analytical strategies to evaluate antioxidants in food: a...
TRANSCRIPT
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Trends in Food Science & Technology 21 (2010) 229e246
Review
* Corresponding author.
0924-2244/$ - see front matter � 2010 Elsevier Ltd. All rights reserved.doi:10.1016/j.tifs.2009.12.003
Analytical strategies
to evaluate
antioxidants in food:
a review
C. Andréa, I. Castanheiraa,
J.M. Cruzb, P. Paseirob and
A. Sanches-Silvaa,*aNational Institute of Health Dr. Ricardo Jorge, Av.
Padre Cruz, 1600 Lisbon, Portugal (National Institute
of Health Dr. Ricardo Jorge, Food and Nutrition, Av.
Padre Cruz, 1600 Lisbon, Portugal. Tel./fax: D351
938380493; e-mail: [email protected])bDepartment of Analytical Chemistry, Nutrition and
Food Science, Pharmacy Faculty, University of
Santiago de Compostela, Campus Sur, 15782 Santiagode Compostela, Spain
Antioxidants are an important group of food additives that
have the ability to protect against detrimental change of oxi-
dizable nutrients and consequently they extend shelf-life of
foods.
The present paper is an updated review on the analysis of
ten antioxidants (both synthetic and natural). Three types of
gallates, propyl (PG), octyl (OG) and dodecyl (DG), tert-Butyl-
hydroquinone (TBHQ), Butylated Hydroxytoluene (BHT), tert-
Butylhydroxyanisole (BHA), a-tocopherol, ascorbic acid,
erythorbic acid and sodium D-isoascorbate were the antioxi-
dants selected. The physico-chemical properties, sample prep-
aration procedures and analytical methods for their
determination are compared and discussed.
IntroductionNowadays, antioxidants receive remarkable attention in
the literature, due to the ability to preserve foodstuffs byretarding deterioration, rancidity and/or discoloration
caused by oxidation. Detrimental effects include undesir-able chemical compounds formation like aldehydes, ke-tones and organic acids than yield off-flavours (Saadet al., 2007).
In biological systems, antioxidants protect against oxi-dative damage and help to prevent cardiovascular, neuro-logical and/or carcinogenic diseases (Lanina, Toledo,Sampels, Kamal-Eldin, & Jastrebova, 2007).
Following the recommendations of international organi-zations, the use of synthetic antioxidants like PG, OG,BHA, BHT and TBHQ is regulated by legal authorities ina limited number of foods, with maximum limits in eachcase or association. There are several documents legislatingfood additives such as European Union Directives and Reg-ulations (Directive 95/2/EC, 1995; EC Regulation No 1333/2008, 2008), FDA in USA (FDA, 2001a, 2001b), FoodStandards Australia New Zealand for Australia and NewZealand (The Australia New Zealand Food StandardsCode, 2009), The Joint FAO/WHO Expert Committee onFood Additives (JECFA, 2003) and Codex Alimentarius(CGSFA, 1995).
The use of antioxidants (AO) is not restricted to food-stuffs. They can also be used to prevent the degradationof food packaging during processing and storage, improv-ing the end-use application. Nevertheless, they or their deg-radation products can migrate into foodstuffs. EUlegislation imposes migration limits of substances thatcan be used in the manufacture of food packaging.
Antioxidants can be classified as primary or long-termantioxidants and as secondary or processing antioxidants.Primary antioxidants include hindered phenols and second-ary aryl amines and secondary antioxidants include orga-nophosphites and thioesters (Dopico-Garcı́a, Lopez-Vilariño, & González-Rodrı́guez, 2003). The primaryare active radical scavengers or hydrogen donors or chainreaction breakers while secondary are peroxidedecomposers.
Most of the methods described in the literature for thequantitative analysis of antioxidants or antioxidant mixturespresent interference problems, low resolution and are time-consuming. The establishment of analytical methods tomonitor the use of prohibited antioxidants and/or the exces-sive use of permitted AO and their degenerative products isa real need. In 2000, Karovi�cová & Šimko (2000) have car-ried out a review regarding the determination of syntheticphenolic antioxidants in food by high-performance liquid
mailto:[email protected]
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Table 1. Chemical and physical information of the antioxidants.
Migrants CAS No Formula/Elementalanalysis
MW/Exactmass
Mp (�C) Bp/Fp (�C) Density (g/cm3) Logkow Enthalpy of vap. Solubility
Propyl gallate, Benzoicacid, 3,4,5-trihydroxy-,propyl ester (9CI)
121-79-9 C10H12O5 212.20a 145e146�Ca
CASFp: 181.3�20.8�C,bp: 448.6�40.0�C,Press: 760Torra
1.363�0.06g/cm3,Temp: 20�C,Press: 760Torra
2.600�0.333,Temp: 25�Ca
73.43�3.0kJ/mol,Press: 760Torra
Slightly soluble inwater; freelysoluble in ethanol,ether and propane-1,2-diolc
Octyl gallate, Benzoicacid, 3,4,5-trihydroxy-,octyl ester (9CI)
1034-01-1 C15H22O5 282.33a 101e104�Ca
91e92�Cabp: 482.9�40.0�C,Press: 760Torr,Fp:177.1�20.8�Ca
1.185�0.06g/cm3,Temp: 20�C,Press: 760Torra
5.256�0.333,Temp: 25�Ca
77.63�3.0kJ/mol,Press: 760Torra
Insoluble in water,freely soluble inethanol, ether andpropane-1,2-diolc
Lauryl gallate, Benzoicacid, 3,4,5-trihydroxy-,dodecyl ester (9CI)
1166-52-5 C19H30O5 338.44 94e96�Ca bp:521.7�45.0�C,
Press: 760Torr,Fp:180.3�22.2�Ca
1.112�0.06g/cm3,Temp: 20�C,Press: 760Torra
7.382�0.333,Temp: 25�Ca
82.50�3.0kJ/mol,Press: 760Torra
Insoluble in water;freely soluble inethanol and etherc
Erythorbic acid,D-erythro-Hex-2-enonicacid, g-lactone (8CI, 9CI)
89-65-6 C6H8O6 176.12 167e174�Ca bp: 552.7�50.0�C,
Press: 760Torr, Fp:238.2�23.6�Ca
1.954�0.06g/cm3,Temp: 20�C,Press: 760Torr (calc),1.654g/cm3 (exp)a
–2.410�0.450,Temp: 25�Ca
95.78�6.0kJ/mol,Press: 760Torra
Freely soluble inwater, soluble inethanolc
Sodium, D-isoascorbatemonohydrate D-erythro-Hex-2-enonic acid,g-lactone, monosodiumsalt, monohydrate (9CI)
63524-04-9 C6H8O6,H2O, Na
216.12b 165�C (dec.)(lit.)b
Ascorbic acid,L-Ascorbic acid (8CI, 9CI)
50-81-7 C6H8O6 176.12 190e194�Cb Fp: 238.2�23.6�C, bp:
552.7�50.0�C, Press:760Torr (calc)a
1.954�0.06g/cm3,Temp: 20�C (calc)a
–2.410�0.450,Temp: 25�C(calc)a
95.78�6.0kJ/mol,Press: 760Torr(calc)a
Freely soluble inwater; sparinglysoluble in ethanol;insoluble in etherc
a-Tocopherol, 2H-1-Benzopyran-6-ol,3,4-dihydro-2,5,7,8-tetramethyl-2-(4,8,12-trimethyltridecyl)-(9CI)
10191-41-0e
C29H50O2 430.71 bp:485.9�0.0�C,Press: 760Torr (calc),Fp: 210.2�24.4�C(calc)a
0.930�0.06g/cm3,Temp: 20�C,Press: 760Torr (calc),a
0.950g/mL at 20�C(lit.)b
11.902�0.267,Temp: 25�C(calc)a
78.00�3.0kJ/mol,Press: 760Torr (calc)a
Insoluble in water,freely soluble inethanol, misciblewith etherc
tert-Butylhydroquinone,1,4-Benzenediol, 2-(1,1-dimethylethyl)-(9CI),TBHQ
1948-33-0 C10H14O2 166.22 126.5e129�C
(exp)abp: 291.3�20.0�C,Press: 760Torr, Fp:138.7�16.4�Ca
1.086�0.06g/cm3, Temp:20�C, Press: 760Torra
2.333�0.225,Temp: 25�Ca
55.20�3.0kJ/mol,Press: 760Torra
Practicallyinsoluble in water;soluble in ethanolc
23
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231C. André et al. / Trends in Food Science & Technology 21 (2010) 229e246
chromatography. Robbins (2003) has also carried out a re-view concerning the analytical methodologies to determinephenolic acids in foods.
