Effect of Fermentation and Drying on Cocoa Polyphenols - Journal

The municipality of Babahoyo, in the province of los Rı́os, is indicated by a red spot. Galapagos Islands are not shown on the map. Pods were opened...
0 downloads 0 Views 755KB Size
Subscriber access provided by UNIV OF MISSISSIPPI

Article

Effect of fermentation and drying on cocoa polyphenols Barbara Albertini, Aurélie Schoubben, Davide Guarnaccia, Filippo Pinelli, Mirco Della Vecchia, Maurizio Ricci, Gian Carlo Di Renzo, and Paolo Blasi J. Agric. Food Chem., Just Accepted Manuscript • DOI: 10.1021/acs.jafc.5b01062 • Publication Date (Web): 18 Jun 2015 Downloaded from http://pubs.acs.org on July 2, 2015

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

254x119mm (96 x 96 DPI)

ACS Paragon Plus Environment

Journal of Agricultural and Food Chemistry

1

Page 2 of 28

EFFECT OF FERMENTATION AND DRYING ON COCOA POLYPHENOLS

2

3

4

Barbara Albertini1, Aurélie Schoubben1, Davide Guarnaccia2, Filippo Pinelli3, Mirco Della

5

Vecchia4, Maurizio Ricci1, Gian Carlo Di Renzo5, Paolo Blasi6*

6

7

8

1

Department of Pharmaceutical Sciences, University of Perugia (Italy);

9

2

Laerbium Pharma S.r.l., Via Togliatti n. 73/A - 06073 Corciano, Perugia (Italy);

10

3

European Network “The chocolate way” [http://www.thechocolateway.eu/];

11

4

Accademia Maestri Cioccolatieri Italiani, Via Sass Muss, 6 32037 Sospirolo, Belluno (Italy);

12

5

Department of Surgical and Biomedical Sciences, S.M. della Misericordia Hospital, S. Andrea

13

delle Fratte, 06156 Perugia (Italy).

14

6

School of Pharmacy, University of Camerino, Via Sant’Agostino 1, 62032, Camerino (Italy).

15

16

17

*Corresponding Author: Paolo Blasi, e-mail: [email protected]; phone +39 0737402289, fax:

18

+39 0737637345.

19 1 ACS Paragon Plus Environment

Page 3 of 28

Journal of Agricultural and Food Chemistry

20

Abstract

21

Cocoa seed polyphenols have demonstrated interesting beneficial effects in humans. Most of

22

polyphenols contained in fresh seeds are chemically modified during fermentation, drying, and

23

cocoa powder or chocolate production. The improvement of these procedures to obtain a high-

24

polyphenol-content cocoa is highly desirable. To this aim, a field investigation on the effect of

25

fermentation and natural drying on fine flavor National cocoa (cacao Nacional) was performed.

26

Cocoa seeds were fermented for 6 days and, every day, samples were sun dried and analyzed for

27

polyphenol content and antioxidant power. During the first 2 days of fermentation, Folin-Ciocalteau

28

and FRAP test evidenced a significant reduction of polyphenol content and antioxidant capacity,

29

respectively. Changes during the following days of fermentation were less significant. Epicatechin,

30

the most studied member of the catechin family, followed a similar pathway of degradation. Data

31

confirmed the high impact of fermentation and drying on cocoa seed polyphenols. Fermentation and

32

drying are, in the one hand, necessary to obtain cocoa flavour and palatability but, in the other hand,

33

are strongly compromising polyphenol content. To obtain high-polyphenol-content cocoa, the

34

existing fermentation, drying, and manufacturing protocols should go through a systemic review to

35

understand and modify the critical steps.

36

37

38

39

40

Keywords: Theobroma cacao L., cocoa, chocolate, polyphenols, catechin, epicatechins, cocoa

41

fermentation and drying.

42 2 ACS Paragon Plus Environment

Journal of Agricultural and Food Chemistry

Page 4 of 28

43

Introduction

44

Cocoa seeds, the seeds contained in the fruits of the plant Theobroma cacao L., and the products

45

derived from its transformation have been known for millennia. At the moment, the oldest traces of

46

the human use of cocoa have been found in Mesoamerica and date back 2000 B.C.1-3 while the

47

beginning of domestication is still controversial and contended between Central and South

48

America1,4-7. Well known is the use of cocoa by Mayans and Aztecs that consumed it in form of

49

unsweetened dark beverage8. The use of cocoa and cocoa derived products has continued through

50

the centuries and many beneficial and/or curative effects on humans have been described. Only

51

recently, thanks to the advancement of the analytical technologies and the availability of in vitro, in

52

vivo, and clinical studies, the mechanism underlying these effects has been attributed to the

53

presence of a plethora of antioxidant compounds9. Among them, the most representatives are

54

catechins, anthocyanins, and proanthocyanins, with (-)-epicatechin being the most abundant

55

polyphenol. The peculiarity of cocoa is the high content of polyphenols per dry weight that is

56

superior to other beverages and foods including tea and wine10,11. Naturally, cocoa polyphenol

57

content varies with the plant variety12, climate and soil characteristics13,14, harvesting15,

58

fermentation16, drying time method17, as well as storage and transportation. In chocolate,

59

polyphenol content is negatively influenced by different manufacturing steps, such as alkalinization,

60

roasting, and conching18-20. On the other hand, fermentation, alkalinization, roasting, and conching

61

are the major steps contributing to the development of the characteristic color and flavors of cocoa

62

and chocolate14.

