Food chemistry and biochemistry are two related fields that study the chemical processes and interactions of food and living organisms. Food chemistry deals with the major and minor constituents of food and their functionality, fate and effects on food quality and safety. Food biochemistry focuses on the composition of foods, especially food components that have beneficial effects on human health, and the metabolic pathways of food ingredients in living systems.
The role of antioxidants, vitamins, minerals and phytochemicals in food and health
Antioxidants are substances that can prevent or slow down the damage caused by free radicals, which are unstable molecules that can harm cells and cause diseases123. Some antioxidants are produced by the body, and some are consumed in the diet. Examples of dietary antioxidants include vitamins C and E, the mineral selenium, and phytochemicals, such as beta-carotene.
Vitamins and minerals are essential nutrients that the body needs in small amounts to function properly and stay healthy. They have different roles in the body, such as helping with energy production, growth, development, immunity, and blood clotting. Some vitamins and minerals also act as antioxidants, such as vitamin C, vitamin E, and selenium.
Phytochemicals are natural compounds found in plants that have various biological effects on the body. They are not considered essential nutrients, but they may have beneficial effects on health by modulating different processes, such as inflammation, hormone metabolism, gene expression, and enzyme activity. Some phytochemicals also act as antioxidants, such as carotenoids, flavonoids, polyphenols, and glucosinolates.
The role of antioxidants, vitamins, minerals and phytochemicals in food and health is to protect the cells from oxidative stress, which is an imbalance between free radicals and antioxidants in the body. Oxidative stress can lead to chronic diseases, such as cancer, cardiovascular disease, diabetes, Alzheimer’s disease, and age-related macular degeneration. By consuming foods rich in antioxidants, vitamins, minerals and phytochemicals, such as fruits, vegetables, whole grains, nuts, seeds, herbs, spices, tea, coffee, and cocoa, you may reduce the risk of these diseases and improve your overall health.
The effects of processing, storage and cooking on food nutrients, flavor, color and texture
That’s another good topic for your blog. Processing, storage and cooking are steps that transform raw agricultural commodities into ready-to-eat foods. However, these steps can also affect the nutrients, flavor, color and texture of food in different ways.
Processing is any operation that alters the form or quality of food, such as peeling, cutting, milling, freezing, drying, canning, pasteurizing, fermenting, etc. Processing can have positive or negative effects on food nutrients, depending on the type and extent of processing. Some positive effects are: increasing the availability and digestibility of some nutrients, enhancing the flavor and color of food, preserving food from spoilage and extending shelf life, adding or fortifying food with vitamins and minerals. Some negative effects are: reducing or destroying some water-soluble vitamins (B-group and C), leaching out some minerals (calcium, iron, zinc), altering the structure and function of some proteins (denaturation, coagulation), producing undesirable compounds (acrylamide, trans fats).
Storage is the keeping of food under suitable conditions to maintain its quality and safety until consumption. Storage can also have positive or negative effects on food nutrients, depending on the time and temperature of storage. Some positive effects are: allowing some enzymatic reactions to occur that improve the flavor and color of food (ripening of fruits), increasing the concentration of some phytochemicals (antioxidants) in food. Some negative effects are: causing some vitamins to degrade due to exposure to light, heat, oxygen or moisture (vitamin C, thiamine), causing some minerals to precipitate or oxidize due to changes in pH or moisture (iron, copper), causing some fats to become rancid due to oxidation or hydrolysis (polyunsaturated fats).
Cooking is the application of heat to food to make it more palatable and safe to eat. Cooking can also have positive or negative effects on food nutrients, depending on the method and duration of cooking. Some positive effects are: enhancing the flavor and color of food by browning reactions (Maillard reaction, caramelization), increasing the bioavailability and absorption of some nutrients (starch, protein, carotenoids), destroying some harmful microorganisms and toxins in food. Some negative effects are: reducing or destroying some heat-sensitive vitamins (vitamin C, folate), leaching out some water-soluble vitamins and minerals into cooking water (thiamine, riboflavin, niacin), altering the texture and moisture of food by gelatinization, evaporation or shrinkage.