This review aims to carry out an updated evaluation ofa wide range of analytical methods used to separate, iden-tify and quantify antioxidants, phenolic and other, in food-stuffs and food packaging.
Chemical and physical information of antioxidantsCurrently, food industry requires simple and rapid ana-
lytical assays for the control of synthetic phenolic antioxi-dants added to food (Morales, González, Reviejo, &Pingarrón, 2005; Morales, González, Serra, Reviejo, & Pin-garrón, 2005).
Many studies have been dedicated to the effects of anti-oxidants (EFSA, 2004a, 2004b, 2008; Fidler, Davidsson,Zeder, & Hurrell, 2004; Georgantelis, Blekas, Katikou,Ambrosiadis, & Fletouris, 2007; Gharavi & El-Kadi,2005; Hirose et al., 1999; Kuwabara, Watanabe, Adachi,Nakanishi, & Matsuno, 2003; Sauberlich, Tamura, Craig,Freeberg, & Liu, 1996; Zurita et al., 2007). In fact, recently,the safety of AO has been questioned (Yang, Lin, &Choong, 2002). Studies demonstrate that excess use ofPG, BHA, BHT and TBHQ, synthetic antioxidants addedto foodstuff, may cause a loss of sustenance and even pro-duce toxic substances to harm people’s health (Guan, Chu,Fu, Wu, & Ye, 2006). The use of high concentrations ofBHA and BHT in rats was associated with cancer develop-ment. Therefore, although they unequivocal advantages,they have been subject of controversy (Saad et al., 2007).
Limits are established according to the toxicity of sub-stances. The Acceptable Daily Intake (ADI) recommendedby the Joint FAO/WHO Expert Committee on Food Addi-tives (JECFA, 2003) is 0e1.4mg of additive/kg bodyweight for Octyl gallate, Dodecyl gallate, BHA, BHT andTBHQ, while the Scientific Committee for Food (SCF) es-tablished a 0.5mg/kg value. Erythorbic acid is allocateda numerical ADI of 6mg/kg bw by the SCF. In the particu-lar case of BHT, the ADI was established at 0e0.3mg/kgbody weight but did not include BHT in the drinking watercontaminants list (JECFA, 2003).
In 2003, SCF set a tolerable upper intake of vitamin E,as a-tocopherol, for adults of 300mg of a-tocopherol equiv-alents per day while JECFA established an ADI of 0.15e2mg/kg of body weight per day calculated as a-tocopherol(JECFA, 2003).
Table 1 is summarizes chemical and physical informa-tion of 10 antioxidants and Table 2 resumes the methodsused to determine antioxidants in foodstuffs (according tothe type of food), packaging and pharmaceutical or cos-metic products.
Sample preparationThe present review has focused the analysis of antioxi-
dants in foodstuffs. However, a few papers that have beenfound also extract antioxidants from food packaging
http://www.fao.comhttp://www.Sigma Aldrich.com
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Table 2. Methods used to determine antioxidants in foodstuffs (according to the type of food), packaging and pharmaceutical or cosmeticproducts.
Type of food Antioxidants Analytical methods References
Fats, oils and theirproducts
BHA, BHT, PG, OG, DG HPLCePDA Sin et al., 2006GCeFIDTLC
BHA, BHT, TBHQ, PG, OG RPeHPLCeUVevis Perrin & Meyer, 2002BHA, BHT, PG, OG, DG RPeHPLCeUVeVis Aparicio et al., 2000BHA, BHT, TBHQ, PG RPeHPLCeUV Saad et al., 2007BHA, BHT, TBHQ HPLCeUV Maziero et al., 2001Tocopherols LCeMSeAPCI Lanina et al., 2007
LCeMSeESIBHA, BHT, TBHQ, PG LCeMS & GCeMS Tsuji, Nakanoi, Terada, Tamura, &
Tonogai, 2005BHA, BHT, TBHQ GCeFID Yang et al., 2002BHA, BHT, TBHQ GCeFID Suh et al., 2005TBHQ, BHA, BHT, PG MECCeED Guan et al., 2006BHA, BHT, DG MECC-UV Delgado-Zamarreño, González-Maza,
Sánchez-Pérez, & Martı́nez, 2007BHA, BHT, TBHQ VT Raymundo, Paula, Franco, & Fett, 2007Tocopherols HPLCeFl Gliszczyńska-Świg1o, & Sikorska, 2004
Cereals and cerealsproducts (e.g.Bakery products)
Tocopherols NPeHPLCeUVevis Devi, Jayalekshmy, & Arumughan, 2007BHA, BHT, PG, OG, DG LCeUV Rafecas et al., 1998
Vegetables andvegetablesproducts
Total AA HPLCeUV & MECC Thompson & Trenerry, 1995AA Enzymatic/Spectrophotometric,
RPeHPLCeFluRaghu, Platel, & Srinivasan, 2007
Tocopherol HPLCeDAD & HPLCeFlu Gómez-Coronado, Ibañez, Rupérez, &Barbas, 2004
TBHQ, BHA, BHT, PG MECCeED Guan et al., 2006LeAA RPeHPLCeFlu Burini, 2007
Fruit and fruitproducts
AA RPeHPLCeFlu Raghu et al., 2007Total AA HPLCeUV & MECC Thompson & Trenerry, 1995LeAA HPLCePDA & HPLCeDADeESIeMS Shui & Leong, 2004AA & EA LCeHILICeUV Tai & Gohda, 2007AA & EA CEeUVeVIS Versari, Mattioli, Parpinello, & Galassi,
2004AA CE e ED Wu, Guan, & Ye, 2007LeAA RPeHPLCeFlu Burini, 2007
Milk and milkproducts (e.g.cheese and cheeseproducts)
Total AA RPeHPLCeFlu Burini, 2007Tocopherol RPeHPLCeUV & RPeHPLCeMSeAPCI
& RPeHPLCeMSeESILanina et al., 2007
Tocopherol NPeHPLCeFl Rodrigo, Alegrı́a, Barberá, & Farré, 2002BHA, TBHQ, PG, OG, DG HPLCeDAD Noguera-Ortı́ et al., 2000BHA, BHT, TBHQ, PG RPeHPLCeUV Saad et al., 2007BHA, BHT, TBHQ GCeFID Yang et al., 2002
