ISSN: CHANGE IN ANTIOXIDANT ACTIVITY OF SPICES TURMERIC AND GINGER ON HEAT TREATMENT

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1 ISSN: CHANGE IN ANTIXIDANT ACTIVITY F SPICES TURMERIC AND GINGER N HEAT TREATMENT Vandana Tiwari, Rakhi Shanker, Jyoti Srivastava and Padma S Vankar * Facility for Ecological and Analytical Testing(FEAT). Indian Institute of Technology, Kanpur KEYWRDS Turmeric and Ginger essential oils, Spices, Curcuma longa, Zinger officinale. ABSTRACT Spices show potential health benefits as they possess antioxidant activity, we tried to evaluate the fate of antioxidant activity during the process of cooking. ut of the many spices used in Indian cooking, turmeric and ginger are used in major quantities. Although these dietary spices are resistant to thermal denaturation, interestingly, in the case of turmeric the AA increase on heating while in the case of ginger it shows reduction of AA when powders and oils of these spices were analyzed INTRDUCTIN Turmeric and ginger are very integral part of Indian cooking both in vegetarian as well as non-vegetarian cooking. These spices are common food adjuncts that impart color, flavor and aroma. The active ingredient in turmeric is curcumin and that in ginger are gingerol and hexahydrocurcumin 1-3. Both these compounds prevent oxidation of oils and fats. As these spices are added as flavoring agents to food preparations as crushed paste or dry powder and cooked at high temperature, the present study was undertaken to evaluate the thermal stability and antioxidant activity of these two spices by DPPH method. We analyzed powders and oils of turmeric and ginger, before and after heat treatment (12 C). H 3 C H H 3 C H H H CH 3 Gingerol Curcumin H 3 C H H Hexahydro-curcumin CH3 * Facility for Ecological and Analytical Testing(FEAT). Indian Institute of Technology, Kanpur psv@iitk.ac.in 1313

2 Table. Composition percentage Turmeric and Ginger essential oils 4 Compound Curcuma longa Zinger officinale Tricyclene.25 α-pinene Camphene 9.98 β-pinene.52 Myrcene α-phellandrene α-terpinene 1.26 p-cymene 3.61 β-phellandrene ,8-Cineole Carene.35 Cis-cimene.39 γ-terpinene 1.1 Terpinolene 6.19 Borneol 1.2 α-terpineol.48 Citronellol.37 Nerol.63 Geraniol 1.11 Geranial.17 Bornyl acetate.29 δ-elemene.25 α-cubebene.84 β-elemene 1.19 Sesquithujene.51 β-ylangene.68 β-copaene.43 α, cis-bergamotene γ-elemene.91 Aromadendrene.53 β, cis-farnesene α-humulene.23 Allo-Aromadendrene.53 γ-muurolene 1.81 Ar Curcumene 8.93 γ-curcumene.7 α-curcumene 2.9 Zingiberene β-bisabolene γ-cadinene 3.82 Cis, γ-bisabolene β-curcumene.51 β-sesquiphellandrene Cis-Nerolidol.51 Ar Turmerol.93 α-turmerone 19.8 β-turmerone 7.35 β-eudesmol.23 Ar Turmerone 1.8 Monoterpene hydrocarbons Monoterpenes oxygenated Alcohols Aliphatics 2.59 Ketones 1.2 -Esters.29 -Aldehydes.17 -Ethers 1.3 Sesquit. hydrocarbons Sesquit. oxygenated Total

3 MATERIAL AND METHDS Chemicals Ginger and turmeric powders were bought from the market ( Ashok Masale) Ginger and turmeric oils were purchased from Swaraj Ashram( Rishikesh). DPPH(2,2-diphenyl-1- picrylhydrazyl free radical was purchased from Aldrich Chemical company. Pyragallol was purchased from S.D.Fine Chemical company. All other chemicals were of the highest analytical grade and purchased from common sources. Spice extracts ne gram each of turmeric powder and turmeric oil were weighed separately and extracted in methanol. This extract was centrifuged at 5 rpm and the supernatant was used as source of spice extract. While for ginger powder and oil, methanol: ethyl acetate (5:5) was used as extracting solvent. The spice extract was used directly for DPPH analysis. Heated Spice extracts The spices ( powder and oil) were heated at 12 C for 1 hour and then allowed to cool at room temperature and extracted in the same manner and evaluated for antioxidant activity. Antioxidant Activity The antioxidant properties were assessed by DPPH radical scavenging method. This method is useful for determining the activity of both hydrophilic and lipophilic substrates, thus ensuring a better comparison of the results. Based on a study on onion 5, we decided to study the effect of heat on turmeric and ginger oil and dry powders. Free radical scavenging activity of dry powder was carried out by the following method: The dry powder extracts of ginger and turmeric were measured in terms of hydrogen donating or radical scavenging ability using a stable radical DPPH. 2.8 ml of DPPH solution (45 μg/ ml) were rapidly mixed with 2 μl and 4 μl of methanolic solution of plant extract one at a time in cuvette placed in the spectrophotometer. The absorbance at 515 nm was measured after 5 min. The initial absorbance of the DPPH was The decline in radical concentration indicated the radical scavenging activity of the sample. Pyragallol solution (125 μg/ ml) was used as a reference corresponding to 1% radical scavenging activity. Radical scavenging activity or antioxidant properties was evaluated as percentage was calculated as ( A A ) test ( A A ) ref 1 where as A is the initial absorbance (DPPH + sample absorbance) and A ref and A test are absorbance after 5 min with pyragallol solution and sample solution. 1315