The effects of processing, storage and cooking on food nutrients, flavor, color and texture can be minimized by following some tips:
- Choose fresh and minimally processed foods whenever possible
- Store foods in a cool, dry and dark place away from light, heat and oxygen
- Use appropriate containers and packaging materials to prevent moisture loss and contamination
- Cook foods using methods that preserve nutrients and moisture, such as steaming, baking or microwaving
- Avoid overcooking or burning foods that can produce harmful compounds
- Use cooking water for soups or sauces to retain some of the leached nutrients
The mechanisms of food spoilage, deterioration and preservation
Food spoilage is any change that renders food unfit for human consumption. Food deterioration is the loss of quality, nutritional value, or sensory attributes of food due to spoilage or other factors.
The mechanisms of food spoilage and deterioration are mainly caused by:
- Microorganisms, such as bacteria, moulds, yeasts, and viruses, that can grow on food and produce toxins, enzymes, acids, gases, odours, or colours that make food unsafe or unappealing.
- Insects, rodents, birds, and other animals that can infest food and contaminate it with their droppings, hairs, or body parts.
- Endogenous enzymes, such as lipases, proteases, and oxidases, that are present naturally in food and can catalyze chemical reactions that alter the flavour, texture, colour, or nutritional value of food.
- Chemical reactions, such as oxidation, hydrolysis, Maillard reaction, or non-enzymatic browning, that can affect the composition and quality of food due to exposure to oxygen, water, heat, light, or metal ions.
- Physical factors, such as temperature, humidity, pressure, or mechanical damage, that can affect the appearance and stability of food by causing wilting, shrinking, bruising, cracking, or leaking.
The mechanisms of food preservation are mainly based on:
- Reducing the water activity of food by drying, salting, sugaring, smoking, or adding preservatives that inhibit the growth of microorganisms and slow down chemical reactions.
- Lowering the temperature of food by refrigeration or freezing that slows down the metabolic activity of microorganisms and enzymes and reduces chemical reactions.
- Increasing the temperature of food by heating or pasteurization that kills or inactivates most microorganisms and enzymes and reduces chemical reactions.
- Modifying the atmosphere of food by vacuum packing or modified atmosphere packaging that reduces the oxygen level and increases the carbon dioxide level around food to prevent oxidation and microbial growth.
- Adding natural or synthetic substances to food by fermentation or addition of acids, spices, herbs, antioxidants, or antimicrobials that enhance the flavour and inhibit the growth of microorganisms and slow down chemical reactions.
- Applying physical treatments to food by irradiation or high pressure processing that damage the DNA or cell membranes of microorganisms and enzymes and reduce chemical reactions.
The mechanisms of food spoilage, deterioration and preservation can be understood by studying the factors that affect them and the methods that control them.
The analysis and detection of food contaminants, adulterants and allergens.
Food contaminants are substances that are not intentionally added to food but may be present as a result of environmental pollution, agricultural practices, food processing, packaging, storage or distribution. Examples of food contaminants are pesticide residues, mycotoxins, heavy metals, dioxins, polychlorinated biphenyls (PCBs), and acrylamide.
Food adulterants are substances that are intentionally added to food to increase its weight, volume, appearance or shelf life, or to substitute for more expensive ingredients. Examples of food adulterants are water, starch, melamine, urea, formaldehyde, and synthetic colours.
Food allergens are substances that can trigger an immune response in some individuals who are sensitized to them. Examples of food allergens are proteins from milk, eggs, peanuts, tree nuts, soy, wheat, fish, shellfish, and sesame.
The analysis and detection of food contaminants, adulterants and allergens are important for ensuring food safety and quality and protecting consumer health and rights. There are various methods and techniques for analyzing and detecting these substances in food samples, such as:
- Chromatography-mass spectrometry (GC-MS or HPLC-MS), which separates and identifies the chemical components of a mixture based on their mass and charge.
- Polymerase chain reaction (PCR), which amplifies and detects the DNA or RNA sequences of specific microorganisms or genes in a sample.
- Enzyme-linked immunosorbent assay (ELISA), which uses antibodies and enzymes to detect the presence and amount of antigens or antibodies in a sample.
