Microwave 가열에 의한 식빵 발효의 최적화에 관한 연구 = (A) study on optimizing bread fermentation through microwave heating

다국어 초록 (Multilingual Abstract)

ABSTRACT

A Study on Optimizing Bread Fermentation through Microwave Heating

Park, Sang Jun
Adviser : Prof. Lee, Kwang Suck
Dept. of Culinary Science and Food Service Management
Graduate School, Kyung Hee University

In order to streamline bread making process that is time-consuming in regard to the characteristics of process, this study focused on microwave irradiation to dough and raising its temperature to monitor potential variations of dough properties and bread quality, and also examined optimum irradiation time, mixture ratio and dough-mixing method to deduce effective ways for streamlining bread making process.
To meet the above purposes, this study measured the content of crude ash, moisture and wet gluten in wheat flour available in domestic market, and every bread was prepared by AACC method and straight dough-mixing method (used commonly in domestic bakeries) depending on variable time of microwave irradiation. Microwave was directly irradiated to every dough to heat up its temperature for analysis on dough properties and bread quality, which was followed by deducing optimum time of microwave irradiation.
Based on the optimum time of microwave irradiation, this study sought to compare and analyze the quality of three bread sample groups, i.e. straight dough group (control), emergency dough group (EM) and microwave irradiation group (MWH). In order to determine potential effects of mixture materials on microwave absorption, this study sought to compare and analyze quality of bread samples that were prepared with variable mixture of salt and fat. In each step of experiment, dough temperature, pH, fermentation rate, specific volume, oven spring and water activity were measured, and crumbScan, texture analyzer and sensory evaluation were performed to compare and analyze quality of bread.
Experiment 1: According to comparison and analysis on dough properties depending on the time of microwave irradiation, it was found that MWH 2 dough (as irradiated every 80 seconds) showed the most ideal dough temperature. According to comparison and analysis on quality of bread samples, it was found that MWH 2 showed the highest specific volume and oven spring of all and the lowest hardness (i.e. the highest softness). Moreover, MWH 2 scored the highest points in overall preference under sensory characteristics. As a result, it found that 80-second heating of 700g bread dough, when exposed to microwave irradiation, contributed to the highest quality of bread.
Experiment 2: For comparison and analysis on bread quality depending on dough-mixing methods, this study sought to compare and analyze the quality of three major bread sample groups, i.e. MWH 80 (a sample scoring the highest points in specific volume, texture and sensory test in the above quality analysis under certain time of microwave irradiation), emergency dough group (EM) and straight dough group without microwave irradiation (control). As a result, it was found that EM had higher specific volume and oven spring than control, but had highest hardness of all under texture test. According to the sensory acceptance, it was found that EM tended to smell much of yeast and sourish, and scored the lowest points in overall acceptance. On the other hand, it was found that MWH 80 had the highest softness under texture test, scored the highest points in overall acceptance under sensory characteristics, and there were significant differences among samples on statistical basis.
Experiment 3: According to comparison and analysis on dough properties and bread quality depending on mixture materials, it was found that Salt 2 (dough with salt added relatively much) had the highest dough temperature of all, and Salt 1 had the highest fermentation rate and specific volume but the lowest hardness (i.e. highest softness). According to sensory characteristics, it was found that Salt 1.5 scored highest points in sweet taste, aftertaste, and overall acceptance, but there were significant differences among bread samples. Likewise, it was found that Fat 6 (dough with fat added relatively much) had the highest dough temperature, and had the highest fermentation rate and specific volume of all. According to texture analysis, it was found that Fat 0 had the highest hardness of all. And according to sensory characteristics, it was found that Fat 3 scored the highest points in overall acceptance.
Summing up, it is concluded that it takes 80 seconds to efficiently irradiate microwave; microwave heating method is superior to emergency dough method in the aspect of dough properties and bread quality; and the optimum mixture ratio of salt and fat for microwave-irradiated bread is 1.5% salt and 3% fat.

목차 (Table of Contents)

• Ⅰ. 서론 1
• 1. 연구배경 1
• 2. 연구목적 3
• 3. 연구구성 4
• Ⅱ. 문헌고찰 7
• 1. Microwave의 특성 및 조리원리 7
• 2. Microwave의 식품응용 10
• 1) 건조 10
• 2) 살균 및 저장 11
• 3) Roasting 12
• 4) 해동 12
• 3. Microwave의 제빵응용 13
• 4. 제빵공정의 변화 17
• 5. 제빵 시 조건변화에 따른 발효변화 22
• Ⅲ. 재료 및 방법 25
• 1. 실험재료 25
• 2. 실험방법 25
• 1) 밀가루 성분분석 26
• (1) 회분 26
• (2) Wet gluten 26
• (3) 수분 26
• 2) 반죽물성 및 식빵의 변화 27
• (1) 수온측정 27
• (2) 식빵의 제조 27
• 가. Microwave 조사시간 차이에 따른 식빵의 제조 31
• 나. 반죽방법의 차이에 따른 식빵의 제조 33
• 다. 첨가재료의 변화에 따른 식빵의 제조 36
• (3) pH 측정 38
• (4) 반죽의 발효율 38
• (5) 반죽의 stickiness, 오븐스프링과 비용적 38
• (6) 디지털 영상 분석 41
• (7) TPA(texture profile analysis test) 41
• (8) 수분활성도(Aw) 43
• (9) 관능검사 43
• 3) 통계처리 43
• Ⅳ. 결과 및 고찰 44
• 1. 밀가루 성분분석 44
• 2. Microwave 조사시간 차이에 따른 식빵의 특성 45
• 1) 반죽온도의 변화 45
• 2) 반죽 및 속질의 pH 변화 48
• 3) 반죽의 발효율 변화 50
• 4) 반죽의 stickiness, 오븐스프링과 비용적 결과분석 53
• 5) 디지털 영상 분석 57
• 6) TPA 결과분석 61
• 7) 수분활성도(Aw) 결과분석 63
• 8) 관능검사 64
• 3. 반죽방법의 차이에 따른 식빵의 특성 67
• 1) 반죽온도의 변화 67
• 2) 반죽 및 속질의 pH 변화 70
• 3) 반죽의 발효율 변화 72
• 4) 반죽의 stickiness, 오븐스프링과 비용적 결과분석 75
• 5) 디지털 영상 분석 78
• 6) TPA 결과분석 81
• 7) 수분활성도(Aw) 결과분석 83
• 8) 관능검사 84
• 4. 첨가재료의 변화에 따른 식빵의 특성 87
• 1) 소금함량 변화에 따른 식빵의 특성 87
• (1) 반죽온도의 변화 87
• (2) 반죽 및 속질의 pH 변화 92
• (3) 반죽의 발효율 변화 92
• (4) 반죽의 stickiness, 오븐스프링과 비용적 결과분석 95
• (5) 디지털 영상 분석 98
• (6) TPA 결과분석 101
• (7) 수분활성도(Aw) 결과분석 103
• (8) 관능검사 104
• 2) 유지함량 변화에 따른 식빵의 특성 107
• (1) 반죽온도의 변화 107
• (2) 반죽 및 속질의 pH 변화 110
• (3) 반죽의 발효율 변화 112
• (4) 반죽의 stickiness, 오븐스프링과 비용적 결과분석 115
• (5) 디지털 영상 분석 118
• (6) TPA 결과분석 121
• (7) 수분활성도(Aw) 결과분석 123
• (8) 관능검사 124
• Ⅴ. 결론 127
• 참고문헌 132
• Appendix 149
• Abstract 153