Meat and meatproducts
BHA, BHT, TBHQ, PG, DG, OG HPLCeUVePAD Pinho, Ferreira, Oliveira, & Ferreira,2000
Fish, fish productsand sea food
Tocopherol HPLCeDAD López-Cervantes et al., 2006TBHQ, BHA, BHT, PG MECCeED Guan et al., 2006AA HPLCeUV and HPLCeFl Quirós, Lopez-Hernandez, & Simal-
Lozano, 2001
Mixed foods BHA, BHT, TBHQ, PG LCeMS & GCeMS Tsuji et al., 2005PG, OG, DG CE-Microchip MEC Amperometric
determinationDing et al., 2006
Spice and otheringredients
BHA, BHT, TBHQ, PG LCeMSeGCeMS Tsuji et al., 2005
Dry foods (e.g.Sugar, honey andproducts thereof)
BHA, BHT, TBHQ, PG, OG RPeHPLCePDA Perrin & Meyer, 2002BHA, BHT, TBHQ, PG LCeMSeGCeMS Tsuji et al., 2005
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Table 2 (continued )
Food for specialnutrition use
Total AA RPeHPLCeUV Fontannaz, Kilinç, & Heudi, 2006Tocopherol NPeHPLCeFlu Rodrigo et al., 2002BHA, TBHQ, PG, OG, DG MLCeDAD Noguera-Ortı́ et al., 2000AA & EA LCeHILICeUV Tai & Gohda, 2007
Other foods BHA, BHT, TBHQ GCeFID Suh et al., 2005BHA, PG (fatty foods) Flow injection solid-phase spectrometry Capitán-Vallvey, Valencia, & Nicolás,
2003
Food simulants BHA, BHT HPLCePDA Dopico-Garcı́a, López-Vilariño, &González-Rodrı́guez, 2005
BHA, BHT RPeHPLCeDAD Dopico-Garcı́a et al., 2003BHA, BHT RPeHPLCeDAD Dopico-Garcı́a, Vilariño, & Gonzalez-
Rodriguez, 2007
Plastic products a-Tocopherol HPLCeFlu & DRIFT-IR Graciano-Verdugo et al., 2006BHT GCeMS Hill et al., 2003
Beverages AA & EA HPLCeUV Tai & Gohda, 2007BHT GCeMS Tombesi & Freije, 2002AA CE conventional microchip Law, Kubán, Zhao, Li, & Hauser, 2005
Chewing gum BHT, BHA, PG, TBHQ HPLCeDAD Ruiz, Garcı́a-Moreno, Barbas, &Pingarrón, 1999
Pharmaceutical&/or Cosmeticproducts
AA HPLCeUVevis Maia et al., 2007AA Iodometric titration/NIR Blanco & Alcalá, 2006Tocopherols RPeHPTLC Pyka & Sliwiok, 2001
NPeHPLCeUVRPeHPLCeUVGC
233C. André et al. / Trends in Food Science & Technology 21 (2010) 229e246
(Graciano-Verdugo, Peralta, González-Rı́os, & Soto-Val-dez, 2006; Hill, Shaw, & Wu, 2003) or pharmaceutical&/or cosmetic products (Blanco & Alcalá, 2006; Maiaet al., 2007; Pyka & Sliwiok, 2001).
Most of the methods found in the literature, to determineAO in foodstuffs, were tested in fats, oils and their prod-ucts, as it can be seen in Table 4. HPLC with UV wasthe most used technique (Aparicio, Andrés, & Vera,2000; Maziero, Baunwart, & Toledo, 2001; Perrin &Meyer, 2002; Sin, Wong, Mak, Sze, & Yao, 2006; Saadet al., 2007).
The quantification of antioxidants in foodstuffs presentsseveral difficulties in what regards to incomplete extractionof antioxidants and co-extraction with interfering sub-stances (Perrin & Meyer, 2002).
Table 3 resumes some of the extraction techniques foundin the literature to determine antioxidants from foodstuffs.The literature reports several extraction solvents due tothe wide range of polarity of antioxidants. Some studies in-clude comparison of several solvents for the extraction ofantioxidants (Perrin & Meyer, 2002) and it has concludedthat methanol was the most suitable for the antioxidantsextraction.
The most common method to extract these antioxidantsis Solvent extraction (SE), which can be either LiquideLiq-uid Extraction (LLE) or liquidesolid extraction (LSE). Insome matrices are also described Solid-Phase Extraction(SPE), SolideLiquid Extraction, SolideGas Extraction
and Solid-Phase Micro Extraction (SPME) (Tombesi &Freije, 2002). SolideLiquid Extraction and SolideGasExtraction are described in order to analyse a-tocopheroland BHT in plastics (Graciano-Verdugo et al., 2006; Hillet al., 2003).
Direct sample injection in a chromatograph is not a com-mon practise, although it has been used (Noguera-Ortı́,Villanueva-Camañas, & Ramis-Ramos, 2000).
Solid-Phase Extraction is more rapid and environmen-tally friendly (due to the solvents save) than LLE.
A lot of different solvents were used to extract BHA,BHT, TBHQ, PG, OG and DG from different matrices.For instance, to extract BHA, BHT, PG, OG and DG inoil samples Sin et al. (2006) used n-hexane, AcN anda methanolic ascorbic acid solution while Aparicio et al.(2000) used only hexane and AcN for BHT and petroleumether and ethanol for the others. The gallates were ex-tracted with methanol and AcN with ammonium acetatesolution from food samples by Ding, Mora, and Garcia(2006).
Regarding the analysis of vitamin C, the official methodinvolves the titration of vitamin C (AA and iso AA) bya mild oxidizing agent (2,6-dichlorophenol-indophenol)(AOAC, 1995).
For the analysis of a-tocopherol, saponification is oftenrequired to obtain full extraction of lipids (Lanina et al.,2007; López-Cervantes, Sánchez-Machado, & Rios-Vaz-quez, 2006).
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Table 3. Extraction techniques used to determine antioxidants.
