High demand for sweet potato starch and high efficiency in timely processing

Sweet potato starch plays a more and more important role in people's daily diet. At present, potato chemical products have become the main raw materials of lactic acid, citric acid, disposable tableware and degraded agricultural plastic film and other chemical products. It is understood that the current price of refined sweet potato starch is nearly 10% higher than that of last year, and the reason for this price trend is undoubtedly the gap between supply and demand of sweet potato starch. Relevant data show that at present, the demand for sweet potato starch in the domestic market is more than 1 million tons, while the production is far less than this figure. Due to the wide use of products, low price of raw materials and large value-added space for processing and development, the prospect of sweet potato starch processing industry is promising.

How to improve the flour yield of fresh potatoes? according to our company's processing experience, there are mainly the following links:

1. Timely harvest sweet potato early harvest is not mature enough, the flour yield is low; late harvest is vulnerable to frost; it also affects the flour yield. The early-maturing varieties started from the local pre-frost, about September 10-20, while the late-maturing varieties started from local Frosts Descent to Frosts Descent 10 days later, and the flour yield was high. Because the temperature is suitable at this time, sweet potato pulps ferment quickly and produce more starch after crushing. If the starting time of the potato is too late and the temperature decreases, the starch in the potato block is gradually converted into sugar, and the flour yield is reduced. In particular, when fresh potatoes are processed into dried potatoes, the flour yield will be greatly reduced.

two。 Try to shorten the storage period, there is the habit of first storage and then processing in rural areas, which has a great impact on the flour yield of sweet potatoes. After the sweet potato comes out, with the extension of storage time, the starch is gradually saccharified, and the flour yield will decrease. It will be crushed immediately after collection, and the powder yield can reach about 35%. After storage for 20 days, the powder yield will be reduced by about 20%. Therefore, if the sweet potato is processed within 20 days after collection, the flour yield can be increased by 10% to 12%. If there are a large number of sweet potatoes, they can also be stored and processed first, but the storage period should be shortened as far as possible, and attention should be paid to the temperature and humidity in the cellar to prevent the sweet potato from drying.

3. There are many sweet potato varieties selected, and white-core varieties such as "Yiwo Hong" and "Shengli 100" are selected, which can produce about 10% more starch than other red-core varieties such as "138". Moreover, the flour is white and the powder quality is good.

4. Wash and remove moldy and spoiled sweet potatoes, wash the sand, mud and other sundries that stick to the potatoes, rinse with clean water many times and then set aside.

5. First soak the sweet potato in dilute alkali water or soda solution to separate the fiber from starch. Then pour the soaked sweet potatoes into the grinding cylinder. When grinding, one hand supports the cylinder and the other rotates constantly, so that the pulp slag slowly precipitates.

6. After precipitation and grinding, do not rush to wash the pulp with clean water. The milk should be placed for 24 hours to precipitate, and then according to the proportion of 50 grams of liquor for every 50 kilograms of sweet potato, the liquor is diluted with an appropriate amount of water and mixed well, and then washed.

7. The gauze of filtered soybean milk (about 1 meter in length and width) for washing milk is tied to a chest-high tripod. Place a large pulp bucket under the rack (preferably with a row of water holes 0.67 meters from the bottom of the barrel wall), and then put the ground potato pulp into a fastened filter cloth, 4kg at a time. While shaking and scrubbing while filtering, slowly add 2 / 2. 5 times of clean water, so that all the powder is filtered into the bucket (the filtered water should be turned clear). Generally 10-12 hours can be precipitated, and then drainage to remove scum and clear liquid. If the water is as muddy as it was just filtered, put 500 kilograms of water into 150 grams of alum (first crush the alum and dilute it with a little water) and pour it into a bucket and stir evenly and drain after 4 hours.

8. After the dry water is drained, the filter cloth is laid flat on the starch. after the starch is dried, it is cut into pieces with a knife, taken out and dried, and can be collected and processed or @ # @ 136.