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Int.J.Curr.Microbiol.App.Sci (2018) 7(10): 1490-1503 International Journal of Current Microbiology and Applied Sciences ISSN: 2319-7706 Volume 7 Number 10 (2018) Journal homepage: http://www.ijcmas.com Original Research Article https://doi.org/10.20546/ijcmas.2018.710.167 Characterization of Physio-Chemical Properties of Starch among Traditional and Commercial Varieties of Rice (Oryza sativa L.) using Rapid Visco Analyser B.N. Rithesh1*, S. Ramchander2, S. Rajeswari1, D. Uma3, S. Robin1 and P. Jeyaprakash1 1 Centre for Plant Breeding and Genetics, Tamil Nadu Agricultural University, Coimbatore-641003, Tamil Nadu, India 2 Visiting Scientist (SERB –National Post-Doctoral Fellow), IRRI-South Asia Hub, ICRISAT, Patancheru, Hyderabad, India 3 Department of Biochemistry, Centre for Plant Molecular Biology & Biotechnology, Tamil Nadu Agricultural University, Coimbatore-641003, Tamil Nadu, India *Corresponding author ABSTRACT Keywords Pasting profile, Rapid visco analyser, Pigmented rice, Cooking quality Article Info Accepted: 12 September 2018 Available Online: 10 October 2018 Cooking and eating quality of rice is predominantly influenced by various physio-chemical characteristics of starch. This study was aimed to characterize the physio-chemical properties of starch in commercially and traditionally cultivated rice varieties using Rapid Viscosity Analyser (RVA) in relation to identify the genotype with prominent starch composition to maximize the consumer’s acceptability. Initially a study conducted to determine the amylose content variations among the selected genotypes and measurement on RVA parameters had a significant difference among the varieties. The polished rice flour showed higher range of peak viscosity, hold viscosity, breakdown viscosity, final viscosity and setback viscosity than brown rice flour. It clearly indicated that the step of polishing had a major influence on the pasting curve. In addition, pigmented rice cultivars had variation among the pasting profile due to the effect of colour parameter. It was found that brown rice exhibited intermediate to high amylose content and rangedfrom18.45 % to 25.97 % whereas the polished rice varied between 17.84 % and 23.19 % with the mean value of 22.39 % and 20.40% respectively. The viscosity profile was also interpreted with the rice amylose content to understand the properties of starch in the selection of grains to improve cooking and eating quality for further development. Introduction Rice (Oryza sativa L.), one of the most dietary staple foods in the human diet and quality of rice is determined by the nutritional composition, which is considered as the major factor affecting the technological properties (Ascheri et al., 2012). The different functional properties such as amylose, amylopectin content, gelatinization temperature and pasting profile are the important starchy properties which influence quality of rice (Juliano et al., 1965; Cruz and Khush, 2000; Vanaja and Babu, 2003). Amylose, a long straight starch 1490 Int.J.Curr.Microbiol.App.Sci (2018) 7(10): 1490-1503 molecule that does not gelatinize during cooking is considered a major determinant of rice appearance and cooking quality (Jeevetha et al., 2014). Amylose content is positively associated with hardness and negatively associated with stickiness (Juliano and Pascaul, 1980; Windham et al., 1997). In addition, the amylose content and pasting behaviour of rice starches varies broadly between different varieties and percentage of polishing among same varieties. Pasting is defined as the phenomenon following gelatinization, involving granular swelling, extrudation of the molecular components and, eventually, the total disruption of the starch granules (Atwell et al., 1988; Meadows, 2002). The starch granules of rice