MindMap Gallery vitamins
Food analysis vitamin PPT, including determination of fat-soluble vitamins, Determination of water-soluble vitamins, determination of vitamin C content, Fluorescence spectrophotometer, etc.
Edited at 2023-12-09 23:22:57One Hundred Years of Solitude is the masterpiece of Gabriel Garcia Marquez. Reading this book begins with making sense of the characters' relationships, which are centered on the Buendía family and tells the story of the family's prosperity and decline, internal relationships and political struggles, self-mixing and rebirth over the course of a hundred years.
One Hundred Years of Solitude is the masterpiece of Gabriel Garcia Marquez. Reading this book begins with making sense of the characters' relationships, which are centered on the Buendía family and tells the story of the family's prosperity and decline, internal relationships and political struggles, self-mixing and rebirth over the course of a hundred years.
Project management is the process of applying specialized knowledge, skills, tools, and methods to project activities so that the project can achieve or exceed the set needs and expectations within the constraints of limited resources. This diagram provides a comprehensive overview of the 8 components of the project management process and can be used as a generic template for direct application.
One Hundred Years of Solitude is the masterpiece of Gabriel Garcia Marquez. Reading this book begins with making sense of the characters' relationships, which are centered on the Buendía family and tells the story of the family's prosperity and decline, internal relationships and political struggles, self-mixing and rebirth over the course of a hundred years.
One Hundred Years of Solitude is the masterpiece of Gabriel Garcia Marquez. Reading this book begins with making sense of the characters' relationships, which are centered on the Buendía family and tells the story of the family's prosperity and decline, internal relationships and political struggles, self-mixing and rebirth over the course of a hundred years.
Project management is the process of applying specialized knowledge, skills, tools, and methods to project activities so that the project can achieve or exceed the set needs and expectations within the constraints of limited resources. This diagram provides a comprehensive overview of the 8 components of the project management process and can be used as a generic template for direct application.
Determination of vitamins
Overview
Classification of vitamins
fat soluble
VA,VD,VE
water soluble
VB,VC
commonality
are found in natural foods
It cannot supply heat energy to the body; it is not the basic raw material of tissues.
The main function is to regulate the metabolic process by acting as a coenzyme component, and the amount required is extremely small.
Generally it cannot be synthesized in the body, or the amount of synthesis cannot meet physiological needs, so it must be taken in from food regularly.
Long-term deficiency of any vitamin can lead to corresponding diseases
Physiological functions of common vitamins
Vitamin A: It is an essential nutrient for the human body, which can promote human development and prevent eye problems. inflammation, night blindness and other diseases
Vitamin B: also called thiamine, its main function for the human body is to prevent beriberi and neurological diseases. inflammation, aids digestion and promotes development
Vitamin B2: prevents angular stomatitis, dermatitis, and photophobia for human body functions
Vitamin C: Prevents scurvy, promotes wound healing, and enhances the body’s resistance.
Vitamin D: Regulates the balance of mineral salts in the body, especially calcium and phosphorus in the body
The significance of vitamin determination
Determination of fat-soluble vitamins
Physical and chemical properties
1.Solubility: Insoluble in water, easily soluble in fat, ethanol, acetone, chloroform, ether, benzene and other organic solvents
2.Acid and alkali resistance: Vitamins A and D are unstable to acids and stable to alkali; Vitamin E is stable to acid and unstable to alkali, but it can also withstand boiling by alkali in the presence of antioxidants or under the protection of inert gas.
Va is easily oxidized (light and heat promote its oxidation); Vd is not easily oxidized; Ve can be slowly oxidized in the air (light, heat Heat and alkali promote oxidation). They have good heat resistance and can withstand boiling.
test methods
When measuring fat-soluble vitamins, usually: Saponified sample → Separation of lipids and vitamins → Organic solvent extraction of fat-soluble vitamins (unsaponifiable matter) → Concentrate → Dissolve in appropriate solvent for measurement
Note
Fat-soluble vitamins in food often coexist with fat and are absorbed by the body together, so they must be removed fat to prevent interference
During saponification and concentration, antioxidants are often added to prevent the oxidative decomposition of vitamins. (Such as pyrogallic acid, vitamin C, etc.)
Commonly used measurement methods include: thin layer chromatography, spectrophotometry, gas chromatography, high performance liquid chromatography, etc.
(First method) HPLC determination of V, and Vg
principle After the food sample is saponified, use an organic solvent to extract the fat-soluble vitamins (such as vitamin A and vitamin E) in the food from the non-saponifiable parts. After concentrating to remove the organic solvent, dissolve it with an appropriate solvent and use HPLC method. C. The reversed-phase column separates V and Vg, and their content is measured using the internal standard method through a UV detector.
Determination of water-soluble vitamins
Physical and chemical properties
Easily soluble in water, insoluble in most organic solvents; Stable in acidic media, unstable in alkaline conditions; susceptible to the influence of air, light, heat, enzymes, and metal ions
test methods
Determination of vitamin B1-fluorescence spectrophotometry
principle: Thiamine is oxidized into a blue fluorescent substance, which is sulfur pigment, in alkaline potassium ferricyanide solution. Under ultraviolet light, sulfur pigment emits fluorescence. Under certain conditions, its fluorescence intensity is proportional to the concentration of sulfur pigment. Directly proportional to the thiamine content
Vitamin B, fluorescence spectrophotometry
principle Riboflavin produces yellow-green fluorescence when illuminated by light with a wavelength of 440 ~ 500nm. In dilute solutions, its fluorescence intensity is proportional to the concentration of riboflavin. The fluorescence intensity was measured at a wavelength of 525 nm. Add low sodium sulfite (Na2S204) to the test solution to reduce the riboflavin to a non-fluorescent substance, and then measure the fluorescence intensity of the remaining fluorescent impurities in the test solution. The difference between the two is the fluorescence intensity produced by riboflavin in the food.
Determination method of vitamin C (first method) Fluorescence method (measurement of total ascorbic acid)
principle: After the reduced ascorbic acid in the sample is oxidized to dehydroascorbic acid by activated carbon, it reacts with o-phenylenediamine to generate fluorescent quinoline. Its fluorescence intensity is proportional to the concentration of ascorbic acid under certain conditions. This is used to determine the content of food in food. Total amount of ascorbic acid and dehydroascorbic acid
Vitamin C content measurement
Determination steps
Sample pretreatment → Set chromatographic conditions → Standard solution preparation → Standard solution measurement → Standard curve drawing → Test solution measurement → Sample content calculation
Fluorescence spectrophotometer
basic structure
Light source → Excitation monochromator → Sample cell → Emission monochromator → Detector → Data processing instrument control
advantage
high sensitivity
Strong selectivity
Small sample size
Simple method
More parameters available
shortcoming
Many interference factors
Limited application but of special importance