스피루리나를 첨가한 기능성 요구르트 개발에 관한 연구 = Quality Characteristics and Functionality of Spirulina added Yoghurt

다국어 초록 (Multilingual Abstract)

This study was performed to develop functional yoghurt with spirulina, based on the selection the strain of lactic acid bacteria and spirulina addition amount to yoghurt, and to evaluate the quality characteristics of spirulina added yoghurt as for physicochemical and sensory properties as well as health-functional aspect.
1. Fermentation properties of yoghurt according to strains of lactic acid bacteria
This experiment was carried out to investigate the effect of spirulina powder on the growth properties of lactic acid bacteria in reconstituted skim milk. Reconstituted skim milk containing 1% spirulina powder was fermented at 37℃ for 15 hr by single or mixed culture of Streptococcus thermophilus, Lactobacillus bulgaricus and Lactobacillus acidophilus. Supplementation of spirulina powder in Streptococcus thermophilus and Lactobacillus acidophilus slightly stimulated lactic acid production. But the growth and acid production of Lactobacillus bulgaricus were enhanced by the addition of spirulina powder. When spirulina powder was added to reconstituted skim milk at the level of 1%, the mixed cultures of Streptococcus thermophilus and Lactobacillus bulgaricus showed higher number of viable cell counts and the acid production than the other cultures. Therefore, it was suggested to inoculate of mixed cultures of lactic acid bacteria for the stimulation of growth of the lactic culture.
2. Fermentation properties of yoghurt according to concentration of spirulina
The effect of addtion amount of spirulina powder (1%, 2% and 3%) to reconstituted skim milk on the growth properties of mixed culture of Streptococcus thermophilus and Lactobacillus bulgaricus was evaluated. The pH of skim milk added spirulina powder was lower than that of control, but the amount of spirulina was not significantly affected. The titratable acidity was increased as incubation time until 12 hr. The number of viable cell counts in skim milk added spirulina was increased according to the amount of spirulina. Thus, spirulina was effective for the increase of lactic acid bacteria in yoghurt.
3. Quality characteristics and functionality of yoghurt added spirulina
Yoghurt base was prepared from skim milk added with 0.25～1%(w/v) of spirulina powder and fermented with lactic acid bacteria (Streptococcus thermophilus : Lactobacillus bulgaricus = 1 : 1) at 40℃ for 12 hr, and then kiwi puree and oligosaccharide was added. All samples were analyzed for nutritional contents, pH, titratable acidity, sugar contents, viscosity, color, number of viable cell, antioxidative activities and sensory property during storage at 4℃. The macronutrients (calories, carbohydrates, proteins, fat, fiber, ash and moisture) amounts of yoghurt added spirulina were higher than those of control. And the micronutrients (Na, K, P, Fe, Mg, Cu, Zn and Al) amounts of yoghurt added spirulina were significantly increased. The addition of 1% spirulina powder stimulated the growth of lactic acid bacteria which showed the highest number of viable cell counts (7.4×109 CFU/mL), enhanced the acid production (pH 3.90), and increased the titratable acidity (1.01%) after 9 hr incubation. The viscosity range of yoghurt was 6000 to 8000 cP, and the sugar contents of yoghurt were around 18 °Brix. The antioxidative activities by DPPH (a-a'-diphenyl-β-picrylhydrazyl) method and hydroxyl radical scavenging activity in yoghurt added spirulina powder were higher than those of control group. The sensory scores of yoghurt added 0.25% spirulina powder was higher than those of the other groups in appearance, odor, taste, overall acceptability and buying intention. According to sensory scores, the optimum concentration of spirulina powder was around 0.25%. The shelf life of yoghurt added spirulina was estimated to be 9 days at 4℃.

목차 (Table of Contents)

• Ⅰ. 서론 1
• 1. 연구배경 1
• 1) 스피루리나 1
• 2) 요구르트 3
• 2 . 연구목적 6
• Ⅱ. 재료 및 실험방법 8
• 1. 실험재료 8
• 2. 사용균주 및 배지 8
• 3. 시료의 제조 11
• 1) 유산균주 종류에 따른 요구르트의 발효 특성 11
• 2) 스피루리나 첨가량에 따른 요구르트의 발효 특성 11
• 3) 스피루리나 첨가 요구르트의 품질특성 및 기능성 평가 11
• 4. 실험 방법 13
• 1) 요구르트의 영양성분 분석 13
• 가. 일반성분 분석 13
• 나. 무기질 분석 14
• 2) 요구르트의 이화학적 특성 14
• 가. pH 14
• 나. 산도 16
• 다. 당도 16
• 라. 점도 16
• 마. 색도 16
• 3) 요구르트의 미생물학적 특성 17
• 가. 유산균수 17
• 나. 대장균군 17
• 4) 요구르트의 항산화력 17
• 가. DPPH 라디칼 소거능 17
• 나. Hydroxyl radical scavenging 활성도 18
• 5) 요구르트의 관능적 특성 19
• 6) 통계처리 19
• Ⅲ. 결과 및 고찰 21
• 1. 유산균주 종류에 따른 요구르트의 발효 특성 21
• 1) pH 및 산도 21
• 2) 유산균수 27
• 2. 스피루리나 첨가량에 따른 요구르트의 발효 특성 31
• 1) pH 및 산도 31
• 2) 유산균수 33
• 3. 스피루리나 첨가 요구르트의 품질특성 및 기능성 평가 35
• 1) 요구르트의 영양성분 분석 35
• 가. 일반성분 분석 35
• 나. 무기질 분석 36
• 2) 요구르트의 이화학적 특성 38
• 가. pH 38
• 나. 산도 40
• 다. 당도 41
• 라. 점도 42
• 마. 색도 43
• 3) 요구르트의 미생물학적 특성 45
• 가. 유산균수 45
• 나. 대장균군 46
• 4) 요구르트의 항산화력 47
• 가. DPPH 라디칼 소거능 47
• 나. Hydroxyl Radical Oxidation 활성도 49
• 5) 요구르트의 관능적 특성 50
• 6) 요구르트의 주성분분석 53
• Ⅳ. 요약 및 결론 54
• 1. 유산균주 종류에 따른 요구르트의 발효 특성 54
• 2. 스피루리나 첨가량에 따른 요구르트의 발효 특성 55
• 3. 스피루리나 첨가 요구르트의 품질특성 및 기능성 평가 55
• Ⅴ. 참고문헌 58
• ABSTRACT 64