63

Among the preventive and/or therapeutic effects reported in literature, cocoa and/or high-cocoa-

64

content chocolate contributed to reduce blood pressure, glycemic and liver pattern during

65

pregnancy21, improved cognitive function, reduced blood pressure and insulin resistance in elderly

66

subjects with mild cognitive impairment22, and showed multiple disease-modifying properties in

67

Alzheimer's disease23,24. Several short-term intervention studies have also reported beneficial health 3 ACS Paragon Plus Environment

Page 5 of 28

Journal of Agricultural and Food Chemistry

68

effects against oxidative stress and chronic inflammation, risk factors for cancer and other chronic

69

diseases25.

70

More clear evidences are probably limited by the small amount of studies focused on the

71

bioavailability of the different cocoa polyphenols in humans. Investigations on the effect of product

72

processing, interactions with other components of the diet, and host factors on polyphenol

73

bioavailability have not been well defined in the scientific literature26,27.

74

For a reliable use of cocoa and cocoa derived products as food supplements or medicines, a deep

75

understanding of the negative effect of the manufacturing steps mentioned above on polyphenols

76

amount is needed. To obtain standardized semi-finished or finished products, the whole procedure

77

(from the agronomical techniques to the manufacturing processes) should be strictly controlled and

78

certified. This is mandatory to obtain a consistent and qualified product. At the moment we are far

79

from having a complete understanding and control of these factors: for instance time and mode of

80

pulp preconditioning may differ according to traditions, fermentation may be performed for

81

different periods of time in heaps, wood boxes, fermentation baskets, or juta sacs in diverse climatic

82

conditions14. In addition, cocoa pods harvesting from small farmers is difficult to standardize since

83

traditional empirical “standards” on pod collection, preconditioning, and fermentation are extremely

84

well established and difficult to eradicate.

85

With the aim of identifying the procedures that impair the production of a high-polyphenol-content

86

cocoa (intending a cocoa with a natural polyphenol content higher than the currently available), a

87

study on the impact of fermentation on total phenolic content (TPC), catechins and epicatechins

88

content, and total antioxidant capacity (TAC) has been performed. This is the beginning of a

89

systematic study aimed at the standardization and certification of the fine flavor National cacao,

90

form Ecuador variety. cacao Nacional as well as at the production of a high quality cocoa naturally

91

enriched in polyphenols with its characteristic taste and flavor. 4 ACS Paragon Plus Environment

Journal of Agricultural and Food Chemistry

Page 6 of 28

92

5 ACS Paragon Plus Environment

Page 7 of 28

Journal of Agricultural and Food Chemistry

93

Materials and methods

94

Materials

95

Folin-Ciocalteu reagent, potassium persulfate, gallic acid, 6-hydroxy-2,5,7,8-tetramethyl-2-

96

carboxylic acid (Trolox), 2,2′-azino-bis-(3-ethylbenzothiazoline-6-sulphonate) diammonium salts

97

(ABTS) and 2,4,6-tris(2-pyridyl)-s-triazine (TPTZ), were purchased from Sigma Aldrich (Milan,

98

Italy). Methanol (MeOH), hexane, acetic acid (AcOH), hydrochloridric acid (HCl) and sodium

99

carbonate were obtained from J.T. Baker (Milan, Italy). Ferric chloride was bought from Carlo Erba

100

(Milan, Italy). Ultrapure water was obtained from Human Power 1 system (Human Corporation,

101

Caserta, Italy). All solvents used were of the highest purity grade commercially available.

102

103

Cocoa harvesting, fermentation and drying

104

Mature pods (the fruit of Theobroma cacao L.) from the variety Arriba Nacional were obtained

105

from farmers located in the Canton Babahoyo (Los Ríos, Ecuador). No reliable information on the

106

days of pod storage after harvesting was available. Fermentation and drying were performed at the

107

collection centre of Pueblo Nuevo in the Municipality of Babahoyo (geographical coordinates of

108

Babahoyo; Latitude: -1 49' 00'', Longitude: -79 31' 00'') (Canton Babahoyo, Los Ríos, Ecuador)

109

(Figure 1). T. cacao L. fruits used in this study were from a variety known as Arriba Nacional or

110

simply cacao Nacional.

111

Pods were opened and the seeds (120 Kg) covered of their mucilaginous pulp were deposited for

112

fermentation in a wood box made of Cordia alliodora (R. & P.) Oken28, also known as mountain

113

laurel29. Fermentation mass was covered with banana leafs and wood to maintain fermentation

114

temperature and avoid arthropod contamination. Temperature of the fermenting seeds was recorded

6 ACS Paragon Plus Environment

Journal of Agricultural and Food Chemistry

Page 8 of 28

115

every day measuring it in three different zones of the mass. Temperature near the fermentation box

116

was recorded as well.

117

The fermenting mass was manually mixed once a day for at least 10 minutes while every 2 days the

118

mass was moved from an upper box to a lower one. The fermentation had a duration of 6 days and

119

every day (including day zero: non-fermented seeds) three samples of 300 g were randomly

120

withdrawn from the mass and dried.

