How to dry chestnut in food dryer

Chestnut is rich in nutrients, in addition to containing more than 40% of carbohydrates, it is also rich in protein, fat, vitamins and calcium, phosphorus, iron, potassium and other minerals. It has a unique flavor of sweet, fragrant and waxy and is very popular in the market. 

Pretreatment of chestnut drying: Newly harvested chestnuts have high moisture content and low soluble sugar content, especially the astringent skin inside is difficult to peel off, such as poor direct processing flavor, and affect product quality. After pretreatment, part of the starch in chestnut is converted into soluble sugar, and part of the water is lost. Relatively, the content of soluble substances is increased, and the flavor is improved. The processing method is to place freshly harvested chestnuts indoors, with a thickness of 4 to 5 cm, flip them 2 to 3 times a day, and stack them for 4 to 5 days (days).

Chestnut cleaning and boiling solution: Wash the chestnuts with clean water, rinse away impurities, and then classify them according to the size of the chestnuts and process them separately. The cooking liquid is composed of star anise, cinnamon, cloves, peppercorns, licorice, salt, sugar and water. The outer skin of chestnut fruit is leathery, and it is difficult to taste when cooked or soaked. You can use the simple vacuum infiltration method to boil the seasoning with water for 30 minutes (minutes) according to the formula to make a seasoning solution. Add the chestnut and cook.

Chestnut drying and packaging: The purpose of chestnut drying is to separate the astringent skin from the pulp. Rinse the cooked chestnuts with water to remove the seasoning liquid adhered to the surface, put the chestnuts into the material tray, insert the material cart, and push them into the heat pump chestnut drying room. The chestnut’s temperature is relatively high, and the temperature can be adjusted directly Dry to 75 degrees, set the time for 6-8 hours, and carry out continuous dehumidification. When the moisture of chestnut fruit drops to 30%, the astringent skin and the pulp are separated, and it is easy to peel off when eating, and the pulp is not broken, and the humidity is moderate. Spread the baked chestnuts and cool them, spray a little cream flavor before bagging, and put them into soft packaging bags according to different amounts of 100g, 200g, 250g, etc., and use a vacuum sealed packaging machine for air-tight packaging.

Use chestnut dryer to process chestnut, pay attention to prevent color browning and affect quality.

Causes of browning during chestnut drying: Browning is the most prominent problem in chestnut processing. It is also the main factor affecting the quality of chestnut finished products. Browning of chestnut includes enzymatic and non-enzymatic browning. Enzymatic browning is a color change caused by the oxidation of phenols and tannins in chestnut fruits caused by oxidases (PPO, POD). The product is a complex polymer: black essence; non-enzymatic browning Mainly Maillard reaction, oxidation of ascorbic acid and browning caused by metal ions.

Treatment of browning during chestnut drying: There are many ways to protect the chestnut kernel from browning. For enzymatic browning, the methods of deoxidation and inhibition of polyphenol oxidase are mainly adopted, such as heating, adding sulfite, adding ascorbic acid, and adjusting pH. For non-enzymatic change, the main measures are to avoid processing materials for a long time at high temperature, avoid using reducing sugar, and use sulfite treatment under non-basic conditions to prevent Maillard browning reaction. Adding chelating agents such as EDTA to the medium to complex the metal ions; or reducing the amount of ascorbic acid to prevent browning reactions.