Chemistry of Food 식품화학
Chapter 16
Chemistry of Food
식품화학
What the body needs!
• 영양소 Nutrients
– substances that are needed by our bodies
• What do are bodies need?
– 물 water
– 탄수화물 carbohydrates
– 지방 (지질) lipids (fats)
– 비타민 vitamins
– 무기질 minerals
Water
• Water
– 가장 간단하고 생명유지에 최소한의 양 필요
– 몸의 65-75% (approx. 40 liters)
• 물의 역할
– solvent - polar OH, NH group
(탄수화물, 단백질, 수용성 비타민)
– key transport system in body
• 삼투
– 세포 안과 밖으로 물이 출입하는 방법
Water
• 일반 음식물의 물 함유량 (표16.1)
– 맥주 90%
– 사과 84%
– 감자 76%
– 힌빵 39%
Carbohydrates
• 탄수화물
– Compounds composed of carbon hydrogen and oxygen, with a H/O ratio of 2 to 1
– Name comes from carbon, C, and hydrate, H2O
– Cx(H2O)y – most common C6H12O6
• Three classes of carbohydrate
– 간단한 당(단당류와 이당류)
– 녹말 (고분자 탄수화물)
– 섬유질
Carbohydrates
• Energy of Carbohydrates
– glucose is the primary energy source
– C6H12O6 + 6 O2 6 CO2 + 6 H2O + 2816kJ/mol
• Calories
– dietary calories = kcal
1 kcal = 4.184kJ
Carbohydrates
• Carbohydrate are made from sugars
– natural polymer
• A single sugar is called monosaccharide
– 3 common monosaccharide
– glucose, galactose, fructose
– all have the same formula, C6H12O6
– different structures
Monosaccharides
• Glucose
– 혈액 속의 당
– 혈당, 포도당
• Fructose
– 꿀과 과일 속의 당
– 과당
• Galactose
– 자연식품에는 존재무
– lactose의 가수분해로 생성
Disaccharides
• 이당류는 두 개의 단당류가 축합 반응
– 2 C6H12O6 C12H22O11 + H2O
• Common disaccharides
– sucrose
• glucose and fructose
• 당(sugar) - 설탕
– lactose
• glucose and galactose
• 포유류의 젖에 들어 있는 당 (젖당)
– maltose
• glucose and glucose
• startch 가수분해로 생성
Glycosidic bond
• 글리코시드 결합
– 두 개의 단당류를 결합
– 물이 빠져 나오는 축합 반응
Sweetener
• 상대적인 당도 (표16.2)
– lactose 0.2
– sucrose (sugar) 1.0
– fructose 1.7
– xylitol 2.0
– aspartame (L-aspartyl-L-phenylalanine methyl ester, 고온분해) 200
– saccharin (사용금지) 500
– monellin 2500
– P-4000 (사용금지) 4000
Sweetener
• 종류
– 탄수화물 계- sucrose, fructose
– 아미노산 계-monellin, aspartame
– 당 알코올 계-xylitol, sorbitol
– 합성 감미료-saccharin, P-4000
Sweetener
• 단 맛을 측정하는 방법
– 온도, 환경 고려
– 관능검사 (sensory evaluation)
• 이점 비교법 paired comparison method
• 일정한 부피의 물에 설탕 100 g을 녹이고 이것을 사카린 1 g, 0.1 g, 0.01 g 등을 녹인 용액과 맛을 보아서 비교
• 비슷한 단맛을 가진 범위가 정해지면 더 세분화해서 용액을 만들고 다시 맛을 보아서 비교
• 통계 처리 - 유의적 차이가 나지 않는 농도 범위
Complex Carbohydrates
• Complex Carbohydrates
– starch and cellulose
• 신문을 읽으며 옥수수를 먹는다
– polymers of glucose
Two Form of Glucose
Complex Carbohydrates
• Starch
– energy storage for quick release
– amylose and amylopectin
– can be found in seed and tubers
Starch from -glucose
• Amylose
– 1,4 glycosidic bond
– long chain of -glucose
– that coils into a helix
– natural organic polymer
• amylopectin
– mostly amylose
– 1,6 glycosidic bond
– 분말형태
Complex Carbohydrates
• Cellulose
– long chains of -glucose
– not digestible
– makes up the fiber in our diet
• 섬유질 - 음식물 속의 셀룰로오스
• 섬유질 결핍은 암 발생 위험도 증가
– cleans digestive tract and carries away toxins
– found in the walls of plants
-glucose for cellulose
Fats, Oils and Lipids
• 지질, Lipids
– biological compounds that do not dissolve in water
– 지방 fats 과 기름 oils
• 몸 안에서의 역할
– 오랫동안 저장될 수 있는 에너지원
