Food Chemistry: Water in Foods

• Food chemistry studies chemical processes and interactions of foods' biological and non-biological elements.
• Food chemistry is like biochemistry, encompassing carbohydrates, lipids, and proteins, also covering water, vitamins, minerals, enzymes, additives, flavors, and colors.
• Understanding food chemistry aids in controlling production techniques to improve food or prevent unwanted effects such as dairy fermentation and apple browning.
• Food chemistry involves reactions and reactions that transform food manufacture, handling, and storage of foods.

Water in Foods

• Water is major component and varies greatly.
• Water dictates stability of food physically, chemically, and microbiologically.
• High moisture equates to juicy, tender foods, for example, fruits and vegetables
• Low moisture equates to crispy which is found in crackers.
• Cooking methods such as caramelization and gelatinization need water.
• Water's role as a reactant includes hydrolysis, which breaks large molecules down.
• Adding or removing water during processing impacts food stability and nature.
• The method to remove water changes food's physical traits and rehydration capabilities.
• Drum dried milk powder rehydrates less effectively than spray dried powder because it is denser.
• Freezing can structurally damage food because ice crystals puncture cell walls.
• Volume expansion when water freezes causes cell stress and potential rupture.

Carbohydrates in Foods

• Carbohydrates serves as the body's main energy, fueling the nervous system and muscles.
• Carbohydrates makes up 80% of human food consumption.
• Carbohydrates function structurally in plants and as food storage in plants and animals.
• Carbohydrates are classifiable as simple or complex, related to chemical structure and absorption and digestion.
• Carbohydrates' sweetness help stabilize food proteins and alter freezing and boiling points.
• Sugar in food is measured in degrees brix.

Glycemic Index

• Glycemic Index measures how fast a food elevates blood sugar.
• High-GI foods are quickly digested, leading to blood sugar spikes.
• High-GI foods do not contribute to long-term health.
• Low-GI choices release energy gradually due to slower absorption.
• Choosing low-GI maintains steady blood sugar, reduces risks of type 2 diabetes, supporting weight control.

Food Proteins

• Protein quality relies on the amounts and availability of essential amino acids.
• Egg protein scores 100, making it a top-quality protein.
• Soybean is rich in lysine but lacking in methionine.
• Potato protein is excellent in quality, similar to whole egg, despite its low amount.
• Animal proteins generally surpass plant proteins in quality.
• Plant proteins upgraded through blending or genetic modification.
• Emphasis on isolating protein from foods is increased for food application.
• ELISA test detects protein sensitivity.

Functional Properties of Food Proteins

• Organoleptic characteristics include color, flavor, and odor.
• Kinesthetic aspects include texture, mouth feel, smoothness, grittiness, and turbidity.
• Hydration properties include solubility, wettability, water absorption, swelling, thickening, gelling, syneresis, and viscosity.
• Surface-related functions are emulsification and foaming film formation.
• Structural qualities of proteins include elasticity, cohesiveness, chewiness, adhesion, network cross-binding, and aggregation.
• Rheological aspects involve viscosity and gelation.
• Enzymatic uses are coagulation, tenderization, and mellowing.
• Blendability refers to Complementarity (wheat-soy, gluten-casein).
• Antioxidant act as off-flavor prevention.

Functional Properties of Proteins in Food Systems

• Solubility in beverages comes from protein solvation.
• Water absorption and binding in meat, sausages, bread, and cakes involves hydrogen bonding and water entrapment.
• Viscosity in soups and gravies through thickening from water binding.
• Gelation in meat, sausages, baked goods, and pasta occurs through protein acting like an adhesive.
• Elasticity in meats and bakery products is due to hydrophobic bonds in gluten and disulfide links in gels.
• Emulsification in sausages, bologna, soups, and cakes involves fat emulsion.
• Fat absorption functions in meat like sausages and doughnuts by binding free fat.
• Flavor-binding occurs via adsorption, entrapment, and release in simulated meats and bakery items.
• Foaming happens in whipped toppings, chiffon, desserts, and angel cakes by enabling stable films to entrap gas.