play active role in less swelling of starch during gelatinization and lower peak viscosity of starch paste (Tananuwong and Malila, 2011). The Rapid Visco Analyser (RVA) has been widely used for assessing the pasting properties of flour or starch. The assessment of the viscosity during heating and cooling cycles by the RVA provide valuable information on the contact between starch and hydrocolloids (Martinez et al., 2015). However, some characteristics of RVA are closely related to eating and cooking quality of rice and it might be used as an indirect index to evaluate the grain quality (Yan et al., 2005). Therefore, this study reveals that different accessions have different pasting properties and amylose content. The visco profile of genotypes in the form of brown and polished rice flour was determined to know its comparative status. In addition, amylose content was also studied to know the starch behaviour in the influence of pasting profile which would be helpful in selection of good quality lines. The consumer demand for better quality has increased in the developing countries and the grain quality is very important determining issue for the consumer preference and market value. Materials and Methods The present investigation was carried out during 2016-2017 at the Departments of Rice, Centre for Plant Breeding and Genetics, Tamil Nadu Agricultural University, Coimbatore ( N latitude and E longitude with an elevation of 426.72 m above the mean sea level). Twenty-eight rice accessions including traditional and commercial varieties collected from several parts of Tamil Nadu (Table 1) were de-husked to make unpolished (brown) and polished (white) rice using laboratory rice mill (Kett rice polisher) and further each of them were made into flour using small volume (150 mg) powder mixer. Talc like powdered samples was needed for analysis. Hence, good grinding of samples and the sediment powder samples obtained were used for analysis. Amylose content Simplified procedure of Juliano et al., (1981) with minor modification was used for the estimation of amylose content. A well powdered milled rice of 100 mg was weighted and taken into 100 ml volumetric flask. It was added with 1 ml 95% ethanol and 9 ml 1 N NaOH and left overnight. On the Subsequent day distilled water was added to the samples to make up the final volume to 100 ml. Mixed solution of 5 ml from 100 ml was pipetted out into another 100 ml volumetric flask. 1 N acetic acid (1ml) followed by 2 ml iodide solution were added and the volume was made upto to 100 ml. The content was stirred and allowed to stand for 20 min before absorbance was measured at 620 nm with a UVSpectrophotometer. Amylose concentration was obtained by plotting the absorbance in the potato amylose standard curve. Amylose content of each genotype was expressed as percentage to total quantity of sample taken for analysis. 1491 Int.J.Curr.Microbiol.App.Sci (2018) 7(10): 1490-1503 Estimation of pasting behaviours The pasting properties of the rice entries were determined with a rapid visco analyser (Newport Scientific, Australia). Rice flour (3 g) was poured into distilled water (25 mL) in a canister and mixed thoroughly. The mixture was stirred at 960 rpm for 10 seconds and then stirred at 160 rpm. The mixture temperature was first maintained at 50°C for 1.5 min and then raised to 95°C at a rate of 12°C/min. After that, the temperature was maintained at 95 °C for 2.5 min; which was followed by a cooling down period to 50°C with a cooling rate of 12°C/min and was maintained at 50°C for 2.1 min. Each test was made in replicates. A plot of pasting viscosity in an arbitrary RVA unit (RVU) versus time was used to determine the peak viscosity, temperature at peak viscosity, breakdown viscosity, final viscosity and setback viscosity. Statistical analysis Analysis of