The 6 valence electrons of oxygen are hybridized to four spi orbitals The 0-H covalent bonds, due to the highly electronegative oxygen, have a partial (40%) ionic character. The dissociation energy of this hydrogen bond is about 25 kJ mole I
Nước trong một số thực phẩm
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Presentation Notes
Water (moisture) is the predominant constituent in many foods (Table 0.1). As a medium water supports chemical reactions, and it is a direct reactant in hydrolytic processes. Therefore, removal of water from food or binding it by increasing the concentration of common salt or sugar retards many reactions and inhibits the growth of microorganisms, thus improving the shelf lives of a number of foods. Through physical interaction with proteins, polysaccharides, lipids and salts, water contributes significantly to the texture of food.
Sự dịch chuyển ion
Hoạt tính của nước
Aw = P/Po = EPR/100P: áp suất hơi riêng phần của nước trong thực
phẩmPo: Áp suất hơi bão hòa của nước ở T độ C
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Presentation Notes
In 1952, W.J. Scott came to the conclusion that the storage quality of food docs not depend on the water content, but on water activity (aw) , which is defined as follows: P = partial vapor pressure of food moisture at temperature T Po = saturation vapor pressure of pure water at T ERH = equilibrium relative humidity at T.
Đường hút ẩm
Hàm lượng nước thấp Hàm lượng nước cao
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Presentation Notes
At a low water content (~50%)e.v en minor changes in this parameter lead to major changes in water activity. For that reason, the sorption isotherm of a food with lower water content is shown with an expanded ordinate in Fig. 0.3b. as compared with Fig. 0.3a. Figure 0.3 b shows that thc dcsorption isotherm, indicating the course of a drying pro
Thời gian bảo quản phụ thuộc vào hoat tính của nước
Hoàng Văn Hà
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Presentation Notes
Chúng cung cấp nguyên liệu cho sự tổng hợp protein trong cơ thể, Trực tiếp tạo nên hương vị thực phẩm và là chất đầu cho sự hình thành các hợp chất thơm và hợp chất màu . Protein cũng góp phần quan trọng tới tính chất vật lý của thực phẩm Nguồn quan trọng nhất của protein là hạt cây lương thực, hạt lấy dầu và đậu tiếp theo là thịt và sữa. Ngoài nguồn protein từ động và thực vật còn có, nấm men, vi khuẩn (protein đơn bào).
Giới thiệu
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Presentation Notes
Chúng cung cấp nguyên liệu cho sự tổng hợp protein trong cơ thể, Trực tiếp tạo nên hương vị thực phẩm và là chất đầu cho sự hình thành các hợp chất thơm và hợp chất màu . Protein cũng góp phần quan trọng tới tính chất vật lý của thực phẩm Nguồn quan trọng nhất của protein là hạt cây lương thực, hạt lấy dầu và đậu tiếp theo là thịt và sữa. Ngoài nguồn protein từ động và thực vật còn có, nấm men, vi khuẩn (protein đơn bào).
DNA
Amino axit
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Presentation Notes
Thu được khoảng 20 amino axit khi thủy phân 1 protein Trong tự nhiên có khoảng 200 amino axit
Phân loại – Dựa vào mạch bên
Amino acids có:• Mạch không phân cực, không mang điện:
glycine, alanine, valine, leucine, isoleucine, proline, phenylalanine, tryptophan and methionine.
• Mạch bên phân cực không mang điện: serine, threonine, cysteine, tyrosine, asparagine and glutamine.
• Mạch bên mang điện: aspartic acid, glutamicacid, histidine, lysine, and arginine..
