Fresh duck intestines are meaty pink in color, and there are distinct shades of color visible on the surface. This is because the skin at the end of the duck intestines is very thin and whitish in color, the middle part is slightly reddish, while the skin of the duck intestines near the stomach will be thicker and relatively reddish in color.

When you eat duck intestines in a restaurant, you will find that the duck intestines are pink and tender, which is because the restaurant has done the preliminary processing of fresh duck intestines to change the color of the duck intestines, so that the duck intestines look more stimulate the consumer's appetite.

Restaurant in the processing of duck intestines, will first fresh duck intestines into the prepared bucket, add a lot of water temperature close to zero degrees of ice water, and then use tools to clean the duck intestines one by one.

First, the oil tendons carried on the duck intestines are torn off by hand, and the remaining oil tendons are scraped clean with a knife. Then use scissors to cut the duck intestines into small sections of about 15 centimeters, so that the duck intestines are clean. Next, clean the clean duck intestines, with about 40 degrees of warm water over again, clean off the residual dirt of the duck intestines. Finally, in the duck intestines to add the prescribed proportion of duck intestines bio-enzymatic tender crisp agent, mix well, marinate for 20-30 minutes, fish out and clean, duck intestines of the initial processing is completed.

The main ingredient of duck intestines Bio-enzyme Tenderizer, also known as duck intestines powder, is the red pigment, red pigment is our traditional natural functional food coloring produced by the fermentation of Aspergillus oryzae, and is also approved by the food department to use the safety of the pigment, which is "nutritious, natural, multi-functional," etc. However, when used, the amount of use is not enough to make the product more effective. However, when used, the amount used should not exceed the safe amount stipulated by the state, so as not to cause harm to human health.

Add duck intestine powder to change the color of duck intestines, the use of duck intestine powder in the role of protease activity. Duck intestine powder contains a papain, which is a green food additive. By cutting off the protease activity in duck intestines, it achieves the effect of changing the color of duck intestines, and at the same time makes the duck intestines taste more crispy.

And once the temperature reaches 85 degrees, papain will lose its original activity and become ordinary protein, which will not affect human health.