This study was conducted to evaluate the characteristics of bread and the rheology of flour dough containing jochung. In the farinogram test, the addition of jochung changed water absorption, development time and mixing tolerance index for making bread As the amount of jochung increased, the water absorption, mixing tolerance index decreased and the development time increased. In the extensograph test, the degree of extension decreased with increasing of jochung content whereas degree of resistance was enhanced with addition of jochung. After fermentation treatment, the volume of the dough with 20% sucrose were less than that of the dough containing 20% of jochung. The dough with 5% jochung showed the lowest dough raising power compared to the other doughs. The bread consisting of 15% jochung showed the highest volume of loaf and specific volume. Therefore, high quality of bread can be achieved by adding jochung instead of sucrose for making bread.

This study was performed to investigate the effect of Gastrodia elata powder on the quality characteristics of Jochung with barley malt. Grain syrups with 0, 2.5, 5, 7.5, and 10% Gastrodia elata powder were produced. The pH value decreased with higher volume of Gastrodia elata powder and showed a significant difference between the samples (p<0.05). Total polyphenol content was 77.45~129.25 mg/100 g, and DPPH radical scavenging ability was 36.70~57.09 μmol. Sensory score of Jochung containing 2.5% Gastrodia elata powder was similar to that of control. Jochung containing less than 7.5% Gastrodia elata powder gave the highest scores in terms of quality characteristics and sensory evaluation. The data from different procedures were compared and analyzed by multivariate techniques (correlation matrix, principal component analysis). Correlations between antioxidant activity and the analyzed parameters were found to be statistically significant (p<0.05).

This study was performed to increase the yield and to reduce the processing times for the preparation to improve the productivity and quality of rice jochung, a traditional food in Korea. In order to evaluate the quality characteristics and yield of jochung, the viscosity, color value, mineral contents and the sensory evaluation were measured. Jochung is prepared from steamed rice (STR), wet-milled rice flour (WRF) and dry-milled rice flour (DRF) by processing methods of rice and reacting times (6 hours or 13 hours) of liquefaction and saccharification. There is commonly added liquefying enzyme for rice liquefaction (0.4%/10 kg rice, at 85~90℃ for 1 hour or 4 hours) and saccharogenic enzyme with malt (2.5% or 4.5%/10 kg rice, at 56~60℃ for 5 hours or 9 hours). The inner structural properties of WRF showed the more distinct shape regular structure of uncombined starch particles but the DRF closely maintained particles of rice flour observed by SEM. If processing times for liquefation and saccharification were reduced from 13 hours to 6 hours, the yield of jochungs prepared with WRF increased 8%, the DRF 7%, and the STR 3% respectively and the sensory evaluation as well as color values and overall desirability received high scores. The viscosity, color a and b values of jochung processed with WRF for 6 hours were lower than that processed for 13 hours. The viscosity and color a, b value and Ca content were decreased in the jochung processed with WRF or DRF for 6 hours, but Mg, P and K were increased than that of STR. Jochung processed by 0.4% liquefying enzyme and 2.5% malt with WRF for 6 hours will increase the yield, save manufacturing times and costs and will thereby enable cost-effective techniques.

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.

본 연구는 조청의 제조공정 및 품질 개선을 위한 기초자료를 마련하고자 수침시간(4, 8, 12시간)을 달리한 멥쌀을 증자기와 microwave로 제조한 고두밥의 일반성분과 수분용해지수, 수분흡착지수, 환원당함량, 페이스트점도를 비교하였고, 전처리를 달리한 고두밥으로 제조한 조청의 당고형분함량, 환원당함량과 포도당당량을 비교하였다. 멥쌀의 수침시간이 증가할수록 일반성분은 감소하였다. 멥쌀원료의 지방함량은 최대 60% 감소하였고, 회분과 단백질 함량 또한 수침시간이 증가함에 따라 유의적으로 감소하였다. 또한, 본 실험에서 사용된 엿기름의 β-amylase의 활성도는 1710 unit의 당화력을 보였다. 멥쌀 원료의 환원당 함량은 수침시간이 4-8시간으로 증가할 때 증가하였지만, 수침 12시간이후 다시 감소하는 경향을 나타내었고, 증자한 고두밥, microwave 처리한 고두밥의 환원당함량은 8시간까지 증가하다가 12시간 때 일정하게 유지되는 경향을 나타내었다. 멥쌀 원료와 전처리를 달리한 고두밥의 수분용해지수는 수침시간 4시간 이후에는 수침시간이 증가함에 따라 감소하는 경향을 보였고, 수분흡착지수는 증자한 고두밥과 microwave 처리한 고두밥과는 크게 차이가 나지 않았다. 수침시간의 증가에 따른 최고점도, 최저점도, 구조파괴점도, 최종점도, 회복점도 등의 페이스트 점도지표는 증가하는 경향을 나타내었고, peak time은 큰 변화가 없었다. 멥쌀을 12시간 수침한 후 증자기와 microwave로 제조한 고두밥을 당화시간(4, 8, 12시간)을 달리하여 제조한 조청의 당고형분 함량과 환원당 함량은 당화시간이 증가할수록 그에 따라 비례하는 결과를 보였고, microwave 처리한 고두밥을 이용하여 제조한 조청보다 증자한 고두밥을 이용하여 제조한 조청의 환원당 함량과 포도당 당량이 높게 측정되었다. 증자한 고두밥을 12시간 당화하였을 때 조청의 환원당함량과 포도당 당량이 59.40±0.11%, 76.99±1.78%로 가장 높게 측정되었으며, 결과적으로 멥쌀을 12시간 수침하여 증자한 고두밥을 12시간 당화시켜 제조한 조청의 품질특성이 가장 높은 것으로 확인되었다.

This study aimed to compare the quality characteristics of developed rice Jochung (E) with those of commercial-rice Jochung (A, B, C, and D). The total soluble solid, reducing sugar, and dextrose equivalent of developed rice Jochung were 80 °Brix, 44.53%, and 56.94%, respectively. The pH and titrable acidity were 6.25 and 0.19%, respectively. The color difference value (ΔE) of developed rice Jochung was 74.42, which was significantly lower than the other samples investigated. The light transmittance and total polyphenol contents of developed rice Jochung were 56.4%T and 108.23 mg GAE/100 g, respectively. The adhesiveness values of various commercial-rice Jochung products were 29.0~66.0 sec, while that of developed-rice Jochung was 61 sec, showing good textural properties for use in manufacturing Hangwa, a Korean traditional cookie. The electron-donating values of various rice Jochung were 20.4~50.3%, among which the developed-rice Jochung showed the highest value. The reducing powers of various rice Jochung products were 0.44~0.72, while that of the developed product was 0.72, which was significantly higher than the other values. Sensory evaluation revealed that the color scores of developed- and commercial-rice Jochung products were 6.70~6.80. Flavor scores of rice Jochung products ranged from 6.00 to 7.00. Taste and mouth feeling scores of developed-rice Jochung did not significantly differ from those of commercial Jochung products. Compared to commercial-rice Jochung products, developed-rice Jochung made with malt extract exhibited high polyphenols content. However, there were no significant differences in the overall acceptability scores between commercial-rice Jochung products and the developed product. The developed-rice Jochung analyzed in this study may be useful as a traditional sweetener for various Hangwa products as a substitute for corn syrup or Jochung.