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Presentation Notes
Alunine was isolated from silk fibroin by Weyl in 1888. It is present in most proteins and is particularly enriched in silk fibroin (35%). Gelatin and zein contain about 9% alanine, while its content in other proteins is 2-7%. Alanine is considered nonessential for humans. Asparagine from asparagus was the first amino acid isolated by Vauguelin and Rohbquet in 1806. Its occurrence in proteins (edestin) was confirmed by Darnodavun in 1932. In glycoproteins the carbohydrate component may bebound N-glycosidically to the protein moiety through the amide group of asparagine (cf.11.2.3.1.1 and 11.2.3.1.3). Aspartic Acid was isolated from legumes by Ritthausen in 1868. It occurs in all animal proteins, primarily in albumins at a concentration of 6- 10%. Alfalfa and corn proteins are rich in aspartic acid (14.9% and 12.3 %, respectively) while its content in wheat is low (3.8 %). Aspartic acid is nonessential. Cystine was isolated from bladder calculi by Wolaston in 18 10 and from horns by Moerner in 1899. Its content is high in keratins (9%). Lystine is very important since the peptide chains of many proteins are connected by two cysteine residues, i.e. by disulfide bonds. A certain conformation may be fixed within a single peptide chain by disulfide bonds. Most proteins contain 1-2% cystine. Although it is itself nonessential, cystine can partly replace methionine which is an essential amino acid. Glutamine was first isolated from sugar beet juice by Schulze and Bosshard in 1883. Its occurrence in protein (edestin) was confirmed by Damodaran in 1932. Glutamine is readily converted into pyrrolidone carboxylic acid, which is stable between pH 2.2 and 4.0, but is readily cleaved to glutamic acid at other pH's: Glutamic Acid was first isolated from wheat gluten by Ritthausen in 1866. It is abundant most proteins, but is particularly high in milk proteins (2 1.7 %), wheat (3 1.4%), corn I 18.4%) and soya (18.5%). Molasses also ~mntains relatively high amounts of glutamic acid. Monosodium glutamate is used in numerow food products as a flavor enhancer. Glycine is found in high amounts in structural protein. Collagen contains 25-30% glycine. h was first isolated from gelatin by Braconnot m 1820. Glycine is a nonessential amino acid aithough it does act as a precursor of many Lmpunds formed by various biosynthetic mechanisms. 5-Hydroxylysine was isolated by van Slyke et al. (1921) and Schryver et al. (1925). It occurs in collagen. The carbohydrate component of glycoproteins may be bound 0-glycosidically to the hydroxyl group of the amino acid (cf. 12.3.2.3.1). 4-Hydroxyproline was first obtained from gelatin by Fischer in 1902. Since it is abundant in collagen (12.4%), the determination of hydroxyproline is used to detect the presence of connective tissue in comminuted meat products. Hydroxyproline is a nonessential amino acid. Proline was discovered in casein and egg albumen by Fischer in 190 1. It is present in numerous proteins at 4-7% and is abundant in wheat proteins (10.3 %), gelatin (12.8 %) and casein (12.3 %). Proline is nonessential. Serine was first isolated from sericin by Cramer in 1865. Most proteins contain about 4- 8 % serine. In phosphoproteins (casein, phosvitin) serine, like threonine, is a carrier of phosphoric acid in the form of O-phosphoserine The carbohydrate component of glycoproteins may be bound 0-glycosidically through the hydroxyl group of serine and/or threonine [cf. 10.1.2.1.1 (x-casein) and 13.1.4.2.41. Tyrosine was first obtained from casein by Liebig in 1846. Like phenylalanine, it is found in almost all proteins at levels of 2-6%. Silk fibroin can have as much as 10 % tyrosine. It is converted through dihydroxyphenylalanine by enzymatic oxidation into brown-black colored melanins.
Phân loại – Dinh dưỡng và chức năng trong cơthể• Các amino axit thiết yếu: Valine, leucine,
isoleucine, phenylalanine, tryptophan, methionine, threonine, histidine (thiết yếu đối vớitrẻ nhỏ), lysine and arginine (bán thiết yếu).
• Amino acids không thiết yếu: Glycine, alanine, proline, serine, cysteine, tyrosine, asparagine, glutamine, aspartic acid and glutamic acid.
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Presentation Notes
Histidine was first isolated in 1896 independently by Kossel and by Hedin from protamines occurring in fish. Most proteins contain 2-3 % histidine. Blood proteins contain about 6 %. Histidine is essential in infant nutrition. Isoleucine was first isolated from fibrin by Ehrlich in 1904. It is an essential amino acid. Meat and ceral proteins contain 4-5 % isoleucine; egg and milk proteins, 6-7%. Leucine was isolated from wool and from muscle tissue by Braconnot in 1820. It is an essential amino acid and its content in most proteins is 7- 10%. Cereal proteins contain variable amounts (corn 12.7 %, wheat 6.9 %). During alcoholic fermentation, fuse1 oil is formed from leucine and isoleucine. Methionine was first isolated from casein by Mueller in 1922. Animal proteins contain 2-4% and plant proteins contain 1-2% methionine. Methionine is an essential amino acid and in many biochemical processes its main role is as a methyl-donor. It is very sensitive to oxygen and heat treatment. Thus, losses occur in many food processing operations such as drying, kiln (lò) -drying, puffing (xông khói), roasting or treatment with oxidizing agents. In the bleaching of flour with NCl3, (nitrogen trichloride), methionine is converted to the toxic methionine sulfoximide: Phenylalanine was isolated from lupins (đậu lupin) by Schulze in 1881. It occurs in almost all proteins (averaging 4-5%) and is essential for humans. It is converted in vivo into tyrosine, so phenylalanine can replace tyrosine nutritionally. Threonine was discovered by Rose in 1935. It is an essential amino acid, present at 4.5-5% in meat, milk and eggs and 2.7-4.7% in cereals. Threonine is often the limiting amino acid in proteins of lower biological quality. The "bouillon" flavor of protein hydrolysates originates partly from a lactone derived from threonine (cf. 5.3.1.3). Tryptophan was first isolated from casein hydrolysates, prepared by hydrolysis using pancreatic enzymes, by Hopkins in 1902. It occurs in animal proteins in relatively low amounts (1 -2 %) and in even lower amounts in cereal proteins (about 1 %). Tryptophan isexceptionally abundant in lysozyrne (7.8 %). It is completely destroyed during acidic hydrolysis of protein. Biologically, tryptophan is an important essential amino acid, primarily as a precursor in the biosynthesis of nicotinic acid. Valine was first isolated by Schutzenberger in 1879. It is an essential amino acid and is present in meat and cereal proteins (5 -7 %) and in egg and milk proteins (7-8 %). Elastin (sợi mô đàn hồi) contains notably high concentrations of valine (15.6%). Arginine was first isolated from lupin seedlings by Schulze and Steigev in 1886. It is present in all proteins at an average level of 3-696, but is particularly enriched in protaniines. The arginine content of peanut protein is relatively high ( 1 1 96). Biochemically, arginine is of great importance as an intermediary product in urea synthesis. Arginine is a semi-essential amino acid for humans. It appears to be required under certain metabolic conditions. Lysine was isolated from casein by Drechsel in 1889. It makes up 7-9% of meat, egg and milk proteins. The content of this essential amino acid is 2-4% lower in cereal proteins in which prolamin is predominant. Crab (cua) and fish proteins are the richest sources (10- 11 %). Along with threonine and methionine, lysine is a limiting factor in the biological value of many proteins, mostly those of plant origin. The processing of foods results in losses of lysine since its &-amino group is very reactive (cf. Maillard reaction).