• 불용성이므로 물에 씻겨 나가지 않음
– 동물의 피부 밑에서 추위 차단
– 세포막의 구성 성분
Fats, Oils and Lipids
• 지방과 기름
– belong to a class of compounds called triglycerides
– found in animals (fats) and plants (oils)
– solid fat, liquid oil
• 삼중글리세리드 Triglycerides
– from four molecules
– three fatty acids and a glycerol
– diglycerides and monoglycerides
Fats, Oils and Lipids
• 지방산 Fatty Acids
– Long hydrocarbon chains with a carboxylic acid group at one end, 8-22 carbon long
– even number of carbon atoms
– Can have one or more double bonds
• 포화 Saturation
– 포화 – fatty acids with no double bonds
– 불포화 – one or more double bonds
– 다중 불포화 – two or more double bonds
Fats, Oils and Lipids
• Saturation
– saturation has become an important health issue
– saturated fats are more easily converted to cholesterol, which is linked to heart disease
– cholesterol is only produced by mammals
• Cholesterol (C27H46O)
– water insoluble lipid
– dissolved in other water soluble media
– building block for vitamins and hormones
– only animals (in meat, milk, egg)
Lipoprotein
• 지방 단백질
– 지질 (지방과 콜레스테롤) + 단백질
– 지질을 물에 녹을 수 있게 해 준다
– 지질이 많을수록 밀도 감소
– Very low density lipoprotein
– low density lipoprotein - 나쁜 콜레스테롤
– high density lipoprotein - 좋은 콜레스테롤
Proteins
• Proteins
– water soluble
– polymers of 20 amino acids with peptide bonds
– complex and highly specific structure
– meat, egg, milk, bean, nuts, rice - cereal
• Role of Proteins
– tissue (muscles and organs)
– enzymes
– biological functions (immune system)
Proteins
• Proteins
– proteins must be broken down before digestion
– cooking denatures the proteins, which assist in digestion
– digestion requires acidic condition and enzymes break down protein to amino acids
• Dietary Essential Amino Acids
– bodies can produce 11 of 20 amino acids
– essential amino acids are those we can not produce (egg white and meat contains all)
Protein Structure
• Primary structure
– 아미노산의 종류와 결합 순서
– 펩타이드 결합
• Secondary structure
– 나선 혹은 판
– 수소 결합
• Tertiary structure
– 이차 구조가 다시 접혀 이루는 구조
– disulfide linkage from -SH
Protein tertiary structure
Vitamins and Minerals
• Vitamins
– 건강을 위해 꼭 필요한 화합물이나 몸에서 만들어 지지 않는 것
– required for many biological functions
• Vitamin C (retinol)
– 생식, 성장, 세포분화, 시각. 괴혈병 Scurvy
– 하루 200-500 mg
• Vitamin D (calciperol)
– 햇빛 비타민.
– 뼈와 치아 성장. 구류병 Rickets
Vitamins and Minerals
• 무기질
– 무기물과 관련된 원소
– 건강 유지에 필요
• 대표적 무기질
– Iron(Fe) – oxygen transport in the blood
– Sodium(Na) – blood serum (ions in blood)
– Calcium(Ca) – bones, blood clotting, nerve signals
– Phosphorus(P) – bones, DNA & RNA, ATP
Red blood cell & Hemoglobin
Hemoglobin
Hemoglobin
• Structural comparisons
– Phycocyanin
• a protein found in cyanobacteria that binds a compound related to heme
• shows no significant sequence matches to modern hemoglobins.
• However, the 3D pattern of helices is similar to the fold found in hemoglobins
– Bacterial hemoglobin (from Vitreoscilla) and a mammalian myoglobin show very similar myoglobin folds
Necessary Elements
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