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Bioaccessibility of glucoraphanin from broccoli using an in vitro gastrointestinal digestion model a
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Valentina Cuomo , Fernando B. Luciano , Giuseppe Meca , Alberto Ritieni & Jordi c
Mañes a
Department of Food Science, University of Naples “Federico II”, Via Universitá 100, 80055, Portici, Napoli, Italy b
School of Agricultural Sciences and Veterinary Medicine, Pontifícia Universidade Católica, BR 376 Km 14, 83010-500 São José dos Pinhais, PR, Brazil c
Laboratory of Food Chemistry and Toxicology, Faculty of Pharmacy, University of Valencia, Avenue Vicent Andres Estelles s/n, 46100 Burjassot, Valencia, Spain Published online: 26 Nov 2014.
Click for updates To cite this article: Valentina Cuomo, Fernando B. Luciano, Giuseppe Meca, Alberto Ritieni & Jordi Mañes (2015) Bioaccessibility of glucoraphanin from broccoli using an in vitro gastrointestinal digestion model, CyTA - Journal of Food, 13:3, 361-365, DOI: 10.1080/19476337.2014.984337 To link to this article: http://dx.doi.org/10.1080/19476337.2014.984337
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CyTA – Journal of Food, 2015 Vol. 13, No. 3, 361–365, http://dx.doi.org/10.1080/19476337.2014.984337
Bioaccessibility of glucoraphanin from broccoli using an in vitro gastrointestinal digestion model Bioaccesibilidad de la glucorafanina de brócoli utilizando un sistema de digestión gastrointestinal in vitro Valentina Cuomoa, Fernando B. Lucianob*, Giuseppe Mecac, Alberto Ritienia and Jordi Mañesc a
Department of Food Science, University of Naples “Federico II”, Via Universitá 100, 80055, Portici, Napoli, Italy; bSchool of Agricultural Sciences and Veterinary Medicine, Pontifícia Universidade Católica, BR 376 Km 14, 83010-500 São José dos Pinhais, PR, Brazil; cLaboratory of Food Chemistry and Toxicology, Faculty of Pharmacy, University of Valencia, Avenue Vicent Andres Estelles s/n, 46100 Burjassot, Valencia, Spain
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(Received 14 July 2014; final version received 2 November 2014) This study investigated the effect of cooking methods on the degradation of glucoraphanin (GR) in broccoli and the bioaccessibility of this compound through simulated gastrointestinal digestion. Broccoli was cooked using three different techniques: boiling, steaming and microwave cooking. Then, GR was extracted and quantified by liquid chromatography coupled with tandem mass spectrometry (LC-MS/ MS). In addition, the cooked samples were added to a system that simulates the digestion characteristics of the mouth, stomach and duodenum. Samples were drawn before and after the digestion, and GR bioaccessibility was calculated. GR losses were higher when broccoli was boiled (47.03%), followed by steaming (31.96%) and microwaving (11.87%). However, steamed broccoli presented the highest bioaccessibility (94.59%), followed by boiled (89.69%) and microwaved (60.88%). Taking into consideration the levels of remaining GR after cooking and its bioaccessibility after simulated digestion, steaming can be considered the best method and may result in the highest levels of this bioactive glucosinolate after broccoli intake. Keywords: glucosinolates; glucoraphanin; cooking methods; bioaccessibility; gastrointestinal digestion
El estudio investiga el efecto de diferentes métodos de cocción sobre la degradación de la Glucorafanina (GR) en brócoli y la bioaccesibilidad de este compuesto mediante un modelo de digestión gastrointestinal simulada. Los brócoli fueron cocidos usando tres diferentes técnicas: ebullición, cocción al vapor y mediante microondas. La GR se extrajo y se cuantificó mediante cromatografía líquida acoplada a espectrometría de masas en tándem (CL-EM/EM). Además las muestras cocidas se trataron con un sistema de digestión simulada incluyendo las fases de: boca, estomago e intestino delgado. El contenido en GR se analizó antes y después de las digestiones. Las pérdidas de la GR fueron mayores en los brócoli hervidos (47,03%), seguidos por los tratados al vapor (31,96%) y con microondas (11,87%). Los brócolis tratados al vapor presentaron los valores más altos de bioaccesibilidad (94,59%), seguidos por las muestras hervidas (89,69%) y las tratadas con microondas (60,88%). Teniendo en consideración los niveles de GR después de la cocción y su valor de bioaccesibilidad tras la digestión simulada, se puede concluir que el tratamiento al vapor fue el mejor método de cocción y las muestras así tratadas fueron las que contenían los niveles más altos del compuesto bioactivo después de la ingesta de los broccoli. Palabras claves: glucosinolatos; glucorafanina; métodos de cocción; bioaccesibilidad; digestión gastrointestinal