Tính chất vật lý
[ ] [ ]A
HAK +
+−+ ×=1
[ ] [ ]−+
+− ×=
AHAK2
Tính axit bazơ
Đường cong chuẩn độ của một axit amin đặc trưng
[O
H- ]
[H
+ ]
1
0.8
0.6
0.4
0.2
0
0.2
0.4
pH
1 2 3 4 5 6 7 8 9 10 11 12 13
pK2 →
← pK1 điểm đẳng điện
Axit amin có mạch nhánh không tíchđiện: pI = (pKa1 + pKa2)/2Axit amin chua: pI = (pKa1 + pKa3)/2Axit amin kiềm: pI = (pKa2 + pKa3)/2Trong đó pKa1 là pK của α-COOH, pKa2 là pK của α-NH3
+ và pKa3 là pKcủa nhóm chức trên mạch nhánh.
Tính chất hóa học
• Phản ứng của nhóm caboxyl– Este hóa nhóm cacboxyl
• Phản ứng của nhóm amino– Acyl hóa
– Akyl và aryl hóa
Dẫn xuất N-Tosyl của amino axit
Tính chất hóa học• Các tác nhân akyl, aryl: HCHO, methyl iodide, hay
Các acyl lipit Tạo thành từMono-, di-, triacylglycerols Axit béo, glycerolPhospholipit (phosphatit) Axit béo, glycerol or
sphingosin, phosphoric axit, bazơ hữu cơ
Glycolipit Axit béo, glycerol or sphingosin, mono-, di- or oligosaccharit
Diol lipit Fatty acid, etan, propan, or butan diol
Sáp (wax) Axit béo, rượu béoSterol este Axit béo, sterol
– Phân loại theo tính phân cực hay trung tính
Lipit trung tính Lipit phân cựcCác axit béo (> C12) GlycerophospholipidMono-, di-, triacylglycerol GlyceroglycolipidSterol, este của sterol SphingophospholipidCarotenoit SphingoglycolipidSápTocopherol
• Gọi tên và phân loạiSự thủy phân các axyl lipit sinh ra các axit béokhác nhau về cấu trúc hóa học. Chúng đượcphân loại dựa vào độ dài mạch cacbon, vị trí, sốlượng, cấu hình của nối đôi và sự xuất hiện củacác nhóm chức trên mạch cacbon.
- Thêm vị tố -oic, -cacboxylic, - Tên rút gọn theo số cacbon, số lượng và vị trí
Các yếu tố ảnh hưởng tới sự oxi hóa• Thành phần axit• Nhiệt độ• Hoạt tính nước• Ion kim loại• Oxy• Ánh sángEnergy required for hydrogen removal from linoleic
acid
• Conjugated hydroperoxideformation from linoleic acid by free radical reaction of triplet oxygen.