Variance was performed to test the differences among the rice cultivars at 5 % significance level and Pearson correlation analysis were also performed to find out the association among the traits. Results and Discussion Rice quality is mainly determined by its physiochemical properties and readily available source of starch (Liu, 2005). Pasting characteristic is an essential function of starch to give thickening and sizing effects in food and non-food applications (Shafie et al., 2016). The Pasting properties determines the functional properties of starch which depend on the amylose content, lipid content, branchchain length of the amylopectin, varieties of the starch and cropping environment (Jane, 2004). Traditional varieties have higher nutritional quality than commercial varieties in the form of whole grain (Shafie et al., 2016). The present study exhibited that the pasting parameters were significantly different (p < 0.05) among the rice cultivars. Wide range of peak viscosity, hold viscosity and final viscosity were observed among the polished rice accessions with different classes of amylose content. The trait value differences among the brown and polished rice accessions are presented in Table 2 and 3 (Fig. 1a and 1b). The variation of peak viscosity often associated with the swelling power and the rate of disruption of the starch granules (Corke et al., 1997). Peak viscosity is also an indicative of water-binding capacity and it is often correlated with final product (Thomas and Atwell, 1999; Tran et al., 2001). The peak viscosity of brown rice flour ranged from 374.00 cP (Purple puttu) to 4204.00 cP (ADT 37) with the mean value of 2221.03 cP whereas polished rice flour ranged between 814.50cP (Purple puttu) to 5529.00 cP (Bhavani) with the mean value of 3165.53cP. This study showed that polished rice flour with higher value of peak value in which the granules swell slowly and the disruption was refuted with initial flattered slow peak compared with brown rice. The variety purple puttu showed low peak viscosity in both derivatives which indicates the starch swelled rapidly and resulted in quick peak (Fig. 2a). High peak viscosity is an index of high starch content (Osungbaro, 1990) and clarifies that polished rice flour have higher mean values of peak viscosity with increased degree of polishing. The results are in accordance with Perdon et al., (2001). However, this study also explains that the pigmented rice flour had reduced peak viscosity specifies that major influence of grain colour in pasting. Viscosity trough value or hot paste viscosity of polished rice varied accordingly with 767.50 cP (CO 51) to 4053.00 cP (ASD16) with the mean value of 2294.87cP and brown rice flour ranged from 267.50 cP (Purple puttu) to 3272.50 cP (Pusa basmathi1) with a 1492 Int.J.Curr.Microbiol.App.Sci (2018) 7(10): 1490-1503 grand mean of 1768.71cP. Hu et al., (2004) reported that samples with high amylose content had low hot paste viscosity in rice. This study showed that lower hot paste viscosity in brown rice with higher amylose content than polished rice flour with higher hot paste viscosity. The significant difference in high trough viscosity observed in this study also indicates the tendency of rice to break down during cooking. Higher breakdown viscosity in rice is considered to be an indicator of better palatability (Danbaba et al., 2012). Break down viscosity of polished rice accessions ranged from -9cP (IR 36) to 2590.00 cP (CO 43) with a mean value of 870.66 cP whereas brown rice flour ranged between -2 cP (Swarna) to 1145.00 cP (CO43 and ADT 37) with a mean value of 452.32 cP (Fig. 2a). The rice accessions with highest breakdown viscosity are regarded as good palatable and indicated that polished rice accessions with high breakdown viscosity is more palatable than brown rice. High