Food Lipids

• Food lipids include waxes, fatty acids, phospholipids, sphingolipids, glycolipids, terpenoids, retinoids, and steroids.
• Lipids are amphiphilic.
• Food's fat content varies from low to high in plant and animal sources.

Invisible Fats

• Fats can be measured with 40% of total fat and oil consumed in dairy, eggs, meat, poultry, fish, fruits, vegetables of grains.

Visible Fats

• Fats can be measured with 60% of total fat and oil consumed as lard, butter, margarine, shortening, and cooking oils.
• Fats are semisolid at room temperature as plastic fats.
• Crystallized triglycerides create solid fats.
• Fat crystallization occurs slowly, yet melting occurs instantly.
• Liquid fat cooling rates matters for solid fat composition and crystal size.
• Lipid microstructure influences food texture.
• Chocolate tempering controls crystal structure and texture.

Food Enzymes

• Enzymes has been used for beer and cheese making.
• Food enzymes affect food's texture, freshness, tenderness, flavor, and smell.
• They are derived from plants, animals, and microorganism fermentation.
• Enzymes is controlled to prevent decay.

Role of enzymes in food processing

• To transform raw materials to main item by adding rennet to milk for cheese.
• As additives, enzymes improve flavor, texture, and machinability in bread, amylase improves crumb structure, and lipoxygenase bleaches dough.

Physical Properties of Food

• Physical properties can be sensed but do not alter chemical composition.
• Physical properties clue about food make-up and how it processes.
• Physical properties include: freezing, melting and boiling point, heat transfer, size and thickness, deformation, density and specific gravity, refractive index, water activity and viscosity.

Freezing, Melting, and Boiling Points

• The freezing point is the temperature needed to turn a liquid solid via cooling.
• The melting point is the temperature at which solids turn to liquids.
• The boiling point represents the temperature at which liquids vaporize.
• Water serves as a benchmark for these temperatures.
• Water freezes/melts at 0°C, boils at 100°C.
• Adding solids in water, such as sugars and salts, raises boiling but lowers the freezing point.
• Hot syrup cause more injury than hot water/steam.
• Sugar in ice cream keeps it soft below freezing.
• Alcohol's lower boiling point (78.37°C) causes faster evaporation than water.
• Hand sanitizers use alcohol to eliminate bacteria and dry hands.
• Cooking oils are used since they exceed the boiling points of 300°C utilized in frying.

Heat Transfer

• Heat transfer measures a food's ability to conduct heat.
• Heat transfer affects cooking and the sterility of food.

Factors affecting heat transfer rates in food

• Specific heat determines the heat for temperature changes.
• High specific heat indicates better heat absorption.
• Water heats faster in microwaves as butter heats more quickly due to fat's high specific heat capacity.
• Low specific heat means less energy consumption for quick heating.
• Thermal conductivity is how well heat passes through a material's thickness.
• High thermal conductivity indicates faster heat transfer.
• Air reduces thermal conductivity, while water and density increases it.
• Thermal diffusivity explains the ability to conduct heat relative to heat storage.
• It also measure of how efficiently a mass can move heat away from an exposed area
• Ice and frozen meals exhibit high thermal diffusivity.
• High moisture boosts thermal diffusivity.

Size and Thickness

• Plant genetics and environment influence size and thickness.
• Example: Tomatoes vary based on the breed.
• Size differs with variables like water and nutrients.
• Processing transforms sizes to cut costs and enhance food properties: reduces handling/transport expenses, refine texture, improve heat flow.
• Lower handling costs come from less tomato juice, fruit pulp and minced meat bulk.
• Milling results in texture control through its fine particle production.
• Size and form affect heat rate.
• Heat transfer improves with smaller particles/thinness.
• Smaller food items cook faster and destroy pathogens thoroughly.

Deformation

• Deformation reduces food through fracturing.
• Grinding, pulping, and milling take advantage of deformation.
• Deformability signals structural or moisture related features.
• Hardness suggests that extra energy is needed to deform the food.