Oxi hoạt hóa và các nhóm nguyên tử có tínhchất tương tự
• Chiết và tinh chế– Dung môi: Chloroform/methanol (2:1, v/v)– Chất ổn định và chống oxi hóa: BHA– Chiết tách các chất không phải lipid bằng
dung dich NaCl• Sắc ký bản mỏng xác định các phân đoạn lipid• Sắc ký cột
– Magiê silicat (florisil), silicic axit, hydrophobic dextran gel or a chất trao đổi ion nền cellulose (Diethylaminoethyl cellulose hay DEAE-cellulose)
• Phân tích các axit béo– Lipid tham gia phản ứng xúc tác bazơ (kali
methylat) với methanol tạo ra methyl esters của axit béo (FAMEs),
– Phân tích bằng GC-FID
III. Carbohydrates
• Sự tồn tại và vai trò của xacarit• Nguồn dinh dưỡng và cung cấp năng lượng quan
trọng nhất• Xacarit không tiêu hóa được đóng vai trò cân bằng
dinh dưỡng, tăng hiệu quả hấp thụ dinh dưỡng,• Đóng vai trò phụ gia làm ngọt, hình thành dạng
gel, nhão, làm đặc, phụ gia ổn định đồng thời làtiền chất tạo các hợp chất màu, mùi đặc biệt trongxử lý nhiệt
• Phân loại– Monoxacarit: Đường đơn điển hình, Deroximonoxacarit,
Monoxacarit phân nhánh, amino xacarit,– Polixacarit: oligoxacarit, polixacarit,– Glicoprotein– Các xacarit khác….
• Monoxacarit
D-glyceraldehyde ( D-glycero -triosa)
C
CH
CH2OH
OHH
O1
2
3 CH2OH
OCH
OHH3
2
1
C
CH
CH2OH
OHH
O1
2
3
L-glyceraldehyde(L -glycero -triose)
C
CH
CH2OH
HHO
O1
2
3
Các monoxacarit
D-erythrose(D-erythro -tetrose)
C
C
CH
CH2OH
O
OH
OH
H
H C
C
CH
CH2OH
O
OHH
HHO
D-threose(D-threo -tetrose)
CCCH
CH2OH
OHH
HOHO
L-erythrose(L-erythro -tetrose)
CCCH
CH2OH
OOHHHHO
L-threose(L-threo-tetrose)
CH
C
H
H
OH
OH
CH2OH
C
C
O
OHH
D-ribose
D-ribo -pentose)
CH
C
H
H
OH
OH
CH2OH
C
C
O
HHO
D-arabinose(D-arabino -pentose)
CH
C
H OH
CH2OH
C
C
O
OH
HO
H
H
D-xylose(D-xylo -pentose)
CH
C
H OH
CH2OH
C
C
O
HO
HO
H
H
D-lyxose(D-lyxo -pentose)
Hexose (hexoz)CH
C
H
H
OH
OHC
C
O
OHH
C
CH2OH
OHH
D-allose(D-allo -hexose)
CH
C
H
H
OH
OHC
C
O
HHO
C
CH2OH
OHH
D-altrose(D-altro -hexose)
CH
C
H OH
C
C
O
OH
HO
H
H
C
CH2OH
OHH
D-glukose(D-gluko -hexose)
CH
C
H OH
C
C
O
HO
HO
H
H
C
CH2OH
OHH
D-mannose(D-manno -hexose)
CH
C
H OHC
C
O
OHH
C
CH2OH
OHH
HO H
D-gulose(D-gulo -hexose)
CH
C
H OHC
C
O
HHO
C
CH2OH
OHH
HO H
D-idose(D-ido -hexose)
CH
C
C
C
O
OH
HO
H
H
C
CH2OH
OHH
HO H
D-galaktose(D-galakto -hexose)
CH
C
C
C
O
HO
HO
H
H
C
CH2OH
OHH
HO H
D-talose(D-talo -hexose)
C OCH2OH
CCCH2OH
OHHHO H
D-xylulose(D-threo-2-pentulose)
C OCH2OH
CCCH2OH
OHOHH
H
D-ribulose(D-erythro-2-pentulosa)
C OCH2OH
CCH2OH
OHH
D-erythrulose(D-glycero-2-tetrulose)
C OCH2OH
CC OHHCCH2OH
OH
OH
H
H
D-psikose(D-ribo-2-hexulose)
C OCH2OH
CC OHH
HO H
CCH2OH
OHH
D-fruktose(D-arabino-2-hexulose)
C OCH2OH
CCCCH2OH
OH
OHHO H
H
H
D-sorbose(D-xylo-2-hexulose)
C OCH2OH
CC
HO H
CCH2OH
OHHO H
H
D-tagatosa(D-lyxo-2-hexulose)
Gọi tên monoxacarit
CCCCCCH 2O H
O HO HH
H
CCCH 2O H
OHHO
HHO HH
HOHO
C OCH2OH
CCC OHHC OH
HOHO H
H
HCH2OH
D-manno -2-heptulose
C OCH2OH
CCC OHHCCCH2OH
OHOH
HOHO H
H
HH
D-glycero -
D-manno -2-octuloseD-erythro-L-gluko-2-nonulose
OCH2OH
OH
OH
OH
HO
D-glukose
234
56
1
Cấu tạo không gian (dạng zig-zăc) Chiếu Fischer
CH
CH2OH
O
HO
HOOH
H
HH
OHH
CCCC
CH
CH2OH
OOH
OHOH
HOH
HHH
α -D-glukopyranose β-D-glukopyranose
OCH2OH
OH
OHOHHO
6
15
4
32
CCCCCH2OH
OH
OHHO
HH
HH
C
O
HO H
CCCCCH2OH
OH
OHHO
HH
HH
CH
O
OH
Công thức vòng Tollen Công thức Công thức vòng Tollen Công thứcChiếu Fischer Haworth Chiếu Fischer Haworth
• Trong dung dịch glucose vòng pyranose là phổbiến 36% dạng alpha, 64 % dạng beta, vòngfuranose dưới 1%.
