Effect of different cooking methods on phenolic compounds and antioxidant properties of Cirsium vulgare stem

Document Type : Research Paper

Authors

Abstract

Introduction: In recent years, increasing attention has been paid by humans to the role of diet in human health. Epidemiological researches have demonstrated that a high intake of plant-originated foods is strongly associated with a reduced risk of a number of chronic diseases, such as atherosclerosis and cancer, neurodegenerative diseases, including Parkinson's and Alzheimer's diseases (Şengül et al., 2014). These beneficial effects have been partly attributed to the compounds present in plants that possess antioxidant activity. Antioxidant compounds, which are found in plants (fruits, vegetables, medicinal herbs, etc.), are free radical scavenging molecules, such as phenolic compounds (e.g., phenolic acids, flavonoids, stilbenes, quinones, coumarins, lignans, tannins), nitrogen compounds (amines, alkaloids, betalains), vitamins (C, E), endogenous metabolites, and terpenoids (including carotenoids) (Cai et al., 2004).
Artichoke is one of the plants with high health properties and usually heat treated before consumption. Stems of artichoke present significant antioxidant activity (Pereira et al., 2013), and for this purpose they are the main ingredients in many dietary supplements and drugs. In particular, stems and leaves are the most common plant part used for therapeutic purposes, since they have numerous medicinal properties including antitumor, antioxidant, antibacterial, antifungal, and hepatoprotective effects and so forth, mostly attributed to their high content of phenolic compounds (Zhu et al., 2004). Vegetables are commonly cooked by different cooking processes, including steaming, boiling in water or microwaving, before being consumed. These processes change the physical and chemical properties of vegetables. Cooking processes may have an effect on the antioxidant content of food due to antioxidant release, destruction, or creation of redox-active metabolites (Wachtel-calor et al., 2008) Antioxidant compounds, such as ascorbic acid and some carotenoids, are very sensitive to heat and storage. On the other hand, polyphenols have shown a certain stability when exposed to high temperatures. Turkmen et al., (2005) reported that after cooking, total antioxidant activity increased or did not change depending on the type of vegetable but not type of cooking. Zhang and Hamauzu (2004) showed that cooking affected the antioxidant compound contents of broccoli. Ismail and et al., (2004) demonstrated that heating decreased the total phenolic content in some vegetables such as swamp cabbage, kale, spinach, cabbage, and shallots. Important parameters in the cooking quality of vegetables, which may strongly influence consumer preferences, are texture and color. Thus, the aim of the current study was to investigate the effects of different cooking methods (boiling, steaming, and microwaving) on artichoke stem. The antioxidant capacity, and physical characteristic changes after cooking were also investigated.
Material and methods: In this research, the effects of different cooking methods (boiling, steaming and microwaving) in three levels of time on the antioxidant properties of the artichoke stem were used. Fresh artichoke was used in this research and obtained from a market in Sari, Iran and immediately cleaned by removed manually non edible parts with a sharp knife. Artichoke carefully washed with water (in consumer conditions), dried air and stems were cut into almost equal small pieces, mixed well. The samples were taken and divided into four portions. One portion was kept raw as control and stored at 4 ◦C in the refrigerator in home consumer conditions, others were subjected for four thermally treatments in triplicate. The best cooking times were determined as previously described and according to common cooking techniques [9] which conducted by trained researchers (Boiling 5, 10 and 15 min, steaming 5, 10 and 15 min, Microwaving 2, 4 and 6 min). Cooking conditions were examined, with a preliminary experiment in our laboratory. Then, total phenol content, total flavonoid content, DPPH radical scavenging, total antioxidant capacity and ferric reducing power and also chemical composition and sensory properties of samples were evaluated.
Result and discussion: The results showed that boiling at all times caused a significant increase in moisture content in the samples (P<0.05). Steaming also increased the moisture content of the samples, but this increase was not significant (P<0.05). There was no significant difference between the control and the cooked samples by microwave in 5 minutes (P<0.05). The fat content of the samples varied from 0.11 to 0.16%. Methods and cooking times did not have a significant effect on fat and protein (P<0.05). Protein levels also varied from 1.2 to 7.2%. Also, there was no significant difference between the amount of ash of the control sample and in boiled, steamed and microwaved samples at different times (P<0.05) except the microwaved sample in 6 minutes, which ash content was 1.9%. The cooking method has a significant effect on total phenol content, total flavonoid and antioxidant activity (P<0.05). The total phenol content and total flavonoid content of the artichoke stem under microwave processing at 2 and 4 min and the steaming process at 5 minutes increased compared to fresh artichoke stem samples and the boiling process decreased significantly (p <0.05). In boiling method, stems are immersed in water and in the loss of phenolic compounds because of leaching (leakage of compounds into water from artichoke). The antioxidant activity of the stem in the microwave cooking process at 2 min and steaming at 5 min showed the highest activity. In the reducing power assays, the antioxidants present in the artichoke stems convert the oxidized form of iron (Fe+3) in ferric chloride to the ferrous (Fe+2) form. The reducing power of the microwave method was significantly higher than other methods (P<0.05). In the sensory evaluation, the microwave method for 2 min and steaming for 5 min obtained the highest overall acceptance. Therefore, the microwaving and steaming methods are recommended in short time for cooking of artichoke and the optimal use of the valuable and useful compounds of this plant.
Conclusion: Therefore, microwave and steaming methods in short time for cooking artichoke stem and optimal use of the beneficial compounds and health of this plant are recommended. In addition, artichoke stems of the studied genotypes showed different bioactive compound profiles and significant antioxidant properties, and could be further used in the food and nutraceuticals industries as a cheap source of phenolic compounds and antioxidants.