Density and Specific Gravity

• Density measures mass relative to volume.
• Density units include g/cm³ or kg/m³.
• Density affects packaging of foods.
• Fudge is denser than airy bread.
• Density relates to air, water, and solid amount.
• Ice cream contains much air and that lowers the density.
• Fruit pulping concentrates solids by eliminating water, promoting shelf life, heat transfer with lower delivery money.
• Specific gravity resembles density as a unit-less equivalent.
• To get it, divide a material's density by water's value.
• Liquids industries, like brewers, check specific gravity.
• In beer, comparing specific gravity of wort prior to end gauges resultant alcohol levels.
• Low specific gravity means bigger alcohol production.

Refractive Index

• Refractive index measures light bending capacity.
• High dissolved solid levels intensifies light bend.
• Syrup curves light more so than base water.
• A refractometer assess how much sugar solids exist inside any liquid products through the refractive index.
• The liquid or semi-solid sample faces refracting meter rays.
• Estimations reflect the sugar composition based on the extent of light refraction.

Water Activity

• Water activity is vapor tension comparative to a pure kind of water.
• Food scientists shape shelf lives via water action.
• Below a value of 0.90, bacterial growth ends.
• At points of 0.88–0.80, molds and yeasts rarely generate.
• Reduced water actins improve periods in the long run.
• Enzymes slow at under 0.85 wa.
• Examples: invertase, amylases, phenoloxidases, peroxidases and lipoxygenase.
• All could deteriorate something.
• Lipases continue their role as little as 0.3 aw.
• Rancid oils in peanuts, flours and crackers.
• Water action standards prevent fluids transferring ingredients.
• Mixing more aqueous raisins with drier flakes causes damp bran and the raisin rigidifies.
• It indicates long time moisture action effect.

Viscosity

• How the fluid thickens describes viscosity.
• Viscosity measure of resistance to flow.
• Flow patterns impact food fluid viscosity.
• Newtonion flow has uniform fluid no matter the stir.
• Water acts like juice here.
• Pseudoplastic flow describes how mixing thins material.
• Yogurt mirrors it.
• Viscosity changes fluids dependening how they become used;

Dilatant Flow

• Viscosity causes mixture thickness.
• Example is corn starch that mirrors that flow.

Bingham Plastic

• Viscosity allows forces or resistance as added example ketchup acts.

Viscoelastic Flow

• Viscosity enables response towards force that dough acts.

Chemical Properties of Food

• Testing foods chemical qualities permanently alters it.
• Measuring water requires removing it, altering composition.
• Testing determines the moisture, pH balance, acidity, flavors, pigments, and enzymes.

Moisture Content

• The amount of moisture present shows how perishable, palatable or costly a product may present itself.
• Big moisture presence heightens the amount for microbial effect and ruins.
• Dehydrated snacks lead to hardness.
• Moisture promotes better feel (softness), in foods.
• Moist products increase costs to delivery for weights.
• Industry relies testing of liquid or solids.

Moisture Content Testing

• Moisture measures in ovens to extract all traces.
• Heating samples determines lost wet by weight via analyzers.

PH

• pH reveals the basic or acidic components via scale.
• Logarithmic scales means it is 10x per amount.
• The change from 5 to 7 grows 100x larger then the 2x greater.
• Low pH balance helps prevent germs.
• Production must check at levels at 3.4 ph to protect foods like mayo.
• pH standards in production must be protected by manufacturers.
• Checking adjusts the taste in food by the use of certain ingredients.
• Jams need gelatin structures that adjust correctly.

Acidity

• Acidity refers to total food acids.
• Acidity, where the relative number describes any food acid, refers to the pH balance.
• The amounts show and affect sour tastes.
• Citric acids come into plays into fruits.
• Broccoli, peppers, are acid.
• Lactic liquids are yogurt.
• Malic is apple and tartaric exists grapes and carbonic gases soda.

Flavors

• Palatable flavors describes odorants.
• Flavor emanates in space in nasal and olfactory ways so the sensory experience can be interpreted.
• As foods mature, they tastes better such as the aroma during it.
• Odor mixtures enhance and complete experiences due flavors.
• Isolating any flavors rarely gives real food sensory impact.

Flavors

• Ingredients enhance smells.
• mint releases menthol.
• Cinnamaldehyde scents cinnamon.
• Citrus emits limonene.
• Volatile items deter food.
• Rotting methanethiol gives off bad cabbage.
• Rotten fish and eggs show signs of sulfide presence.

