Can anyone tell me how to determine the starch content in fresh potatoes, thank you

Use a pressure cooker at a temperature of 121 degrees to hydrolyze starch with sulfuric acid, time: 10min. The starch is hydrolyzed into glucose sugar, and the starch is checked with iodine solution to see if it is completely hydrolyzed, and then neutralized with lye.

Then, lead acetate, sodium sulfate are added to remove impurities, lead, etc. Rated volume 250ml. Filtration, the filtrate is used to detect the content of total sugar, and then another filtrate is taken to determine the content of reducing sugar by direct titration, and the total sugar minus reducing sugar is equal to the glucose content after acid hydrolysis, multiplied by the content of starch.

The key control link is to control the degree of hydrolysis of the sample as much as possible, because potatoes contain more hemicellulose, which is easy to be hydrolyzed and produce errors.

Potatoes contain about 17% starch, and the gelatinization temperature of starch is 58 65, the viscosity can reach 2000bu, and the amylopectin content is about 80%. Compared with other varieties of starch, the excellent quality and unique properties of potato starch are mainly reflected in the following aspects: first, potato starch has the highest viscosity and can be used as a thickener, and potato starch has a high degree of molecular polymerization (about 3000) and large particles, so it has high expansion and excellent water retention performance, which is suitable for puffed food, meat products and instant noodles and other products.

Secondly, potato starch has low protein and fat residues, high phosphorus content and white color, natural phosphorescence, and high transparency of the solution, so it can improve the color and appearance of the product. Thirdly, potato starch has a particularly mild taste, without the typical grain flavor of corn or wheat starch, and can be used even for flavor-sensitive products.

Hello, I'm glad that your Duanqin problem oh The national standard moisture of potato starch is 18%-20%, and there are many kinds of moisture to detect starch. Deficit is for your reference.

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Hello, I'm Teacher Pingbu! I've seen your question and am sorting out the answer for you, please wait a moment.

The national standard moisture of potato starch is 18%-20%, and there are many kinds of water state to detect starch. FYI.

<> won't such a large amount of moisture get moldy?

No, it won't. Got it, thanks.

You're welcome.

Potato tuber dry matter weight %--6% (3) starch % = starch value % (Huisun Gaojian 1--0·015). The simple calculation method of potato dry matter and starch content can be used in a series of production and scientific research practices such as potato high-yield cultivation, variety breeding and chain processing before storage, and the potato starch content data are often required to be determined and used, and the formula is: potato tuber dry matter weight %--6% (3) starch % = starch value % (1--0·015).

Potatoes are one of the most important food crops in the world. Not only does it have a high nutritional value, but it can also produce a lot of by-products, such as starch. Potato starch grain size is of great significance in starch processing.

Classification of potato starch grain size.

The size of potato starch grains can be divided into five categories according to the size of their diameter

Large granular starch (greater than 35 m).

Medium granular starch (25 m - 35 m).

Small granular starch (17 m - 25 m).

Microgranular starch (10 m - 17 m).

Ultra-fine granular starch (less than 10 m).

Among them, large granular starch and medium granular starch are often used to make beverages, jellies, dairy products, etc., small granular starch and microgranular starch are more suitable for making meat products, flour products, etc., while ultra-fine granular starch is more suitable for making oil and fat products.

Factors influencing the size of potato starch grains.

The size of potato starch grains is affected by a variety of factors, mainly in the following aspects:

Variety: Different varieties of potato starch grains vary in size. For example, the variety "Kapozo" has larger starch grains of up to 60 m, while the variety "Capunac" has smaller starch grains of only about 15 m.

Growing season: Starch grain size can also be affected by differences in potato growing season. The longer the growth period, the larger the starch grains.

Soil: Soil moisture, texture, fertilization, etc. of potatoes will also have an impact on starch grain size.

Handling methods: Potato storage, processing and other processing methods will also affect the size of starch grains. For example, the starch grains will become smaller after the potato is processed at high temperatures.

The relationship between the size of potato starch grains and the quality of starch.

The size of starch grains not only affects the application performance of starch, but also directly affects the quality of starch. Generally speaking, the larger the starch grains, the higher the starch content and nutritional value; The smaller the starch grains, the higher the stability of the starch, the easier it is to absorb, and the more beneficial it is to the human body.

In practical applications, it is necessary to choose the appropriate starch grain size according to the use of starch. For example, dairy products require products with large starch grains, while meat products require products with smaller starch grains.

Conclusion Potato starch grain size plays an important role in starch application and quality, and different starch grain sizes are suitable for different applications. In the production process, the starch processing plant needs to choose the right starch grain size according to different uses to achieve the best quality and profit purposes.