Bài giảng Phụ gia thực phẩm - Chương 5: Chất chống oxy hóa

Bài giảng Phụ gia thực phẩm - Chương 5: Chất chống oxy hóa có nội dung trình bày về các chất chống nâu hóa, kiểm soát nâu hóa, hóa học của phản ứng hóa nâu trong thực phẩm, quá trình oxy hóa (oxidation),... Mời các bạn cùng tham khảo chi tiết nội dung bài giảng!

PART FOOD ADDITIVES CONTRIBUTING TO IMPROVE THE SHELF-LIFE Chương 5: ANTIOXIDANTS Group 4: Antioxidant A food additive, which prolongs the shelf-life of foods by protecting against deterioration caused by oxidation    antibrowning agent antioxidant antioxidant synergist Các chất chống nâu hóa Nâu hóa vấn đề • Thực phẩm nguồn gốc thực vật bị biến đổi hóa học q trình: sau thu hoạch, chế biến, hoặc lưu trữ, Các phản ứng biến đổi màu (nâu hóa) chia thành loại: Nâu hóa enzyme Nâu hóa khơng enzyme Ví dụ: - Nâu hóa q trình cắt rau tươi tiếp xúc khơng khí? - Nâu hóa q trình trùng nước quả? Nâu hóa enzyme kết của: - Oxy hóa hợp chất polyphenols chuyển thành quinones, - Được xúc tác enzyme polyphenol oxidase: • PPO • Tyrosinasa • o-diphenol oxidase • catechol oxidase - Các phản ứng tiếp tục diễn polymer hóa quinones Kiểm sốt nâu hóa enzyme: Sử dụng phương pháp chần, Acid hóa; ứng dụng sulfites or sử dụng chất thay sulfites như: – ascorbic acid – cysteine Các chất thay hiệu so với sulfites Chemistry of browning reactions in foods Chemistry of browning reactions in foods • The optimum pH for PPO activity is between and • PPO is relatively heat labile • and PPO-catalyzed reactions can be inhibited by: acids phenolic acids, sulfites ascorbic acid Sulfites • Sulfite may be applied as:  E220 Sulphur dioxide  E221 Sodium sulphite  E222 Sodium bisulphite,  E223 Sodium metabisulphite  E224 Potassium metabisulphite  E225 Potassium sulphite  E226 Calcium sulphite  E227 Calcium hydrogen sulphite,  E228 Potassium bisulphite E310 Propyl gallate, E311 Octyl gallate, E312 Dodecyl gallate Limitations The gallates are fat-soluble, but need to be dissolved in a small quantity of hot fat first before being diluted with the rest of the fat BUTYLATED HYDROXYANISOLE (BHA) ISN 320 OH OH C(CH3)3 C(CH3)3 O–CH3 O–CH3 Chemical names : 3-Tertiary-butyl-4-hydroxyanisole, a mixture of 3- and 2-tertiarybutyl-4-hydroxyanisole DESCRIPTION : White or slightly yellow crystals or waxy solid, with a faint characteristic odour SOLUBILITY : Insoluble in water; freely soluble in ethanol and propane-1,2-diol MAX LEVEL : 200mg/Kg ADI : – 0,5 mg/Kg BUTYLATED HYDROXYANISOLE (BHA) ISN 320 Function in Food • Butylated hydroxyanisole is an antioxidant and is added to delay or prevent rancidity in fats and oils in foodstuffs • It is insoluble in water and is best suitable to foods with a high fat content • BHA is often used in combination with other antioxidants such as BHT to give a synergistic effect BUTYLATED HYDROXYANISOLE (BHA) ISN 320 Benefits BHA is stable to heat and mildly alkaline conditions, giving it a property that makes BHA particularly suitable in baked and fried foods Limitations BHA is a very effective antioxidant for animal fats, but its effect is less marked in vegetable oils that are being stored at ambient temperatures BUTYLATED HYDROXYTOLUENE (BHT) ISN 321 OH (H3C)3C C(CH3)3 O–CH3 Chemical names: 2,6-Ditertiary-butyl-p-cresol, 4-methyl-2,6-ditertiary-butyl-phenol DESCRIPTION: White, crystalline or flaked solid, odourless or having a characteristic faint aromatic odour SOLUBILITY: Insoluble in water and propane-1,2-diol; freely soluble in ethanol MELTING POINT: 69 – 72oC MAX LEVEL: 100mg/Kg ADI: – 0,3 mg/Kg BUTYLATED HYDROXYTOLUENE (BHT) ISN 321 Function in Food • Butylated hydroxytoluene is an antioxidant and is added to delay or prevent rancidity in fats and oils in foodstuffs • It is insoluble in water and is best suitable to foods with a high fat content • BHT is often used in combination with other antioxidants, such as BHA, to give a synergistic effect BUTYLATED HYDROXYTOLUENE (BHT) ISN 321 Limitations BHT is more steam-volatile than BHA, and this makes it unsuitable for use on its own in frying oils, particularly where high-moisture foods are being fried ANTIOXIDANT Chelating agent (sequestrant) STABLILSED COMPLEX METAL IONS EDTA (Ethylene Diamine Tetra Acetate) Calcium Disodium Ethylene Diamine Tetra Acetate Disodium Ethylene Diamine Tetra Acetate Polyphosphates Ortho- , Pyro-phosphoric acid Isopropyl citrate CALCIUM DISODIUM ETHYLENE DIAMINE TETRA ACETATE INS CH 385 – –COO– OOC–H2C NCH2CH2N –OOC–H 2C 2Na+ , Ca++ CH2–COO– SYNONYMS : Calcium disodium EDTA Chemical names: N,N'-1,2-Ethanediylbis[N-(carboxymethyl)-glycinate](4-)-N,N',O,O',ON,ON]calciate(2-) disodium; Calcium disodium ethylenediaminetetraacetate; Calcium disodium (ethylene-dinitrilo)tetraacetate DESCRIPTION: White, odourless crystalline granules or a white to nearly white powder; slightly hygroscopic FUNCTIONAL USES : Sequestrant, preservative SOLUBILITY: Freely soluble in water, practically insoluble in ethanol pH : 6.5 - 7.5 MAX LEVEL : beverages : 25 – 35mg/Kg, fish : 50, fruits vegetables products 100 – 200, dried vegetables 600 – 800 ADI : 0-2.5 mg/kg DISODIUM ETHYLENE DIAMINE TETRA ACETATE INS 386 CH2–COO– –OOC–H C NCH2CH2N –OOC–H 2C 2Na+ CH2–COO– SYNONYMS : Disodium EDTA, disodium edetate Chemical names : Disodium salt of N,N'-1,2-Ethanediylbis[N-(carboxymethyl)glycine]; disodium dihydrogen ethylenediaminetetraacetate; disodium dihydrogen (ethylenedinitrilo)-tetraacetate DESCRIPTION: White, odourless crystalline granules or a white to nearly white powder FUNCTIONAL USES : Sequestrant, antioxidant synergist, preservative SOLUBILITY : Freely soluble in water, practically insoluble in ethanol pH : 4.3 – 4.7 MAX LEVEL : beverages : 25 – 35mg/Kg, fish : 50, fruits vegetables products 100 – 200, dried vegetables 600 – 800 ADI : 0-2.5 mg/kg SODIUM POLYPHOSPHATES INS 452 O– O P O– O– O O O P P O– O– O P O– O O– O O– P O O O P O– O O– P O– n O– O O P O– O– SODIUM POLYPHOSPHATES INS 452 pH changing from 3-9 Chemical names : Sodium tetrapolyphosphate, sodium hexametaphosphate, sodium polyphosphate DESCRIPTION : Colourless or white, transparent platelets, granules, or powders FUNCTIONAL USES : Emulsifier, sequestrant, texturizer SOLUBILITY : Very soluble in water MAX LEVEL : 0.6 – 1.0 % MTDI (Maximum Tolerable Daily Intake): 70 mg/kg O O PENTASODIUM TRIPHOSPHATE INS 451 NaO P NaO O P NaO O O P ONa NaO SYNONYMS : Pentasodium tripolyphosphate, Sodium triphosphate, Sodium tripolyphosphate, Triphosphate Chemical names : Pentasodium triphosphate, pentasodium tripolyphosphate DESCRIPTION : White, slightly hygroscopic granules or powder FUNCTIONAL USES: Sequestrant, texturizer SOLUBILITY : Freely soluble in water; insoluble in ethanol pH : 9.1 - 10.1 MAX LEVEL : 0.6 – 1.0 % No ADI was established, MTDI : 70 mg/kg CH2 – COOR HO CH ISOPROPYL CITRATE INS 384 COOR R isopropyl or hydrogen CH2 – COOR Chemical names : Citric acid mixed ester of 2-propanol FUNCTIONAL USES : Antioxidant, sequestrant SOLUBILITY : Soluble in water and ethanol MAX LEVEL : 200mg/Kg ADI : 0-14 mg/kg Antioxidative factor (AF) = IA/I0 AF values of some antioxidants (0.02%) in refined lard Antioxidant d--tocopherol d--tocopherol BHA BHT AF 12 9.5 Antioxidant Octyl gallate Ascorbyl palmitate BHA+BHT (0.01%+0.01%) AF 12 ... Oxidation Oxy hóa làm biến đổi thực phẩm: ơi hóa (rancidity), mất mùi vị, mất màu sắc mất giá trị dinh dưỡng Oxidation Mức độ oxy hóa phụ thuộc vào: Tồn chất oxy hóa tự nhiên thực phẩm, Có mặt oxy, ... 2,3-didehydro-L-threo-hexono-1,4-lactone-6-palmitate; ▪ 6-palmitoyl-3-keto-L-gulofuranolactone Chemical formula : C22H38O7 Description : White or yellowish-white solid, with a citrus-like odour... thành loại: Nâu hóa enzyme Nâu hóa khơng enzyme Ví dụ: - Nâu hóa q trình cắt rau tươi tiếp xúc khơng khí? - Nâu hóa q trình trùng nước quả? Nâu hóa enzyme kết của: - Oxy hóa hợp chất polyphenols