Food Science: Chemistry, Carbohydrates, Gluten, and Plant Tissues

Comprehensive vocabulary flashcards reviewing foundational food science concepts, chemical bonding, water states, carbohydrate chemistry, starch gelatinization and retrogradation, gluten mechanics, and fruit and vegetable structures.

Food science

An applied science associated with foods and food systems that incorporates biology, chemistry, physics, and engineering.

Food technology

The application of food science to the selection, preservation, processing, packaging, distribution, and use of safe, nutritious, and wholesome food.

GRAS

"Generally Recognized as Safe"; a designation for any substance intentionally added to food that is subject to premarket FDA approval unless qualified experts adequately establish its safety under intended use conditions.

Flavor enhancer

A food additive used to improve flavor without contributing to a specific identifiable taste of its own (e.g., MSG).

Flavor inhibitor

A substance that blocks taste perception (e.g., miracle fruit).

Threshold level

The concentration level at which a specific taste can be noted or perceived.

Sub threshold level

The concentration of a taste compound that is not individually detectable but can influence other taste perceptions.

Electronegativity

The strength of an atom's attraction for shared electrons in a chemical bond.

Bound water

Water that is held tightly by other molecules (such as proteins), makes up approximately $1\%$ of water in food, and no longer exhibits normal flow properties or solvent capabilities.

Standard of identity

A defined set of criteria that must be met for a food product to be legally labeled or named as desired, identifying primary and optional ingredients as well as processing aids.

Hygroscopic

The physical property of a substance (such as sugar) referring to its ability to attract and hold water, which helps maintain freshness in baked goods.

Invert sugar

A sweet syrup consisting of glucose and fructose formed by the hydrolysis of sucrose.

Caramelization

A non-enzymatic browning reaction that occurs when a sugar is heated to the point that its molecules break apart, yielding a nutty flavor and brown color.

Maillard reaction

A non-enzymatic browning reaction facilitated by heat involving a chemical reaction between an amino acid and a reducing sugar in low moisture conditions.

Reducing sugar

A sugar containing an anomeric carbon bound by two oxygens in a ring structure that can be oxidized (includes all monosaccharides).

Polyols

Sugar alcohols formed from corresponding sugars by catalytic hydrogenation that have reduced caloric value, are noncariogenic, and are nonfermentable.

Cellulose

The most abundant carbohydrate polymer and primary structural component of plant cell walls, composed of glucose units linked by $\beta$-glycosidic bonds.

Amylose

The simpler, linear fraction of starch consisting of $200+$ glucose units arranged in a helical structure, which functions primarily to form gels.

Amylopectin

A branched fraction of starch joined by $\alpha$-1,4 and $\alpha$-1,6 glycosidic linkages, functioning primarily in culinary applications as a thickener to increase viscosity.

Inulin

A non-digestible, non-glucosidic fructose polymer found in chicory, sugar beets, and Jerusalem artichoke that adds dietary fiber and can impart a creamy texture.

Gelatinization

A physical change occurring when starch is heated with water, wherein intermolecular hydrogen bonds break, water enters and swells the granules, and a gel forms.

Dextrinization

A chemical breakdown that occurs when starch is heated without water at high temperatures, splitting amylose and amylopectin into shorter fragments known as dextrins.

Pasting

The process that occurs when heating of gelatinized starch continues in excess water, causing the starch granule to lose organization and implode.

Gelation

The cooling phase after gelatinization where amylose molecules form hydrogen bonds to build a continuous superstructure that entraps swollen starch granules.

Retrogradation

The recrystallization and realignment of amylose and linear fractions of amylopectin as gelatinized starch cools, often resulting in a gritty texture.

Syneresis

The squeezing out of liquid water from a gel network caused by the retrogradation and crystallization of starch molecules.

Resistant starch

A form of starch that resists digestion in the small intestine and passes to the large intestine to be fermented by gut microbes, providing approximately $2.4\,\text{kcal/g}$ to $2.9\,\text{kcal/g}$.

Gluten

A large protein complex formed in wheat dough from glutenin and gliadin that hydrates to provide elasticity, plasticity, and gas-trapping structure.

Glutenin

An insoluble, long coiled chain protein within gluten featuring sulfur-containing amino acids at its ends that strongly cross-link to form a tight, elastic network.

Gliadin

A soluble, compact protein within gluten that folds upon itself and functions like ball bearings, allowing glutenin strands to slide and providing dough plasticity.

Plasticity

The property of dough that allows it to change shape under pressure without breaking, provided by gliadin proteins.

Elasticity

The property of dough that resists deformation and returns to its original shape when pressure is removed, provided by the coiled network of glutenin.

Amyloplasts

Membrane-bound plant cell organelles specialized for the synthesis and storage of insoluble starch granules.

Vacuoles

Plant cell compartments taking up to $90\%$ of cell space, filled with enzymes, sugars, organic acids, proteins, water-soluble pigments, and defensive compounds.

Tubers

Thickened underground storage stems (e.g., potatoes, yams) with nodes appearing anywhere across the flesh that can sprout both roots and shoots.

Rhizomes

Thickened horizontal underground storage stems (e.g., ginger, turmeric) that grow perpendicular to gravity and sprout roots along the bottom and stems along the top.

Climacteric fruit

Fruits (e.g., bananas, avocados) that exhibit increased ethylene production upon ethylene exposure, allowing them to be harvested mature yet green and ripened off the plant.

Non-climacteric fruit

Fruits (e.g., citrus, strawberries) that do not respond to ethylene to produce additional sugars after harvest and must ripen fully on the parent plant.

Lignin

A rigid, non-polysaccharide structural compound found in the secondary cell wall of plants that imparts strength and is impervious to breakdown during cooking.

Enzymatic browning

A chemical discoloration reaction occurring when bruised, cut, or peeled plant tissue exposes phenolic compounds to polyphenol oxidase enzymes and oxygen.