Food Science Final

aims/goals of food process engineering

• Food process engineering aims to transform raw biological materials into safe, stable, nutritious, convenient, and value-added foods by applying scientific principles, labor, energy, and equipment in a controlled series of operations

• goals include extending the time food remains wholesome, providing or supplementing nutrients, increasing variety and convenience, and adding economic value

define shelf-life, unit operation, hurdle technology

shelf life: period during which a food remains safe and acceptable in terms of microbiological stability, chemical integrity, physical quality, and sensory attributes under stated storage conditions

unit operation: basic step or stage in processing that applies a specific physical principle to bring about a defined change in the food

hurdle technology: use of a suitable combination of different lethal agents such as heat, acidity, low water activity, pressure, preservatives, and packaging so that each individual treatment can be milder but effectively ensure microbial safety & quality.

6 primary unit operations used in food processing

Heat transfer: heat exchange between product and surrounding medium.destroys microorganisms or enzymes for shelf-life, food health, and acceptable taste

Fluid flow: transporting liquid food through pipes during processing (centrifugal and positive displacement pumps)

Mass transfer: migration of a constituent of fluid or a component of a mixture in or out of a food product. Controlled by diffusion of component in the mixture.

Mixing: evenly distributes each ingredient during manufacturing. achieves uniformity

Size adjustment: increases or decreases product size. slicing, grinding, cutting, etc.

Separation: recovery of targeted food components from a complex mixture of compounds. separates solids or liquids 

different processes and technologies that use addition or removal of heat to preserve a product

Addition of heat

• Pasteurization & Blanching: heating to destroy microorganisms and inactivate enzymes

• Thermal sterilization: severe heating to achieve sterility for long shelf life

• Aseptic processing: continuous heating of pumpable foods then held, then cooled

• Sous vide cooking: vacuum packaging and low temp cooking

• microwave cooking: volumetric heating by electromagnetic energy

• Ohmic heating: electrical resistance heating

Heat Removal

• Refrigeration

• Freezing

• Drying/dehydration

examples of non-thermal food processing techniques

• Irradiation: Use of ionizing radiation (gamma rays or electron beams)

• Pulsed electric field processing: Application of short high-voltage pulses

• high pressure processing: Application of very high hydrostatic pressure at chilled or moderate temperatures

• ultrasound: Use of high-frequency sound waves to create cavitation and strong shear forces in liquids

define food fermentation

biological process that change the properties of food (with oxygen or without)

what are the uses of fermentation in food science?

fermentation is used to add stability (extends shelf-life) or value in foods. It can destroy or reduce natural toxins and develops sensory properties like texture, flavor, and aroma.

why are starter cultures often used in dairy fermentation? what is their significance to the fermentation process?

Using starter cultures in dairy fermentation initiates fermentation and guarantees predictable acidification. This improves the consistency of products and controls the moisture. It also helps determine the products sensory characteristics.

***match food products to the microorganisms used in their production

Lactococcus lactis: cheeses, buttermilk, sour cream

Streptococcus thermophilus: swiss, mozzarella, yogurt

Proponibact. frev: swiss “eyes”

VEGGIES: leuconostoc mesen., lactobacillus brevis & plantarum

main unit operations in dairy and vegetable fermentation processes

DAIRY:

• clarification/separation: removes sediment; fat is standardized

• formulation: adding other ingredients

• heat treatment: pasteurization to kill microorgs

• homogenization: stabilizes and distributes components

• inoculation/incubation: adding starter culture

VEGGIES:

• pretreat

• fermentation vessel (starter cultures can be added)

• cover with brine

• fermentation

what compounds are responsible for taste and aroma in fermented foods?

Lactic acid contributes to an acidic taste but not aroma.

aromas and flavors (in fermented milks) come from acetic acid, diacetyl, and acetaldehyde

define food additives, indirect food additive, and direct food additive

Food additive: substance that has been added to a food and regulated by federal authorities to ensure they are accurately labeled and safe to eat

Direct food additive: substance that has been intentionally added

Indirect food additive: substance that has been unintentionally added

what are the diff food laws and what is their purpose to food safety, quality, and nutrition

FD&C Act of 1938: specified the standard of identity for different types of foods & requirements for truthful labeling of ingredients

FDA GRAS list: foods recognized as safe

Food additives amendment of 1958: FDA must approve an additive prior to its inclusion

NLEA of 1990: regulate nutrition labeling, health claims, and nutrient content claims

what types of evidence/info a food company must provide before a substance can be approved to use in foods

• chemical identity and natural occurrence

• realistic use levels and mean intake

• substance’s manufacturing process

• toxicity information

why are direct food additives used in food products?

functional properties such as

1. provides color and enhances flavor

2. controls acidity, alkalinity, provides leavening

3. maintains palatability and wholesomeness

4. improves/preserves nutrient value

5. maintains product consistency

what are the major categories of food additives

preservatives, color additives, sweeteners, flavor/spices, flavor enhancers, emulsifiers, stabilizers,

define sensory evaluation and focus groups

Sensory evaluation: scientific discipline used to measure analysis and interpret human reactions to characteristics of foods as they are perceived by the senses

Focus groups: moderated discussions with small groups (6-12) of target consumers to gather qualitative insights on food products

in what ways can sensory analysis be used in the food industry

what are the different types of sensory analysis, and what is their purpose?

what is the difference between objective and subjective data in sensory evaluation?

what are the different steps in the stage/gate process used in new food product development

what are the challenges in each step of the food product development

what are some sources of information on food market trends and consumer preferences?