주석산을 처리한 한국산 밀 전분과 백미의 이화학적 특성규명 = Physicochemical properties of tartaric acid-treated Korean wheat starch and rice granule

국문 초록 (Abstract)

본 연구의 목적은 반응표면분석법(RSM)을 통해 밀전분의 주석산처리에 의한 저항전분(RS)형성에 대한 최적 조건을 확립하고 이에 따른 물리화학적 특성을 조사하였다. 전분은 소화 속도에 따라 급소화성전분(rapidly digestible starch), 지소화성전분(slowly digestible starch), 저항전분(resistant starch)으로 분류된다. 이에 따라 다양한 농도(1-3 M), 온도(110-150°C) 및 반응시간(1-9 h)에서 밀 전분과 반응하였다. Box-Behnken 설계에 기초한 반응표면분석법을 이용해 결정된 최적조건은 3 M 150°C 5 h반응으로 99.3%인 RS최대함량을 가졌다. 주석산 처리 전분의 FT-IR은 1733cm-1에서 피크가 생성되어 에스테르결합(C=O)이 형성되었음을 확인하였다. DS를 분석한 결과 주석산의 농도가 증가함에 따라 에스테르결합의 정도가 증가하였다. 또한 주석산 처리 밀 전분의 DS함량이 증가함에 따라 RS함량이 상대적으로 높았다. 그러나 XRD를 통한 전분의 결정성 및 호화특성은 주석산의 농도, 반응시간, 반응온도가 증가함에 따라 감소하였다. 주석산 처리 밀 전분은 저칼로리 식품소재로 사용이 가능하며, 열 안정성이 우수해 저칼로리 식품에 적용될 수 있다.
수침시간에 따른 주석산처리 쌀의 물리화학적 특성과 저항전분(RS) 형성에 미치는 영향을 조사하였다. 수침시간이 증가함에 따라 전반적인 모양과 크기에는 영향을 미치지 않았으나 쌀알 내부의 수분 또는 산의 상호작용이 변화되어 쌀의 가공성이 낮아졌다. 또한 수침시간이 증가함에 따라 명도가 낮아졌다. DS는 수침시간에 따라 증가하다가 TA-16h에서 가장 높은 값을 얻었으며 FT-IR에서 검출된 에스테르 결합의 피크와 유사한 경향을 보였다. 그러나 쌀의 결정성은 XRD와 호화특성에서 수침시간이 증가함에 따라 감소하였다. 수침시간이 증가할수록 DS가 증가함에 따라 RS함량이 32.8 %에서 63.7 %까지 점진적으로 증가가 관찰되었으며, 12시간 이후 최대값을 가졌다. 따라서 쌀의 효율적인 RS제조를 위한 수침시간은 12시간이 적당하다고 할 수 있다. 주석산을 처리한 쌀은 열안정성이 높아 쌀가공제품에 적용이 가능하며, 저칼로리 식품으로 이용될 수 있다.

다국어 초록 (Multilingual Abstract)

