Irradiation of Turmeric and Quality Evaluation

Transcription

1 Irradiation of Turmeric and Quality Evaluation Somashekhar.R *Azyme Biosciences Pvt.Ltd, Jayanagar, Bangalore, Karnataka, India ID: Abstract: Turmeric is the dried rhizome of Curcuma longa L. but in many occasions, it contains high microbial load. Irradiation of turmeric rhizome and powder was conducted at different doses (0-10 kgy) using Co 60 batch irradiation unit to make it safe for human consumption. The samples (100g) were packed in metalised polyster polythene laminated pouches prior to irradiation. The irradiated samples were analyzed for physical, chemical and microbial quality. Colour of powder, determined using the principle of reflectance employing CIE system, indicated marginal changes in colour parameters such as hue, chroma and brightness. The extracted colour (Curcumin), oleoresin and volatiles were also determined, and were subjected to further analysis using GC and GC/MS to ascertain the effect of irradiation on volatile oil constituents. The microbial load decreased from 10 6 /g to about 3 x 102/g at a dose rate of 10 kgy wile pathogens (coliform) were eliminated at dose rate of 6kGY. A mathematical model to predict the dose-dependent microbial loads has been proposed. Key words: Oleoresin, color, turmeric, irradiation, volatile oil, pathogens INTRODUCTION Turmeric is the golden spice, and valuable cash crop, native to Southern tropical Asia. It is rich in phenolic compounds- Curcuminoids, is widely used as a dietary spice and coloring agent in food, herbal, medicine and textile industries (Ravindran et al., 2007). Curing is essentially a process of boiling (Cooking) of raw rhizomes in water till the bulbs become soft. Cooking gives the rhizomes (or bulbs) a uniform colour; the starch gets gelatinized, and the time of drying is considerably reduced. Cooked turmeric rhizomes is spread on prepared yards and dried in the sun for days. It gives a metallic sound when shaken inside the palm or broken. Turmeric is the dried rhizome of Curcuma longa L. (Zingiberaceae), an herbaceous plant native to tropical South East Asia. The world production of turmeric is estimated to be about 11 lakh MT, of which India alone accounts for about 90 percent but only some 50, 000 tons of turmeric are exported from India, the rest being consumed within the country (Pradeep etal., ). It is known that exposure of spices to ionizing radiation helps to substantially bring down the microbial load, and also prevents infestation during storage. -irradiation of spices is allowed by international and various national regulatory agencies. A maximum dosage of 10 kgy is permitted. Hence, It was proposed to undertake studies on hygienisation of turmeric rhizomes and powder. The emphasis was on product-oriented approach ie., delivering the spice as a total product with qualities of good flavour, hygiene, acceptable low levels of microbial load and to present as a packaged and shelf-stable product. MATERIAL AND METHODS Turmeric rhizomes were obtained from local archery. were dried using cross flow dryer at 55 0 C± 5 0 C for 3-4 hours to reduce the moisture up to 10-12%. Dried rhizomes were subjected to hammer mill using the 0.77 mm sieve. Samples of dried turmeric rhizome and powder (-30 mesh) were also packed in metalized polyster polythene laminated pouches. The packed rhizome and powder samples were loaded into the irradiation chamber separately and exposed to an irradiation dosage of 0, 2, 4,6,8 and 10kGy to optimize the dose level. Samples was packed in the same packaging material but without irradiation served as control. 310

2 After irradiation all samples were analyzed for physical chemical & microbial quality. The samples was studied for their microbial load and quality parameters namely, curcumin, moisture, volatile oil and oleoresin content. The results are presented in Table 1, 2,.3 and 4. Also, volatile oil distilled (using Clevenger distillation) from both irradiated and control samples were subjected to GC and GCMS to ascertain the effect of irradiation on volatile oil constituents was made various parameters relevant for assessing the quality of turmeric rhizomes and powder was considered and standard analytical procedures (ASTA 1998) were followed. a. Estimation of moisture Moisture content in macerated samples of turmeric rhizomes as well as ground turmeric powder was estimated by toluene codistillation method. [American Spice Trade Association method (ASTA ) method] b. Estimation of Volatile oil Volatile oil content in ground turmeric powder as well as ground irradiated turmeric powder was carried out by hydro distillation method using the Clevenger apparatus (ASTA method). Sodium anhydrous sulphate were added to volatile oil to remove the traces of moisture and stored in refrigerator till use. The volatile oil were subjected to GC and GC/MS to ascertain the effect of irradiation on volatile oil constituents. The sample ( L) 1was subjected to GC-MS analysis. c. Preparation of oleoresin Ground turmeric samples (20 g each in duplicate) was transferred to a small glass column (2.5cm diameter 18 cm length) and extracted individually with the acetone. Material to solvent ratio of 1:12.5 was used for extraction in each case (Naidu et al., 2007). The solvent was added in 10 installments of 25 ml each allowing 30 minutes contact time. The extracts were drained and pooled. The pooled extracts were distilled on hot water bath under reduced pressure and the solvent-free extract was subjected to vaccum to remove the traces of water. The yields of extracts/oleoresin are recorded and presented in Table D. Microbial analysis Analysis for E.coli,, yeast, mould and total bacterial counts was carried out on turmeric rhizomes and powder (both control and irradiation). For yeast and mould count, commercially available Potato dextrose agar media (24g / L) was used. 4.8g of agar were dissolved in 200ml of water in a conical flask with cotton plug and sterilized using autoclave. For E.coli and bacterial count, Mecconky agar media and plate count agar media (17.5g / L each) respectively, was used and results are presented in Table.. e. GC-MS analysis GC-MS analysis was carried out on Shimadzu 17A chromatography coupled with a QP 5000 qudrupole Mass spectrometer. Carrier gas Helium; Flow rate 1ml / min.; Column Temperature: 40(2)-1/min-90-3/min-220; Injection port temperature: 220 C; Detector temperature: 220 C. Ionization voltage 70 ev. Column specification: A fused silica capillary column SPB-1TM -1 (30 m x 0.32 i.d; film thickness 0.25µm) coated with poly dimethyl silican was used. Retention induces of all the constituents were determined by Kovate method using n-alkane as standard (Jenning and Shibamoto, 1980). The sample comparison of their kovate indices with these reported in the literature (Jenning and Shibamoto, 1980). Computer matching of their mass spectral fragmentation pattern with those compounds in the NIST-MS Library (Shimadzu. Tokyo, Japan) and MS data reported in literature compared (Strenhagen et al., 1974, Adams, 1989). The results are presented in table.5 311

