FOOD PRESERVATION by Nazzira Azliza https://padlet.com/nazziraazliza98/8j0fkqlvc2iqtbom 2019814414 en-us 2021-10-26 03:00:01 UTC 2023-05-03 01:03:33 UTC hello@padlet.com TOPIC 2 nazziraazliza98 https://padlet.com/nazziraazliza98/8j0fkqlvc2iqtbom/wish/1844014139 1. With more advance technologies and applications nowadays, I thinks it has become unsuitable to rely on chemical preservative since the usage of organic substances for preservative have been widely used where the taste is more natural and pose less hazard towards the body.

2. Based on the research that I have made, the best chemical preservation is the usage of sugar due to its ability to prevent microbial activity and growth, can preserve the color, texture and flavor of the food. other than that, sugar can be easily obtained from honey, sugarcane and crystal sugar, thus making it a low cost alternative for preservation of food. one example of food preservation using sugar is fruits preservation in sugar syrup or be made into jams.]]> 2021-10-26 05:42:03 UTC https://padlet.com/nazziraazliza98/8j0fkqlvc2iqtbom/wish/1844014139 nazziraazliza98 https://padlet.com/nazziraazliza98/8j0fkqlvc2iqtbom/wish/1847046594 2021-10-27 03:31:47 UTC https://padlet.com/nazziraazliza98/8j0fkqlvc2iqtbom/wish/1847046594 nazziraazliza98 https://padlet.com/nazziraazliza98/8j0fkqlvc2iqtbom/wish/1847051876 2021-10-27 03:34:16 UTC https://padlet.com/nazziraazliza98/8j0fkqlvc2iqtbom/wish/1847051876 TOPIC 3 nazziraazliza98 https://padlet.com/nazziraazliza98/8j0fkqlvc2iqtbom/wish/1877043082 1. Definition

The removal of small amounts of water or other liquid from a material by the application of heat.

2. Examples

Some fruits and vegetables suitable for drying include apples, pears, peaches, plums, apricots, bananas, cantaloupe, strawberries, blueberries, carrots, celery, corn, green beans, potatoes, and tomatoes. Fruits can also be dried as fruit, leathers and rolls. Other than that includes jerky, powdered milk, dried beans and peas, potatoes in a box, dried fruits and vegetables, pasta, and rice.

2.2 How they can be dried

Increasing the temperature of food makes its moisture evaporate, and air moving over the food carries the moisture away. A balance of temperature and humidity is needed to successfully dry foods.

As for vegetables, they are tough, brittle, or crunchy when dry and do not need conditioning. Store dried vegetables in air-tight containers to prevent food from absorbing the moisture in the air. Storing them in a dark place retains the vitamin content of the food.

3. Why does food need to be dried?

It is a method of food preservation that removes enough moisture from the food so bacteria, yeast and molds cannot grow

Other than that, food becomes lightweight and easy to carry due to the reduced water content in it. A research conducted by Dr. Naseer Ahmed, of RIMT University, says, "Dried foods are tasty, nutritious, lightweight, easy-to-prepare, and easy-to-store and use]]> 2021-11-09 03:01:18 UTC https://padlet.com/nazziraazliza98/8j0fkqlvc2iqtbom/wish/1877043082 Week 6 nazziraazliza98 https://padlet.com/nazziraazliza98/8j0fkqlvc2iqtbom/wish/1892979919 1. Why drying is a complex process

Drying is a complex process that involves the elimination of moisture. Two processes occur concurrently during drying. To begin, energy is transferred, primarily as heat, from the surrounding environment and/or an energy source to the wet solid. Following that, mass is transferred from the inside of the solid to the surface as moisture, and it evaporates as a result of the mechanism of that process

The process of drying food materials in conventional hot air dryers is extremely
complex involving coupled transient mechanisms of heat, mass and momentum
transfer processes accompanied by physical, chemical and phase change transformations. This method requires large amounts of energy and usually imparts significant alterations in product quality and functionality attributes due to the exposure to longer drying times or higher temperatures. There is a significant interest in developing innovative drying approaches that will accelerate the drying process in order to increase production throughput and reduce the energy consumption (i.e. thereby decreasing both environmental and financial costs) with improved quality of the
product.