121

Since the experimentation was performed during the dry season (May 31, 2014 - June 11, 2014),

122

sun drying was chosen. Natural seed drying was performed in the collection centre by laying the

123

seeds on a suspended net situated under a plastic canopy. Seeds were mixed three times a day and

124

left to dry for 5 days. The temperature under the drying structure was recorded every day in

125

triplicate. After the 5 days of fermentation, cocoa seeds were collected in plastic bags and frozen

126

until use.

127

128

Extraction of polyphenols

129

Cocoa beans were ground to obtain a fine powder that was defatted using n-hexane. 150 mL of n-

130

hexane were added to 30 g of cocoa powder and the mixture was kept under magnetic stirring for 2h

131

to remove the fat components30. The suspension was filtered through a paper filter and the solid

132

material (defatted cocoa powder) was washed with 50 mL of n-hexane and then dried at room

133

temperature. Polyphenol extraction was performed using a mixture of MeOH:H2O:AcOH

134

(79.2:20:0.8 v/v/v) as solvent31. Defatted cocoa powder (0.5 g) was added to 200 mL of extraction

135

mixture and maintained under stirring for 3 hours at room temperature. Clear polyphenol solution,

136

obtained by filtration, was used for polyphenol content and antioxidant activity analysis.

137 7 ACS Paragon Plus Environment

Page 9 of 28

Journal of Agricultural and Food Chemistry

138

Total Polyphenol content

139

Folin-Ciocalteu assay

140

Folin-Ciocalteu reagent was diluted 10-fold and 750 µL of diluted reagent was added to 100 µL of

141

the solution containing cocoa extract. The mixture was incubated at room temperature for 10

142

minutes then 750 µL of sodium carbonate aqueous solution (2% w/v) was added. The mixture was

143

incubated at room temperature, in the dark for 3h before to read the absorbance at 765 nm using an

144

ultraviolet/visible (UV/VIS) Agilent 8453 spectrophotometer (Agilent, Waldbronn, Germany).

145

Different times of sample incubation have been reported in literature before spectrophotometric

146

analysis32. Gallic acid was used as a standard. Calibration curve was prepared in concentration

147

range of 2.382-19.062 µg/mL and the results obtained were expressed as mg of gallic acid

148

equivalents/g of defatted cocoa (mgGAE/gDC).

149

150

Ferric reducing antioxidant power test

151

This test was performed to determine the TAC and it is based on the reducing capacity of

152

antioxidant compounds to reduce Fe3+ to Fe2+ forming a complex [TPTZ-Fe(II)] that absorbs at a

153

wavelength of 593 nm. Ferric reducing antioxidant power (FRAP) reagent was prepared by mixing

154

2.5 mL of a HCl (0.04 M) solution of TPTZ (0.3 % w/v) with 2.5 mL of a ferric chloride aqueous

155

solution (0.3 % w/v) and 25 mL of acetate buffer (0.3 M, pH= 3.6). 100 µL of ultrapure water and

156

100 µL of cocoa extract solution were added to 1.5 mL of the FRAP reagent. This mixture was

157

incubated for 4 minutes at room temperature before reading the absorbance at 593 nm. Trolox was

158

used as a standard. Calibration curve was elaborated in a concentration range of 0.794-6.353 µg/mL

159

and the results obtained were expressed as mg of Trolox equivalents/g of defatted cocoa

160

(mgTE/gDC)32.

8 ACS Paragon Plus Environment

Journal of Agricultural and Food Chemistry

Page 10 of 28

161

Catechins and epicatechins quantification

162

HPLC separation was performed as previously reported33 using an amide C18 column, 5 µm, 250 x

163

4.6 mm i.d. (MetaChemTechnologics Inc., CA, USA). For LC/ESI-MS experiments an Agilent

164

1100 SeriesLC/MSD system (Agilent Technologies, Waldbronn, Germany), equipped with a

165

quaternary pump, diode-array detector, column compartment temperature control, degasser, MSD

166

ion trap with an electrospray ionization source.

167

168

ABTS assay

169

This analytical methodology, based on the capacity of the antioxidant compounds to inhibit the

170

oxidation of ABTS to radical cation ABTS+•, allows determining the TAC. An aqueous solution of

171

ABTS (20 mL, 3.6 % w/v) was added to 10 mL of an aqueous solution of potassium persulfate

172

(0.2% w/v) to obtain the ABTS+•. The solution was incubated in the dark at room temperature

173

overnight and then diluted with methanol to an absorbance of 0.7±0.05 at 734 nm. 10 µL of cocoa

174

extract solution were added to 1 mL of diluted ABTS+• solution and incubated for 2 minutes before

175

reading the absorbance at 734 nm. Trolox was used as a standard in a concentration range from 0 to

176

3.6 µg/mL. In this case increasing the amount of Trolox (antioxidant compound) decreases the

177

absorbance. Results obtained with this assay were expressed as inhibition percentage of ABTS

178

oxidation due to antioxidant compounds34.

179

9 ACS Paragon Plus Environment

Page 11 of 28

Journal of Agricultural and Food Chemistry

180

Results

181

Cocoa harvesting, fermentation and drying

182

The genetic origins of the different T. cocoa L. varieties domesticated and nowadays cultivated is

183

not completely elucidated and is still under discussion1,3-6,35. Criollo seems the first to be cultivated

184

but, due to its extreme sensitivity, hybrids with foreign genotypes (i.e., Forastero) have been created

185

and named Trinitario35. Criollo and Forastero groups correspond to the 2 subspecies T. cacao ssp.

