The aim of this study was to evaluate the effect of cooking temperature on the in vitro starch digestibility of four varieties of rice: Basmati, Calrose, Arborio and Bomba. Total starch, resistant starch and amylose contents were determined in raw and cooked samples. The in vitro kinetics of starch hydrolysis were also determined, and the hydrolysis and glycemic indexes were estimated. Both the initial amylose content and the cooking temperature had a significant influence on the resistant starch content. Rice cooked at 95ºC retained a higher resistant starch content than rice cooked at 100ºC. The in vitro study of starch hydrolysis showed that hydrolysis tended to be slower and less complete for rice with a higher amylose content and for rice cooked at a lower temperature. Cooking rice at 95ºC instead of 100ºC reduced the estimated glycemic index by approximately 10% for the varieties tested.
1. AACC Approved Methods. 2000. American Association of Cereal Chemistry, 10th ed., St. Paul, Minnesota.
2. Ahmed N., Tetlow I.J., Nawaz S., Iqbal A., Mubin M., Rehman M.S.N., Butt A., Lightfoot D.A., Maekawa M., Effect of high temperature on grain filling period, yield, amylose content and activity of starch Biosynthesis enzymes in endosperm of basmati rice. J. Sci. Food Agric., 2015, 95, 2237–2243.
3. Al-Mssallem M.Q., Hampton S.M., Frost G.S., Brown J.E., A study of Hassawi rice (Oryza sativa L.) in terms of its carbohydrate hydrolysis (in vitro) and glycaemic and insulinaemic indices (in vivo). Eur. J. Clin. Nutr., 2011, 65, 627–634.
4. AOAC Official Methods of Analysis. 1990. Association of Official Analytical Chemists, 15th ed.,Washington, DC.
5. Champ M., Langkilde A.M., Brouns F., Kettlitz B., Le Bail-Collet Y., Advances in dietary fibre characterisation. 2. Consumption, chemistry, physiology and measurement of resistant starch; implications for health and food labelling. Nutr. Res. Rev., 2003, 16, 143–161.
6. Chung H., Liu Q., Lee L., Wei D., Relationship between the structure, physicochemical properties and in vitro digestibility of rice starches with different amylose contents. Food Hydrocolloid., 2011, 25, 968–975.
7. Goñi I., García-Alonso A., Saura-Calixto F., A starch hydrolysis procedure to estimate glycemic index. Nutr. Res., 1997, 17, 427–437.
8. Han S.H., Lee S.W., Rhee C., Effect of cooking methods on starch hydrolysis kinetics and digestion resistant fractions of rice and soybean. Eur. Food Res. Technol., 2008, 227, 1315–1321.
9. Hu P.S., Zhao H.J., Duan Z.Y., Zhang L.L., Wu D.X., Starch digestibility and the estimated glycemic score of different types of rice differing in amylose contents. J. Cereal Sci., 2004, 40, 231–237.
10. Kaur B., Ranawana V., Henry J., The glycemic index of rice and rice products: A review, and table of GI values. Crit. Rev. Food Sci. Nutr., 2016, 56, 215–236.
11. Leelayuthsoontorn P., Thipayarat A., Textural and morphological changes of Jasmine rice under various elevated cooking conditions. Food Chem., 2006, 96, 606–613.
12. Li H., Prakash S., Nicholson T.M., Fitzgerald M.A., Gilbert R.G., The importance of amylose and amylopectin fine structure for textural properties of cooked rice grains. Food Chem., 2016, 196, 702–711.
13. Lu S., Cik T., Lii C., Lai P., Chen H., Effect of amylose content on structure, texture and α-amylase reactivity of cooked rice. LWT-Food Sci. Technol., 2013, 54, 224–228.
15. Mestres C., Ribeyre F., Pons B., Fallet V., Matencio F., Sensory texture of cooked rice is rather linked to chemical than to physical characteristics of raw grain. J. Cereal Sci., 2011, 53, 81-89.
16. Meullenet J.F.C., Gross J., Marks B.P., Daniels M., Sensory descriptive texture analyses of cooked rice and its correlation to instrumental parameters using an extrusion cell. Cereal Chem., 1998, 75, 714–720.
17. Miao W., Wang L., Xu X., Pan S., Evaluation of cooked rice texture using a novel sampling technique. Measurement, 2016, 89, 21–27.
18. Ranawana D.V., Henry C.J.K., Lightowler H.J., Wang D., Glycaemic index of some commercially available rice and rice products in Great Britain. Int. J. Food Sci. Nutr., 2009, 60, 99–110.
19. Reed M.O., Ai Y., Leutcher J.L., Jane J.L., Effects of cooking methods and starch structures on starch hydrolysis rates of rice. J. Food Sci., 2013, 78, H1076-H1081.
20. Sagum R., Arcot J., Effect of domestic processing methods on the starch, non-starch polysaccharides and in vitro starch and protein digestibility of three varieties of rice with varying levels of amylose. Food Chem., 2000, 70, 107–111.
21. Singh N., Kaur L., Sodhi N.S., Sekhon K.S., Physicochemical, cooking and textural properties of milled rice from different Indian rice cultivars. Food Chem., 2005, 89, 253–259.
22. Srikaeo K., Sangkhiaw J., Effects of amylose and resistant starch on glycaemic index of rice noodles. LWT-Food Sci. Technol., 2014, 59, 1129–1135.
23. Syahariza Z.A., Sar S., Hasjim J., Tizzotti, M.J., Gilbert, R.G., The importance of amylose and amylopectin fine structures for starch digestibility in cooked rice grains. Food Chem., 2013, 136, 742–749.
24. Tamura M., Singh J., Kaur L., Ogawa Y., Impact of the degree of cooking on starch digestibility of rice – An in vitro study. Food Chem., 2016, 191, 98–104.
25. Trinidad T.P., Mallillin A.C., Encabo R.R., Sagum R.S., Felix A.D.R., Juliano B.O., The effect of apparent amylose content and dietary fibre on the glycemic response of different varieties of cooked milled and brown rice. Int. J. Food Sci. Nutr., 2013, 64, 89–93.
26. Varavinit S., Shobsngob S., Varanyanond W., Chinachoti P., Naivikul O., Effect of amylose content on gelatinization, retrogradation and pasting properties of flours from different cultivars of Thai rice. Starch-Stärke, 2003, 55, 410–415.
27. Yu S., Ma Y., Sun D-W., Impact of amylose content on starch retrogradation and texture of cooked milled rice during storage. J. Cereal Sci., 2009, 50, 139–144.
28. Yun S.H., Matheson N.K., Estimation of amylose content of starches after precipitation of amylopectin by concanavalin-A. Starch-Stärke, 1990, 42, 302–305.
29. Zhang X., Wang L., Cheng M., Wang R., Luo X., Li Y., Chen Z., Influence of ultrasonic enzyme treatment on the cooking and eating quality of brown rice. J. Cereal Sci., 2015, 63, 140–146.
30. Zhu L.J., Liu Q.Q., Wilson J.D., Gua M.H., Shi Y.C., Digestibility and physicochemical properties of rice (Oryza sativa L.) flours and starches differing in amylose content. Carbohydr. Polym., 2011, 86, 1751–1759.