values of breakdown are associated with high peak viscosities, which in turns are related to degree of swelling of starch granules during heating. Higher cool paste or final viscosity is the most commonly used parameter to determine a particular starch based sample quality and it gives an idea for the ability of the starch to have gel structure after cooking (Danbaba et al., 2012). In the present study, the cool paste viscosity of polished rice ranged from 1000.00 cP (Purple puttu) to 6583.00 cP (ASD 16) with the mean performance of 4366.05cP. In case of brown rice flour, the value ranges from 389.00cP (Purple puttu) to 6276.00cP (IR 20) with the mean value of 3563.55cP (Fig 2a).The cool paste viscosity was higher in all the rice flours when compared to peak viscosity and break down viscosity except CO 43 of polished rice flour which had low cool paste viscosity but higher break down viscosity. There was a significant difference in the setback viscosity of the brown and polished rice flour was observed in all the samples. Setback viscosity indicates the tendency of starch granules to retrograde on cooling. High setback is an indication of the amount of swelling power of the rice sample and is usually related to the amylose content of the sample (Jennifer and Les, 2004; Martin and Smith, 1995) and low set back values also indicates low rate of starch retro-gradation. The setback viscosity has also been correlated with the texture of various end products. This study showed that the brown rice flour with higher amylose had wide range of setback value and varied from 15.00 cP (Purple puttu) to 2436.00 cP (IR 50) with the mean value of 1342.50cP (Fig. 2a). Polished rice flour had a setback value with low mean value of 1200.51 cP compared to brown rice flour. Brown rice flours had varied range of setback value with higher amylose content than polished rice and the rice accessions with similar amylose content may also differ in the pasting curve indicating the heating and cooling cycle among the same sample concentration. Peak time is the measure of the cooking time and it ranged between 5.40min and 7.00 min and 3.80 min to 6.77 min among the polished and brown rice flour respectively. The influence of polishing was also observed in the peak time and significant variation was also observed between different flours. Pasting temperature indicates the initial increase in the temperature. Amylose content also influenced pasting temperature, high amylose content was associated with high pasting temperature and low amylose with lower amylose content (Pongjanta et al., 2016). The higher pasting temperature showed the resistance potential against swelling in the ingredient and in this study it varied according with respect to influenced amylose content of brown and polished rice flours. 1493 Int.J.Curr.Microbiol.App.Sci (2018) 7(10): 1490-1503 Table.1 List of traditional and cultivated varieties of rice used in this study S.no. Genotypes GEB 24 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. TKM 9 BPT 5204 CO 43 CO (R) 50 CO 51 ASD 16 ADT 37 ADT 43 ADT R 45 IR 20 IR 36 13. IR 50 14. CO RH 3 15. 16. 17. Improved White Ponni Pusa basmati 1 CR 1009 Sub 1 18. Bhavani 19. 20. Swarna Improved Kavuni 21. Kavuni 22. 23. 24. 25. 26. Norungan Purple puttu ThavalaKannan Jeeraga Samba Rasacadam 27. 