186

cacao and T. cacao ssp. spharocarpum, respectively. The Forastero group is composed of

187

extremely different populations from different origins and trees are generally discriminated by pod

188

morphology. The pods collected for the field experiment were from trees of Arriba Nacional, a

189

hybrid between Criollo and Forastero belonging to the Trinitario group4,5.

190

Pods were delivered to the collection centre for 2 consecutive days and the following day the fruits

191

were opened and the seeds collected to perform the fermentation.

192

The first day of fermentation the pulp covering the seeds became liquid and draws off from holes

193

drilled at the bottom of the box. The temperature of the mass did not increase in the first 24 hours.

194

Between 24 and 48 hours, the temperature of the mass raised up to about 43°C, remaining between

195

43 and 45°C for the following 3 days and then starting to decrease after day 5, indicating the end of

196

the fermentation (Figure 2).

197

Five days of natural drying allowed to obtain a residual humidity below 7 % (w/w) necessary for a

198

good conservation and to avoid mould development. Only the unfermented sample (day 0) seemed

199

susceptible to mildew. Natural drying has been seen to be adequate to achieve the desired cocoa

200

seed residual humidity if performed during the dry season.

201

202 10 ACS Paragon Plus Environment

Journal of Agricultural and Food Chemistry

Page 12 of 28

203

Total Polyphenol content

204

Folin-Ciocalteau analytical protocol has been modified with respect to data reported in the scientific

205

literature. In the reports describing this methodology there is no consensus on different variables,

206

such as: reaction time, incubation temperature and wavelength of analysis. Different Authors

207

conditioned the sample at room temperature for 4532, 6036 or 12037 minutes before reading the

208

absorbance at 765 nm, while others incubated the mixture for 15 min at 50°C before analysis38.

209

Preliminary kinetics experiments allowed setting the preconditioning to 3 hours at room

210

temperature in the dark as the optimal incubation time length. The reaction was monitored by

211

analysing the absorption spectra in the range 300-800 nm every 60 seconds for 3 hours. The

212

reaction was faster during the first hour; it began to decrease, slowing down without stopping or

213

reaching a plateau, after two hours. The absorption peak during the first hour was not symmetrical,

214

maximum of absorption slightly deviated from 765 nm and lower standard concentrations absorbed

215

below 0.1 (A.U.). Calibration curves were built by plotting the absorbance at 765 nm of different

216

standards after 40, 60, 120, and 180 minutes. An incubation of 3 hours permitted to have higher

217

sensitivity, lower standard errors and higher r2 (0.99833)of the extrapolated curves.

218

Folin-Ciocalteau and FRAP test methods gave the same trend but different results in terms of the

219

relative amount of total polyphenols (Figure 3). Even though it is not easy (and maybe not possible)

220

to compare the two methods and the results obtained (Folin-Ciocalteau uses gallic acid equivalents

221

while FRAP test trolox equivalents) unfermented seeds showed similar amount of total polyphenol

222

with a value around 60 g/Kg. The results of both methods indicate that the first 2 days are the most

223

critical for the loss of polyphenols. Folin-Ciocalteau recorded about 20 gGAE/gDC after 6 days of

224

fermentation and 5 of drying while, according to the results of FRAP test, less than 10 gTE/gDC

225

were detected at the end of the fermentation/drying process (Figure 3).

226 11 ACS Paragon Plus Environment

Page 13 of 28

Journal of Agricultural and Food Chemistry

227

Catechins quantification

228

Eight different antioxidant compounds of the catechins family, namely catechin, epicatechin,

229

catechin gallate, epicatechin gallate, epigallocatechin, epigallocatechin gallate, gallocatechin,

230

gallocatechin gallate39, as well as gallic acid, were quantified by HPLC. Catechins and epicatechins

231

were present in large amount in the cocoa samples (Figure 4) while the other compounds above

232

mentioned were present in concentrations below 5 mg/Kg and were not of interest in our study.

233

Epicatechins have been found in the range of g/KgDC while catechins were present in the range

234

between 100 and 20 mg/KgDC (Figure 4). The concentration trend during fermentation is

235

superimposable to that of the TPC analysed using Folin-Ciocalteau methodology with a surprising

236

high concentration recorded the fourth day of fermentation (Figure 3). The experimental setup used

237

in this work does not allow any further speculation on the origin of this data. At the moment, even

238

though unlikely, it can be explained just accounting for non-uniformity in the fermentation mass

239

and/or in the sample of day 4.

240

12 ACS Paragon Plus Environment

Journal of Agricultural and Food Chemistry

Page 14 of 28

241

Discussion

242

Fermentation is a crucial process in the production of cocoa and chocolate because it is responsible

243

for the development of flavors and flavor precursors that confer to cocoa its characteristic

244

bouquet40. At the same time, fermentation contributes to the elimination of the astringency and the

245

bitter taste characteristics of fresh unfermented cocoa seeds. Fermentation inhibits germination and

246

contributes to the mixing of enzymes with substrates by eliminating the compartmentalization of the

247

seeds, a step necessary to allow enzymatic reactions.

248

It has been reported that the optimal fermentation length is generally 5 or 6 days for Forastero14.