Extraction technique Analyte determineda Sample Solvent used in the extractionprocedure
References
LiquideLiquid Phenolicantioxidants
BHA, BHT, PG, OG, DG Oil n-Hex, ACN Sin et al., 2006BHA, BHT, PG, OG, DG Oil sample For BHT: Hex, ACN Aparicio et al., 2000
For others: petroleum ether,EtOH (72%, v/v)
PG, TBHQ, OG, DG, BHA, BHT Oils and fats MeOH IUPAC, 1992AOAC, 1995AOCS, 1997
BHA, BHT, PG, OG, DG Bakery products ACN-isopropanol (1:1, v/v) Rafecas et al., 1998BHA, BHT, TBHQ Cooking oil, fish oil, butter, margarine,
cheese, mayonnaise, salad dressingDiethyl ether Yang et al., 2002
BHA, BHT, TBHQ Mayonnaise MeOH Raymundo et al., 2007BHA BHT TBHQ PG Vegetable oil, butter, margarine, cheese MeOH/ACN (1:1, v/v) Saad et al., 2007BHA BHT TBHQ PG OG Gravies, dehydrated soups, bouillons,
dehydrated meat, dry pet foodMeOH; Hex/2-propanol Perrin & Meyer, 2002
BHA BHT TBHQ PG DG OG Liver pâtés n-Hex saturated with ACN,ACN saturated with n-Hex
Pinho et al., 2000
BHA BHT LDPE n-Hex Dopico-Garcı́a et al., 2003BHA BHT DG Sunflower oil, olive oil MeOH, ACN Delgado-Zamarreño et al., 2007PG OG DG Food sample (gravy mix) MeOH Ding et al., 2006
Vitamin C Total AA Fortified food products TCEP$HCl, trichloroacetic acid.For starch containingsamples, taka-diastase wasalso used.
Fontannaz et al., 2006
AA & EA (1) Tea drinks, (2) Nutritionalsupplementfood, (3)dried fruit
For (1) and (2): ACNe66.7mMammonium acetatesolution (85:15, v/v)
Tai & Gohda, 2007
For (3): acetonitrileewater(30:70, v/v)
AA & EA Apricot Juices Dilution 1:1, v/v with 10%Metaphosphoric acid
Versari et al., 2004
Total AA Fruit vegetables 3% Metaphosphoric acid, Thompson & Trenerry, 1995AA Star fruit 50% aqueous acetone Shui & Leong, 2004AA Emblica officinalis, guava fruits,
chilli fruitsand amaranth leaves
2% m-phosphoric acid Raghu et al., 2007
AA Grapefruit EtOH 99.7% Wu et al., 2007Vitamin E a-tocopherol Shrimp waste n-Hex López-Cervantes et al., 2006
a-tocopherol Olive, grapeseed, corn rapeseed,peanut,sunflower, soybean oils
2-propanol Gliszczyńska-Świg1o, & Sikorska,2004
tocopherol (1) Sunflower oil, (2) Milk For (1):Saponification with KOHin ethanol. Extraction with Hex
Lanina et al., 2007
For (2): Saponification withaqueous KOH. Extraction with Hex
23
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235C. André et al. / Trends in Food Science & Technology 21 (2010) 229e246
Analytical methods to determine antioxidantsA large variety of methods were found in the literature.
Antioxidants analysis of food and plastic samples aremainly performed by chromatographic methods as it canbe confirmed by Table 4 which resumes the separation tech-niques and conditions used for the determination of theantioxidants.
Method performanceAntioxidants have a wide polarity range. Therefore,
when analysing them simultaneously a low recovery canbe achieved for some of these compounds (Rafecas, Guar-diola, Illera, Codony, & Boatella, 1998). As shown in Table5 the difference methods have different behaviour concern-ing the property and kind of food. These antioxidants aremost use in fats, oils and their products.
TBHQ was determined in many samples but only foundin fats and fish and fish products. All recoveries are good,being in the range 88.7e108.3%. There are no limits ofquantification in the references and the higher limit of de-tection was achieved in fats, oils and their products andin other foods.
BHA was found in more foods than TBHQ and also inplastics. In vegetables, fish, milk, food for special nutri-tional use and other foods BHA was not found. The limitsof detection found were lower than TBHQ. The worst re-covery was in oil and butter (81.80%).
BHT is very similar to BHA but it was also found in bev-erages. The recoveries are not so good, the lowest wasfound in cereals (57.8%).
The most used gallate is PG. It was determined in fats,oils, vegetables and mixed foods. OG and DG were notfound in any kind of foods. The limit of detection (LD) isvery similar being the higher in other foods. The worst re-covery found was for DG in cereals and cereals productsfrom 94.5 to 95.8%.
From the selected food, tocopherol was not found in ce-reals and cereals products and presents the worst recoveryin this kind of food. The LD was higher in the plasticproducts.
Total vitamin C, was just checked in food for special nu-tritional use. The recoveries were around 100%.
Ascorbic acid is used in different kind of food and alsoin cosmetic and pharmaceutical products. The only valuenot found was for food for special nutritional use. Thehigher limit of detection determined was for beverages. Re-coveries were tested with 2 different solvents which presentsignificant different values.
Erythorbic acid was just found in beverages with a limitof detection lower than the one found in fruit. Recoverywas tested with 2 different methods of extraction, givinga good recovery for the first method and worst for thesecond.
For sodium D-isoascorbate there are no values in thereferences.
-
Table 4. Separation techniques and conditions used for the determination of selected antioxidants.
