Minerals and Vitamins in Human Nutrition

Chapter 5: Vitamin & Mineral Analysis in Food

• This chapter covers vitamin and mineral analysis in food.
• The course is Food Chemistry and Analysis (BWD 22303).

RPP-04 Subchapters

• 5.1 Vitamin and minerals in food
• 5.2 Change of vitamin and mineral contents in foods
• 5.3 Ash determination by wet digestion and dry ashing for mineral analysis
• 5.4 Vitamin analysis in food

Introduction to Vitamins & Minerals in Food

• What are vitamins and their classification?
• Hydrosoluble vitamins (B, C)
• Liposoluble vitamins (A, D, E, K)

Vitamins & Minerals Function

• Vitamins are organic substances found in plants and animals needed for normal body function.
• Vitamins are needed in small amounts for various physiological processes.
• Water-soluble vitamins (e.g., B, C) dissolve in water and are not stored in the body for long periods.
• Fat-soluble vitamins (e.g., A, D, E, K) dissolve in fat and can be stored in the body for longer periods.
• Vitamin/mineral function includes vision, immune function, skin health, bone and immune function, cell protection, blood clotting, energy production, metabolism and nervous system function.

Vitamin B & Function

• Vitamin B1 (Thiamine): helps convert carbs to energy, nerve function and muscle contraction, supports heart and brain functions.
• Vitamin B2 (Riboflavin): plays a role in energy production, supports healthy skin, eyes and nervous system; an antioxidant protecting against oxidative damage
• Vitamin B3 (Niacin): aids energy production and DNA repair, maintains healthy skin and nerves; helps lower LDL cholesterol and increase HDL cholesterol.
• Vitamin B5 (Pantothenic Acid): crucial for synthesizing coenzyme A which metabolizes fats, proteins, and carbohydrates; supports hormone and cholesterol production, amino acid metabolism and neurotransmitter synthesis.
• Vitamin B6 (Pyridoxine): helps make brain chemicals, red blood cells and immune system cells
• Vitamin B7 (Biotin): needed for metabolism of various compounds, for strengthening hair.
• Vitamin B9 (Folate): important for brain function and mental health, supports DNA and RNA production; important in early stages of development
• Vitamin B12 (Cobalamin): important for the nervous system, and in making red blood cells, production of DNA and RNA

Change of Vitamin and Mineral Contents in Foods

• Mineral and trace element contents in cereal products, fruits, and vegetables have changed significantly in certain regions (e.g., Finland) over the past several decades, generally showing a downward trend, particularly in trace elements.
• The average daily mineral and trace element intakes appear to have decreased, though consumption of vegetable foods has increased.
• More detailed research on mineral and trace element quantities in foods is needed.
• Changes in the mineral and trace element quantities have been observed in some cereal, fruits, and vegetables in Finland, comparing them to 30 years prior.

Essential Vitamins and Minerals

• Major plant nutrient levels have decreased by 25%.
• Phosphorus use in fertilizers has decreased by 66% since 1975.
• There have been complete changes in cereal cultivars, and a notable decrease in the growth of older varieties.
• Cadmium levels are consistently low in Finland cereals due to phosphate fertilizer use.
• Consumption of fruits and vegetables has increased in certain regions, but mineral and trace element contents have decreased in these foods.
• Selenium levels in food have increased.

Processing Methods and Effect on Nutrients

• Processing methods significantly affect nutrients.
• Water-soluble vitamins (B-complex and C) are more susceptible to degradation by heat, light, and oxygen exposure.
• Cooking, processing, and storage will lead to nutrient loss for certain vitamins and minerals.
• Water-soluble vitamins are more vulnerable to processing and cooking compared to fat-soluble vitamins.
• Folate, thiamine, and vitamin C are among the most vulnerable water-soluble vitamins during processing and storage.

Some Fact on Vitamin C

• Vitamin C is soluble in water and alcohol, but practically insoluble in chloroform.
• It has a melting point between 190-192°C.
• It's easily oxidized by copper and iron and is unstable in alkaline solutions.
• Heat, light, and alkaline solutions will destroy vitamin C.

Analysis of Vitamin C, E, and K

• Several problems are related to cooking, storing, processing, and preservation of vitamin C, E, and K.
• These vitamins are not stored in the body and are vulnerable to destruction at elevated temperatures, and therefore, cause significant loss during cooking.
• Elevated temperatures and length of cooking have a significant effect on the amount of vitamin C loss.

Analysis of Vitamin (Extraction Methods)

• Vitamin assays usually involve extracting the vitamin from the biological matrix prior to analysis.
• Techniques may include heat, acid, alkali, or enzymes.
• Extraction procedures vary according to the specific vitamin under consideration.
• Some procedures are applicable to many vitamins.

Extraction of Vitamin A

• Vitamin A is extracted using a series of steps that involve dissolving the substance in a mixture of chemicals.
• This procedure includes specific chemical reagents and temperatures involved for the extraction of vitamin A.
• The extraction process should be conducted away from light.
• The final product is usually a liquid with a specific density and composition.

Determination of Water Soluble Vitamins

• Various methods are utilized to detect water-soluble vitamins. These include fluorimetric determination, microbiological determination, and liquid chromatography.
• The method chosen often varies with the specific vitamin being evaluated.
• Depending on the type of vitamin and the equipment available, the process can vary.

Determination of Vitamins D and Their Metabolites

• The process includes liquid chromatography under specific conditions for determining vitamins D2, D3, as well as their respective metabolites.
• The specific conditions may involve chemical conditions like temperature, flow rate of the liquid, and specific wavelengths for detection of the vitamins and metabolites.

Determination of Vitamin E

• Methods for detecting Vitamin E can include colorimetric determination or liquid chromatography.
• Methods for detecting the vitamin may involve extracting the substance using n-heptane, adding a dipyridyl solution, and analyzing the absorbance.
• Liquid Chromatography may be done using particular column and solvent conditions to detect this vitamin..

Extraction of Hydrosoluble Vitamins

• The extraction of hydrosoluble vitamins is based on physically dissolving the vitamins.
• Enzymatic methods are employed with proteolytic enzymes.

Ashing Methods

• Wet digestion methods and dry ashing methods are employed for precise and accurate trace element determination in materials.
• The wet method is generally faster but requires more reagents, leading to higher blank contributions for certain elements.

Comparison of Wet vs. Dry Ashing

• Wet ashing involves using acids to break down organic matter, typically at lower temperatures.
• Dry ashing involves high heat and combustion of organic materials, to oxidize organic matter.
• Significant differences exist between these two methods in terms of principle, reagents employed, time required, apparatus needed, sample loss possibility, and cost/complexity.

Conclusions

• All types of processed food can lose nutrients, although processing can increase bioavailability.
• Following proper procedures can increase nutrient availability.
• Improper treatment of food products or exposure may still impact nutrient levels.

Phytic Acid

• Phytic acid is a natural substance predominantly found in plant seeds.
• Phytic acid is an important form of phosphorus storage.
• It hinders the absorption of certain minerals (e.g., iron, zinc, and calcium) in the gut, possibly leading to deficiencies.

This quiz explores the critical roles of various minerals and vitamins in the human body, including their functions and sources. Test your knowledge on how deficiencies and processing methods can impact bioavailability and health. Perfect for students studying human nutrition or health sciences.