Detailed explanation of potato preservation techniques: learn these methods to store them longer

In recent years, China's total fresh potato exports have shown an upward trend year by year. In 1996, a total of 440,000 tons were exported, earning 75 million US dollars in foreign exchange. However, exported fresh potatoes have relatively strict quality requirements, and compared with Europe's major potato-producing countries, China's exported fresh potatoes lag in variety, grading, packaging, storage and transportation. This article gives a brief introduction to potato preservation techniques:

1. Anti-browning and sterilization and antisepsis

For anti-browning of potatoes, the most effective concentration of sodium hypochlorite is 17.5ppm, the pH of the soaking solution is 4, and the soaking time is more than 5min. The effective concentration of calcium hypochlorite is also 17.5ppm, but the color-protecting effect of soaking is not limited by the pH of the solution; the most effective concentration of ascorbic acid for color protection is 0.3%. 2-Phospho-ascorbic acid is a newly developed non-sulfur color-protecting agent with good effects.

2. Antisepsis and preservation

Preventing rot of fresh-preserved potatoes during storage and transportation is also a problem that manufacturers of fresh-preserved potatoes must pay attention to and face. Before the 1980s, protective fungicides such as copper sulfate and carbendazim were mostly mixed into cleaning and color-protecting solutions for antibacterial and antisepsis treatment. For potato antisepsis, sec-butylamine fumigation and washing of potato tubers are both acceptable. When washing potatoes, each kg of a commercial sec-butylamine formulation with a net content of 50%, after dilution with water, can wash 20,000kg of tubers. For fumigation, 60mg-14g per kg of potato tubers per cubic meter of 50% sec-butylamine is used, and the fumigation time is more than 12min, with good antisepsis effects.

Another newly developed potato preservation measure is the use of film-forming preservatives. That is, using film-forming agents such as chitin, chitosan, maltodextrin, konjac glucomannan, sodium alginate, paraffin, and beeswax sucrose ester, adding certain antibacterial agents and antioxidants, and carrying out coating preservation by soaking to form a film, brushing on a film, or spraying. Coating preservation has a very good effect and also has the functions of modified atmosphere and inhibiting respiration. Film-forming agents such as chitosan, which themselves have very strong antibacterial effects, have especially broad application prospects.

Recently, Japan developed a new type of natural food preservative. This product is extracted from nucleoprotein and has good antibacterial and antisepsis effects. Its 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 a high temperature of 60-120°C for 30min, its antibacterial activity still remains 100%. Even if this protective agent is eaten into the human body, it is harmless to health. This protective agent has been recognized by the standards and patents of 6 countries including the US FDA.

3. Storage and sprout inhibition

Fresh-preserved potatoes are generally required to be stored under cold, dark, and high-humidity conditions. Where conditions permit, high-humidity controlled-atmosphere storage (rh90%-95%) should be used. Before storage and during storage, sprout inhibition treatment is usually carried out. Common sprout inhibitors include the following:

The sprout inhibitor promoted in China's potato-producing areas by some foreign companies has maleic hydrazide as its main component, used at a concentration of 2500ppm, and sprayed on potato plants 4-6 weeks before harvest.

Isopropyl n-(3-chlorophenyl)carbamate (cipc): cipc is currently the most widely used potato sprout inhibitor in the world. cipc is commonly used in potato storage in all European countries, the United States, Australia, and a few developing countries. There are 4 application methods for cipc: fumigation, dusting, spraying, and potato washing. Fumigation has the best sprout inhibition effect, lasting up to 9 months. The suitable range for fumigation: 0.5%-1%, the time for one fumigation is about 48h, and the suitable concentration for washing potato tubers is 1%. The allowable residue limit of cipc in tubers announced by the FDA and EPA in 1996 is 30mg/kg.