Technique Detector Matrix Analytes Conditions References
HPLC DAD (l¼280nm) Oil BHA, BHT, PG,OG, DG
Column: C18 Hypersil ODS (150mm�4.6mm, 5mm) Sin et al., 2006Mobile phase solvents: A e acetic acid 5%;B e methanol/AcN 1:1 (Gradient elution)
DAD (l¼280nm;220e320nm)
Dry food PG, OG BHA,BHT, TBHQ
Column: Supelcosil LC-18 30�C (150mm�4.6mm, 5mm) Perrin & Meyer,2002Mobile phase solvents: A e Water pH3.0 acidified with
phosphoric acid 1% (v/v)B e MeOH-AcN 1:1 (v/v) (gradient elution)
DAD (l¼276nm) Aqueous foodsimulants
BHA, BHT Column: Nova Pack C18 (150mm�3.9mm, 4mm) Dopico-Garcı́aet al., 2005Mobile phase solvents: MeOH/Water
DAD Aqueous foodsimulants
BHA, BHT Column: Symmetry (150mm�3.0mm, 3.5mm) Dopico-Garcı́aet al., 2007Mobile phase solvents: MeOH/Water (gradient elution)
DAD Fatty foodsimulants
BHA, BHT Column: Symmetry (150mm�3.0mm, 3.5mm) Dopico-Garcı́aet al., 2007Mobile phase solvents: MeOH/Acn/THF/Water (gradient
elution)DAD (l¼280nm)HPLCeDADeESIeMS-ESIeMS 250�C4.5kV
Star fruit AA Column: Shim-Pack VPeODS (250mm�4.6mm) Shui & Leong,2004Column temperature: 27�C
Mobile phase solvents: A e 0.1% formic acid in water;B e MeOH
DAD (l¼208nm) Shrimp waste a-Tocopherol Column: SS Exil ODS (250m�4.6mm, 5mm) López-Cervanteset al., 2006Column temperature: 36�C
Mobile phase solvents: MeOH:ACN:water (68:28:4, v/v/v)DAD (l¼276nm) Food simulant BHA, BHT Column: Nova-Pak C18 (150mm�3.9mm, 4mm) Dopico-Garcı́a
et al., 2003Column temperature: 30�CMobile phase solvents: A e MeOH; B e Water (gradientelution)
DAD (l¼295nm)Fl (lex¼295nm,lem¼350nm)
Fresh leaves Tocopherol Column: Discovery C18 (250mm�4.6mm, 5mm) Gómez-Coronadoet al., 2004Column temperature: 35�C
Mobile phase solvents: A e Purified-for-HPLC water; B eAcNemethanol (70:30, v/v) with 0.1% (v/v) of acetic acidadded (gradient elution)
UV DAD(l¼280nm)
Liver pâtés TBHQ, BHA, BHT,PG, DG, OG
Column: Spherisorb C18 (250mm�4.6mm, 5mm) Pinho et al., 2000Mobile phase solvents: A e 5% acetic acid in water; B eAcN with 5% acetic acid
UV (l¼254nm) Fruits andvegetables
AA, EA Column: C18 NOVAPAK Radial-PAK (100mm�80mm,4mm) Thompson &Trenerry, 1995Mobile phase solvent: 0.2% (v/v) aqueous orthophosphoric
acidUV (l¼280nm) Vegetable oil,
hydrogenatedvegetable fat,margarine,vegetable cream,halvarina
TBHQ, BHA, BHT Column: C18 (ODS) Vydac 201-TP 54 (250mm�4.6mm,5mm)
Maziero et al.,2001
Mobile phase solvents: AcN: methanol:5% acetic acidTBHQ and BHA: (25:25:5 0 v/v/v)BHT:(42.5:42. 5:15 v/v/v)
UV (l¼280nm) Vegetable oil,butter, cheesemargarine,
PG, TBHQ, BHA,BHT
Column: LiChrospher RP (250mm�4.0mm, 5mm) Saad et al., 2007Mobile phase solvents: A e AcN; B e water with 1% aceticacid (gradient elution)
UVeVis(l¼290nm)
Oil sample BHA, BHT, PG,OG, DG
Column: Lichrosorb RP-18 (150mm�3.9mm, 10mm) Aparicio et al.,2000Mobile phase solvents: SDS/H3PO4/n-propanol 20e50% v/v
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CTAB/H3PO4/n-propanol 20e50% v/vUV (l¼265nm) Fortified food
productsTotal vitamin C Column: LiChrospher RP-C18 (250mm x4.6mm, 5mm) Fontannaz et al.,
2006Mobile phase solvents: decylamine, AcN, sodium acetatesolution; distilled water (pH¼5.4 phosphoric acid 85%);TCEP.HCl (isocratic elu n)
UV (l¼280nm) Bakery products PG, OG, DG, BHT,BHA
Column: C18 Extrasil O S2 (250mm�4.6mm, 5mm) Rafecas et al.,1998Mobile phase solvents: e acetic acid-MeOH (5:95,v/v); B
e acetic acid-water (5 v/v) (gradient elution)UV (l¼260nm) Tea drinks, dried
fruit, nutritionalsupplement
AA, EA Column: GL Sciences 0mm x4.6mm, 5mm) Tai & Gohda, 2007Mobile phase solvents: cN:water with 66.7mMammonium acetate (85 ,v/v)
UVeVis (l¼�297nm)
Deffated rice bran Tocopherol Column: Shim-pack (2 m�4.6mm) Devi et al., 2007Mobile phase solvents: Hex/isopropanol (96:4); v/v
NPeUV(l¼290nm)
Mix of tocopherolsin ethanol
Tocopherol Column: Hypersil Silic 250mm�4.6mm, 5mm) Pyka & Sliwiok,2001Mobile phase solvents: ex:amyl alcohol (99.5:0.5, v/v)
RPeHPTLCeUV(l¼254nm)
Mix of tocopherolsin chloroform
Tocopherol Column: RPeHPTLC (1 m �10cm) Pyka & Sliwiok,2001Solvents: EtOH:water v me proportions 10:0; 9.5:0.5; 9:1
RPeUV(l¼290nm)
Mix of tocopherolsin ethanol
Tocopherol Column: RP C18 (150m �4mm, 5mm) Pyka & Sliwiok,2001Mobile phase solvents: eOH-water (9:1, v/v)
UV (l¼292nm)MS-APCI(þ)(�)MS-ESI(þ)(�)
Sunflower oil milk Tocopherol Column: Fluophase PF 200mm�4.6mm, 5mm) Lanina et al., 2007Column temperature: 2 CMobile phase solvents: eOH:water 95:5,v/v or AcN:water78:22, v/v
UVevis(l¼254nm)
Semisolidpharmaceutical/cosmeticormulations
AA Column: Phenomenex hrospher 100-RP18(250mm�4.6mm, 5mm
Maia et al., 2007
Mobile phase solvents: 2% metaphosphoric acid/MeOH/AcN (90:8:2, v/v/v)
UV (l¼245nm) Sea urchin AA Column: Kromasil 100 50mm�4mm, 5mm), Teknokroma Quirós et al., 2001Mobile phase solvents: illi-Q Water adjusted to pH 2.2with metaphosphoric a
Fl (lex¼350nm,lem¼430nm)
Sea urchin AA Column: Kromasil 100 50mm�4mm, 5mm), Teknokroma Quirós et al., 2001Mobile phase solvents ethanol/0.1% metaphosphoricacid (7:1)
Fl (lex¼295nm,lem¼330nm)
Infant formulas tocopherol ColumnNova-Pak: (150 m�3.9mm, 5mm) Rodrigo et al.,2002Column temperature: r m temp
Mobile phase solvents ex-ethyl acetate (98:2, v/v)Fl (lex¼290nm,lem¼330nm)DRIFT-IR
Plastic LDPE a-tocopherol Column: Omnispher C column (150mm�4.6mm, 5mm);Microsorb
Graciano-Verdugoet al., 2006
Mobile phase solvents eOH:water (98:2) (isocraticelution)
Fl (lex¼295nm,lem¼325nm)
Olive, peanut,grapeseed,rapeseed,sunflower,corn,soybean oils
tocopherols Column: Symmetry C1 50mm�3.9mm, 5mm) Gliszczyńska-Świg1o, & Sikorska,2004
Mobile phase solvents: cN/MeOH (1:1) (elution gradient)
Fl (lex¼355nm,lem¼350nm)425nm emission
Various food, milk AA Column: Nova-Pak C18 50mm�3.9mm, 4mm) Burini, 2007Mobile phase solvents: osphate pH¼7.8containing16%MeOH v) (isocratic elution)
Fl (lex¼350nm, Emblica fruits, AA Column: SS Excil C18 0mm�4.6mm, 10mm) Raghu et al., 2007(continued on next page)
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tioD
A:95(25A:15
50mn-
a (H0columM
P (3�
M
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: M
8 (1A
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Table 4 (continued).