α -pyranose β -pyranose
α -furanose β -furanose
Mở vòng
Tên gọi ologomer
β
β
α
1
2
3
1
2O
OH
CH2
CH2
HO
HO
OOH
OHO
O
CH2OH
H
O
OH
CH2 O
CH2OHHO
HOβ
β
β
α
O
OH
CH2
HO
CH2
HO
O
OH
CH2
CH2
HO
HO
OOH
OHO
O
CH2OH
H
O
OH
CH2 O
HO
CH2
O
HO
β-D-Fruf-(2→1)-β-D-Fruf-(2↔1)-α-D-Glcp
[β-D-Fruf-(2→1)]2-β-D- β-D-Fruf-(2↔1)-α-D-Glcp
Disaccharide quan trọng
Độ tan trong nước
Hàm lượng saccharide trong một số thực phẩm
Biến đổi của hồ tinh bột
Vitamin
• Phân loại:– Vitamin tan trong nước: B1, B2, B6,
nicotinamide, pantothenic acid, biotin, folic acid, B12 và C.
– Vitamin tan trong chất béo: A, D, E and K1,
Presenter
Presentation Notes
- Vitamin co hàm lượng nhỏ song rất quan trọng trong thực phẩm , một số tồn tại trong thực phẩm dạng provitamin -Hàm lượng vitamin giảm trong quá trình bảo quản hoa quả, rau (bảng). Sự mất mát có thể do phản ứng hóa học hay do chiết, lọc ví dụ vitamin mat trong quá trình chần nóng, nấu nướng. Thiếu vitamin gây ra bệnh nhiều bệnh nguy hiểm, tuy nhiên sử dụng nhiều vitamin gây ra tác động độc hại . Do đó phải kiểm soát cẩn thận trong việc thêm vitamin vào thực phẩm. IU (tiếng Đức là IE) a unit used to measure the activity (that is, the effect) of many vitamins and drugs. For each substance to which this unit applies, there is an international agreement specifying the biological effect expected with a dose of 1 IU. Other quantities of the substance are then expressed as multiples of this standard. Examples: 1 IU represents 45.5 micrograms of a standard preparation of insulin or 0.6 microgram of a standard preparation of penicillin. Consumers most often see IU's on the labels of vitamin packages: in standard preparations the equivalent of 1 IU is 0.3 microgram (0.0003 mg) for vitamin A, 50 micrograms (0.05 mg) for vitamin C, 25 nanograms (0.000 025 mg) for vitamin D, and 2/3 milligram for (natural) vitamin E. Please note: for many substances there is no definite conversion between international units and mass units (such as milligrams). This is because preparations of those substances vary in activity, so that the effect per milligram of one preparation is different from that of another.
Các vitamin tan trong chất béo
• Retinol (vitamin A),
• Carotene• Dạng alpha
123
456
7
8
9
10
11
12
13
14
151617
18
19 20
O R
CH 3
CH 3CH 3H 3C
CH 3CH 2
123
456 7
8
9
10
11
12
13
14
1516 17
18
19 20
1´2´3´
4´5´6´7´
8´
9´
10´
11´
12´
13´
14´
15´16´17´
18´
19´20´
CH3
CH3H3CCH3 CH3
CH3
H3C
H3CCH3CH3
Presenter
Presentation Notes
- Vitamin A : retinol, retinal, retinoic acid, dehydroret., ret. esters, beta-carotene) - Trong tự nhiên tồn tại chủ yếu ở dạng este của axit béo. Có hàm lượng lớn trong dầu gan cá tuyết, cá ngừ Other important sources are mammalian liver, egg yolk, and milk and milk products. Essential for eyes, skin and the proper function of the immune system. Helps maintain hair, bones and teeth. - National Research Council Food and Nutrition Board is 5000 IU for an adult. Other sources quote the human requirement at about 1 μg/day Deficiency: Night blindness; reduced hair growth in children; loss of apetite; dry, rough skin; lowered resistance to infection; dry eyes. Overdose: Headaches; blurred vision; fatigue mệt mỏi; diarrhea tiêu chảy; irregular periods chu kỳ không đều; joint and bone pain; dry, cracked skin; rashes phát ban; loss of hair; vomiting nôn, liver damage. Pro vitamin A: beta-carotene Carrots, Squash qua bí, Broccoli xúp lơ xanh, Green Leafy Vegetables Antioxidant. Converted to Vitamin A in the body. (See Vitamin A) The antioxidant properties of this nutrient may be a factor in reducing the risk of certain forms of cancer.
