Food Processing Flashcards by Sabby Hamir

What is food processing?

Food processing is the transformation of agricultural products into food, or of one form of food into other forms.

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What causes food to spoil?

Microorganism - bacteria, yeast, moulds and fungi

Oxidation

Light

Rodents

Physical damage

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How does oxidation cause food products to spoil?

Oxidation occurs when food interacts with air, resulting in undesirable changes in colour, flavour and nutritional content.

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How does physical damage cause food products to spoil?

Bruises and cracks on raw produce, and damaged or poorly sealed packaging, can allow microorganisms, air and pests to enter. Microorganisms also cause physical contamination

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How does food spoilage occur?

Food spoilage by microorganisms and yeast mould growth, due to nutrients and water content of food

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Give 2 advantages of food preservation

Extends shelf life

Prevent spoilage by the action of microorganisms and enzymes

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How does enzymatic browning occur in apples?

Phenols and the enzyme phenolase are found in the cells of the apple, and when these are exposed to oxygen in the air this triggers the generation of dark pigments (melanin)

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Explain how food is preservation using freezing

Food temperature reduced below its freezing point and a proportion of water undergoes a change in state to form ice crystals.

Freezing solidifies water and thus makes it unavailable for bacteria

Temperature = -18 degrees

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Explain the stages in the freezing curve

The temperature falls fairly rapidly to just below 0 degrees

Heat is removed in order to turn the bulk of the water to ice. Temperature remains constant - this is knows as thermal arrest

When about 55% of the water is turned to ice, the temperature begins to fall rapidly. A comparatively small amount of heat has to be removed during this stage

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Give 2 pros and 1 cons of freezing

Pros: Frozen storage preserves food for months/ years if properly packaged, slows microbial growth and enzyme activity

Cons: Damage caused to cells by ice crystal growth

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What does HTST AND UHT stand for

High temperature short time

Ultra heat treatment

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Explain how and why pasteurisation is carried out

Relatively mild heat treatment: 63 degrees for 30 mins

Kills microorganism but not spores

Refrigeration is essential

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Effects of pasteurisation on food

Minor changes to the nutritional and sensory characteristics of most foods

Shelf life of pasteurised foods is extended by a few days or weeks

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Explain how and why HTST is carried out in milk pasteurisation

High temperature short time (HTST) is carried out at 72 degrees for at least 15 mins

Destroys mycobacterium tuberculosis and brucella abortis bacteria

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Give 2 advantages of using heat sterilisation in food processing

Complete destruction of microorganisms to prevent spores formation

Sterilized foods shelf-life in excess of 6 months at ambient temperatures

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Explain how UHT in milk is carried out and why

138 - 15o degrees for 1-3 seconds

Destroys all bacteria or spores

Denaturation of whey protein occurs

Continuous process and the product is packaged after sterilisation into sterile containers

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Explain canning

Heat sterilisation and sealing under vacuum

Cans cooled in chlorinated water

Addition of other elements: salt, sugar, acid

Critical Ph 4.5 - below which clostridium botulinum is inhibited

Texture and taste changes

Longer shelf life at ambient temperature

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Give 2 concerns in food industry with canning

Clostridium botulinum

Gram positive bacteria produces spores

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Give 5 ways to control water activity/pH using preservation

Drying

Sugaring

Curing

Pickling

Fermentation

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Explain the process of Irradiation

Using ionising radiation which kills bacteria and moulds, and insect pests

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Explain the process of chemical preservatives and give examples

Antioxidants used to prevent wine oxidation (e.g. sulphites) and fat rancidity (e.g. rosemary extracts)

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Explain the process of vacuum packing

Oxygen-free conditions to inhibit microbial growth

Explain the process of Modified atmosphere packaging (MAP)

Alters the proportion of oxygen in the pack (e.g. beef mince) by replacing with inert gases, such as nitrogen, to inhibit microbial growth

Pros of food packaging

Controls food immediate environments

Protects from damage

Provides a barrier to spoilage and disease- causing microorganism and pests

Protecting from oxygen, moisture, strong odours and light

Cons of food packaging

Package waste Air and water pollution Burning for energy can emit greenhouse gas and pollutants Bisphenol A (BPA) presence concerns

What factors may influence chemical reactions and therefore nutrient content of foods?