1. Introduction In recent years, scientific research has focused on the health benefits associated with the consumption of Brassica vegetables. Many epidemiological studies have shown that the consumption of three to five servings of Brassica vegetables per week may reduce the risk of bladder, breast, colon, kidney and prostate cancers (Cohen, Kristal, & Stanfordm, 2000; Vig, Rampal, Singh Thind, & Arora, 2009). Brassica vegetables, like many other plants, contain a large number of antioxidants and vitamins, but, distinctively, they also contain high levels of glucosinolates (GLSs). This is a class of ~300 sulphurous compounds (Luciano & Holley, 2009), which have a common structure, consisting of a glucose combined with an oxime sulfonate by a β-D-thioglucosidic bound, and a variable side chain (R). Brassica vegetables also contain an enzyme known as thioglucoside glucohydrolase, EC 3.2.1.147 (myrosinase). In homeostasis, GLSs are compartmentalized in vacuoles, while myrosinase is located in the cytoplasm of the plant cell (Grob & Matile, 1979). Upon tissue damage, GLSs are released and cleaved by myrosinase in the presence of moisture. This degradation results in the *Corresponding author. Email:
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© 2014 Taylor & Francis
formation of glucose plus an intermediate thiohydroximate-O-sulfonate component, which is extremely unstable and rearranges, releasing sulphate plus one or more of the following: isothiocyanates (ITCs), thiocyanates, nitriles, epithionitriles, oxazolidinethiones and elementary sulphur (Vig et al., 2009). Intact GLS can be also hydrolysed in the colon by microbial thioglucosidase activity (Cheng, Hashimoto, & Uda, 2004). At neutral pH, the reaction proceeds spontaneously to the formation of ITCs (Tiedink et al., 1991). Although parent GLS show little bioactivity, ITCs possess the ability to inhibit cancer development, by multiple anticarcinogenic mechanisms, such as inhibition of carcinogen-activating enzymes, induction of carcinogen-detoxifying enzymes, triggering apoptosis and arrest of cell-cycle progression (Nastruzzi et al., 1996). Researchers have shown the anticarcinogenic properties of sulforaphane (SFN), which is derived from glucoraphanin (GR) (Figure 1), the main GLS found in broccoli (Fahey, Zalcmann & Talalay, 2001). Given the anticancer properties of SFN, it is of paramount importance to understand the bioavailability
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Figure 1.
Glucoraphanin conversion to sulforaphane by the enzyme myrosinase.
Figura 1. Conversión de la glucurafanina en sulforafano por la enzima mirosinasa.
characteristics of this compound after ingestion. Therefore, several factors must be considered:
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(a) GR loss during cooking; (b) bioaccessibility of glucoraphanin; (c) and denaturation of myrosinase as a result of heat treatment. The aim of this study was to examine the total loss of GR during broccoli cooking through boiling, steaming and microwaving and its bioaccessibility employing an in vitro gastrointestinal digestion model. GR bioaccessibility represents the fraction of compound that is released from the food matrix in the gastrointestinal tract without any structural modification and that becomes available for intestinal absorption. This is an important feature since it quantifies the fraction of a bioactive compound that can be converted in SFN by colonic bacteria, absorbed by the intestinal epithelium, and act on different organs of the human body (Gil-Izquierdo, Zafrilla, & Tomás-Barberá, 2002).
2. Material and methods 2.1. Chemicals Sinigrin, potassium chloride (KCl), potassium thiocyanate (KSCN), monosodium phosphate (NaH2PO4), sodium sulphate (NaSO4), sodium chloride (NaCl), sodium bicarbonate (NaHCO3), urea, α-amilase, hydrochloric acid (HCl), pepsin, pancreatin, bile salts and sinigrin were obtained from SigmaAldrich (St. Louis, MO, USA). Acetonitrile, methanol and formic acid were purchased from Carlo Erba (Milano, Italy). Deionized water (