249

The first day, the sweet mucilaginous pulp adhering the seed surface liquefies and drains out while

250

the temperature of the fermenting mass remains low. Temperature rises 24-48 hours after the

251

beginning of the fermentation process. The sugar of the seed pulp contributes to initiate what is

252

known as “external fermentation” that, under anaerobic conditions, produces ethyl alcohol and

253

acetic acid. “Internal fermentation” comprises all the biochemical changes that happen in the

254

cotyledons. Polyphenols undergo enzymatic oxidation by polyphenol oxidase and condensate in

255

high molecular weight tannins.

256

Independently of the employed analytical method (Folin-Ciocalteau or FRAP test), data showed an

257

initial content of total polyphenols of ~ 60 mg/gDC. Previous studies have reported a high variation

258

in polyphenol content in seeds from different T. cocoa L. varieties and/or cultured in different

259

regions12,41. Contents as high as ~80 mgGAE/gDC have been recorded for the variety Forastero

260

(Ivory Coast), Amazon (Columbia), and Amazon hybrid (Ecuador)42 while other Authors have

261

found amounts of polyphenols in the range 34-60 and 45-60 mg/gDC15,43.

262

Most of polyphenols (80-90%) were lost during the first 48 hours but the remaining amount can be

263

considered high12,44. Polyphenol loss is generally ascribed to multiple factors: diffusion of soluble

264

polyphenols into fermentation sweating, enzymatic oxidation, and non-enzymatic oxidation, the 13 ACS Paragon Plus Environment

Page 15 of 28

Journal of Agricultural and Food Chemistry

265

latter happening especially during sun drying. The additional fermentation days do not seem to

266

affect in a significant way the content of polyphenols.

267

The present experimental setup contemplated 5 days of natural drying (sun drying) for each sample.

268

The loss of polyphenols in the samples 1-6 is due to the combined negative effects of fermentation

269

and drying while the polyphenols in unfermented sample (sample 0) have been affected by the sole

270

drying. However, it cannot be neglected that polyphenol loss could be due to a certain degree of

271

fermentation occurring during drying . The process of sun drying might reduce the content of

272

polyphenols because of non-enzymatic oxidation45. Polyphenols and especially epicatechin, the

273

most abundant compound of the catechin family, was surely present in larger amount in fresh

274

seeds41,46.

275

The loss of epicatechins followed the trend of total polyphenols with the maximum lost during the

276

first 2 days. At the end of fermentation and drying, epicatechin concentration was reduced by

277

approximately 75%.

278

The concentration of epicatechin in fermented cocoa beans seems to be more variable than the

279

concentration of total polyphenols41,43,47. Kim and Keeney41 reported values ranging from about 2.5

280

to 16.5 mg/gDC while Wilson et al. have found concentrations of 3.0-3.3 mg/gDC43.

281

Considering the lack of knowledge on eventual pod storage and the data available in literature, it

282

seems that the pods were not freshly harvested even though a strong reduction in pulp volume was

283

not evidenced during fruit opening. The low content of epicatechins could be due to the time lag

284

between pod collection and the beginning of the fermentation process48,49.

285

Preliminary results confirmed the high impact of fermentation and drying on the content of

286

polyphenols in cocoa seeds. Being the first and mandatory step necessary to obtain cocoa and

287

chocolate bouquet and palatability, attention should be paid to these 2 steps to obtain high-

288

polyphenol-content cocoa. 14 ACS Paragon Plus Environment

Journal of Agricultural and Food Chemistry

Page 16 of 28

289

Due to the discordance of the data reported in literature, systemic investigation aimed at a full

290

characterization of the whole cocoa transformation process is mandatory. To have high significance,

291

investigations should consider and analyse all the possible variables influencing the initial

292

polyphenol content and should avoid artefacts generated from unreal working conditions, such as

293

microfermentation. Knowledge of agronomic techniques, plants location, soil and climate

294

conditions, T. cocoa L. variety, maturation stage and pod conditioning are of fundamental

295

importance to know polyphenol variability in the starting material.

296

To produce high-polyphenol-content cocoa and to build a successful certification protocol, all the

297

factors mentioned have to be carefully controlled and standardized.

298

299

300

301

302

303

304

305

306

307

308

15 ACS Paragon Plus Environment

Page 17 of 28

Journal of Agricultural and Food Chemistry

309

Acknowledgment

310

The Authors are indebted to the Istituto Italo-Latino Americano for financial and logistic support

311

during the experimental part performed in the municipality of Babahoyo (Ecuador). The authors

312

would like to acknowledge the Mayer of Babahoyo, Mr. Johnny Terán Salcedo and the Ing.

313

Jonathan Romero Jacome for the support during the scientific activities.

314

16 ACS Paragon Plus Environment

Journal of Agricultural and Food Chemistry

315

316 317

Page 18 of 28

REFERENCES 1. Coe, S.D.; Coe, M.D. The True History of Chocolate, Thames and Hudson Ltd.: London, England, 1996.

318

2. Henderson, J.S.; Joyce, R.A.; Hall, G.R.; Hurst, W.J.; McGovern, P.E. Chemical and

319

archaeological evidence for the earliest cacao beverages. Proc. Natl. Acad. Sci. USA 2007,

320

104, 18937-18940.