Pigments

• Pigmentations offers sensory input.
• Blending items helps adjust these details.
• Red cabbage and beans receive anthocyanins.
• Yellow shows presence from carrots or other produce.
• Black, maroon come mostly betanins.
• Myoglobin makes meat.
• Prepared food can release Carmine a unique compound.

Pigments and How They React

• Chlorophyll greens exist but are removed.
• Compounds interact with outside components such as anthocyanins responding to the pH balance.
• Acids lead to reds but alkalis offer blue for pigment.
• Pigments such as myoglobin interact.
• High oxygen equals pink (oxymyoglobin), but low oxygen browns down (metmyoglobin), purpling and oxygen elimination releases deoxymyoglobin.

Food Enzymes

• Beer, bread requires and cheeses use enzymes to enhance.
• Food preparation benefits flavor, texture, aroma and overall qualities to add the best sensory experience.
• Extracted compounds help make foods for industrial effects.

Role of food processing and enzymes

• Transformation requires processing such as Rennet into milk such to process cheeses.
• Additives changes flavor and features along making products that amylases produce breads with bleaching with oxidases.

Factors Affecting Physicochemical Properties

• Physical factors are freezing, volume and other features.
• Chemical balance relates to water amount.

Enzymatic Reactions - Softening

• Softening alters cells.
• Pectinase acts protopectinase that softens as such hemicelluloses and other functions, it all promotes industrial fruit.
• Determines life and value for fruits.
• Immature food has soluble versions
• Protopectin forms cell glucoses
• 36 cellulose structures combine then make microfibrril crystalline

Enzymatic Reactions - Tenderization

• The food item must be tender.
• A flavor helps taste better.
• Enzymes tenderize meat.
• Fiber shows it and fat amounts.
• The fruit and items, like Papain in papaya are Proteases.

Enzymatic Reactions - Oxidation

• Presence can deteriorate flavor and odor.
• Oxygen makes food darken oxidation causes.
• Polyphenols are quinones that from surface dark layers

Steps

• Enzyme speed relates polyphenol amounts.
• Oxidation relates PPO enzymes and such as benzoquinones in those categories.

Enzymatic Reactions - Oxidation

• Ascorbic item is a basic taste.
• Ascorbic oxidases lead cation formations and oxidants from air affect other types.
• Electron sharing stops chains so oxidation remains stable.
• Ascorbic oxidase requires 02 items by it

Enzymatic Reactions - Hydrolyzing

• Enzymes promote water.
• Its effect makes items easier and smaller.
• Hydrolyzing contains acids that perform well on most foods.
• As such items affect what microbial actions exist.
• Lipid reactions cause rancidity and affect qualities.

Chemical Reactions Change the Colors

• Major plant life diminishes after heating.
• Key for green items color changes and is Chlorophyll reduction with heating.
• Tissues break by pH.
• Sensitive pH creates olive.

Enzymatic Reactions - Hydrolyzing

• High temps makes blanched greens less active.
• Cucumber green changes because of enzymes.
• The colors have no blanch temperature effect due to enzymes.
• Drying greens affects water.

Colors Change

• Heating causes anthocyanins breakdown plus tin as an additive.
• Heat ruins anthocyanin by system interaction.
• Glucosidases and other parts can remove enzymes.
• Essential measures remove these.
• Proanthocyanidins react turning other fruits such a pear rose.
• Maillard heat browns and alters.

Flavors

• Heating produce affects taste.
• Flavor declines as volatility occurs or from substances with other mixes.
• Heat treats decline the carbonyl components in bananas.
• Volatility shows chemical action in stored food.
• Plain tins cause action in surface aluminum in ketones reduction of some alcohols.
• New mixtures can be removed as canned items.

Flavors Reactions

• Sulfur causes bad items such as corn.
• Nonvolatile smells turn aromas to worse parts.
• Canned fruits get worse for glutamine with pyro items.
• Industrial errors prevent effects and heating ruins smells and flavor from forming.
• Peroxidase that makes aroma by regenerative act via thermal procedures that alter items quickly.