Bền với nhiệt, môi trường bazơ, kém bền với UV light, oxi, axit, kim loại, bảo quản kín và trong bóng tối.
Một số sản phẩm từ sự phân hủy carotene
Vitamin D
D3: cholecalciferol D2 ergocalciferol
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Presentation Notes
Cholecalciferol (vitamin D3) is formed from cholesterol in the skin through photolysis of 7-dehydrocholesterol (provitamin D,) by ultraviolet light ("sunshine vitamin“. Similarly, vitamin D2 (ergocalciferol) is formed from ergosterol. Vitamin D1: molecular compound of ergocalciferol with lumisterol, 1:1 Vitamin D2: ergocalciferol (made from ergosterol) Vitamin D3: cholecalciferol (made from 7-dehydrocholesterol in the skin). Vitamin D4: 22-dihydroergocalciferol Vitamin D5: sitocalciferol (made from 7-dehydrositosterol) Rất bền , bền trong môi trường base, dề hỏng bởi ánh sáng UV và oxi, acid, kim loại. bảo quản tối kín và lạnh. Vitamin D does not occur in plant products. Vitamin D2 occurs in small amounts in fish liver oils; vitamin D3 is widely distributed in animal products, but large amounts occur only in fish liver oils. Smaller quantities of vitamin D3 occur in eggs, milk, butter, and cheese The unit of activity of vitamin D is the IU, which is equivalent to the activity of 1 mg of a standard preparation issued by the WHO. One IU is also equivalent to the activity of 0.025 |ig of pure crystalline vitamin D2 or D3. The human requirement amounts to 400 to 500 IU but increases to 1,000 IU during pregnancy and lactation. Adults who are regularly exposed to sunlight are likely to have a sufficient supply of vitamin D. Excessive intakes are toxic.
Sự hình thành vitamin D
CH3
CH3R
HO
provitamin D
CH3R
OH
CH3previtamin D
CH3R
CH2
HOvitamin D
UV Nhiệt độ
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Presentation Notes
Xây dựng và nuôi dưỡng răng, xương, tăng khả năng hấp thụ canxi. Thiếu: Còi xương ở trể nhỏ; mềm xương ở người lớn; loãng xương. Thừa: tích canxi ở nội tạng; giòn xương; phá hủy thận và hệ tim mạch.
játra ledviny
ledviny cílové buňky
CH3
HO
CH2
CH3
CH3
H3C
cholekalciferol
CH3
HO
CH2
CH3
CH3
H3C
OH
25-hydroxycholekalciferol
CH3
HO
CH2
CH3
CH3
H3C
OH
OH
1a ,25-dihydroxycholekalciferol
cílové buňky
CH3
HO
CH2
CH3
CH3
H3C
OH
OH
24,25-dihydroxycholekalciferol
CH3
HO
CH2
COOHH3C
OH
kalcitrová kyselina
CH3
HO
CH2
CH3
CH3
H3C
OH
OH
OH
1a ,24,25-trihydroxycholekalciferol
Tocopherols (Vitamin E) 1922, Herbert McLean Evans
Presenter
Presentation Notes
Vitamin E�Men: 9-10 mg�Women: 6-7 mg Corn or Cottonseed Oil, Butter, Brown Rice, Soy bean Oil, Vegetable oils such as Corn, Cottonseed or Soybean, Nuts, Wheat Germ. Antioxidant. Helps form red blood cells, muscles and other tissues. Preserves fatty acids. Deficiency: Rare, seen primarily in premature or low birth weight babies or children who do not absorb fat properly. gây rối loạn thần kinh. Overdose: Unknown. The antioxidant properties of this nutrient may be a factor in reducing the risk of certain forms of cancer.
Sản phẩm chính của phản ứng giữa tocopherol và lipit peroxit
(T-OH)
(T-O )
O
CH3
H3C
C16H33
H3C OO
C16H33H3C
OO
CH3
H3C
OCH3
CH3
CH3
C16H33α-tocopherolspirotrimer
-
OCH3
H3CCH3
C16H33
CH3
O
6-O-alkyl-α-tocopherol
OO
O
C16H33
OCH3
CH3
CH3
CH3
H3C
C16H33
H3C
α-tocopherolspirodimer
OCH3
H3CCH3
C16H33
CH3
O
radical α-tocopherolu
OCH3
H3CCH3
C16H33
CH3
O
radical α-tocopheron
OCH3
H3CCH3
C16H33
CH3
HO
α-tocopherol
OCH3
H3CCH3
C16H33
CH3
O
OO
8a-alkylperoxy-α-tocopheron
T-O
R
R
R
R-O-O
R-O-OH R-O-O
- 2 H
Presenter
Presentation Notes
Bền với UV, bảo quản lạnh môi trường trung tính, dạng este bền với cả nhiệt, oxi và ion kim loại Fe3+, Cu2+.
