What potato preservation techniques are used abroad?

1. Anti-browning, sterilization and preservation. The agents include sodium hypochlorite, calcium hypochlorite, ascorbic acid, etc. For anti-browning of potatoes, the most effective concentration of sodium hypochlorite is 17.5mg/L soaking solution, pH value 4, soaking time more than 5 minutes; the most effective concentration of calcium hypochlorite is also 17.5mg/L, but the color-protecting effect of soaking is not limited by the pH value of the solution. The most effective concentration of ascorbic acid for color expansion is 0.3%. 2-Phospho-ascorbic acid is a newly developed non-sulfur color expansion agent with good effects.

2. Preservation and freshness keeping. To prevent potatoes from rotting during storage, abroad in the 1980s, protective fungicides such as copper sulfate and carbendazim were mostly mixed and dissolved in cleaning and color-protecting solutions for antibacterial and preservative treatment; in recent years, sec-butylamine fumigation, washing or film-forming preservatives have been used instead. When washing potatoes with sec-butylamine, each kilogram of a 50% sec-butylamine commercial preparation, after dilution with water, can wash 20 tons of tubers. If the sec-butylamine fumigation method is used, at 6-14g of 50% sec-butylamine per cubic meter of space per kilogram of potato tubers, fumigating for more than 12 minutes gives a good preservative effect. Coating preservatives for preserving potatoes are a newly developed measure, that is, using film-forming agents such as chitin, chitosan, maltodextrin, konjac glucomannan, sodium alginate, paraffin, beeswax sucrose ester, etc., adding certain antibacterial agents and antioxidants, and preserving potatoes by coating through soaking to form a film, brushing the film or spraying. The coating preservation effect is very good, and it also has the functions of modified atmosphere and inhibiting respiration. Film-forming agents such as chitosan, which themselves have strong antibacterial effects, are especially more widely used. Recently, Japan developed a new type of natural food preservative. This product is extracted from nucleoprotein and has good antibacterial and preservative effects. The main components are: fish protein extract 35%, glycine 35%, sodium acetate 25%, sodium polyphosphate 5%. It has been trial-used for preserving potatoes and potato salad with good results, and after heating at 60-120°C for 3 minutes, the antibacterial activity still remains 100%, and it is also harmless to human health.

3. Storage and sprout inhibition. Preserved potatoes are generally required to be stored under cool, dark and high-humidity conditions. Where conditions permit, high-humidity controlled atmosphere storage should be carried out (relative humidity 90%-95%). Before storage and during storage, sprout inhibition treatment is usually carried out. Common sprout inhibitors include: ① Maleic hydrazide. It is a sprout inhibitor promoted by some foreign companies in China's potato production areas, with a use concentration of 2.5g/L, sprayed on potato plants 4-6 weeks before harvest. ② Isopropyl n-(3-chlorophenyl) carbamate (hereinafter referred to as CLPC). It is currently the most widely used potato sprout inhibitor in the world, commonly used in potato storage in all European countries, the United States, Australia and a few developing countries. The application methods of CLPC include fumigation, dusting, spraying and potato washing, among which fumigation has the best sprout inhibition effect, and the preservation time can be as long as 9 months.