321 322 323 324 325 326

3. Powis, T.G.; Cyphers, A.; Gaikwad, N.W.; Grivetti, L.; Cheong, K. Cacao use and the San Lorenzo Olmec. Proc. Natl. Acad. USA 2011, 108, 8595-8600. 4. Motamayor, J.C.; Risterucci, A.M.; Lopez, P.A.; Ortiz, C.F.; Moreno, A.; Lanaud, C. Cacao domestication I: the origin of the cacao cultivated by the Mayas. Heredity 2002, 89, 380-386. 5. Motamayor, J.C.; Risterucci, A.M.; Heath, M.; Lanaud, C. Cacao domestication II: progenitor germplasm of the Trinitario cacao cultivar. Heredity 2003, 91, 322-330.

327

6. Motamayor, J.C.; Lachenaud, P.; da Silva e Mota, J.W.; Loor, R.; Kuhn, D.N.; Brown, J.S.;

328

Schnell, R.J. Geographic and genetic population differentiation of the Amazonian chocolate

329

tree (Theobroma cacao L). Plos one 2008, 3, e3311-e3319.

330

7. Loor Solorazano, R.G.; Fouet, O.; Lemainque, A.; Pavek, S.; Boccara, M.; Argout, X.;

331

Amores, F.; Courtois, B.; Risterucci, A.M.; Lenaud, C. Insight into the wild origin, migration

332

and domestication history of the fine flavor Nacional Theobroma cacao L. variety from

333

Ecuador. Plos one 2012, 7, e48438-e48449.

334

8. Dillinger, T.L.; Barriga, P.; Escárcega, S.; Jimenez, M.; Salazar Lowe, D.; Grivetti, L.E. Food

335

of the Gods: Cure for humanity? A cultural history of the medicinal and ritual use of

336

chocolate. J. Nutr. 2000, 130, 2057S-2072S.

337

9. Ackar, D.; Valek Lendić, K.; Valek, M.; Šubarić, D.; Miličević, B.; Babić, J.; Nedić, I. Cocoa

338

polyphenols: can we consider cocoa and chocolate as potential functional food? J. Chem.

339

2013, 2013, Article ID 289392, 7 pages.

340 341

10. Arts, I.C.W.; Hollman, P.C.H.; Kromhout, D. Chocolate as a source of tea flavonoids. The Lancet 1999, 354, 488.

342

11. Arts, I.C.W.; van de Putte, B.; Hollman, P.C.H. Catechin contents of foods commonly

343

consumed in the Netherlands. 1. Fruits, vegetables, staple foods, and processed foods. J.

344

Agric. Food Chem. 2000, 48, 1746-1751. 17 ACS Paragon Plus Environment

Page 19 of 28

Journal of Agricultural and Food Chemistry

345

12. Bruna, C.; Eichholz, I.; Rohn, S.; Kroh, L.W.; Huyskens-Keil, S. Bioactive compounds and

346

antioxidant activity of cocoa hulls (Theobroma cacao L.) from different origins. J. Appl. Bot.

347

Food Qual. 2009, 83, 9-13.

348

13. Yapo, K.D.; Ouffoue, S.K.; Okpekon, T.A.; Kouakou, T.H. Soil effect on polyphenols content

349

and antioxidant capacity of new hybrid variety of cocoa from Côte d’Ivoire. Int. J. Biol.

350

Chem. Sci. 2013, 7, 1794-1803.

351

14. Wollgast, J.; Anklam, E. Review on polyphenols in Theobroma cacao: changes in

352

composition during the manufacture of chocolate and methodology for identification and

353

quantification. Food Res. Int. 2000, 33, 423-447.

354

15. Nazaruddin, R.; Seng, L.K.; Hassan, O.; Said, M. Effect of pulp preconditioning on the

355

content of polyphenols in cocoa beans (Theobroma Cacao) during fermentation. Ind. Crop.

356

Prod. 2006, 24, 87-94.

357

16. Efraim, P.; Pezoa-García, N.H.; Jardim, D.C.P.; Nishikawa, A.; Haddad, R.; Eberlin, M.N.

358

Influência da fermentação e secagem de amêndoas de cacau no teor de compostos fenólicos e

359

na aceitação sensorial. Ciênc. Tecnol. Aliment. 2010, 30, 142-150.

360

17. Guehi, T.S.; Zahouli, I.B.; Ban-Koffi, L.; Fae, M.A.; Nemlin, J.G. Performance of different

361

drying methods and their effects on the chemical quality attributes of raw cocoa material. Int.

362

J. Food Sci. Tech. 2010, 45, 1564-1571.

363 364 365 366

18. Jalil, A.M.; Ismail, A. Polyphenols in cocoa and cocoa products: is there a link between antioxidant properties and health? Molecules 2008, 13, 2190-219. 19. Hii, C.L.; Law, C.L.; Suzannah, S.; Misnawi; Cloke M. Polyphenols in cocoa (Theobroma cacao L.). As. J. Food Ag-Ind. 2009, 2, 702-722.

367

20. Radojčić Redovniković, I.; Delonga, K.; Mazor, S. ; Dragović-Uzelac , V.; Carić, M.;

368

Vorkapić-Furač, J. Polyphenolic content and composition and antioxidative activity of

369

different cocoa liquors. Czech J. Food Sci. 2009, 27, 330-337.

