Uptake and Volumetric Expansion of Rice during Cooking

Transcription

1 Studies of Solids Leached, Water Uptake and Volumetric Expansion of Rice during Cooking Rice Processing Program Industry Alliance Meeting August 5 6, 2009 Center of Excellence for Poultry Science University of Arkansas Marianne C. Rice Dr. Rubén O. Morawicki

2 Overview Cooking Study Effects of milling duration, cultivar and water-to- rice ratio on solids leached, water uptake and volumetric expansion NIR Study Preliminary results of using NIR to predict solids Preliminary results of using NIR to predict solids leached, water uptake and volumetric expansion

3 Cooking Rice INTRODUCTION

4 Solids Leached Related positively to the water uptake and inversely to the amylose content (Bergman, 2004) Increases with cooking time (Yadav, (Yd 2007) Increases with water-to-rice ratio (Nierle, 1981)

5 Water Uptake Amount of water absorbed by a known quantity of rice (Bergman, 2004) Fluctuates in excess water (Yadav, 2007) Bhattacharya and Sowbhagya (1971) Physical size and shape of the grain Characteristics different in short-, medium-, and long-grain rice Greatest in long-grain U.S. rice cultivars

6 Volumetric Expansion Affected by grain properties (Ge, 2005) Cooking temperatures (Ramesh, 2001, Sowbhagya, 1994) Increases with an increase in milling duration g (Mohapatra, 2006)

7 Cooking Rice METHODS

8 Diagram of Analysis Factors Cultivar Milling Duration (sec) Water to Rice Ratio Levels Francis; Jupiter 10; 20; 30 10:1; 15:1; 20:1 Cooked Rice Water Water Uptake Volumetric Expansion Solids Leached Amylose Protein

9 Cooking Method 20-g samples Placed in boiling water Covered with aluminum foil with an ice cube Simmered for 20 min

10 Solids Leached Collected water in a pre-weighed beaker Evaporated water in a 239 F oven for 24 h Determined weight of dried solids

11 Water Uptake Water absorbed during cooking

12 Volumetric Expansion Uncooked rice 50 ml of hexane in a graduated cylinder 20 g rice added Cooked rice 150 ml of hexane in a graduated cylinder Cooked rice added Calculation (cooked volume uncooked volume) / uncooked volume

13 Cooking Rice RESULTS

14 Solids Leached 2.6 The Effects of Increasing Water-to-Riceto Ratio on Solids Leached ached (g) Solids Le Francis Jupiter to 1 15 to 1 20 to 1 Water-to-Rice to Ratio Significance in a linear fashion (p<0.0001)

15 Solids Leached Francis Jupiter Leached (g) Solids s 20 s 30 s Leached (g) Solids s 20 s 30 s to 1 15 to 1 20 to to 1 15 to 1 20 to 1 Water-to-Rice to Ratio Water-to-Rice to Ratio

16 Water Uptake The Effects of Milling Duration on Water Uptake Wate er Uptake 270% 250% 230% 210% 190% 170% Francis Jupiter 150% Milling Duration (s) Milling Duration (s) Linear and cultivar dependent

17 Water Uptake Francis Jupiter 270% 270% 250% 250% Wate er Uptake 230% 210% 190% 10 to 1 W/R 15 to 1 W/R 20 to 1 W/R Wate er Uptake 230% 210% 190% 10 to 1 W/R 15 to 1 W/R 20 to 1 W/R 170% 170% 150% % Milling Duration (s) Milling Duration (s)

18 Volumetric Expansion Percen nt Volume etric Expan nsion The Effects of Milling Duration on Percent Volumetric Expansion Milling Duration (s) Milling Duration (s) Linear trend of DOM Francis Jupiter

19 Volumetric Expansion Francis Jupiter % Volume etric Expansio on to 1 W/R 15 to 1 W/R 20 to 1 W/R % Volume etric Expasnio on to 1 W/R 15 to 1 W/R 20 to 1 W/R Milling Duration (s) Milling Duration (s)

20 Cooking Rice CONCLUSION

21 Cooking Conclusions Water uptake and volumetric expansion increase with milling duration Solids leached increases with water-to-rice ratio

22 NIR Scanning METHODS

23 NIR Study 75 samples from 3 locations in Arkansas One milling duration 30 s Scan milled rice using i Perten P t DA 7200 One water-torice ratio = 10:1 Multivariate data analysis Scanned cooking water Cooking water was strained Cook 20 minutes

24 Scanning of Cooking Water 1 ml was used A white scanning cup with filter was used for substances when A >1.4 Placed under the scanner: stationary method

25 NIR Scanning PRELIMINARY RESULTS

26 Milled Rice Scans: Solids Leached NIR Absorban nce y = x R² = Solids Leached (g)

27 Milled Rice Scans: Solids Leached Long Grain Medium Grain NIR Absorbance y = x R² = NIR Absorbance y = x R² = Solids Leached (g) Solids leached (g)

28 Milled Rice Scans: Water Uptake NIR Absorban nce y = x R² = Water Uptake (g)

29 Milled Rice Scans: Water Uptake Long Grain Medium Grain NIR Absorbance y = x R² = NIR Absorbance y = x R² = % 200% 250% 300% Water Uptake 0 150% 200% 250% 300% Water Uptake

30 Milled Rice Scans: Volumetric Expansion NIR Absorban nce y = x R² = Percent Volumetric Expansion

31 Milled Rice Scans: Volumetric Expansion Long Grain Medium Grain NIR Absorbance y = x R² = NIR Absorbance y = x R² = Percent Volumetric Expansion Percent Volumetric Expansion

32 Water Scans: Solids Leached NIR Absorban nce y = x R² = Solids Leached (g)

33 Water Scans: Water Uptake Volumetric Expansion NIR Absorbance NIR Absorbance y = x R² = % 150% 200% 250% 300% 315 y = x R² = Water Uptake Percent Volumetric Expansion

34 NIR Scanning CONCLUSIONS

35 Conclusions No one general model can be made for predictions Dividing milled rice scans by grain type improved correlations Water scans have a high correlation with solids leached but not water uptake or volumetric expansion

36 Questions? THANK YOU! Special Thanks to Dr. Mohammed Saleh for all his help and input with my research.