ملک قاسمى ا، صادقى ماهونک ع، قربان م، اعلمى م، مقصودلو ی، 1393،تاثیر روش پخت برخواص آنتى اکسیدانى و رنگدانه بتالائین در چغندر قرمز. فصلنامه علوم وفناوری­های نوین غذایی،سال اول، شماره٤، 29-٣٦.
قادری قهفرخی م، عزیزی م ح، قربانی م، صادقی ماهونک ع، اعلمی م، 1390، ترکیبات شیمیائی و تاثیر روشهای فرآوری حرارتی بر میزان ترکیبات فنولی میوه دو واریته بلوط ایرانی. نشریه پژوهش­های صنایع غذایی، جلد 21، شماره 4، 421-431.
AOAC, 2007. Official methods of analysis. Washington, DC: Association of Official Analytical Chemists.
Arlai A, Nakkong R, Samjamin N and Sitthipaisarnkun B, 2012. The Effects of Heating on Physical and Chemical Constitutes of Organic and Conventional Okra. Procedia Engineering 32: 38 – 44.
Cai Y, Luo Q, Sun M, and Corke H, 2004. Antioxidant activity and phenolic compounds of 112 traditional Chinese medicinal plants associated with anticancer. Life Sciences, 74: 2157–2184.
Dewanto V, Wu, X, Adom KK and Liu RH, 2002. Thermal processing enhances the nutritional value of tomatoes by increasing total antioxidant activity. Journal of Agricural Food Chemistry 50: 3010–3014.
El-Din MHAS, Abdel- Kader MM, SK, Makhlouf SK and Mohamed OSS, 2013. Effect of some cooking methods on natural antioxidants and their activities in some brassica vegetables. World Applied
Sciences Journal 26 (6): 697-703.
Ferreres F, Sousa C, Valento P, Seabra RM, Pereira JA and Andrade PB, 2006.Chemical composition and antioxidant activity of tronchuda cabbage internal leaves. European Food Research Technology 222:88–98.
Hayat K, Zhang X, Farooq U, Abbas S, Xi, S, Jia C, and Zhang J, 2010. Effect of microwave treatment on phenolic content and antioxidant activity of citrus mandarin pomace. Food Chemistry 123(2):423- 429.
Ismail A, Marjan ZM, Foong CW, 2004. Total antioxidant activity and phenolic content in selected egetables. Food Chemistry 87: 581–586
Jung UJ, Baek NI and Chung HG, 2008. Effects of the ethanol extract of the roots of brassica rapa on glucose and lipid metabolism in C57BL/Ksj-Db/Db Mice. Clinical Nutrition 27(1): 158-67.
Juin Kao F, Chia Y and Chiang W, 2014.  Effect of ater cooking on antioxidant capacity of carotenoid rich vegetables in Taiwan. Jounal of Food and Drug Analaysis 22:202-209.
Lattanzio V, Kroon PA, Linsalata V and Cardinali A, 2009. Globe artichoke: A functional food and source of nutraceutical ingredients, Journal of Functional Foods 1(2): 131–144.
Li Q, Shi X, Zhao Q, Cui Y, Ouyang J and Xu F, 2016. Effect of cooking methods on nutritional quality and volatile compounds of chinese chestnut (CastaneaMollissimaBlume). Food Chemistry 201:80–86.
Mc Donald S, Prenzler PD, Autolovich M and Robards K, 2001. Phenolic Content and Antioxidant Activity of Olive Extracts. Food Chemistry 73: 73-84.
Migilio C, Chavaro EM, Viscont A, 2008. Effects of different cooking methods on nutritional and physicochemical characteristics of selected vegetables. Agricultural and Food Chemistry 56: 139-147.
Nuutila AM, Puupponen-Pimia R, Aarni M and Oksman-Caldentey KM, 2003. Comparison of antioxidant activities of onion and garlic extracts by inhibition of lipid peroxidation and radical scavenging activity. Food Chemistry 81: 485-93.
Pereira C, Calhelha RC, Barros L and Ferreira ICFR, 2013. Antioxidant properties, anti- hepatocellular carcinoma activity and hepatotoxicity of artichoke, milk thistle and borututu Industrial Crops and Products 49: 61–65