370

21. Di Renzo, G.C.; Brillo, E.; Romanelli, M.; Porcaro, G.; Capanna, F.; Kanninen, T.T.; Gerli,

371

S.; Clerici, G. Potential effects of chocolate on human pregnancy: a randomized controlled

372

trial. J. Matern. Fetal Neonatal Med. 2012, 25, 1860-1867.

373

22. Desideri, G.; Kwik-Uribe, C.; Grassi, D.; Necozione, S.; Ghiadoni, L.; Mastroiacovo, D.;

374

Raffaele, A.; Ferri, L.; Bocale, R.; Lechiara, M.C.; Marini, C.; Ferri, C. Benefits in cognitive

375

function, blood pressure, and insulin resistance through cocoa flavanol consumption in elderly 18 ACS Paragon Plus Environment

Journal of Agricultural and Food Chemistry

Page 20 of 28

376

subjects with mild cognitive impairment: the Cocoa, Cognition, and Aging (CoCoA) study.

377

Hypertension 2012, 60, 794-801.

378

23. Wang, J.; Varghese, M.; Ono, K.; Yamada, M.; Levine, S.; Tzavaras, N.; Gong, B.; Hurst,

379

W.J.; Blitzer, R.D.; Pasinetti, G.M. Cocoa extracts reduce oligomerization of amyloid-β:

380

implications for cognitive improvement in Alzheimer's disease. J. Alzheimers Dis. 2014, 41,

381

643-650.

382 383 384 385 386 387

24. Corti, R.; Flammer, A.J.; Hollenberg, N.K.; Lüscher, T.F. Cocoa and cardiovascular health. Circulation 2009, 119, 1433-1441. 25. Maskarinec, G. Cancer protective properties of cocoa: a review of the epidemiologic evidence. Nutr. Cancer. 2009, 61, 573-579. 26. van het Hof, K.H.; Kivits, G.A.; Westrate, J.A.; Tijburg, L.B. Bioavailability of catechins from tea: the effect of milk. Eur. J. Clin. Nutr. 1998, 52, 356-539.

388

27. Dreosti, I.E. Antioxidant polyphenols in tea, cocoa, and wine. Nutrition 2000, 16, 692-694.

389

28. Boshier, D.H. Cordia alliodora (Ruiz & Pav.) Oken. Part II-Species Description • Cordia

390

alliodora (Ruiz & Pav.) Oken. 411-414. http://www.rngr.net/publications/ttsm/species (accessed

391

May 23, 2015).

392

29. Aguirre, Z. 2012. Especies forestales de los bosques secos del Ecuador. Guia dendrológica

393

para su identificación y caracterización. Proyecto Manejo Forestal Sostenible ante el Cambio

394

Climático. MAE/FAO – Finlandia, Quito, Ecuador. 140p.

395

30. Natsume, M.; Osakabe, N.; Yamagishi, M.; Takizawa, T.; Nakamura, T.; Miyatake, H.;

396

Hatano, T.; Yoshida, T. Analysis of polyhenols in cacao liquor, cocoa, and chocolate by

397

normal-phase and reversed-phase HPLC. Biosci. Biotechnol. Biochem. 2000, 64, 2581-2587.

398

31. Risner, H.C. Simultaneous determination of theobromine, (+)-catechin, caffeine and (-)-

399

epicatechin in standard reference material baking chocolate 2384, cocoa, cocoa beans, and

400

cocoa butter. J. Chromatogr. Sci. 2008, 46, 892-899.

401

32. Lu, X.; Al-Qadiri, H.M.; Ross, C.F.; Powers, J.R.; Tang, J.; Rasco, B.A. Determination of

402

total phenolic content and antioxidant capacity of onion (Allium cepa) and shallot (Allium

403

oschaninii) using infrared spectroscopy. Food Chem. 2011, 129, 637-644.

404

33. Wu, Q.; Wang, M.; Simon, J.E. Determination of pronthocyanidins in fresh grapes and grapes

405

products using liquid chromatography with mass spectometric detection. Rapid Commun.

406

Mass Sp. 2005, 19, 2062-2068. 19 ACS Paragon Plus Environment

Page 21 of 28

Journal of Agricultural and Food Chemistry

407

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

408

activity applying and improve ABTS radical cation decolorization assay. Free Radic. Biol.

409

Med. 1999, 26, 1231-1237.

410 411

35. Argout, X.; Salse, J.; Aury, J.M. et al. The genome of Theobroma cacao. Nat. Genetics 2011, 43, 101-109.

412

36. Anesini, C.; Ferraro, G.E.; Filip, R. Total polyphenol content and antioxidant capacity of

413

commercially available tea (Camellia sinensis) in Argentina. J. Agric. Food Chem. 2008, 56,

414

9225-9229.

415

37. Lee, E.J.; Nomura, N.; Patil, B.S., Yoo K.S. Measurement of total phenolic content in wine

416

using an automatic Folin-Ciocalteu assay method. Int. J. Food Sci. Technol. 2014, 49, 2364-

417

2372.

418 419

38. Brat, S.G.P.; Alter, P.; Amiot, M.J. Rapid determination of polyphenols and vitamin c in plant-derived products. J. Agric. Food Chem. 2005, 53, 1370-1373.

420

39. Medina, I.; Gallardo, J.M.; Gonzalez, M.J.; Lois, S.; Hedges, N. Effect of molecular structure

421

of phenolic families as hydroxycinnamic acids and catechins on their antioxidant

422

effectiveness in minced fish muscle. J. Agric. Food Chem. 2007, 55, 3889-3895.

