This is a comparative study of Byung-Kwa-Ryu (Korean rice cake and cookie) of the Chungcheon Province Area in the late Joseon Dynasty, based on「Jusiksiui」 in the late 1800s,「Eumsikbangmunnira」 in 1891, and 「Banchandeungsok」 in 1913. This study was also compared with the recipes of「Suunjapbang」 of 1540,「Eumsikdimibang」 of around 1670, 「Siuijeonseo」, and Gyuhabchongseo of the late 1800s. As for the Byung-Kwa-Ryu(Korean rice cake and cookie) introduced in the recipe book,「Eumsikbangmunnira」 recorded the most with 18 types of rice cakes and two types of Korean sweets, followed by「Jusiksiui. There were 14 types of rice cakes, and two types of Korean sweets. 「Banchandeungsok」 had eight types ofrice cakes and six types of Korean sweets. Yogi-tteok in「Jusiksiui」 and「Banchandeungsok」 were foods that could not be found in other recipes. Yakgwa and Jeungpyeon were in all three books as well as 「Eumsikdimibang」. These were also included in「Siuijeonseo」 and were introduced to most cookbooks. The materials used and the method of making it differed for each recipe. Many studies on cookbooks have focused on the Yeongnam region so far. This study served as an opportunity to confirm the dietary life data of the Chungcheong-do region through a review of the recipe books containing food from the Chungcheong-do region. In addition, it was possible to examine the ingredients and cooking methods used in each cookbook at the time through comparative analysis with the cookbooks in the Yeongnam region.

본 연구에서는 가래떡에 오염된 곰팡이를 분리 동정한 후 곰팡이독소 생산 가능성을 조사하여 식품 이물 중 곰 팡이에 대한 위험성을 분석하였다. 실험에 사용된 가래떡 은 전라남도 소재 떡 제조업체에 곰팡이로 추정되는 이물 이 발견되어 반품된 제품을 사용하였다. 곰팡이 이물을 채 취한 후 Potato dextrose agar, Malt extract agar, Czapek yeast extract agar에 접종하고 25oC에서 7일간 배양하여 순수 분리 결과를 판단하였다. 순수 분리가 확인된 집락 에 대해 광학현미경으로 포자의 미세구조를 관찰하여 형 태학적으로 동정하였다. 유전학적 동정은 ITS primer를 이 용하여 증폭된 PCR 산물의 유전자 염기서열을 분석하였 다. Colony-1과 2는 각각 배지에서 동일한 성상을 나타내 어 순수분리 되었음을 확인하였다. Colony-1은 출아세포 가 관찰되어 효모로 판정하였다. Colony-2는 방추형의 분 생자가 관찰되어 Fusarium 속 곰팡이로 판정하였다. 유전 자 염기서열 분석 결과 Fusarium 속 곰팡이가 총 76건으 로 나타났으며, 그중 Fusarium solani가 53건으로 가장 높 게 나타났다. 형태학적 동정 결과와 유전학적 동정 결과 를 바탕으로 Colony-2는 Fusarium spp.로 동정되었고 그 중 Fusarium solani로 추정되었다. Fusarium 속 곰팡이는 Nivalenol, Zearalenone, Fumonisin 등의 곰팡이독소를 생 산하여 구토, 설사, 암 등을 유발한다. 이러한 결과를 종 합해 볼 때 가래떡에서 분리된 Fusarium 속 곰팡이에 의 한 곰팡이독소 생산 가능성은 상존하는 것으로 판단되었 다. 따라서 곰팡이 이물이 보고되면 곰팡이를 분리 동정 하여 곰팡이독소를 생산할 수 있는 균종인지 판단하고, 그 결과에 따라 행정조치를 강화하여야 할 것으로 판단된다.

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.

Korean sliced rice cakes, or tteokguk, are conventionally dried and rehydrated during their preparation. In this study, the effects of the perforation process and various drying methods (e.g., hot-air drying, vacuum drying, low temperature drying, and freeze drying) on the quality characteristics of tteokguk (rice cake soup) were evaluated. In the experiment, the rehydration capacity and lightness increased as the pore number increased. The hardness, redness, and yellowness of tteokguk, in contrast, tended to decrease as perforations increased. The texture, taste, and overall acceptability scores of tteokguk increased as perforations increased. With respect to drying methods, the rehydration capacity was greatest for vacuum drying. The hardness of tteokguk was lowest for vacuum drying. The redness, yellowness, pH, and sensory characteristics did not differ significantly among tteokguk samples treated through various drying methods. These results suggest that high-quality ready-to-eat Korean sliced rice cakes could be created by perforation and vacuum drying.

