This study investigated the effect of dry heat treatment (DHT) on the physicochemical properties of hard type (HR) and floury type (FR) rice to improve the processing aptitude of rice flour. The rice flour was heated at 130oC for 0, 2 and 4 hours, and the color value, water absorption index (WAI), water soluble index (WSI), swelling power, solubility, pasting properties, particle shape and the X-ray diffraction were measured. After DHT, the L value of rice flour decreased, and the b value increased. The WAI, WSI, swelling power and solubility of HR and FR increased with the increase of treatment time. The cold viscosity and setback increased, while breakdown decreased. Cracks and lumps formed with fine particles were observed. The X-ray diffraction pattern was A-type, while the diffraction intensity decreased. According to the results of the two-way analysis of variance (ANOVA) test, the hydration and pasting properties were significantly different between HR and FR and were affected by DHT time. The results suggest that the properties of modified rice flour by DHT can be used in the food industry.

This study was carried out to investigate milling's effect on the pasting properties and storage stability of dry-milled rice flour. Rice flour's moisture content was increased from 9.48% to 9.80% after going through a rice polisher, and the crude fat content of rice flour was decreased from 0.91% to 0.62% after going through a rice polisher. In the color index of rice flour, the rice polisher was only affected by yellowness. The pasting properties were verified through RVA, and it was confirmed that the use of a rice polisher had no significant effect on the pasting properties. As a result of observing the changes in fatty acid value, it was ascertained that the storage period could be increased using the rice polisher. These results suggest that the rice polisher can increase the storage period without changing the pasting properties.

In this study, the effects of different varieties and particle sizes of dry milled rice flour on Jeolpyeon quality were investigated. Classify particle size of dry milled rice flour according to rice variety into 50, 100, and 150 μm. A particle size of 50 μm in the varieties Boramchan and Hanareum resulted in the highest damaged starch contents (p<0.05). Additionally, the Boramchan and Hanareum varieties had the highest water absorption index (WAI) values (p<0.05). Analysis of the gelatinization characteristics of dry milled rice flour according to varieties revealed the peak viscosity of Dasan and Hanareum was high (p<0.05), regardless of particle size, while the breakdown was highest for Hanareum at all particle sizes (p<0.05). The moisture content of Jeolpyeon made with Boramchan varied between 48.83 and 53.64% among particle sizes, with no significant differences relative to the control. The hardness of the control was 3.15 kg, while the hardness of Jeolpyeon made with Boramchan decreased significantly 2.60-2.63 kg (p<0.05).

In this study, dry-milled rice flour from different varieties (Samgwang, Boranchan, Hanareum, Dasan, Hangaru) and different particle sizes were used to manufacture Jeung-pyun and the quality characteristics were analyzed. The Jeung-pyun produced from Samgwang, Dasan and Hangaru milled rice flour showed highly dense pores. The Jeung-pyun produced from Hanareum only showed a significant difference according to the particle size. Samgwang, Boranchan and Dasan varieties with a particle size of 150 m showed a significant decrease in volume (p<0.05). Samgwang showed the lowest pH at all particle sizes (p<0.05). The sweetness of Samgwang varieties was the highest at 3.27-3.63°Brix (p<0.05). The hardness of Jeung-pyun increased with increasing particle size (p<0.05). The highest acceptance of Jeung-pyun in terms of volume and bitter taste was observed with Hanareum at a particle size of 50 m. When the particle size was 50 m, the overall acceptance was highest for Jeung-pyun made from Samgwang followed by Hanareum. The acceptance of all the sensory characteristics was high when the particle size of rice flour was 50 m. When the appearance of Jeung-pyun was measured, Samgwang showed a dense structure and low hardness. Hanareum showed an increasing volume and springiness. Overall Samgwang and Hanareum were found to be the most suitable varieties for the production of Jeungpyun.

본 연구에서는 쌀 가공식품에 대한 쌀가루 종류, 유지 종류 및 첨가량의 효과를 제공하고, 쌀빵의 제빵 특성 및 제조방법을 확립하기 위해 습식 및 건식 쌀가루의 물리적 특성을 조사하였으며, 버터 및 식용유를 4.0~5.8% 첨가하였을 때 반죽 및 쌀빵의 특성, 텍스처 특성을 비교 분석하였다. 습식 및 건식 쌀가루의 물리적 특성에서 수분함량은 습식 쌀가루가 건식 쌀가루에 비해 높았고(p<0.001), 전분손상도는 건식 쌀가루가 습식 쌀가루에 비해 높았으며(p<0.001), 쌀가루의 평균 입자크기는 습식 쌀가루가 건식 쌀가루보다 크게 나타났다(p<0.001). 습식 및 건식 쌀가루의 amylogram과 RVA에 의한 pasting 특성에서 습식 쌀가루 A가 결과값들이 크게 조사되었고, 그 다음 건식 쌀가루 C와 B 순으로 나타났다(p<0.001). 습식 및 건식 쌀가루 현탁액의 DSC 측정 결과, 습식 쌀가루 A는 건식 쌀가루 B와 C에 비해 전분호화 개시온도와 전분호화 최고온도가 낮았고, 쌀가루의 호화엔탈피는 습식 쌀가루 A는 10.5 cal/g, 건식 쌀가루 B와 C는 10.1과 2.71cal/g으로 조사되었다(p<0.001). 습식 및 건식 쌀가루의 유지류 첨가 비율에 따른 쌀빵 반죽의 발효 전과 후 비중은 버터 첨가군이 식용유 첨가군보다 높았고, 색도 분석에서는 습식 쌀가루 A가 건식 쌀가루 B와 C에 비해 L값이 높게 나타났다(p<0.001). 쌀가루 종류에 따라 쌀빵의 부피와 비용적은 건식보다 습식 쌀가루가 크게 나타났으며, 버터 첨가군보다 식용유지 첨가군이 크게 나타났다(p<0.001). 쌀빵의 색도 분석에서는 L, a 및 b값이 유의적인 차이를 나타내었다(p<0.001). 쌀빵의 텍스처 특성에서 식용유 첨가군이 버터 첨가군보다 경도가 낮았으며(p<0.001), 습식 쌀가루 A와 건식 쌀가루 B로 만든 쌀빵은 식용유 첨가 수준이 증가할수록 경도가 낮아졌으며, 이러한 경향은 건식 쌀가루 C로 제조한 쌀빵의 경우에서는 보이지 않았다(p<0.001). 쌀빵의 모양은 습식 쌀가루보다 건식 쌀가루에서 빵 중간이 푹 커진 모양을 볼 수 있었으며, 그리고 식용유 첨가군보다 버터 첨가군에서 이러한 현상을 볼 수 있었다. 따라서 쌀빵 제조에 건식 쌀가루보다 습식 쌀가루가, 버터 첨가군보다 식용유 첨가군이, 식용유 첨가군에서는 4.0%보다 5.8% 첨가할 경우, 제빵 효과가 있는 것으로 조사되었다.