Reaction

• The maillard is any non-enzymatic operation involving ketone with aldehydes via sugar production and proteins reaction.
• Heating lowers sugar in compounds making a maillard reaction.
• Milk gains rapid color so it reacts.
• Other chains add with limited reaction and other outcomes.
• Cooking browning forms these.
• Sensory change for aroma texture.

Reactions

• Heat browns via actions.
• The process needs a high degree then turns to brown polymer.
• Boiling and then the addition, it browns after melting.
• Water loses and pulls until furans turn it brownish.

Caramelization

• Caramelization happens three ways when it is formed
• Sugars start and then it creates heating.
• Moisture changes then it breaks some down too.
• Polymerization offers color.

Phenophytinization

• It is easy that heat breaks parts such acids that oxidize then degrade the product.
• Determining and keeping product to high levels matters in sensory taste.
• Green declines turns to pheophytins with acidity from heating processes.

Degradation

• Acidity causes heat degradation or such addition for processes that prevent other issues.
• Freeze at low state to preserve other colorings instead of damage.
• Blanch to halt degradation enzymes.
• Radiation combines storage so that you heat sensory traits
• Synthetic colors and items create natural tastes.
• High pH items need bicarbonate.

Lipid Oxidation

• Food is unhealthy for its lipid oxidants.
• These actions impact flavor of shelf life and waste.
• Those processes of chains involving both then create radicals.
• Fat also becomes dangerous so oxygen ruins products.
• Lipids interact from these items by modifying qualities.
• They involve sugars taste and all flavors.

Mechanism

• Lipid chains link reactions to compounds.
• Reaction depends with acids or structures depending water, rates all.
• Oxidation has forms to all aspects.
• To stop change to the items a antioxidant must change its levels.
• This causes items with those actions.

Ripening

• Desirable product traits or taste such color texture from the process.
• Action relies on non-climacteric then turns climates.
• Ethylene increases traits.

Unripe Fruits

• Chlorophyll or acidity.
• Acidity or solids.
• Mealy parts.

Ripe Fruits

• Redden with those other components then taste sweet and have less acid.

Ripeness

• Cell walls: saccharides degrade soluble parts.
• Sugar loss occurs to items.
• Pectin also causes hydrolysis.
• Starch comes then action and converts at each.

Starch Quality

• Amylase reduces high water features often with enzymes
• Key parts are action hydrolyses those amyloses which converts starch to make it better.
• Taste of components:
• As parts decompose fruits that effect tastes as water membrane structure which increases their access.
• Pigments for tastes are made all that create aroma and quality.

Meat Stages Post Mortem

• Tissue lessens quickly, they then get tougher 6 to 24 hours later.
• Dead forms have time for rigormortis and occur quickly until it is exhausted
• Temporary hardness, but its not edible from the hardness.
• To reduce its need to age parts and lower tension must stop fiber structure with breakdown for it taste edible.

Hardness

• Glycolysis stops after high amounts blood and oxygen stop.
• Actions decline anaerobic parts.
• Glycolysis changes structures so they acidify with ATP compounds.
• Balance at 5.5 and low pH creates breakdown so those stages finish.
• Acid kills and the glycolysis ceases.
• Acid declines before it ends.

Phases in Tissue

• After ceasing comes low supply with low use.
• Absent calcium actions and prevents connections inside those myosin filaments to affect action bands.
• Actins then create fibers.
• Then there stops with reactions from that cycle as none available, causing inflexibility.
• Stiffness results with ATP decrease inside muscle.
• Cross chains create high stability.

Myosin Minimizations

• Chains prevent tenderness.
• That requires chain limits so as
• Stretching limbs causes action with less linking actions occur.
• Cold stops and declines fiber amounts after they cut
• 150 C or 200 C for correct warmth levels.
• Increased amounts occur because if it.
• Low ranges need parts so pumped parts get contraction levels.

Final Steps inside MEAT

• The final ranges at pH balance are 5.5.
• Higher ones occur from death before slaughter so they create less acid.
• That high scale makes great levels with holding that are close to other points
• Microbial life declines during low pH range effects.
• High-pH decreases microbial issues often
• Autolytic spoilage
• Enzymes cause waste from fish enzyme.
• Rapid effects with such then result low acidity.
• Those activities can decline from colder temperatures since these spoil quickly.