Furthermore, the processes of drying are
very complex to model since they involve transient energy and mass and momentum transfer through a porous or nonporous medium with phase changes and with
or without chemical reactions]]> 2021-11-16 03:05:58 UTC https://padlet.com/nazziraazliza98/8j0fkqlvc2iqtbom/wish/1892979919 TOPIC 4 - FREEZING nazziraazliza98 https://padlet.com/nazziraazliza98/8j0fkqlvc2iqtbom/wish/1946078617 1. Whether freezing is a
good technique in food preservation.

Yes though it will deteriorate the taste, freezing keeps food safe by slowing the movement of molecules, causing microbes to enter a dormant stage. Freezing preserves food for extended periods because it prevents the growth of microorganisms that cause both food spoilage and foodborne illness.

2. Examples of food that can be preserved using low temperature processing

Freezing is a means of preserving food through the application and maintenance of extreme cold temperature (−4°C to −40°C). 

Examples: Meat, poultry, eggs, fish, fresh milk and milk product, fruits, vegetable.

  • Slow freezing process
It also known as sharp freezing. The food is frozen at temperatures between 4oC and 29oC in this method. Under these conditions, freezing can take anywhere from three to seventy-two hours. This method is used for home freezing

• Quick freezing method

The temperature ranges from 32oC to 40oC in the quick freezing process. It rapidly freezes food to the point where tiny crystals form. In comparison to slow freezing, the amount of time it takes to freeze quickly is significantly less time. Large quantities of food can be frozen quickly by using the technique of "quick freezing." It is more expensive to freeze and store food at very low temperatures, but this is the best option for many foods because it preserves their flavour and nutritional value.

• Dehydration freezing

Preserving food by drying it to about half its original weight and volume and then freezing it is known as dehydro-freezing. Fruits and vegetables that are dehydrated before being frozen are just as good as those that are frozen without pre-drying. Packing, freezing, storing, and shipping are all less expensive because of weight and volume savings..
]]> 2021-12-14 03:29:29 UTC https://padlet.com/nazziraazliza98/8j0fkqlvc2iqtbom/wish/1946078617 TOPIC 5 - nazziraazliza98 https://padlet.com/nazziraazliza98/8j0fkqlvc2iqtbom/wish/1973405323 1.  Examples

  • cultured milk and yoghurt.
  • wine.
  • beer.
  • cider.
  • tempeh.
  • miso.
  • kimchi.

2. How does fermentation help in preserving food products

The fermentation process involves the oxidation of carbohydrates to generate a range of products, which are principally organic acids, alcohol, and carbon dioxide. Such products have a preservative effect by limiting the growth of spoilage or pathogenic microbiota in the food.

3. Opinion on the safety of fermented food

Fermented foods have a good safety record in general, but improperly fermented foods can be dangerous. Vegetable fermentation is primarily caused by lactic acid bacteria, though yeasts and other microorganisms may be present depending on salt concentration and other factors.

Clostridium botulinum, which causes botulism, is one of the most difficult bacteria to preserve. Clostridium botulinum can thrive in poorly canned or jarred foods. Bacteria prefer low acidity foods (most vegetables) and temperatures ranging from 40 to 120 degrees Fahrenheit. As a result, in my opinion, it's critical not to eat food from a jar if it's spoiled in some way. Even a single drop of the highly lethal toxin produced by Clostridium botulinum can be fatal. Before you give up canning, there are a few simple ways to tell if a product has gone bad:
Examine the lids for swelling and broken seals.
Examine the jar's contents for rising air bubbles and unusual colour.
Check the lids for tightness and vacuum. Lids with concave centers have good seals
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