본 연구는 저장 중 조랭이떡에 존재하는 자연균총의 생장특성 및 프로피온산 생성능을 조사하여 떡류에서 프로피온산의 천연유래를 입증하고자 한다. 실험은 저장 중 신선한 조랭이떡과 cocktail Propionibacterium을 오염시킨 조랭이떡 두 가지를 약 3개월까지 저장하여 진행하였다. 저장온도와 저장기간에 따른 조랭이떡에서의 프로피온산 생성량을 측정하였으며, 프로피온산 분석은 GC-FID (Gas chromatograph with Frame ionization detector)를 사용하였다. 30℃에 저장한 주정처리하지 않은 신선한 조랭이떡에서는 1주만에 프로피온산이 약 95 mg/L 검출되었고, 4주 후에 약 330 mg/L, 6주 후에 약 850 mg/L, 8주 후에 약 970 mg/L, 12주 후에 약 1,040 mg/L이 검출되었다. Cocktail Propionibacterium에 오염시킨 조랭이떡은 30℃에서 1주만에 프로피온산이 약 100 mg/L이 검출되었고, 2주 후에 270 mg/L, 4주 후에 약 470 mg/L, 8주 후에 약 660 mg/L이 검출되었다. 본 연구는 조랭이떡에 존재하는 자연균총인 프로피온산 생성균이 조랭이떡 저장 중 프로피온산을 생성하는 것을 증명하였으며, 이러한 떡류 중 천연유래 프로피온산 생성을 예방하기 위해서는 철저한 위생관리와 20℃ 이하에서의 보관이 필요한 것으로 판단된다.

Effects of acid soaking (AS) and thermal sterilization (TS) on the shape and quality characteristics of Tteokbokki rice cake (TRC) were investigated. The F-value of a sequential process (SP) of the combination of AS and TS was quantitatively determined with a reference microorganism of Bacillus cereus. F-values were evaluated according to the minimum and the maximum D-value of B. cereus and the reduction exponent (m=12). The heat penetration curves at cold point (CP) of TRC (400 g) were used to estimate the TS time at 121, 100, and 95℃. F-values of the SP were revised according to the adjusted m values after AS at different pH. The non-uniformity parameters (NUP) of TRC had no significant changes during AS but it dramatically increased after applying TS at a low pH by AS. The result of solubilized starch contents (SSC) demonstrated that the shape changes during SP are related to SSC. The texture characteristics and the whiteness were significantly influenced by a low pH condition (3.5) (p<0.05). Sensory analysis showed that a lower pH and a longer thermal processing time influenced negatively on the acceptability. This study showed that pH 4.0 and 95℃ was an optimum condition for the SP.

본 연구는 조랭이떡에 존재하는 미생물 군집분석과 자 연균총의 프로피온산 생성능을 분석하였다. 조랭이떡의 자연균총을 유전자 분석을 통하여 군집분석을 수행해 프로 피온산 생성균을 선별하였다. 선별된 프로피온산 생성균을 포도당이 첨가된 액체배지(TSB)에 배양해 온도별 생장 특성을 분석하고 가스 크로마토그래피(GC-FID)를 이용하여 프로피온산 생성량을 분석하였다. 에테르로 용매 추출 하는 전 처리 방법을 확립하였고, 직선성, 검출한계, 정량 한계, 회수율을 측정해 프로피온산 분석법을 검증하였다. 유통기한이 지나 미생물이 많이 자란 조랭이떡의 미생물 군집 분석 결과 총 98종의 균이 검출되었고 그 중 가장 큰 비중을 차지하는 우점종은 Lactobacills casei group으 로 50.48%를 차지했고, Lactobacillus buchneri가 29.60% 였다. 프로피온산 생성균은 Propionibacterium thoenii, P. cyclohexanicum, Propionibacterium_uc, P. jensenii, P. freudenreichii 등으로 나타났으며, 전체 자연균총의 약 2.4%를 차지했다. 조랭이떡 자연균총과 Lactobacillus 속은 14일 배양에서도 프로피온산을 생산하지 않았으나 P. cyclohexanicum, P. freudenreichii subsp. Shermanii, P. thoenii, P. jesenii는 4일차부터 프로피온산을 각각 263.47, 338.90, 325.43, 222.17 μg/mL를 생산하였고, 7일차에는 1,572.78, 2,496.63, 1,519.65, 2,660.41 μg/mL, 14일차에는 각각 2,462.02, 2,904.78, 2,220.64, 3,519.17 μg/mL로 프로피온 산 생성량이 급격히 증가하였다. 본 연구의 결과로 살펴 볼 때 전분과 포도당으로 구성된 떡류의 특성상 저장중 자연균총 미생물의 성장으로 높은 농도의 프로피온산이 천연유래로 생성될 수 있음을 알 수 있다. 본 연구는 떡 류 등 전분질 식품의 프로피온산 등 천연유래 보존료 검 출의 인정 및 기준규격 등 안전관리 자료로 활용될 것이다.