Technique Detector Matrix Analytes Conditions References
lem¼430nm) guava, chilli fruits,amaranth leaves
Mobile phase solvents: Me :water (55:45) (isocraticelution)
Amperometricdetection
Chewing gum AA Nickel phthalocyanine pol er-coated glassy carbonelectrodes
Ruiz et al., 1999
GC MS m/z 35e500V¼70eV
Drinking water BHT Column: HP5 column (30m 0.25mm) Tombesi & Freije,2002Oven ramp: 40�C 5min; to 50�C 20�C/min 5min
MS m/z 10e55070eV
PVC tubes BHT Column: Supelcowax 10(3 �0.25mm, thickeness0.25mm)
Hill et al., 2003
Injector temperature: 250�
Oven ramp: 35�C held 2m increased at 15�C/min to250�C
FID Cooking oil, fishoil, butter,margarine, cheese,mayonnaise, saladdressing
BHA, BHT, TBHQ Column: ChromPack CP-Si CB (30m�0.53mm, 1.5mm) Yang et al., 2002Injector temperature: 250� Detector temperature: 290�COven ramp:150�C held 1m , increased to 200�C at 7�C/min, increased to 300�C a 0�C/min, held 5min at 300�CCarrier gas: H2 (4ml/min)
FID Soybean oil, cornoil, other vegetableoil, shortening,margarine,seasoned driedfish, dried fish,salted fisheryproduct and frozenfishery product(combined),chewing gum,mayonnaise andbreakfast cereal
BHA, BHT, TBHQ Suh et al., 2005
FID Oil BHA, BHT, PG,OG, DG
Column: AT-5 (30m�0.53m ) Sin et al., 2006Injector temperature: and d ector temperature: 250�CColumn oven: 125�C held min; increased to 250�C at20�C/minCarrier gas. H2 30mL/min 300mL/min
Electroforesis CEElectrochemicaldetection
Grapefruit AA Column: Fused-silica capil y (75cm�25mm i.d. and360mm o.d.)
Wu et al., 2007
Electrochemical cell (WE: 0mm diameter carbon disk þplatimium electrode þ SCE n combination with BAS LC-4C AD
CE Capillary zonemode (CZE) UVeVis
Fruit juice AA and EA Uncoated fused-silica capi ry (total length¼50cm;effective length to the dete r¼42.4cm; i.d.¼75mm)conditioned with 0.1M Na (3min); CE-grade water(5min) rinsed with running ffer 50mM tricine at pH 8.8(5min) sample injection ca ed out at the anode for 5s.T¼30�C; V¼11kV across th capillary applied for 15min.
Versari et al., 2004
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OH
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MECC l¼254nm Fruit andvegetables
AA and EA Fused-silica capillary columns (65cm�7.5mm i.d., effectivelength to the detector¼40cm for fruit; 75cm�75mm id.effective length to the detector¼50cm for vegetables)
Thompson &Trenerry, 1995
Buffer 0.05M sodium deoxycholate, 0.01M sodium borateand 0.01M potassium dihydrogen orthophosphate.V¼25kV; T¼28�C; Buffer for 2min between runs.
MECC-UV l¼200,214, 254, 280nm
Edible oils BHA, BHT, DG Column: Fused-silica capillary (57cm�75mm i.d.) Delgado-Zamarreño et al.,2007
Separation solution: 20% AcN, 20mM boric-borate buffer(pH¼9.2) and 20mM bis-(2-ethylhexyl))sodiumsulfosuccinate surfactant
MECCelectrochemicaldetection
Stock solutions BHA, BHT, PG,TBHQ
Column: fused-silica capillary (75cm�25mm i.d. and360mm o.d.)
Guan et al., 2006
Injector: V¼18kV for 6s; T¼25�CElectrochemical cell (WE: 300mm diameter carbondiscþplatinium electrodeþSCE in combination with BASLC-4C AD
Microchip MEC Food sample PG, OG, DG Detection electrode: 25mm diameter, 99.95% gold wire Ding et al., 2006T¼22�2�C
TLC Edible oil BHA, BHT, PG,OG, DG
TLC plate: silica gel 60, 20�20cm2, Merck Sin et al., 2006Mobile phases: Petroleum ether(40:60):toluene:aceticacid:AcN (4:4:1:0.4 by volume)Spraying 0.5% Gibb’s reagent; dried at 105�C for 15minExposed to ammonia vapour
NIR Pharmaceuticalproducts
AA 1100e2498nm, 32 scans/spectrum Blanco & Alcalá,2006
DRIFT-IR Plastic LDPE A-Tocopherol 4000e400cm�1 Graciano-Verdugoet al., 2006
Voltametrictechniques
Mayonnaise BHA, TBHQ, BHT WE: glassy carbon disk (GC, 0.950cm2) and Pt disk (Pt,0.502cm2). Reference: Hg/Hg2Cl2/KCl (sat.) electrodes andhome made plate auxiliary electrode
Raymundo et al.,2007
Cyclic voltammetry: yb¼50mVs�1Differential pulse voltammetry: DE¼25mV; yb¼50mVs�1Square wave voltammetry: DE¼25mV; f¼60Hz
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Table 5. Method performance of analytical methods for determination of antioxidants.
Compound Food group Range LOD Recovery References
TBHQ Meat and meatproducts
n.d. e 93.6% at 30.3mg/mLPinho et al., 2000
Fish and fishproducts
7.35�103 mg/kg 0.80 � 10�6mol/l 95.40% Guan et al., 2006
Cheese and cheeseproducts
n.d. 0.1mg/ml 97.3e108.4% Yang et al., 2002n.d. 0.5mg/l Cheese 85.3e93.1%Saad et al., 2007
Milk and cheeseproducts
e 0.12 ng 98e105% Noguera-Ortı́ et al.,2000
Fats, oils and theirproducts
n.d.e 20.2 mg/kg 0.5mg/l Oil: 103.9e104.0%Bread Spread: 95.0e108.3%
Saad et al., 2007
n.d.e70.3mg/kg 0.1mg/ml 97.3e108.4% Yang et al., 2002n.d.e 143 mg/kg 3.0mg/kg 103e108% Maziero et al., 2001e 5mg/kg 95.40% Suh et al., 200556.7e73.8 mg/kg e e Raymundo et al., 2007n.d. 0.80 � 10�6mol/l 95.80% Guan et al., 2006
Other foods(mushroom cream)
n.d. 0.80 � 10�6mol/l 99.70% Guan et al., 2006
Several foods(shortening,seasoned dried fish,dried fish, saltedfishery product andfrozen fisheryproduct, chewinggum, mayonnaise,breakfast cereal, etc)
e 5mg/kg 88.70% Suh et al., 2005e 2mg/kg e Perrin & Meyer, 2002
Food for specialnutritional use
e 0.12 ng 94.8e100.8% Noguera-Ortı́ et al.,2000
BHA Meat and meatproducts
92.4 mg/kg e 97.80% Pinho et al., 2000
Fish and fishproducts
n.d. 1.0�10�6mol/l 102.30% Guan et al., 2006
Cheese and cheeseproducts
n.d. 0.5mg/l 97.4e101.2% Saad et al., 20075.4e12.4 mg/kg 0.1mg/ml Yang et al., 2002
Milk and cheeseproducts
e 0.3 ng 92e102% Noguera-Ortı́ et al.,2000
Bakery (doughnuts,biscuits, varioustypes of cakes)
Sample:3.9e10.7 mg/kgFat fraction: 17.5e55.6 mg/kg
