Glycaemic index of parboiled rice depends on the severity of processing: study in type 2 diabetic subjects

Eur J Clin Nutr. 2000 May;54(5):380-5. doi: 10.1038/sj.ejcn.1600969.


Objective: To study the influence of parboiling and the severity of the process on glycaemic and insulinaemic responses to rice in type 2 diabetes. Moreover, to examine changes in starch structure related to parboiling, which may affect the metabolic responses and digestibility.

Design: Nine type 2 diabetic subjects ingested four test meals: white bread (WB) and three meals of cooked polished rice of the same variety being non-parboiled (NP), mildly traditionally parboiled (TP) and severely pressure parboiled (PP). The participants ingested the test meals (50 g available carbohydrates) on separate occasions after an overnight fast.

Setting: Outpatient clinic, Dept. Endocrinology and Metabolism, Aarhus University Hospital, Denmark.

Results: All three rice samples elicited lower postprandial plasma glucose response (NP: 335+/-43; TP: 274+/-53; PP: 231+/-37 mmol/1*180 min.; means+/-s.e.m.) than white bread (626+/-80; P<0.001), within rice samples PP tended to be lower than NP (P=0.07). The glycaemic indices were: NP: 55+/-5, TP: 46+/-8 and PP: 39+/-6, and lower for PP than NP (P<0.05). The insulin responses were similar for the three rice meals, which were all lower than that to white bread (P<0.001). Differential scanning calorimetry showed the presence of amylose-lipid complexes in all rice samples and of retrograded amylopectin in PP. Amylose retrogradation was not detected in any of the rice samples.

Conclusions: All rice test meals were low-glycaemic in type 2 diabetic subjects. There was no effect of TP on glycaemic index, whereas PP reduced the glycaemic index by almost 30% compared to NP.

Sponsorship: The Royal Veterinary and Agricultural University, Aarhus University Hospital, Danish International Development Assistance (DANIDA), Ministry of Foreign Affairs and the 'Konsul Johannes Fogh-Nielsens og Fru Ella Fogh-Nielsens Legat' foundation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Blood Glucose / metabolism*
  • Calorimetry, Differential Scanning
  • Diabetes Mellitus, Type 2 / blood*
  • Diet*
  • Female
  • Food Handling*
  • Hot Temperature*
  • Humans
  • Insulin / blood
  • Kinetics
  • Male
  • Middle Aged
  • Oryza* / chemistry
  • Starch / analysis
  • Thermodynamics


  • Blood Glucose
  • Insulin
  • Starch