This study investigated the physicochemical properties and acceptability of yellow layer cake prepared using various levels of wet-milled rice flour (RF). RF was used to substitute 0% (control group), 15% (RF-15 group), 30% (RF-30 group) and 45% (RF-45 group) of wheat flour (WF) to manufacture yellow layer cakes. The substitution of WF with RF showed no significant effect on the pH but decreased the specific gravity and viscosity of the batter. Baking loss rates ranged from 4.65% to 5.03%, showing no significant difference among samples. In the color measurement, the experimental groups showed higher redness (a) and yellowness (b) than the control group (p<0.05). The experimental groups showed lower gumminess and chewiness than the control group. According to the results of intensity measurement of sensory properties, the RF-30 and RF-45 groups showed stronger intensities for darkness, sweetness, moistness and softness than the control group. The acceptance test found that the RF-45 group had significantly higher or similar results for all acceptance attributes than the control group. These results indicate that RF addition as a replacement of WF at a ratio of 45% is optimal for producing yellow layer cakes.

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.

Korea. Two kinds of jochung products were prepared from steamed rice(SR) and wet-milled rice flour(WRF) by rice cultivated from 2006 to 2010. It is common to add a liquefying enzyme for rice liquefaction(4 ㎖/1, 000 g rice, at 90～95℃, 3 h) and saccharogenic enzyme with malt(45 g/1, 000 g rice, at 55～57℃, 6 h). In order to evaluate the quality characteristics of jochung, producing rate, pH, solidity, reducing sugar, dextrose equivalence(D.E.), viscosity, total phenolic compound, color value and sensory evaluation were carried out. In terms of the producing rate of jochung, WRF jochung was produced about 7.4% much more than SR jochung. There was no difference in producing rate between the jochung cultivated from 2006 to 2010 rice. The pH varied from 4.86～5.66, solidity was 79.48～82.28%. Color L value was 25.82～27.92, a value of 1.28～2.81, b value were 2.98～4.33. The results of sensory evaluation for jochung, as a whole, received higher score than for the commercial product(Daesang Co., Ltd, Seoul, Korea), overall acceptability score was the highest in the 2008SR. Reducing sugar, dextrose equivalence(D.E.) and total phenolic compounds were determined to be higher WRF jochung than SR jochung, while viscosity was lower WRF jochung than SR jochung. These results are thought to be due to increased surface area of rice by milling. SR jochung manufacturd by wet-milled rice flour will increase the producing rate for jochung, thereby saving manufacturing time and costs.

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.