e 94.5e95.8% Rafecas et al., 1998
Other foods(mushroom cream)
n.d. 1.0�10�6mol/l 97.40% Guan et al., 2006
Fats, oils and theirproducts
n.d.e103.9 mg/kg 0.5mg/l Oil-96.7e97.6%Bread spread-97.5e97.7%
Saad et al., 2007
e 0.41-0.67pg 96.2e105.7% Aparicio et al., 2000n.d.-135.4 mg/kg 0.1mg/ml 101.2e103.8% Yang et al., 2002n.d. 0.45ppm Found 0.75g/Kg
adding 0.8g/Kg(MeOH)0.79g/kg adding0.8g/Kg (sunfloweroil)0.70g/Kg adding0.8g/Kg
Delgado-Zamarreño etal., 2007
21.3e58.1mg/kg e e Raymundo et al., 2007164mg/kg 2e4mg/g 97.60% Sin et al., 2006e 3mg/kg 81.80% Suh et al., 2005n.d. 0.6mg/kg 87e98% Maziero et al., 2001n.d. 1.0�10�6mol/l 96.50% Guan et al., 2006e 0.6mg/kg e Maziero et al., 2001
Food for specialnutritional use
e 0.3 ng 93.4e99.7% Noguera-Ortı́ et al.,2000
240 C. André et al. / Trends in Food Science & Technology 21 (2010) 229e246
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(continued on next page)
Table 5 (continued )
Several foods(shortening,seasoned dried fish,dried fish, saltedfishery product andfrozen fisheryproduct, chewinggum, mayonnaise,breakfast cereal, etc)
e 3mg/kg 89.20% Suh et al., 2005
Dry foods e 95e104% Perrin & Meyer, 2002Chewing gum n.d. 5.5ng e Ruiz et al., 1999Food simulant e 0.052mgL�1 104% Dopico-Garcı́a et al.,
20054.2�10�3mgdm�2(aqueous simulant)
Dopico-Garcı́a et al.,2005
4.4�10�3mgdm�2(simulant D-olive oil)
Plastic products 16�10�3e30�10�3g/l 6.5mgl�1 88% Dopico-Garcı́a et al.,2003
BHT Meat and meatproducts
e e 99.90% Pinho et al., 2000
Fish and fishproducts
n.d. 2.7�10�6mol/l 95.90% Guan et al., 2006
Cheese and cheeseproducts
56.7e87.1mg/kg 0.1mg/ml Yang et al., 2002n.d. 0.5mgl�1 Cheese e 89.5e
91.4%Saad et al., 2007
Other foods(mushroom cream)
n.d. 2.7�10�6mol/l 94.30% Guan et al., 2006
Bakery products Sample: 3.0e17.0mg/kg e 85.7e89.4% Rafecas et al., 1998Fat fraction: 14.9e90.0mg/kg
Fats, oils and theirproducts
e 3mg/kg 94.50% Suh et al., 200517.0e319mg/kg 0.1mg/ml 92.5e97.6% Yang et al., 2002n.d. e 154.2mg/kg 0.5mgl�1 Oil e 88.2e94.6% Saad et al., 2007
Bread spread e73.9e80.2%
46.5mg/kg 2e4mg/g/10mg/g 75.80% Sin et al., 2006e 1.42e5.12pg 83.0e85.5% Aparicio et al., 200017.6e26.7mg/kg e e Raymundo et al., 2007n.d. 1.47ppm Adding 0.8g/kg
found 0.064g/kg(MeOH) 0.99g/kg(Sunflower oil)0.64g/kg (olive oil)
Delgado-Zamarreñoet al., 2007
n.d. e 197mg/kg 2.7mg/kg 78e98% Maziero et al., 2001n.d. 2.7�10�6mol/l 92.10% Guan et al., 2006
Other foods e 2mg/kg e Perrin & Meyer 2002e 3mg/kg 92.60% Suh et al., 2005
Beverages 0e38mg/L 4.2ml�1 84%e119% Tombesi & Freije, 2002Chewing gum 51�3mgg�1 30ng 97�4% Ruiz et al., 1999Food simulant e 0.045mgl�1 82% Dopico-Garcı́a et al.,
2005n.d. 5.1�10�3 mgdm�2
(aqueous simulant) 7.7�10�3mgdm�2 (simulant D)
Dopico-Garcı́a et al.,2007
Plastic products 5.1e5.6�10�10mol 0.13nmol e Hill et al., 200316e30mg/l/100mL simulant 5.6mgl�1 70% Dopico-Garcı́a et al.,
2003
PG Meat and meatproducts
n.d. e 78.00% Pinho et al., 2000
Fish and fish n.d. 0.29�10�6mol/l 98.70% Guan et al., 2006
241C. André et al. / Trends in Food Science & Technology 21 (2010) 229e246
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productsFats, oils and theirproducts
n.d. 0.3mgl�1 Oil e 103.5e108.3%
Saad et al., 2007
n.d. Bread spread e103.6e107.3%
e 2e4mg/g Spike 0.01 e 7.6% Sin et al., 2006e 0.14e0.23pg 95.3e100.9% Aparicio et al., 2000103mg/kg 0.29�10�6mol/l 99.10% Guan et al., 2006
Cheese and cheeseproducts
n.d. 0.3mgl�1 93.3e99.5% Saad et al., 2007
Milk and cheeseproducts
e 0.05ng 96e103% Noguera-Ortı́ et al.,2000
Other foods(mushroom cream)
217mg/kg 0.29�10�6mol/l 101.80% Guan et al., 2006
Bakery products n.d. e 88.9e89.5% Rafecas et al., 1998Food for specialnutritional use
e 0.05ng 100.6e101.3% Noguera-Ortı́ et al.,2000
Mixed foods 45mg/kg 2.2mM 95�6% Ding et al., 2006Chewing gum n.d. 7.5ng e Ruiz et al., 1999Other foods e 85e106% Perrin & Meyer, 2002
OG Meat and meatproducts
n.d. e 82.10% Pinho et al., 2000
Bakery products n.d. e 77.9e79.7% Rafecas et al., 1998Milk and cheeseproducts
e 0.2ng 99e100.1% Noguera-Ortı́, et al.,2000
Fats, oils and theirproducts
e 0.31e0.40pg 92.5e105.0% Aparicio et al., 2000
e 2e4mg/g 95.80% Sin et al., 2006Mixed foods e 2.3mM 95�6% Ding et al., 2006Food for specialnutritional use
e 0.2ng 100e103% Noguera-Ortı́ et al.,2000
Other foods e 83e85% Perrin & Meyer, 2002
DG Meat and meatproducts
n.d. e 94.30% Pinho et al., 2000
Bakery products n.d. e 39.8e40.7% Rafecas et al., 1998Fats, oils and theirproducts
e 2e4mg/g 97.60% Sin et al., 2006e 0.30e0.33pg 95.7e105.7% Aparicio et al., 2000n.d. 0.27ppm Adding 0.8g/kg,
found 0.77g/kg(MeOH), 0.75g/kg(sunflower oil,0.82g/kg (olive oil)
Delgado-Zamarreñoet al., 2007
Mixed foods e 4.1mM 95�6% Ding et al., 2006
Tocopherol Fish and fishproducts
351mg/kg 80ng/mL 100.80% López-Cervantes et al.,2006
Fats, oils and theirproducts
100.16e203.78mg/kg 28ng/mL (a-tocopherol) Gliszczyńska-Świg1o, &Sikorska, 20048ng/mL (g and
d tocopherol)393mg/kg APCI(-): 2.5e3ng/mL 102e112% Lanina et al., 2007
ESI(-): 5e20ng/mLVegetables andvegetable products
13e1322mg/kg 0.05mg/100g a e 87% Gómez-Coronado et al.,2004g e 57e60%
Cereals and cerealproducts
51e347ppm (alltocopherols)
e 19.9%e47.7%based on crudeextraction
Devi et al., 2007
Milk and milkproducts
0.939mg/kg APCI(�): 3.0ng/mL 104e109% Lanina et al., 2007ESI(�): 20ng/mL
Food for specialnutritional use
275mg/kg 1.60ng/50mL inj volume e Rodrigo et al., 2002
Plastic product (LPPEfilm)
0.26e1.59% (HPLC)/0.21e1.42% (DRIFT-IR)
0.25mg/mL (HPLC)/1300mg/g (DRIFT-IR)
71.3e86.0% (HPLC)Graciano-Verdugo et al.,2006
Table 5 (continued).