The objectives of this study were to establish the optimal conditions for the formation of resistant starch (RS) by tartaric acid treatment of wheat starch using response surface methodology (RSM), to investigate the physicochemical properties of the RS produced. Starch is classified into rapidly digestible starch (RDS), slowly digestible starch (SDS), and resistant starch (RS) according to the rate of digestion. Different amounts of tartaric acid (1–3 M) were reacted with wheat starch at various temperatures (110–150 °C) and reaction times (1–9 h). The optimization conditions determined using a RSM based on a Box-Behnken design were: reaction temperature, 150°C; reaction time, 5 h; and tartaric acid content, 3 M. This a maximum RS content was 99.3%. The resistant starch levels increased with increased tartaric acid content, reaction temperature, and reaction time. FT-IR spectrum of tartaric acid treated-starches showed a remarkable carbonyl peak at 1733 cm-1 as an evidence of ester bond formation. Analysis of the degree of substitution (DS) indicated an increase in the extent of ester bonds with increasing concentrations of tartaric acid. Higher DS content in the tartaric acid treatment starch meant relative higher RS content. However, the crystallinity of starch decreased as the tartaric acid content, reaction temperature, and reaction time increased, confirmed by the X-ray diffraction and thermal transition properties. According to tartaric acid treatment starches can be used to develop a low-digestible food ingredient and lead to further application of the study.
The effects of immersion time on the physicochemical properties and resistant starch (RS) formation of tartaric acid-treated rice were investigated. As the immersion time increased, the overall shape and size were not affected; however, the interaction with moisture within the rice grain was altered, indicated by the lower occurrence of cracks and fissures, which enable the processability of rice grains. The color (lightness) was significantly affected by the immersion time, reflecting the browning of rice. The degree of substitution (DS) gradually increased with the immersion time and reached a plateau after 16 h and the intensity of the C=O bond peak detected in the Fourier-transform infrared spectroscopy showed a similar trend. However, the crystallinity of rice decreased as the immersion time increased, confirmed by the X-ray diffraction and thermal transition properties. A gradual increase in RS was observed as the immersion time and DS increased, ranging from 32.8 to 63.7%, reaching a maximum after 12 h of immersion. Therefore, 12 h was determined to be the optimal immersion time for maximizing RS content, while a very short time (0 h) also resulted in a significant elevation of RS in rice kernels. This information about the structural characteristics and heat stable properties of tartaric acid-treated rice in starch digestion can be used to develop a low-digestible food ingredient and lead to further application of the study.

목차 (Table of Contents)

• Chapter 1. Physicochemical properties and digestibility of
• tartaric acid-treated Korean wheat starch
• I. 서론··············································································11
• II. 이론적 배경 ································································14
• 1. 주원료의 특성(전분) ··············································14
• 2. 변성전분의 종류와 특징 ·········································16
• 3. 전분의 영양학적 측면 ············································20
• 4. 저항 전분의 종류 ··················································21
• III. 연구내용 및 방법 ······················································25
• 1. 실험재료·····························································25
• 2. 실험방법·····························································25
• 1) 금강 밀의 전분 분리 ···········································25
• 2) 저항전분 생산의 최적화 ······································26
• 3) 금강 밀 전분의 저항전분 제조·······························27
• 4) 금강 밀 전분의 소화율 측정··································27
• 5) 광학현미경 관찰················································28
• 6) 주사전자현미경 관찰··········································28
• 7) 색도 측정·························································28
• 8) 전분의 치환도 측정 ············································29
• 9) FT-IR (Fourier-transform–infrared spectroscopy)측정·····30
• 10) XRD (X-ray diffractometer)측정 ····························30
• 11) 저항전분의 점도측정(RVA, Rapid Visco Analyser) ····30
• 12) 전분의 호화특성 ··············································31
• 13) 마우스를 이용한 내당성 측정······························31
• 14) 통계분석 ························································32
• IV. 연구결과 및 고찰·······················································33
• V. 요약 및 결론································································70
• Chapter 2. Physicochemical properties and digestibility of
• tartaric acid-treated Korean rice granule
• I. 서론··············································································74
• II. 이론적 배경 ································································76
• 1. 주원료의 특성
• 1) 벼 ········································································76
• 2) 쌀 ········································································77
• III. 연구내용 및 방법 ······················································84
• 1. 실험재료·····························································84
• 2. 실험방법·····························································84
• 1) 주석산 처리 쌀의 저항전분 조제····························84
• 2) 색도 측정·························································85
• 3) 주사전자현미경 관찰··········································85
• 4) 치환도 측정······················································85
• 5) FT-IR (Fourier-transform–infrared spectroscopy)측정·····86
• 6) XRD (X-ray diffraction)측정 ··································86
• 7) 쌀의 호화특성···················································87
• 8) 주석산 쌀의 소화율 측정 ·····································87
• 9) 통계분석··························································88
• IV. 연구결과 및 고찰·······················································89
• V. 요약 및 결론·······························································106