Phytomenadione, Vitamin K, 1929, Henrik Dam
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Presentation Notes
None established.�Estimated at 0.03 mcg/kg Green Vegetables, Liver, also made by intestinal bacteria. Needed for normal blood clotting. Deficiency:�Defective blood coagulation. Overdose: Jaundice in infants, bệnh vàng gia ở trẻ nhỏ dưới 10 tuổi. Bền với nhiệt và môi trường axit, kém bền với các tác nhân khử.
Ảnh hưởng của tác nhân khử
Ascorbic acid, Vitamin C
L D-iso
D L-iso
6
5
4 3 21
OO
HO H
CH2OH
HO OH
OO
H OH
CH2OH
HO OH
O
OH OH
O
OHH
CH2OH
O
OH OH
O
HHO
CH2OH
Presenter
Presentation Notes
Men: 40 mg�Women: 30 mg Citrus Fruits, Strawberries, Cải xúp lơ xanh Broccoli, Green Peppers Antioxidant. Helps bind cells together and strengthens blood vessel walls. Helps maintain healthy lợi gums. Aids in the absorption of iron. Deficiency: Muscle weakness, bleeding gums; easy thâm tím bruising. In extreme cases, scurvy. Overdose: Unknown. The antioxidant properties of this nutrient may be a factor in reducing the risk of certain forms of cancer. May reduce the effects of the common cold.
disulfide form hydrochlorided bền với UV, bảo quản môi trường trung tính, dạng hydrochlorided bảo quản kín. Men: 0.8 - 1.3 mg�Women: 0.8 mg Sunflower Seeds, Pork, whole and enriched Grains, dried Beans. Necessary for carbohydrate metabolism and phối hơp cơ muscle coordination. Promotes đúng proper nerve function. Deficiency:�Lo âu Anxiety; loạn thần kinh hysteria; depression; chuột rút muscle cramps; ko ngon miệng loss of appetite; in extreme cases bệnh tê phù beriberi (mostly in alcoholics). Overdose:�Unknown, although excess of one B vitamin may cause deficiency of others.
Phân hủy thiamin
+
+N
N
CH2OH
NH2H3C
4-amino-5-hydroxymethyl-2-methylpyrimidin
thiaminasa I,niacin
thiaminasa II,
N
NH3C NH2
CH2 N
COOH
CH2CH2OH
thiamin (bazơ tự do)
N
N
H3C NH2
CH2 N
S
CH3 +H2O, - H
N
S
CH3
CH2CH2OH
5-(2-hydroxyethyl)-4-methylthiazol
o
Hình thành thiol, disulfide a thiochrom
CH2CH2OH-N
N
N
N
CH3
H3C SOHH
N
N
N
N S
CH3
H3C
thiochrom
Oxi hóa
CH2CH2OH
thiamindisulfid thiaminthiol (thiaminthiolat)
+
Dạng màu vàng
N
N
N
N S
CH3
H3C H
H2O
-
N
N
N
N
CH3
H3C SCH2CH2OH CH2CH2OH-
CH2CH2OH
thiamin
N
S
CH3CH2
NH2H3C N
N+
HO-
-
H2O
- H2O
-HO
CH2CH2OHS-
N
NH3C NH2
NCH3
CHO
CH2CH2OH
N
NH3C NH2
N
S
CH3
CH3
S
N
CH2CH2OHNH2H3C N
N
OCH
CHO
Oxi hóa - 2 H
CH2CH2OH
N
S
CH3
H3C N
N
NH H
- 2 H
Presenter
Presentation Notes
Thiamine stability in aqueous solution is relatively low. It is influenced by pH (Fig. 6.2), temperature (Table 6.8), ionic strength and metal ions. The enzyme-bound form is less stable than fi-ee thiamine (Fig. 6.2). Strong nucleophilic reagents, such as HSOj or OH-, cause rapid decomposition by forming 5-(2- hydroxyethy1)-4-methylthiazole and 2-methyl- 4-amino-5(methylsulfonic acid)-pyrimidine, or 2-methyl-4-amino-5-hydroxymethylpyrimidine (see Reactions 6.7). Thermal degradation of thiamine, which also initially yields the thiazole and pyrimidine derivatives mentioned above, is involved in the formation of meat-like aroma in cooked food. Thiamine is inactivated by nitrites, probably through reaction with the amino group attached to the pyrimidine ring. Strong oxidants, such as H,O, or potassium ferricyanide, yield the fluorescent thiochrome. This reaction is often used in chemical determination of the thiamine content in food
Riboflavin (Vitamin B2)
• Dạng khử và dạng oxi hóaN
N
NH
NH3C
H3C
O
OCH2
CHO H
CHO H
CHO H
CH2OH5´
4´
3´
2´
1´
10a9a8a
7a5a 4a
10
98
76
5
4 3
21
N
N
NH
NH3C
H3C
O
O
R
riboflavin (dạng oxi hóa) Gốc anion (đỏ)-
N
N
NH
NH3C
H3C
O
O
R
Gốc (xanh da trời)
N
N
NH
NH3C
H3C
O
O
H
R
N
N
NH
NH3C
H3C
O
O
R H
H
1,5-dihydroriboflavin (dạng khử)
e-
e-H ,
H +
+
Presenter
Presentation Notes
Riboflavin�Vitamin B2 Bền: với oxy, môi trường axit; kém bền: với UV, nhiệt, bazơ, kim loại�Men: 1.3 - 1.6 mg�Women: 1.1 mg Liver, Milk, Spinach, enriched Noodles, Mushrooms. Needed for metabolism of all foods and the release of energy to cells. Essential to the functioning of Vitamin B6 and Niacin. Deficiency: Cracks and sores around the mouth and nose; visual problems. Overdose: See Vitamin B1.
