Sweet potato making caramel

1. Technological process: raw material selection-washing potato-making starch-gelatinization-saccharification-heating concentration-finished product

2. Key points of process operation:

① raw material selection: fresh, mildew-free, pest-free sweet potato should be selected as raw material. The amount of starch converted sugar contained in the sweet potato used in the production of sugar has no effect on the yield of boiled sugar. However, if the sweet potato is stored for too long, the color of the sugar will be darker and the quality of the sugar will be reduced. Fresh potato is the most suitable for processing Yee sugar.

② potato washing: take sweet potatoes into the potato washing machine, load about 1x3 of the machine volume, buckle the door buckle of the machine, that is, shake the potato washing machine vigorously. At the same time, it is constantly drenched with water. As sweet potatoes collide with each other in the machine, the sediment attached to the potato skin is washed away by clean water. The more clean it is, the better. If it is not washed, there will be sediment in the finished product in the future, affecting the quality. You must keep shaking until most of the skin of the sweet potato is removed, then you can stop shaking, open the door and take out the sweet potato.

③ starch: put the washed sweet potato in the stone mill groove or on the stone mill, add the right amount of water to start grinding. The parts that mill or mill come into contact with sweet potato shall not contain iron, otherwise it will affect the color, smell and appearance of the product. Grind the sweet potato into a pulp, the finer the better, if the grinding is not fine, there will be a part of starch loss. Take thin bamboo or sticks to tie a cross, and another 0.8 meters square of thin white cloth, four ends tied to the cross, followed by a bucket. Move the milled paste into the cloth bag with a ladle, shake the cloth bag with force, and the starch flows into the bucket through the rarefied surface with water until it is dry. Shake all the pulp, then add the right amount of potato water clarified in the bucket in the residue, grind it ten times, be sure to make it completely pulpy. Only in this way can the starch be put forward completely to avoid loss. If the filtrate is combined with the above filtrate, the residue can be used as pig feed, or as soy sauce, sweet sauce and so on. Let the filtered potato pulp stand for about 1 hour. After the above liquid has been clarified, the supernatant can be poured out. The white pulp sunk at the bottom of the bucket is starch, and the water is dried with a cloth bag, that is, crude starch. Generally, 16-17 kg of starch can be obtained from every 100 kg of sweet potatoes.

④ gelatinization: put the filtered sweet potato starch into a sandwich pot, add about 1.50kg of water to the starch made from 100kg raw sweet potato, and prepare about 10% starch size. Boil for about half an hour, while constantly stirring until the paste, starch has been cooked, gelatinization is the end.

Preparation of ⑤ barley malt: barley malt is used as saccharifying agent for making Yee sugar, and barley needs to be treated. First put the barley in cold water, the water temperature is about 23 degrees Celsius, soak for about 1-2 hours. If the water temperature is low in winter, the impregnation time must be prolonged. Barley used as raw material must clean up sundries and separate the sewage after impregnation. The wheat grain should not be impregnated too much, or the germinating power will disappear. The appropriate water content for wheat impregnation is 40% to 45%. After impregnation, the barley is sent to germinate. At the beginning of germination, the temperature rises due to breathing and action, which can be turned to dissipate heat. In addition, sprinkle water 2 or 3 times a day. Germination can be completed in 4 days at room temperature 25-30 degrees Celsius, and can be used when the bud is 2 cm long.

⑥ saccharification: cool the gelatinized starch to 60-63 degrees Celsius to add wort and stir well. Wort can be obtained by crushing the malt with an extruder. The amount of malt is 8% of the raw material of fresh sweet potato, and the wort must flow out completely during extrusion. The saccharification temperature should be kept at 55-60 degrees Celsius. Under the action of wort, starch was gradually saccharified and turned into maltose and dextrin, and the starch paste gradually became thinner and saccharified for 8 hours, that is, sampling iodine test solution was used to check whether there was starch reaction. When the iodine test solution shows blue, black or purplish red after shaking, it is proved that the starch has not been saccharified, so the temperature should be maintained to continue saccharification. So every hour sampling inspection, until the test solution shows a light red or similar to the color of iodine test solution, that is, saccharification is complete, starch has become maltose or dextrin. At the same time, the saccharification solution of half of the test tube was heated on an alcohol lamp and boiled for 1 minute or 2 minutes. Pay attention to observation. If the suspension in the test tube gradually aggregates into a larger floc and can be separated from the liquid, and the liquid in the upper part of the test tube can be clarified after 1 minute or 2 minutes, it is proved that the saccharification has reached the end point. The saccharification time to reach this level usually takes 2 to 14 hours. After the saccharification reaches the end point, the saccharification solution can be boiled at high temperature, which can not only kill the Glucoamylase preparation, but also agglomerate the suspension, which is convenient for filtration operation.

⑦ heating concentration: after the end of the saccharification process, the clarified dilute sugar solution is obtained by using a plate and frame filter press or cloth bag, and then concentrated. Concentration is generally concentrated by heating and evaporating water, the initial temperature of heating can be higher, and full stirring should be carried out continuously in the heating process. When the sugar solution is steamed and concentrated gradually, the temperature is high, coking is easy to occur, which deepens the color and affects the quality. Therefore, the thicker the sugar solution, the lower the heating temperature. In the process of heating and concentration, there is a layer of foam on the liquid surface, which should be removed continuously. These floating foams are proteins and other substances, and floating on the surface of the sugar solution will also hinder water evaporation, prone to overflow pot phenomenon. The time required for the whole concentration process depends on the water content of the sugar solution, and when the heating temperature is small, when the concentration of the sugar solution is 40 Baume degrees, it is the finished product of maltose.

3. Finished product specifications:

① chemical quality: the sugar content of the finished product (in terms of reducing sugar) should be more than 50%.

② physical appearance Metrics:

Specific gravity: measured at 40 degrees Celsius, a specific gravity of L38 (Baume 40 degrees) is qualified.

Color, smell: should be a light yellow translucent thick liquid, no bad gas and peculiar smell, ignorant sweet fragrance.