- Biosensors, which use biological molecules or cells to generate an electrical signal in response to a specific analyte in a sample2.
- Mass spectrometry (MS), which measures the mass-to-charge ratio of ions derived from proteins or peptides in a sample and compares them with reference databases to identify the allergens3.
The analysis and detection of food contaminants, adulterants and allergens require careful sample preparation, validation and quality control to ensure accuracy, sensitivity and reliability.
The development and application of novel food ingredients, additives and functional foods
Novel food ingredients and additives are developed and applied for various reasons, such as:
- Enhancing the nutritional, sensory, functional or health properties of food.
- Improving the shelf life, stability, safety or quality of food.
- Reducing the environmental impact, waste or cost of food production.
- Meeting the consumer demand, preference or expectation for novel or diverse food products.
The development and application of novel food ingredients, additives and functional foods involve various scientific disciplines, such as biotechnology, nanotechnology, genomics, proteomics, metabolomics and bioinformatics. They also require rigorous evaluation and regulation to ensure their safety, efficacy and quality before they can be marketed and consumed
The interaction of food components with gut microbiota, enzymes and hormones
Food components are the nutrients and other substances that are present in food and have various effects on the body. Some examples of food components are carbohydrates, proteins, fats, vitamins, minerals, antioxidants, polyphenols, prebiotics and probiotics.
The interaction of food components with gut microbiota, enzymes and hormones is complex and dynamic. Food components can affect the composition, diversity and activity of gut microbiota, which in turn can produce metabolites that influence the function of enzymes and hormones.
For example;
Carbohydrates, especially dietary fiber and resistant starch, can be fermented by gut microbiota into short-chain fatty acids (SCFAs), which can modulate the activity of enzymes involved in glucose and lipid metabolism and the secretion of hormones such as glucagon-like peptide-1 (GLP-1) and peptide YY (PYY) that regulate appetite and blood glucose.. Proteins and amino acids can be metabolized by gut microbiota into various compounds such as indole, phenylacetic acid, branched-chain fatty acids (BCFAs) and ammonia, which can affect the expression and activity of enzymes involved in detoxification, inflammation and oxidative stress and the secretion of hormones such as ghrelin, leptin and insulin that regulate hunger, energy balance and blood glucose.. Fats and fatty acids can be absorbed by the intestinal cells or metabolized by gut microbiota into various compounds such as bile acids, conjugated linoleic acid (CLA) and endocannabinoids, which can modulate the activity of enzymes involved in lipid metabolism and inflammation and the secretion of hormones such as cholecystokinin (CCK), GLP-1 and PYY that regulate appetite, fat digestion and blood glucose.. Vitamins and minerals can act as cofactors or regulators for various enzymes and hormones involved in metabolism, immunity and health. For example, vitamin B12 is essential for the activity of methionine synthase, an enzyme that is involved in DNA synthesis and methylation; zinc is important for the function of insulin, a hormone that regulates blood glucose; iron is required for the synthesis of thyroid hormones, which regulate energy expenditure.. Antioxidants and polyphenols can modulate the activity of enzymes involved in oxidative stress, inflammation and detoxification and the secretion of hormones involved in metabolism, immunity and health. For example, curcumin from turmeric can inhibit the activity of cyclooxygenase-2 (COX-2), an enzyme that produces pro-inflammatory prostaglandins; resveratrol from red wine can activate sirtuin-1 (SIRT1), an enzyme that regulates cellular energy homeostasis; epigallocatechin gallate (EGCG) from green tea can increase the secretion of adiponectin, a hormone that improves insulin sensitivity.. Prebiotics are non-digestible food components that selectively stimulate the growth or activity of beneficial gut microbiota. For example, inulin from chicory root can increase the abundance of bifidobacteria in the gut, which can produce SCFAs that modulate enzyme and hormone function.. Probiotics are live microorganisms that confer health benefits to the host when administered in adequate amounts. For example, Lactobacillus rhamnosus GG can reduce intestinal permeability and inflammation by enhancing the expression of tight junction proteins; Bifidobacterium animals subsp. lactis BB-12 can improve glucose tolerance and insulin sensitivity by increasing GLP-1 secretion.
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