3 Table 1. Quality analysis of irradiated turmeric samples Control (%) Irradiation (10 kgy) Quality parameters Moisture Volatile oil Oleoresin Curcumin Moisture Volatile oil Oleoresin Curcumin The samples were analyzed for microbial quality in terms of various parameters as covered under Table.2 Table.2 Microbial quality of irradiated turmeric samples Sl.No. Microbial quality Control Irradiated Control Irradiated 1 Standard plate 10 x est. 2.7 x Coliform count 8800 Not detected 3500 Not detected 3 E.coli (MPN/g) 95% 240 <3 93 <3 confidence limit= Staphylococci/g >3000 Absent in 500 Absent in 0.1g 0.1g 5 S.aureus/g Absent in Absent in Absent in Absent in 0.1g 0.1g 0.1g 0.1g 6 Bacillus cereus/g 140 Not detected 20 Not detected 7 Salmonella in 25 g Absent Absent Absent Absent 8 Yeast 520 Not detected 230 Not detected 9 Mole 30 Not detected 60 Not detected Table.3. Effect of irradiation on turmeric constituents Sl.No. 0 kgy (%) 2 kgy (%) 4kGy (%) 6 kgy (%) 8 kgy (%) 10 kgy (%) Moisture Volatile oil Curcumin Oleoresin Sl.No. 0 kgy (%) 2 kgy (%) 4kGy (%) 6 kgy (%) 8 kgy (%) 10 kgy (%) Moisture Volatile oil Curcumin Oleoresin

4 Table.4 Microbial analysis of irradiated turmeric samples Sl.No. Irradiated dose Standard plate Coliform Yeast & mold 1 2kGy 5,50, kGy 1,80, Absent 3 6kGy 12,000 Absent Absent 4 8kGy <10 est. Absent Absent 5 10kGy <10 est. Absent Absent Sl.No. Irradiated dose Standard plate Coliform Yeast & mold 1 2kGy 6,60, absent 2 4kGy 35,000 Absent Absent 3 6kGy 11,000 Absent Absent 4 8kGy 1,800 Absent Absent 5 10kGy 260 Absent Absent Chemical composition of essential oil of Turmeric #.(GC) S.N o. RT (min) Compound name Peak area (%) KI T0 T4 T8 T Ethylcaproate Caryophyllene ar-curcumene Zingeberene Bisabolene trans-farnesene Nerolidol Dehydrocurcumene Compound-1* ar-turmerone Turmerone Curlone Compound-2* Compound-3* Compound-4* Compound-5* Hexadecanol Octadecanol # Column : SPB-1 (30 M) *MS was compared with that of Hiserodt et al. (1996). 313

5 References ASTA. American Spice Trade Association (1988): Method.1.0 Official Analytical Methods of the American Spice Trade Association, 3 rd ed.; American Spice Trade Association: Englewood Cliffs. Adams, R. P. Identification of Essential Oils by Ion Trap Mass Spectrometry; Academic Press: New York, 1989; p 29. Hiserodt, R.; Hartman, T. G.; Ho, C.-T.; Rosen, R. T. Characterization of powdered turmeric by liquid chromatographymass spectrometry and gas chromatography-mass spectrometry, J. Chromatogr. 1996, 740, Naidu, M.M., Shyamala, B.N., Manjunath, J.R., Sulochanamma, G., & Srinivas, P. (2009). Simple HPLC method for resolution of curcuminoids with antioxidant potential. Journal of Food Science, 74, C312-C318. Pradeep, K., R. Ravi, JamunaPrakash and M. Madhava Naidu (2016) Influence of blanching and drying methods on the quality characteristics of fresh turmeric (Curcuma longa l.) International Journal of Applied and Pure Science and Agriculture (IJAPSA) 2: (3), Ravindran, P., Babu, K.N., & Sivaraman, K. (2007). In: Turmeric: The Genus Curcuma. Ed. CRC Press, Taylor & Francis, Boca Raton, Florida,