI SGJ SIJ1 SIJ2

CPJR 20.41 ±0.59Cab 14.40±1.27Ba 7.17±0.26Aa 7.50±0.33Aa 13.83±1.16Ac 14.66±0.49Abc 14.47±0.36Abc 13.87±0.27Aa 13.94±0.56Ba 10.80±0.51Aa 10.15±0.43Ab 10.68±0.53Ab

CPJI

FPJBB

18.85±1.40Ca 13.07±1.33Ba 9.79±2.60ABa 6.95±0.74Aa 12.52±0.15Aabc 14.03±0.85Bd 13.84±0.40Babc 14.02±0.60Ba 13.32±0.39Ca 12.27±0.24Ba 10.16±0.43Ab 10.01±0.04Ab

FPJLP (mmol Trolox/ L) 20.40±0.95Aab 22.22±1.05Abc Bb 27.27±0.25 27.99±0.60Bb Bb 27.22±0.46 26.50±0.18Bb Bb 27.26±0.37 27.05±1.13Bb Aab 11.97±0.23 12.87±0.92Abc Bd 15.41±0.27 15.74±0.44Bd Bbc 15.35±0.50 14.56±0.20Bc Bb 15.39±0.40 15.16±0.68Bb Cb 15.99±1.46 13.51±0.58Ca Ba 12.05±0.72 11.98±0.99Ba Aab 9.10±0.69 8.58±0.21Aa Ab 8.42±0.18 8.41±0.24Ab

FPJBL 24.04±0.75Ac 27.32±0.19ABb 27.08±0.47Bb 26.39±0.42ABb 11.88±0.82Aab 13.23±0.21Bab 13.52±0.31Bab 14.44±0.45Bab 14.68±0.91Cab 11.31±1.41Ba 8.63±0.35Aa 8.71±0.13Ab

FPJLA 22.93±0.23Ac 27.90±0.45Cb 26.32±0.37Bb 26.56±0.49Bb 10.67±0.25Aa 12.08±0.40ABa 12.48±1.14Ba 14.63±0.53Cab 16.06±1.35Cb 12.41±0.16Ba 8.99±0.08Aa 8.84±0.32Ab

Values are the mean of 3 replications (± standard error). Capital letters are the evolution of period: After Incubation (AI)*, Simulated Gastric Juice (SGJ), Simulated Intestinal Juices after 60 min (SIJ1) and Simulated Intestinal Juices after 120 min (SIJ2). Lowercase letters are the comparison among Pomegranate Juices [Unfermented Control Pomegranate Juice Refrigerated (CPJR), Unfermented Control Pomegranate Juice Incubated (CPJI); and Fermented Pomegranate Juice with: Bifidobacterium bifidum (FPJBB), Lactobacillus plantarum (FPJLP), Bifidobacterium longum subsp. Infantis (FPJBL) and Lactobacillus acidophilus (FPJLA)]. Values followed by the same letter within the same column or row were not statistically different according to Tukey’s multiple range test (p < 0.05). *AI refers to the results after incubation period for CPJI, FPJBB, FPJLP, FPJBL and FPJLA compared to CPJR that were not incubated and remained at 4 ºC as refrigerated control juices.

ACS Paragon Plus Environment

Page 25 of 28

Journal of Agricultural and Food Chemistry

Figure 1. Evolution of flavan-3-ol after incubation period and during the different steps of the in vitro digestion in different fermented pomegranate juices. The bars are the mean of 3 replications (± standard error). Capital letters refer to the flavan-3-ol evolution: After Incubation period (AI)*, Simulated Gastric Juice (SGJ), Simulated Intestinal Juices after 60 min (SIJ1) and Simulated Intestinal Juices after 120 min (SIJ2) for the same type of juice. Lowercase letters refer to the comparison among pomegranate juices for the same step: Control Pomegranate Juice Refrigerated (CPJR), Control Pomegranate Juice Incubated (CPJI), Fermented Pomegranate

Juice

with:

Bifidobacterium

bifidum

(FPJBB),

Lactobacillus

plantarum

(FPJLP),

Bifidobacterium longum subsp. infantis (FPJBL) and Lactobacillus acidophilus (FPJLA). *AI refers to the results after incubation period for CPJI, FPJBB, FPJLP, FPJBL and FPJLA at 37 º C compared to CPJR that was not incubated and remained refrigerated at 4 ºC.

ACS Paragon Plus Environment

Journal of Agricultural and Food Chemistry

ACS Paragon Plus Environment

Page 26 of 28

Page 27 of 28

Journal of Agricultural and Food Chemistry

Figure 2. Ellagitannins evolution after incubation period and during in vitro digestion in different fermented pomegranate juices. The bars are the mean of 3 replications (± standard error). Capital letters refer to the ellagitannins evolution: After Incubation period (AI)*, Simulated Gastric Juice (SGJ), Simulated Intestinal Juices after 60 min (SIJ1) and Simulated Intestinal Juices after 120 min (SIJ2) for the same type of juice. Lowercase letters refer to the comparison among pomegranate juices for the same step: Control Pomegranate Juice Refrigerated (CPJR), Control Pomegranate Juice Incubated (CPJI), Fermented Pomegranate Juice with: Bifidobacterium bifidum (FPJBB), Lactobacillus plantarum (FPJLP), Bifidobacterium longum subsp. infantis (FPJBL) and Lactobacillus acidophilus (FPJLA). *AI refers to the results after incubation period for CPJI, FPJBB, FPJLP, FPJBL and FPJLA at 37 º C compared to CPJR that was not incubated and remained refrigerated at 4 ºC.

ACS Paragon Plus Environment

Journal of Agricultural and Food Chemistry

TOC GRAPHIC 4 different fermented juices

Bioconversion of phenolic compounds?

ACS Paragon Plus Environment

Page 28 of 28