28. Sivapuchithiraikar Mappillai samba Parentage Spontaneous mutant Special Characteristics Good quality rice, fine and best table variety Short bold and red grain Fine grain with good cooking quality Fine grain, Alkalinity and saline tolerant Medium Slender rice Fine grain, High yielding Short bold grain and more straw yield Short bold white rice Medium slender grain Medium slender grain Medium slender grain Medium grain and white rice TKM-7/ IR-8 GEB 24/ Mahsuri Dasal/ IR 20 CO 43/ ADT 38 ADT 43/ RR 272-1745 ADT 31/ CO39 BG 280-12/PTB 33 IR 50/White ponni IR 50/ADT 37 IR 262/ TKM 6 IR 1561-228/1 IR 244/O.nivara/CR 94-13 IR-2153-14-1-6-2/IR 28/ IR- High yielding and short duration 36 TNAU CMS 2A/CB 87 R Medium slender grain and short duration hybrid Selection from white ponni Fine grain white rice and highly preferred for cooking Pusa -150/ Karnal Local Super fine aromatic and white grain Improved version CR 1009 Submerge tolerant, short bold grain with with sub 1 gene high milling percentage Peta / BPI 76 White rice colour and highly preferred for cooking Vasisa / Mahsuri Short bold grain Improved from of Kavuni Black rice, High antioxidant and Antidiabetic Land race of Tamil Nadu Anti-diabetic, High antioxidant, Black rice and Photosensitive Land race of Tamil Nadu Red Rice and Long bold Land race of Tamil Nadu Purple grain and High antioxidant Land race of Kerala Red rice and Photosensitive Land race of Tamil Nadu Fine variety, aromatic and Short slender Land race of Tamil Nadu Grain is very small and round, short slender Land race of Tamil Nadu Open panicle type, long bold Land race of Tamil Nadu Anti-diabetic, Red rice and Medium slender 1494 Int.J.Curr.Microbiol.App.Sci (2018) 7(10): 1490-1503 Table.2 Mean performance of pasting properties (Viscosity parameters) and amylose content for brown rice flour Genotypes GEB 24 TKM 9 BPT 5204 CO 43 CO (R) 50 CO 51 ASD 16 ADT 37 ADT 43 ADT (R) 45 IR 20 IR 36 IR 50 CO R(H) 3 Improved white Ponni Pusabasmathi 1 CR 1009 sub 1 Bhavani Swarna Improved kavuni Kavuni Norungan Purple puttu Thavalakannan Jeeraga samba Rasacadam Sivapuchitiraikar Mapillai samba Mean CV (%) CD @ 5% Peak Hot viscosity paste (cP) viscosity (cP) 1611.50 1419.00 1395.00 1263.50 1204.50 1166.50 3216.00 2071.00 3684.50 2584.50 745.00 447.50 3736.00 2944.00 4204.00 3059.00 1483.50 1473.00 1614.00 1451.00 4157.00 3176.50 2168.50 2050.00 2740.00 2398.50 1557.50 1065.50 1427.00 1283.50 3706.00 3208.00 2556.50 464.50 1326.00 984.50 2232.00 374.00 2482.00 2062.00 1787.00 2453.00 3610.00 2221.03 14.30 651.43 3272.50 2320.00 1753.00 466.50 1309.00 970.50 1713.50 267.50 2105.50 1718.50 1268.00 1831.00 2675.50 1768.71 10.16 368.43 Break down viscosity (cP) 192.50 131.50 38.00 1145.00 1100.00 297.50 792.00 1145.00 10.50 163.00 980.50 118.50 341.50 492.00 143.50 433.00 888.00 803.50 -2.00 17.00 14.00 518.50 106.50 376.50 343.50 519.00 622.00 934.50 452.32 50.00 463.65 Cool Setback Peak Pasting Amylose paste viscosity time temperature content viscosity (cP) (mins) (̊C) (%) (cP) 3807.00 2195.50 6.17 90.55 22.09 2313.00 918.50 6.57 90.55 19.69 2841.00 1637.00 6.50 93.30 19.76 4276.00 1060.50 5.60 79.73 18.45 4925.00 1240.50 5.70 79.70 21.50 1542.00 797.00 5.50 88.95 21.84 5158.00 1422.50 5.93 83.30 22.14 5533.00 1329.00 5.80 82.15 21.62 3101.00 1618.00 6.77 90.15 23.49 3503.00 1888.50 6.30 88.88 20.36 6276.00 2119.00 6.10 82.15 23.45 3894.00 1725.50 6.64 88.53 20.15 5176.00 2436.00 5.97 85.68 23.28 2860.00 1302.50 5.93 88.13 20.80 2701.00 1274.00 6.40 89.73 23.88 5192.00 5190.50 3735.00 831.00 2693.50 1945.00 3397.50 389.00 3710.50 3718.00 2953.00 3702.00 4414.00 3563.55 14.60 1066.59 1486.00 1982.50 1179.00 366.50 1367.50 961.00 1165.50 15.00 1228.50 1656.00 1166.00 1249.00 804.00 1342.50 44.55 1226.14 6.35 6.00 5.50 6.40 6.60 6.24 5.87 3.80 6.40 6.07 5.83 5.87 5.43 6.00 5.13 0.63 *Data are based on the average of two replicates and the values are significantly different at p<0.05 1495 86.45 80.13 82.95 92.90 89.80 84.90 84.10 73.80 84.83 86.55 77.73 77.75 80.45 85.13 2.44 4.27 22.62 23.32 21.06 22.28 23.71 25.66 24.75 23.10 23.88 19.97 25.97 23.67 24.53 22.39 5.91 2.71 Int.J.Curr.Microbiol.App.Sci (2018) 7(10): 1490-1503 Table.3 Mean performance of pasting properties (Viscosity parameters) and amylose content for polished rice flour Genotypes GEB 24 TKM 9 BPT 5204 CO 43 CO (R) 50 CO 51 