Although rice production gradually increased in Korea, rice consumption has been significantly reduced during the last decade. To increase rice consumption, it is necessary to develop a wide range of rice-processed foods and functional rice materials. In association with digestion in rice-functional materials, people are interested in resistant starch (RS). The purpose of this study was to develop the citrated organic rice flour by dry process with different treatments and to investigate its physicochemical properties. Citric acid (0, 20, 30, 40% dry basis) was mixed with organic rice flour and reacted at 105oC and 150oC for 5 h. The degree of substitution increased with increasing citric acid concentration and reaction temperature. In DSC, when reacted at 105oC, onset temperature gradually decreased with increasing citric acid concentration but no DSC thermal characteristics were observed when reacted at 150oC. Relative crystallinity determined by XRD did not greatly change at 105oC but dramatically decreased at 150oC. As citric acid concentration and reaction temperature increased, rapidly digestible starch, slowly digestible starch, and total starch decreased but RS significantly increased. Therefore, RS content in organic rice flour increased with dryprocessed citric acid treatment and this could be applicable to produce functional foods for diabetes.

Rice flours from five rice (Oryza sativa L.) varieties with different amylose content were prepared by both wet and dry milling processes. The moisture content of wet-milled rice flours (WMR) was approximately three-times higher than that of dry-milled rice flours (DMR). Water absorption index (WAI), water solubility index (WSI), and swelling power (SP) increased in proportion to temperature. The WAI, WSI and SP values of DMR were higher than those of WMR. Baeokchal (BOC), which is a waxy rice cultivar, had a significantly high WSI value. Pasting properties of DMR, except for the BOC cultivar, resulted in an increase in peak, trough, final, and setback viscosities. The levels of resistant starch in four cultivars, except for Dodamssal (DDS), were under 1%, irrespective of the milling process, whereas the resistant starch contents of DMR and WMR in DDS were 9.18% and 6.27%, respectively. In vitro digestibility of WMR was higher than that of DMR, and the estimated glycemic index of the rice flour varieties ranged from 57.6 to 81.3. Damaged starch content of WMR was less than that of DMR; in addition, a negative correlation was observed between the amylose and damaged starch contents of WMR. These results suggest that the properties of rice flour vary depending on the milling method and flour variety, and could be a reference for selecting the appropriate processing method.

본 연구를 통하여 조생 다수성 벼 품종인 남일벼의 돌연변이 후대계통으로 'Namil(SA)2652-RGA-l-l-l-l'의 계보를 지니며 Namil(SA)-flo1로 명명된 분질계통의 건식제분 적성과 쌀가루의 이화학적 특성과 호화특성 등을 평가하였다. 배유절단면의 전자현미경 관찰결과 원품종인 남일벼는 배유절단면이 부드러우며 다변각의 전분립들이 치밀하게 배열된 반면 Namil(SA)-flo1은 원형모양의 전분립들이 매우 성기게 배열되어있었다. Namil(SA)-flo1의 작물학적 특성은 남일벼와 유사하였으나 등숙비율과 천립중이 낮았으며 이러한 특성은 백미수량 감소로 이어짐을 알 수 있었다. 조직분석기들 이용한 곡립경도측정 결과 Namil(SA)-flo1는 3,417 g으로 남일벼 (7,526 g)의 45% 수준으로 매우 낮았다. 건식제분기인 Buhler 제분기를 이용해 동일조건에서 생산된 쌀가루들에 대한 입도분석결과 Namil(SA)-flo1는 평균 86.1um 로서 원품종인 남일벼 (109.1um )는 물론 화성벼(112.2um )나 설갱벼 (97.6um )보다 매우 고운입자로 이루어져 있음을 확인하였다. 건식제분에 의한 쌀가루의 손상전분량 역시 Namil(SA)-flo1가 5.1% 수준으로 남일벼 (9.2%), 화성벼(10.3%) 및 설갱벼(7.1%) 보다 매우 낮아 Namil(SA)-flo1의 높은 건식제분 적합성을 확인할 수 있었다. 반면 Namil(SA)-flol에서 생산된 쌀가루의 이화학적 특성과 호화특성은 원품종인 남일벼의 고유한 특성을 견지하고 있는 것으로 사료되었다.