Pulsed Light Applications in Food Processing

Currently, the more mature sterilization techniques in food processing are heat sterilization, irradiation sterilization, ultraviolet sterilization, ozone sterilization, etc., but they all have unsatisfactory areas. The traditional heat sterilization method can make the protein coagulation in the cells of food spoilage bacteria denature, leading to bacterial inactivation; physical or chemical changes in agricultural products or food, resulting in color, fragrance, taste, tissue structure changes and nutritional value reduction. Pulsed light packaging sterilization equipment provides a high-speed, serialized solution for surface microbial decontamination and in-line integration upstream of cup filling, capping, or bottle blowing in sensitive product packaging lines. 

Ultraviolet light penetration is poor, so its bactericidal ability is greatly limited, and ultraviolet light irradiation is easy to make the fat in the food oxidation produce odor, the protein deterioration produce discoloration and other phenomena, so that vitamins, chlorophyll and other beneficial components decomposition. Irradiation sterilization is prone to produce obvious taste, and the infrastructure costs are relatively high. In 1996, the U.S. Food and Drug Administration (FDA) passed the Pulsed Light Sterilization in Food Processing Act 21, which provides for the use of pulsed light in food processing to kill all kinds of microorganisms, with little impact on the nutritional composition and taste of food, low heat, high bactericidal efficiency, no by-products, easy to control, etc. In 1996, the U.S. Food and Drug Administration (FDA) passed the 21 Act on the application of pulsed light in food processing. 

1.Pulsed light sterilization principle

Pulsed light sterilization is a technology that uses pulses of intense white light to sterilize microorganisms by flash photography. The principle of sterilization by pulsed bright light is: the visible light, infrared and ultraviolet light will act synergistically on the microorganisms, through the instantaneous, high-intensity pulsed light energy on the microbial cell wall proteins and nucleic acid active structure, so that the cells denature, lose biological activity, inhibit their growth and reproduction, and thus achieve the purpose of sterilization.

2.Pulsed strong light sterilization effect

Compared to traditional sterilization methods, Pulsed Light Sterilization has the advantages of short sterilization processing time (generally processing time is a few seconds to tens of seconds), less residue, less environmental contamination, no direct contact with materials and equipment, and easy operation and control. A large number of tests conducted on the chemical composition (including nutrients) and microbial flora changes in food have proven the safety and reliability of Pulsed Light treatment of food.

2.1 Pulsed light can effectively reduce the number of microorganisms on the surface of food Pulsed light has a very high peak energy, like lightning, the same amount of energy in the form of peak value is released instantaneously, penetrate the food packaging, and completely destroy microbial DNA. 2.2 Pulsed bright light can passivate enzymes in foods.

2.2 Pulsed light can passivate enzymes in foodstuffs The test results showed that after 40 flashes of pulsed light, amylase activity decreased by 70% and protease activity decreased by 90%, Dunn et al. used 3 J/cm 2 pulsed light to treat fresh potato slices for two to five times to avoid browning on the surface of potato slices, while the control group had serious browning, which indicated that the pulsed light was a good solution to the problem. Strong light can inhibit polyphenol oxidase (PPO) activity and prevent fruit from being damaged.

Browning of vegetables.

2.3 Pulsed light has little effect on the nutritional content of the food. The low temperature characteristics of pulsed light help to preserve the flavor of the food being treated, and pulsed light acts only on the surface of the food, thus having little effect on the flavor and nutritional content of the food. Pulsed light is thousands to tens of thousands of times more intense than untreated food. 

The above information is provided by pulsed light packaging sterilization equipment supplier.