국내 쌀가공산업의 활성화로 인해 떡류 시장은 활발해지고 있으나 떡의 저장성이나 보관성이 취약한 문제로 인한 유통상의 제한으로 시장개척에 어려움이 따르고 있다. 따라서 떡볶이 떡의 적합한 산 침지 조건을 설정하고자 떡볶이 떡 제조 시 가수량이 산 침지 후 수분함량, pH, 기계적 조직감 특성에 미치는 영향을 검토하였으며 떡의 산 침지 특성을 Peleg 모델을 적용하여 설명하였다(R2>0.9679). 모든 배합비의 떡과 산미료 농도에서 떡의 침지 시간에 따라 수소이온농도가 증가하였으며, 동일한 가수량의 떡에서는 5% 보다 10%의 산미료에 침지한 떡의 수소이온농도 값이 높았다. 이는 떡의 가수량과 산미료의 농도가 증가할수록 산미료 확산 현상에 더 유리하다는 것을 나타낸다. Peleg 모델 식에서 K1과 K2의 값은 가수량이 높을수록 산미료 농도가 높을수록 더 작은 경향을 보였으며, 이는 가수량이 높고 산미료 농도가 높을수록 떡의 산미료 흡수 속도와 평형 수소이온농도가 높다는 것을 의미한다. 수분함량은 가수량이 높을수록 높았으며, 가수량과 pH가 동일할 때에는 산미료의 농도가 더 낮을 때 수분함량 증가율이 더 높았다. 동일한 pH에서 떡의 경도는 가수량이 높을수록 낮아졌으며 산미료가 떡의 조직을 연화시킬 수 있다는 것을 확인하였다. 떡의 가수량이 높을 때에는 pH가 구조에 큰 영향을 미치지 않았으며, 떡의 색도는 산미료보다 수분 함량에 더 크게 영향을 받는 것을 확인하였다. 본 연구결과를 통 하여 배합비와 산미료의 농도에 따른 산의 확산도를 확인 하였으며, 배합비의 높은가수량 및 높은 산미료 농도에서 침지 시 침지에 의한 품질 변화를 최소화할 수 있음을 확인하였다.

Calcium is widely used for calcium supplement, additives. In the case of oyster shell which is intaked for calcium supplement have caused serious problems including environmental pollution because almost of it is thrown out so that is demanded expanding of using. However, there is no examples that develop a high value product available for food industry from oyster shell. In advanced research, It is confirmed that fired oyster shell has Anti-microbial effect and therefore, this study apply the anti-microbial effect of fired oyster shell to rice cake. Control is made by rice flour 300g, water 150mL. Experimental group are made by rice flour 300g, water150mL and Sample A (fired oyster shell), Sample B (fibrous calcium carbonate), Sample C (calcium + citric acid) and Sample D (coral calcium) 0.5wt% respectively. Texture properties are measured by texture analyzer (TA-XT, MHK corp. Korea) 5kg load cell. Rice cake added sample A, B, C had anti-microbial effect and rice cake added sample D had not anti-microbial effect.

This study was conducted to develop easily chewable Korean rice cake (Garaedduk) for the elderly while maintaining its original form and flavor. We developed two types of easy-to-chew Garaedduk products by adding starch-degrading enzyme or trehalose, respectively. Characteristics of Garaedduk products were investigated and comparative analysis was carried out between control and experimental groups. The water content of control and enzyme-added Garaedduk was 43.55% and 44.11%, respectively, which was significantly higher than trehalose-added Garaedduk (40.30%) as free water content was reduced by the formation of hydrogen bonds between trehalose and water molecules. Due to the browning of reducing sugar produced by the decomposition of rice starch, Hunter b-value of enzyme-added Garaedduk was significantly higher compared to others. Hardness, adhesiveness, gumminess, and chewiness of experimental groups were lower than the control group. Consumer test scores showed significant differences with respect to overall liking, chewiness, and swallowing between control and experimental groups. Elderly preferred experimental Garaedduks over control and the experimental groups were evaluated to be softer, easily chewable, and swallowable.

Ohmic heating is one of advanced thermal processing techniques which utilize conversion of electrical energy into heat. In our study, a feasibility of ohmic heating was tested to cook instant rice cake to improve energy efficacy as an alternative heating methods of conventional electrical kettle. Ohmic heating was conducted using customized ohmic cell (7.5×4.5×9.5 cm) equipped with titanium electrodes. Instant rice cakes in soup were ohmically heated up to 100°C at different electric fields (9, 12, 15 & 18 V/cm) and temperature holding times (60, 80, 100 & 120 s). Thermocouple was placed into both soup and rice cake to evaluate the temperature profile and energy efficacy. Temperature, voltage and current across the sample were measured and recorded at every 3 s using data acquisition system (DAQ). Mathematical model was developed to calculate the internal energy generation rate (QR, W). Internal energy generation rate (QR, W) was integrated versus temperature come-up time (s) to compute the total internal energy dose (ET, J) using MATLBA software. For energy efficacy (Eff), it was calculated ratio of total internal energy dose (ET, J) to heat quantity (Qh, J). During ohmic heating, temperature come-up time was significantly reduced as a function of elevated electric field (P<0.05). For example, 9V/cm of electric field showed 6.2±0.4 min of temperature come-up time up to 100°C. Higher electric field at 18 V/cm reduced temperature come-up time to 1.9±0.1 min. The electric field of 15 V/cm showed the best energy efficacy as 0.78 which meant 78% of electrical energy was converted into thermal energy for heating. In the texture profile analysis, the most preferable harness was found as 6.191 N at 15 V/cm and 100 s holding time. Our study showed the potential of ohmic heating to cook instant rice cakes for home meal replacement (HMR) and outdoor foods.