423

40. Jiménez, J.; Amores, F.; Nicklin, C.; Rodríguez, D.; Zambrano, F.; Bolaños, M.; Reynel, V.;

424

Dueñas, A.; Cedeño, P. Micro fermentación y análisis sensorial para la selección de árboles

425

superiors de cacao. Estacion Experimental Tropical Pichilingue, 2011, Boletín Técnico 140.

426

41. Kim, H.; Keeney, P.G. (‐)‐epicatechin content in fermented and unfermented cocoa beans. J.

427

Food Sci. 1984, 49, 1090-1092.

428

42. Tomas-Barberan, F.A.; Cienfuegos-Jovellanos, E.; Marín, A.; Muguerza, B.; Gil-Izquierdo,

429

A.; Cerda, B.; Zafrilla, P.; Morillas, J.; Mulero, J.; Ibarra, A.; Pasamar, M.A.; Ramón, D.;

430

Espín, J.C. A new process to develop a cocoa powder with higher flavonoid monomer content

431

and enhanced bioavailability in healthy humans. J. Agric. Food Chem. 2007, 55, 3926-3935.

432 433 434 435 436 437

43. Vinson, J.A.; Proch, J.; Zubik, L. Phenol antioxidant quantity and quality in foods: Cocoa, dark chocolate and milk chocolate. J. Agric. Food Chem. 1999, 47, 4821-4824. 44. Aikpokpodion, P.E.; Dongo, L.N. Effects of fermentation intensity on polyphenols and antioxidant capacity of cocoa beans. Int. J. Sustain. Crop Prod. 2010, 5, 66-70. 45. Hansen, C.E.; del Olmo, M.; Burri, C. Enzyme activities in cocoa beans during fermentation. J. Sci. Food Agric. 1998, 77, 273-281. 20 ACS Paragon Plus Environment

Journal of Agricultural and Food Chemistry

Page 22 of 28

438

46. Payne, M.J.; Hurst W.J.; Miller, K.B.; Rank, C.; Stuart, D.A.. Impact of fermentation, drying,

439

roasting, and dutch processing on epicatechin and catechin content of cacao beans and cocoa

440

ingredients. J. Agric. Food Chem. 2010, 19, 10518-10527.

441

47. Hurst, W.J.; Krake, S.H.; Bergmeier, S.C.; Payne, M.J.; Miller, K.B; Stuart, D.A. Impact of

442

fermentation, drying, roasting and Dutch processing on flavan-3-ol stereochemistry in cacao

443

beans and cocoa ingredients. Chem. Cent. J. 2011, 5, 53.

444

48. Afoakwa, E. O.; Quao, J.; Takrama, F. S.; Budu, A. S.; Saalia, F. K. Changes in total

445

polyphenols, o-diphenols and anthocyanin concentrations during fermentation of pulp pre-

446

conditioned cocoa (Theobroma cacao) beans. Int. Food Res. J. 2012, 19, 1071-1077.

447

49. Afoakwa, E.O.; Budu, A.S.; Mensah-Brown, H.; Takrama, J.F.; Akomanyi, E. Changes in

448

biochemical and physico-chemical qualities during drying of pulp preconditioned and

449

fermented cocoa (Theobroma cacao) beans. J. Nutrition Health Food Sci. 2014, 2, 1-8.

450

21 ACS Paragon Plus Environment

Page 23 of 28

Journal of Agricultural and Food Chemistry

451 452

FIGURE CAPTIONS

453 454

Figure 1. Map of Ecuador. The municipality of Babahoyo, in the Province of los Ríos, is

455

indicated by the red spot. Galapagos Islands are not reported in the map.

456 457

Figure 2. Mean temperatures recoded in the fermentation mass (grey columns) and outside the

458

fermentation box (white columns). Bars indicate the standard deviations.

459 460

Figure 3. Results of Folin-Ciocalteau and FRAP tests. Results are expressed in mg of gallic

461

acid equivalents per g of defatted cocoa (mg GAE/g DC) in Folin-Ciocalteau assay and in mg

462

of trolox equivalents per g of defatted cocoa (mg TE/g DC) in FRAP test. Bars indicate the

463

standard deviations.

464 465

Figure 4. Plots showing the amount of catechins and epicatechins during fermentation. Bars

466

indicate the standard deviations.

467 468

Figure 5. Results of the ABTS assy. Data are reported as percentage of inhibition of the

469

oxidation reaction. Bars indicate the standard deviations.

470

22 ACS Paragon Plus Environment

Journal of Agricultural and Food Chemistry

Page 24 of 28

471 472

Figure 1.

473

474 475 476

23 ACS Paragon Plus Environment

Page 25 of 28

Journal of Agricultural and Food Chemistry

477 478

Figure 2.

479

480 481 482

24 ACS Paragon Plus Environment

Journal of Agricultural and Food Chemistry

Page 26 of 28

483 484

Figure 3.

485

486 487 488

25 ACS Paragon Plus Environment

Page 27 of 28

Journal of Agricultural and Food Chemistry

489 490

Figure 4.

491

492 493 494

26 ACS Paragon Plus Environment

Journal of Agricultural and Food Chemistry

Page 28 of 28

495 496

Figure 5.

497

498 499 500

27 ACS Paragon Plus Environment