Influence of Olive Leaf Processing on the ... - ACS Publications

Jun 13, 2014 - Copyright © 2014 American Chemical Society. *(J.V.G.-P.) ... Green extraction approach for the recovery of polyphenols from Croatian o...
2 downloads 0 Views 773KB Size
Subscriber access provided by University at Buffalo Libraries

Article

Influence of olive leaf processing on the bioaccessibility of bioactive polyphenols Margarita H. Ahmad-Qasem, Jaime Canovas, Enrique BarrajonCatalan, Jose E. Carreres, Vicente Micol, and Jose V. Garcia Perez J. Agric. Food Chem., Just Accepted Manuscript • Publication Date (Web): 13 Jun 2014 Downloaded from http://pubs.acs.org on June 15, 2014

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 39

Journal of Agricultural and Food Chemistry

85x47mm (300 x 300 DPI)

ACS Paragon Plus Environment

Journal of Agricultural and Food Chemistry

1

Influence of olive leaf processing on the bioaccessibility of bioactive

2

polyphenols

3

Margarita H. Ahmad-Qasem a, Jaime Cánovas, Enrique Barrajón-Catalán b,

4

José E. Carreres c, Vicente Micol b and José V. García-Pérez a,*

5 6

a

7

Departamento de Tecnología de Alimentos. Universitat Politècnica de València.

8

Valencia 46022, Spain.

9

b

Grupo de Análisis y Simulación de Procesos Agroalimentarios (ASPA).

Instituto de Biología Molecular y Celular. Universidad Miguel Hernández.

10

Elche 03202, Spain.

11

c

12

Paterna 46980, Spain.

AINIA Centro tecnológico. Parque tecnológico de Valencia. Benjamin Franklin.

13 14 15 16 17 18 19 20 21 22 23 24 25

* Corresponding author. Tel.: +34 96 3879376; Fax: +34 96 3879839 E-mail address: [email protected] (José V. García-Pérez) 1

ACS Paragon Plus Environment

Page 2 of 39

Page 3 of 39

Journal of Agricultural and Food Chemistry

26

ABSTRACT

27

Olive leaves are rich in bioactive compounds which are beneficial for

28

humans. The objective of this work was to assess the influence of the

29

processing conditions (drying and extraction) of olive leaves on the extract’s

30

bioaccessibility. Thus, extracts obtained from dried olive leaves (hot air drying at

31

70 and 120 °C or freeze drying) by means of conventional or ultrasound

32

assisted extraction were subjected to in vitro digestion. Antioxidant capacity,

33

total phenolic content and HPLC-DAD/MS-MS analysis were carried out during

34

digestion.

35

The dehydration treatment used for the olive leaves did not have a

36

meaningful influence on bioaccessibility. The digestion process significantly

37

(p0.9999).

263

Quantitative evaluation of oleuropein, verbascoside luteolin glucoside was

264

performed by means of a six-point regression curve (r2>0.996, 0.997 and 0.986, 11

ACS Paragon Plus Environment

Page 13 of 39

Journal of Agricultural and Food Chemistry

265

respectively) in a concentration range between 0.25 µg/mL and 10 mg/mL,

266

using oleuropein, verbascoside and luteolin glucoside as reference external

267

standard and evaluated by DAD signal. LOD (Limit of Detection) was 0.10

268

µg/mL and Limit of Quantification (LOQ) was 0.25 µg/mL.

269 270

Statistical analysis

271

Analysis of variance (ANOVA) was applied in order to determine the

272

significant effects of in vitro digestion on extract composition taking a

273

significance level of 95 %. The statistical analysis was performed using

274

Statgraphics-Plus software 5.1 (Statistical Graphics, Rockville, MD, USA).

275 276 277

RESULTS AND DISCUSSION

278

Initial characterization of olive leaf extracts

279

Previous studies have reported that the composition of olive leaf extracts

280

is greatly influenced by processing conditions, namely the drying and extraction.

281

In such a way, a conventional extraction method 10 was used with leaves hot air

282

dried at 70 (HAD-70) and 120 °C (HAD-120) and freeze dried (FD). Moreover,

283

HAD-120 leaves were subjected to ultrasound assisted extraction (HAD-

284

120+US) 20.

285

As can be observed in Table 1, the TPC and AC of the extracts used

286

were significantly (p