Compound Food group Range LOD Recovery References
242 C. André et al. / Trends in Food Science & Technology 21 (2010) 229e246
-
Fruits 979.17�10�6g/mL(grapefruit juice)/500�10�6g/g grapefruit peel
1�10�6g/mL 95% Wu et al., 2007
Total vitamin C Food for specialnutritional use
6.2e208.5mg/100g 0.1mg/100g 93e105% Fontannaz et al., 2006
Ascorbic acid Beverages 30mg/L 3mg/L (conventional CE) e Law, Kubán et al., 200510mg/L (microship E)
31.9e267.5mg/l 0.3mg/ml AcN/water 30/70using dithiothreitol:92%
Tai & Gohda, 2007
AcN/water 30/70:38%
Wu et al., 2007
Fruit and fruitproducts
500�10�6g/g (grapefruitpeel)/979.17�10�6g/g(grapefruit juice)
1.0�10�6g/mL 95%
45e243mg/l 1.6mg/l e Versari et al., 200458.6e236.2mg/100g(HPLC)
e e Raghu et al., 2007
52.4e213.5 (Enzymatic)71.1e206.8 (indophenol-xylene)55.0e468.8 (2,4-DNPH)2e38mg/100g 0.27mg/mL e Burini, 20072e101mg/100g e e Thompson & Trenerry,
1995n.d. 0.3mg/ml AcN/water 30/70
using dithiothreitol:92%
Tai & Gohda, 2007
AcN/water 30/70:38%
Vegetables andvegetable products
41.1mg/100g (HPLC) e e Raghu et al., 200736.8mg/100g (Enzymatic)60.4mg/100g (indophenol-xylene)62.3mg/100g (2,4-DNPH)2e200mg/100g e e Thompson & Trenerry,
19952.8e7.0mg/100g 0.27mg/mL e Burini, 2007
Milk and milkproducts
1.15e1.44mg/kg 0.27mg/mL e Burini, 2007
Sea Food HPLCeFl: Fresh 26.57mg/100g
HPLCeFl: 0.19mg/ml,0.082mg/ml
98.12% (HPLCeFl) Quirós et al., 2001
Canned 14.25mg/100gPharmaceutical/cosmetic products
1.909e10.154mg/ml 0.05mg/mL�1 95.46e101.54% Maia et al., 20070.17mg/mL�1
2.5% wt. e e Blanco & Alcalá 2006
Erythorbic acid Beverages 23.4mg/ml 0.3mg/ml AcN/water 30/70using dithiothreitol:92%
Tai & Gohda, 2007
Food for specialnutrition use
n.d. AcN/water 30/70:38%
Fruit and fruitproducts
n.d.
Fruit and fruitproducts
e 1.1mg/l e Versari et al., 2004
Table 5 (continued).
243C. André et al. / Trends in Food Science & Technology 21 (2010) 229e246
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244 C. André et al. / Trends in Food Science & Technology 21 (2010) 229e246
ConclusionsThe use of antioxidants has been growing in the past few
years due to the advantages offered in the preservation of food.The most common method to analyse these antioxidants
is reversed phase HPLC with UV detection. This UV detec-tion can be a simple UVevis detector or DAD. Althoughtocopherol can be detected by RPeHPLC there aremethods in normal phase. Various solvents can be used,but usually is selected an organic phase, AcN or methanoland an aqueous phase, water acidified or not.
The present legislation is being very strict in the concen-tration limits of antioxidants that can be use in variousfoods. The analytical methods reviewed for this articlepresents limits of detection below the maximum permittedby legislation. In this way the methods used are suitable fordetect and quantify the antioxidants in study.
AcknowledgementsAuthors are grateful to the ‘‘Fundaç~ao para a Ciência e
Tecnologia’’, Portugal, for the Postdoctoral contract ofAna Sanches Silva in the frame of the Program ‘‘Science2007’’ and for the Bilateral Cooperation between Portugaland Italy. The authors are also grateful to ‘‘Instituto Nacio-nal de Saúde Doutor Ricardo Jorge’’ for the PhD scholar-ship of Catarina André (BID 04/2006-I).
Abbreviations
AA: ascorbic acidAcN: acetonitrileAD: amperometric detectionAPCI: atmosphere pressure chemical ionizationCE: capillary electrophoresisDAD: diode array detectorDDTD: dynamic thermal desorptionDG¼LG: dodecyl gallate or lauryl gallateDRIFT: diffuse reflectance Fourier transform infraredEA: erythorbic acid (D-isoascorbic)ED: electrochemical detectionESI: electrospray ionizationEtOH: ethanolFID: flame ionization detectorFlu: fluorescence detectorGC: gas chromatographyHex: hexaneHILIC: hydrophilic interaction chromatographyHPLC: high-performance liquid chromatographyIR: infraredLC: liquid chromatographyMECC: micellar electrokinetic capillary chromatographyMeOH: methanolMLC: micellar liquid chromatographyMS: mass spectrometryNIRS: near infrared spectroscopyNP: normal phase
PDA: photodiode arrayRP: reverse phaseSCE: saturated calomel electrodeSFE: supercritical fluid extractionSPME: solid-phase microextractionTCEP$HCl: tris-(2-carboxyethyl)-phosphine hydro-chlorideTHF: tetrahydrofuranTLC: thin layer chromatographyUVevis: ultraviolet and visible detectorVT: voltametric techniquesWE: working electrodeWt.: weight
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Analytical strategies to evaluate antioxidants in food: a reviewIntroductionChemical and physical information of antioxidantsSample preparationAnalytical methods to determine antioxidantsAnalytical methods to determine antioxidantsMethod performanceConclusionsConclusionsConclusionsAcknowledgementsAbbreviationsReferences