Heat Light Oxygen pH

Give 3 positive impacts of heat processing

Gelatinisation of starches (toasting bread) Protein Coagulation ( fried eggs) Anti-nutrition compounds in legumes and cereals grains are destroyed (oxalates, lectins, phytates)

Give an example of an oxalate

Calcium Absorption

Give examples of Lectins

Calcium Iron Phosphorus Zinc Absorption

Give examples of Phytates

Iron Zinc Magnesium Calcium Absorption

Give examples of 2 food preparation methods that reduce lectins and 2 preparation methods that increase lectins

Reduce: Soaking, Boiling Increase: Roasting, Baking

Give examples of 2 food preparation methods that reduce oxalate and 2 preparation methods that increase oxalate

Reduce: Steaming, Soaking Increase: Roasting, Grilling

Give examples of 2 food preparation methods that reduce phytates

Fermentation, Soaking, Boiling, Germination

Give some impacts that heat processing has on nutritional value of foods

Destroys heat-liable vitamins Reduces biological value of proteins (due to destruction of amino acids or Maillard browning reactions) Removes volatile odour compounds Promotes lipid oxidation

Explain what the Maillard browning reaction is and the outline the steps in this process

The Maillard reaction is also known as non-enzymatic browning. It involves the reaction between reducing sugars and proteins by the impact of heat. STAGE 1: Reaction of an amine with a reducing sugar with the formation of glycosyl amine, followed by the Amadori rearrangement STAGE 2: Dehydration of the intermediary products, fragmentation of the saccharidic moiety, and the Strecker degradation of the products STAGE 3: Reactions of intermediary products resulting in the formation of heterocyclic flavor compounds, that is, high molecular weight brown pigments, which are responsible for the typical flavour of brown product

Name 3 places where nutrient losses occur

Harvesting Distribution Storage

Name 2 things that can inhibit lipid oxidation

Antioxidants (Vitamin C,E) Chelating Agents (EDTA)

Give 4 factors that affect variation in nutrient losses

Different cultivars or varieties Growth conditions Handling Preparation procedures prior to processing

Name the 4 most labile nutrients

Vitamin A (Retinol) Vitamin C Folate (B9) Thiamine (B1)

What processes' causes Vitamin E to have the highest loss

Broiling Roasting

Name the 4 water soluble vitamins

Vitamin C Thiamine (Vitamin B1) Riboflavin (Vitamin B2) Folate (Vitamin B9) Pantothenic Acid (Vitamin B5) Niacin (Vitamin B3) Vitamin B6 Vitamin B12 Biotin

Give 3 ways Vitamin C is loosed during cooking

Degree of heating (Sensitive to heat) Leaching into the cooking medium Surface area exposed to water and oxygen (easily oxidised)

Name the cooking method that causes Vitamin C to have the highest loss and by what percent is is lost

Boiling 75%

Name 2 food that Thiamine (Vitamin B1) is lost in and how

Meat - Losses during heat treatment varies with the type and part of meat and the water and fat content Milk - Degradation about 10%

What food additive caused destruction of folate?

Sodium Nitrite used in some cured products

Name the most soluble vitamin during thermal processing and give the pH

Pantothenic Acid (Vitamin B5) pH levels of 5-7

Name the most stable water-soluble vitamin

Niacin (Vitamin B3)

How are proteins denatured? DO denatured amino acids still provide nutrient value if eaten?

Denatured by cooking Heart - disrupts hydrogen bonds and non polar hydrophobic interactions pH Denatured amino acids still provide nutrient value if eaten

Give 3 public health issues with food processing

Salting, pickling & smoking linked to increase cancer mortality due to formation of carcinogenic substances such as nitrosamines. Salt-preserved /salted foods increases sodium intake associated with stomach cancer and high blood pressure/cardiovascular disease Limit added salt intake to <6 (2.4 g sodium)/day

Give a public health issues on eating meat?

For people who eat meat, eat no more that moderate amounts or red meat, such as beef, pork and lamb, and eat little, if any, processed meat

How does food processing contribute to health?

Helps ensure population can access sufficient food, wider variety, choice Keeps food microbiologically safe Maintains taste/flavour

Name the 4 categories processed foods are classified by

Unprocessed or minimally processed foods Processed culinary ingredients Processed foods Ultra-processed foods

Give 3 ways food processing can promote well-being

Food processing technologies can promote the health and wellness of consumers Major focus will be on ways to use the technologies to address the chronic diseases facing the population Evolving food processing approaches could encourage and enhance healthy lifestyle

Explain 3 ways food processing technologies and innovations may benefit consumer

Reduce Allergy - Plant modification to reduce antigen exposure, Prevention of allergic responses Improved food safety and reduces food waste - Smart packaging materials, reduced landfill waste Reduce salt intake - Altered salt crystals structures such as micro crystallization provides flavour and food quality while reducing excessive salt intake