4 Free radical scavenging activity of oils were determined by the following method: An aliquot of ginger or turmeric oil(1 μl) was mixed with 9 μl of 1mM Tris-HCl buffer (ph 7.4), 4 μl of ethanol and 5 μl of.5% (w/w) Tween 2 solution and then added to 1 μl of.5mm DPPH in ethanol. The mixture was shaken vigorously and then immediately placed in UV-Vis spectrophotometer to monitor the decrease in absorbance at 515 nm. Table 1 DPPH results of Dry powders of Ginger and Turmeric Dry Ginger / Powder Turmeric powder Standard Before After Before After BHT 8.46% 6.16% 1.81% 6.1% Pyragallol 3.19% 1.63% 4.13% 1.36% Table 2 DPPH results of ils of Ginger and Turmeric Turmeric oil Ginger oil Before heating After heating RESULTS AND DISCUSSIN Ginger and turmeric are very commonly used dietary spices in Indian cooking both in vegetarian and nonvegetarian preparations. Both of them are cooked at temperatures higher than 1 C. The main objective of this study is to evaluate antioxidant potential of crude spice extract and to check their thermal stability during the process of cooking. We evaluated both the dry powder as well as the oils of these two spices. The crude extracts of the spices and their oils contain more than one antioxidant so it is the synergistic effect of all the potent antioxidant molecules that cumulatively show their antioxidant activity. It is interesting to note that when ginger and turmeric dry powders and oils were heated for 12 C for 1 hour as shown in Table-I and II, the turmeric oil not only retained the antioxidant activity but also showed significantly higher antioxidant activity, as it is known to have higher monoterpenic abundance(34.6) in oil, the situation on the dry powder is reverse. indicating that the spice constituents were resistant to thermal denaturation. The possible release of bound antioxidant principles during heat treatment could be responsible for the higher antioxidant activity. However, it was reverse in the case of ginger oil. These observations imply that thermal stability of spices varies with the individual spice and the cooking conditions. ne study related to freeze-dried ginger powder 6 shows that heat treatment by boiling and frying, shows no change in the antioxidant activity. The heat treatment had no effect on the antioxidant activity. But we have results which show apparent change in antioxidant properties of both these spices. With these results, it might be possible for the food industry to use secondary plant products instead of synthetic compounds to increase the storage stability of processed food items, which might be a good alternative asked for by the consumer. 1316

5 CNCLUSIN ften it is difficult to decide how to protect the antioxidant property from denaturation while cooking,this study shows when and how to add spices to food for retaining their fullest antioxidant properties, for best antioxidant and/or scavenging activities Antioxidant activity (%) Ginger Turmeric Before Different oil before and after heating After ACKNWLEDGEMENT The authors wish to thank Department of Science and Technology, DST, New Delhi under State Council s program on location specific research and technology program- grant. REFERENCES 1..P. Sharma,, Biochemical Pharmacology, Vol-25, 1811, (1976). 2. Y. Masuda; H. Kikuzaki, M.Hisamoto; N. Nakatani, BioFactors 21(1-4), 293, (24). 3. Sugiyama, Y., Kawakishi, S. and sawa, T., Biochemical Pharmacology,Vol-52, 519, (1996). 4. G. Sacchetti, S. Maietti, M. Muzzoli, M. Scaglianti, S. Manfredini, M. Radice, and R. Bruni, Food Chemistry,(in press), (25). 5. M. Takenaka; K. Nanayama; I. hnuki; M. Udagawa,; E. Sanada; S. Isobe, Food Science and Technology Research 1(4), 45, (24).. 6. K. Shindo; N. Masui; Y. Yamada; M. Asano; R. Nakamura, Nippon Kasei Gakkaishi 55(5), 375, (24). 1317