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1

HPP funcionamento

400-600 MPa a temperatura ambiente
aumenta 3-6ºC cada 100MPa- dependendo do produto
>2 minutos reduz 4Log e inativa enzimas
Gram + mais resistentes que Gram-
Esporos muito resistentes
Virus resistentes

2

HPP eficácia

will be dependent on the pressure applied, the holding time, temperature, the type of food matrix and the target organism - validação, é fundamental

3

HPP aplicação

particularly those with high water contents including fishery products, shellfish, meat and dairy products, fruit and vegetable juices, smoothies, dips, jams and baby food.

4

HPP aplicações

-Spoilage control – by reducing the foods microbial load, HPP may be used to extend shelf-life by increasing the period over which the food can be marketed and sold
- Pathogen control – by elimination or reduction to safe levels pathogens of concern such as Listeria monocytogenes.
- Organoleptic preservation/improvement – as HPP is a non-thermal process it can preserve or improve the organoleptic properties that can be compromised when the food is heat treated. In cheese for example, HPP can decrease the microbial load which slows the ripening process. This can help ensure the organoleptic properties are consistent between batches of cheese and are maintained throughout its shelf-life. HPP can also be used to tenderise and improve the texture of meat products
- Product reformulation – the use of HPP for enhancing the characteristics of reformulated products, e.g. low salt meats
- Product forming – by subjecting food products such as reformed/restructured meats to the very high pressures used in HPP, the binding or cohesion of many small pieces of meat into one larger piece may be facilitated
- Shucking of shellfish – at lower pressures and for shorter times than those used for the processes described above

5

Drying

AB equilibration
BC constant rate stage
CD falling rate period

C is critical point- beginning od drying

6

freeze drying

(i) freezing the food material,
(ii) subliming the ice (primary drying), and
(iii) removal of the small amount of water bound to the solids (secondary drying or desorption).

7

freeze drying

The advantages of freeze drying as compared with other methods lie in the quality of the dried product. There is no movement of liquid within the solid during freeze drying.
Thus, shrinkage does not occur and solutes do not migrate to the surface. The dried product has a light porous structure, which facilitates rehydration.
The temperature to which the product is exposed is lower than in most other methods of drying, soheat damageis relatively low.

8

freeze drying

Freeze-dried food materials are usually hygroscopic, prone to oxidation and fragile. Relatively expensive packaging may be necessary, compared to other types of dried foods. The capital cost of freeze-drying equipment is relatively high and so are the energy costs. It is the most expensive method of drying food materials

9

irradiation

Living organisms deprived of intact DNA or RNA will cease to function.. denature sensitive cell material, importantly DNA.
Food irradiation is the process of exposing food to a carefully controlled amount of energy in the form of high-speed particles or electromagnetic radiation.

Can destroy spores but not virus
vitamins pouco impacto A, E

10

irradiation

• Prevention of Foodborne Illness – to effectively eliminate organisms that cause foodborne illness, such as Salmonella and Escherichia coli (E. coli).
• Preservation – to destroy or inactivate organisms that cause spoilage and decomposition and extend the shelf life of foods.
• Control of Insects – to destroy insects in or on tropical fruits imported into the United States. Irradiation also decreases the need for other pest-control practices that may harm the fruit. Low dose (less than 1 kGy) irradiation for insect control (for instance in grain and grain products) where a dose of 150-700 Gy is sufficient.
• Delay of Sprouting and Ripening – to inhibit sprouting (e.g., potatoes) and delay ripening of fruit to increase longevity.
• Sterilization – irradiation can be used to sterilize foods, which can then be stored for years without refrigeration.

11

Irradiation dosis

Doses of up to 3 kGy (fresh) and up to 7 kGy (frozen) have been recommended.
Doses up to 10 kGy have been recommended. Herbs and spices are the food materials most commonly irradiated.

12

irradiation method

The choice of irradiation method will depend on the material needing to be treated.
Surface- to treat the surface or a thin layer of a food - eletrões beta particles
Bulk- such as an entire sack of spices - gamma rays or X-rays.

13

irradiation chemical effects

None, including enzymes. Onli in fats- increase oxidation- pack without oxigene to avoid rancidic