ASD 16 ADT 37 ADT 43 ADT (R) 45 IR 20 IR 36 IR 50 CO R(H) 3 Improved white ponni Pusabasmathi 1 CR 1009 sub 1 Bhavani Swarna Improved kavuni Kavuni Norungan Purpleputtu Thavalakannan Jeeraga Samba Rasacadam Sivapuchitiraikar Mapillai samba Mean CV (%) CD @ 5% Peak Hot Break Cool paste Setback Peak Pasting Amylose viscosity paste down viscosity viscosity time temperature content (cP) viscosity viscosity (cP) (cP) (mins) (̊C) (%) (cP) (cP) 1842.00 1686.00 156.00 3146.00 1304.00 6.50 87.75 20.29 1543.00 1379.00 164.00 2321.50 778.50 6.33 88.90 19.67 992.00 894.50 97.50 2065.00 1073.00 6.24 86.55 17.84 5145.00 2555.00 2590.00 4974.00 -171.00 5.40 78.55 18.43 5086.00 2974.00 2112.00 5615.50 529.50 5.54 78.58 20.51 1399.00 767.50 631.50 1706.00 307.00 5.70 80.48 20.45 5471.00 4053.00 1418.00 6583.00 1112.00 6.10 82.15 19.54 4705.00 3357.00 1348.00 6446.00 1741.00 5.87 82.45 18.19 2975.00 2816.00 159.00 6101.00 3126.00 6.44 88.90 20.01 3813.50 3180.50 633.00 6158.00 2344.50 5.94 83.80 19.88 4495.00 2514.50 1980.50 5206.00 711.00 5.60 80.90 23.19 2357.00 2366.00 -9.00 4405.00 2048.00 7.00 89.80 18.62 4170.50 3256.50 914.00 6116.00 1945.50 5.94 84.45 21.32 2699.00 1762.00 937.00 3523.50 824.50 6.04 79.75 20.10 1889.00 1626.00 263.00 3221.00 1332.00 6.27 87.15 19.45 3721.00 4505.00 5529.00 1146.50 2930.00 1972.50 3006.50 814.50 2644.50 3255.50 2366.00 2612.50 4306.00 3165.53 9.84 638.69 3164.00 2987.00 3293.50 961.50 2407.00 1762.50 2039.00 781.00 2295.00 2453.00 1753.00 1959.50 3123.00 2294.87 10.13 476.68 557.00 1518.00 2235.50 185.00 523.00 210.00 967.50 33.50 349.50 802.50 613.00 653.00 1183.00 870.66 26.52 473.44 6370.00 6185.00 6006.50 1761.00 4464.00 3250.50 3876.00 1000.00 4282.50 4931.50 3388.50 3754.50 5153.50 4366.05 6.99 626.16 2649.00 1680.00 477.50 614.50 1534.00 1278.00 869.50 185.50 1638.00 1676.00 1022.50 1142.00 847.50 1200.51 20.30 499.62 6.04 5.87 5.64 6.03 6.30 6.00 5.64 5.60 6.47 5.97 5.97 5.94 5.43 5.93 6.72 0.81 *Data are based on the average of two replicates and the values are significantly different at p<0.05 1496 88.03 78.90 81.68 88.20 82.55 84.20 80.90 72.95 85.73 86.10 77.00 77.78 80.48 82.66 2.10 3.57 18.66 20.58 20.93 21.97 21.71 22.23 20.97 21.53 21.40 19.75 21.49 21.01 21.53 20.40 5.91 2.47 Int.J.Curr.Microbiol.App.Sci (2018) 7(10): 1490-1503 Table.4 Genotypic correlation among the pasting profile traits and amylose content for brown rice flour Peak Peak Hot Break Cool Set Time Temp Amy 1 0.977** 0.872** 0.978** 0.648** -0.006 -0.442* -0.029 1 0.748** 0.971** 0.687** 0.139 -0.313 0.010 1 0.819** 0.442* -0.303 -0.660** -0.116 1 0.792** 0.152 -0.297 -0.034 1 0.543** 0.211 -0.037 1 0.750** -0.022 1 -0.298 Hot Break Cool Set Time Temp 1 Amy **,* Correlation is significant at 1% and 5 %. Table.5 Genotypic correlation among the pasting profile traits and amylose content for polished rice flour Peak Hot Break Peak Hot Break 1 0.922** 1 Time Temp Amy 0.871** 0.895** 0.102 -0.943** -0.220 -0.123 0.613** 0.981** 0.442* -0.483* 0.008 -0.167 1 0.582** -0.351 -0.971** -0.458* -0.039 1 0.536** -0.307 0.071 -0.178 1 0.947** 0.573** -0.164 1 0.971** 1 0.073 -0.282 Cool Cool Set Time Temp Set 1 Amy PV : Peak viscosity HPV : Hot paste viscosity BV : Break down viscosity SV : Setback viscosity CPV : Cool paste viscosity Time : Time at viscosity peak Temp : Pasting temperature Amy : Amylose content **,* Correlation is significant at 1% and 5 %. 1497 Int.J.Curr.Microbiol.App.Sci (2018) 7(10): 1490-1503 Fig.1a Comparative pasting profile of brown rice in traditional and cultivated varieties of rice Fig.1b Comparative pasting profile of polished rice in traditional and cultivated varieties of rice 1498 Int.J.Curr.Microbiol.App.Sci (2018) 7(10): 1490-1503 Fig.2a Comparison of starch pasting properties between brown and polished rice of traditional and cultivated varieties of rice 1499