Cereal grains are the dietary staple in many countries, including the Republic of Korea. These grains are usually consumed cooked. Korean grown raw and cooked brown non-glutinous rice (BNR), white non-glutinous rice (WNR), oats, and barley were analyzed to assess the effects of cooking on dietary fiber and free sugar content. The largest decrease in total dietary fiber (TDF) after cooking was observed in barley (11.62±1.26 to 2.96± 0.90 g/100 g), and the smallest decrease was observed in oats (8.1±0.34 to 8.1±0.32 g/100 g). Soluble dietary fiber decreased in oats (3.35±0.94 to 1.25±0.03 g/100 g) while insoluble dietary fiber increased (4.76±0.78 to 6.90±0.30 g/100 g) after cooking. TDF content was not changed. Of the six free sugars routinely assessed, only sucrose was detected in BNR and WNR. Sucrose decreased by about 0.6 g/100 g in BNR, and was not detected in WNR, after cooking. Fructose, sucrose, and raffinose were detected in oats (0.08, 0.83, and 0.19 g/100 g) and barley (0.09, 0.58, and 0.22 g/100 g) Maltose was also detected in barley (0.09 g/100 g). Total sugar content decreased in every cereal grain sample after cooking. This research reveals that dietary fiber and free sugar content can be reduced by cooking cereal grains.

ABSTRACT
Materials and Methods
    Sample preparation
    Analysis of dietary fiber
    Standard sample preparation for free sugar analysis
    Free sugar analysis using HPLC
    Statistical analysis
Results and Discussion
    Dietary fiber contents of raw cereal grains
    Change in dietary fiber contents of cooked cereal grains
    Free sugar content of raw cereal grains
    Change of free sugar content in cooked cereal grains
Acknowledgement
국문요약
Conflict of interests
ORCID
References

• Rheeno Lee(Department of Food Science and Technology, Jeonbuk National University, Jeonju, Korea)
• Yong-Suk Kim(Department of Food Science and Technology, Jeonbuk National University, Jeonju, Korea) Corresponding author