Petropoulos SA, Pereira C, Barros L and Ferreira ICFR, 2017. Leaf parts from Greek artichoke genotypes as a good source of bioactive compounds and antioxidants. Food & Function 8: 2022-2029.
Pokorny J, Yanishlieva N and Gordon M, 2001. Antioxidant in food. First Edition. CRC Press. New York.
Preti R, Rapa M and Vinci G, 2017. Effect of Steaming and boiling on the antioxidant properties and biogenic amines content in green bean (Phaseolus vulgaris) varieties of different colours. Journal of Food Quality Article ID 5329070, 8 pages. https://doi.org/10.1155/2017/5329070
Prieto P, Pineda M and Aguilar M, 1999. Spectrophotometric quantitation of antioxidant capacity through the formation of a phosphomolybdenum complex: specific application to the determination of vitamin E. Analytical Biochemistry 269: 337-341.
Ramirez ME, Cordoba D, Sanches-M M, Marques C and Goni I, 2013, Effect of boiling on nutritional, antioxidant and physicochemical characteristics in cladodes (OpuntiaFicusIndica). LWT - Food Science and Technology 51:296-302.
Raupp DDS, Rodrigues E, Rockenbach II, Carbonar A and Campos PFD and Borsato ALV, 2011.Effect on antioxidant potential and totalphenolics content in beet (Beta Vulgaris L.). Food Science and Technology (Campinas) 31: 688-693.
Şengül M, Yildiz H and Kavaz A, 2014. The Effect of Cooking on Total Polyphenolic Content and AntAntiioxidant Activity of Selected Vegetables Memnune. International Journal of Food Properties 17(3): 481-490.
Shi J, Nawaz H, Pohorly J and Mittal G, 2005. Extraction of polyphenolics from plant material for functional foods–engineering and technology. Food Reviews International 21: 1–12.
Sun L, Bai X and Zhuang Y, 2012. Effect of different cooking methods on total phenolic contents and antioxidant activities of four Boletus mushrooms. Journalof Food Science and Technology: 51:3362-3368.
Shyamala BN and Jamuna P, 2010. Nutritional content and antioxidant properties of pulp waste from daucuscarota and beta vulgaris. Malaysian Journal of Nutrition 16: 397-408.
Soares AA, Souza CGM, Daniel FM, Ferrari GP, Costa SMG and Peralta RM, 2009. Antioxidant Activity and Total Phenolic Content of Agaricus Brasiliensis (AgaricusBlazeiMurril) In two Stages of Maturity. Food Chemistry 112: 775-781.
Tian J, Chen J, FeiyanLv, ChenSh, Chen JI, Donghong L, Xingqian Y, 2016. Domestic cooking methods affect the phytochemical composition and antioxidant activity of Purple-Fleshed potatoes. Food Chemistry 197: 1264–1270.
Turkmen, N., Sari, F. and Velioglu, Y.S. 2005. The effect of cooking methods on total phenolics and antioxidant activity of selected green vegetables. Food Chemistry, 93: 713–718.
Wachtel-Galor S, Wong KW, and Benzie IFF, 2008. The effect of cooking on Brassica vegetables. Food Chemistry, 110: 706–710.
Yildirim A, Mavi A and Kara AA, 2001. Determination of antioxidant and antimicrobial activities of RumexCrispus L.extracts, Journal of Agricultural and Food Chemistry 49: 4083–4089.
Zhang D, Hamauzu Y, 2004. Phenolics, ascorbic acid, carotenoids and antioxidant activity of broccoli and their changes during conventional and microwave cooking. Food Chemistry 88: 503–509.
Zhu X, Zhang H and Lo R, 2004. Phenolic compounds from the leaf extract of artichoke (Cynara scolymus L.) and their antimicrobial activities, Journal of Agricultural and Food Chemistry 52 52 52 (24): 7272–7278.