Niacin
• Thuật ngữ niacin dùng để chỉ nicotinic axit và nicotinamit (Vitamin B3)
• Nhu cầu hàng ngày: ♂ 16-23 mg; ♀ 14-16 mg• Thực phẩm giàu niacin: Nấm, cám, cá ngừ, thịt gà,
thịt bò, lạc, thóc lúa.• Trong cơ thể nicotinic axit chuyển đổi thành
niacinamit, tryptophan cũng có thể được chuyển hóa thành niacin
N
CONH2
N
COOH
Presenter
Presentation Notes
Niacin�Vitamin B3�Men: 16-23 mg�Women: 14-16 mg�Niacin is converted to niacinamide in the body. Mushrooms, Bran, Tuna, Chicken, Beef, Peanuts, enriched Grains. Needed in many enzymes that convert food to energy. Helps maintain a healthy digestive tract and nervous system. In very large doses, lower cholesterol (large doses should only be taken under the advice of a physician). Deficiency:�In extreme cases, pellagra, a disease characterized by dermatitis, diarrhea and mouth sores. Overdose:�Hot flashes; ulcers; liver disorders; high blood sugar and uric acid; cardiac arrythmias.
vitamin này dẫn đến bệnh penlagrơ (gây nứt da, có thể dẫn đến bệnh tâm thần), tiêu chảy, lở miệng. Dùng quá liều dẫn đến bừng nóng (Hot flashes); mụn; rối loạn chức năng gan, nhiều đường và axit uric trong máu; loạn nhịp tim.
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Presentation Notes
In extreme cases, pellagra, a disease characterized by dermatitis, diarrhea and mouth sores. Overdose:�(bừng nóng) Hot flashes; mụn; rối loạn chức năng gan; high blood sugar and uric acid; cardiac arrythmias.
Pantothenic Acid, Vitamin B5 (R)-pantothenic acid, n = 1(R)-hopantenic acid, n = 2
• Men: 2.5 mgWomen: 2.5 mg
• Abundant in animal tissues, whole grain cereals and legumes.
• Converts food to molecular forms. Needed to manufacture adrenal hormones and chemicals that regulate nerve function.
• Deficiency: Unclear in humans. Overdose: See Vitamin B1.
HOCH2 C
CH3
CH3
C CO NH CH2 (CH2)n COOH
H
OH
Presenter
Presentation Notes
Pantothenic Acid�Vitamin B5�Men: 2.5 mg�Women: 2.5 mg Abundant in animal tissues, whole grain cereals and legumes. Converts food to molecular forms. Needed to manufacture adrenal hormones and chemicals that regulate nerve function. Deficiency:�Unclear in humans. Overdose:�See Vitamin B1. Pantothenic acid (Formula 6.14) is the building unit of coenzyme A (CoA), the main carrier of acetyl and other acyl groups in cell metabolism. Acyl groups are linked to CoA by a thioester bond. Pantothenic acid occurs in free form in blood plasma, while in organs it is present as CoA. The highest concentrations are in liver, adrenal glands, heart and kidney.
• Bền với nhiệt, axit, kim loại, bảo quản lạnh và môi trường trung tính.
•
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Bền với
Pyridoxine, Vitamin B6
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Presentation Notes
Vitamin B6�Pyridoxine�Men: 1.8 mg�Women: 1.5 mg Animal protein foods, Spinach, Broccoli, Bananas. Needed for protein metabolism and absorption, carbohydrate metabolism. Helps form red blood cells. Promotes nerve and brain function. Deficiency:�Anemia, irritability, patches of itchy, scaling skin; convulsions. Overdose:�Nerve damage. unstable: UV light, heat
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Presentation Notes
Vitamin B12�Cyanocobalamin�Men: 2 mcg�Women: 2 mcg Found almost exclusively in animal products. Builds genetic material. Helps form red blood cells. Deficiency:�Pernicious anemia; nerve damage. (Note: Deficiency rare except in strict vegetarians, the elderly or people with malabsorption disorders.) Overdose:�See Vitamin B1.
