Characteristics and packaging technology principle

2022-07-23
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Characteristics of fatty food and principle of packaging technology

I. characteristics of fatty food

oily food is a traditional food with unique flavor and is deeply loved by people. Its oil has nutritional value, but at the same time it has become the main reason for the deterioration of oily food. Under the action of the external environment, Oils and fats are easy to cause oxidative rancidity. In serious cases, they will produce "Khara flavor", which will make the food taste and fragrance. However, due to the loss of flavor in a variety of control modes, the original color of the food will be changed, and the nutritional value of the food will be reduced, so that it can not be eaten

the oxidation mechanism of oil is that oil is oxidized by oxygen in the air under the catalysis of ultraviolet light and heat to produce peroxide. Ultraviolet light, humidity and metal ions will further promote the oxidation reaction and decompose the peroxide. Therefore, effective measures must be taken to prevent and stop the oxidation reaction. There are usually several methods as follows:

1. Select the oil raw materials that are not easy to oxidize to process food, that is, select the oil with low unsaturated bond content to process food, or add antioxidants to the food

2. Use vacuum packaging or inflatable packaging to minimize the oxygen content in the packaging, or use deoxidizer in the packaging

3. Shading or aseptic packaging was used to delay and inhibit the evolution of oxidation reaction. The degree of oil oxidation can be determined by acid value (an) and peroxide value (POV). For example, the oxidation process standard for processing noodles is: the acid value shall not exceed 3, and the peroxide value shall not exceed 30

II. Packaging technology for oily food

the key to the packaging of oily food is how to prevent the oxidation of grease. Therefore, removing oxygen from the packaging and keeping the packaging in an oxygen free state during circulation become the key. Usually by adding oxygen, we have developed a unique method to change the layer structure, as well as vacuum packaging or inflatable packaging. All these put forward corresponding requirements for the sealing of packaging materials and seals. Whether it is vacuum packaging or inflatable packaging, the air permeability of the packaging material must be the lowest, and its air permeability must be the least affected by the surrounding temperature and humidity, so as to maintain the stability of the vacuum and atmosphere in the packaging. For example, for the nitrogen filled packaging of oily foods such as peanut butter and sesame paste, if the relative humidity of the environment is below 50%, ordinary cellophane/polyethylene composite materials can be used for packaging. If the relative humidity of the environment is as high as 80%, the oxygen permeability of cellophane/polyethylene will also increase, so it is not suitable to use. Composite materials with an oxygen permeability of less than 10ml/m2.24h should be used, such as Kon (PVDC coated directional nylon) KPT (PVDC coated cellophane/polyethylene), etc. Of course, the most ideal packaging material should have both light shielding and moisture-proof properties to eliminate humidity and ultraviolet light. The electronic universal testing machine is composed of four parts: force adding device, accessories, measurement control system and force value display and recording device. The oxidation of oil and grease promotes the "opening" of the International Science and technology feast; nbsp; The role of Ningbo in the new material industry

oily food is generally packaged with transparent plastic film. Because of its economic and convenient characteristics, it is increasingly widely used. However, due to its transparency to light (transparency) and permeability to oxygen and moisture, especially oxygen permeability, it will cause oxidation of oil and affect the shelf life of packaged food. Therefore, the air permeability of packaging plastic film, the air content during bag sealing, the change of oxygen partial pressure during storage The quantitative relationship between oxygen uptake of oil and POV and the volume change of bag has a guiding role in improving the packaging and shelf life of oil food. (to be continued)

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