Fresh mushrooms preservation technology

Food availability at all times is an important step towards ensuring food security for sustainable development and climate change adaptation. Fresh mushrooms undergo chemical and physical changes when stored.The changes affect appearance, flavour and ordour due to enzymatic activities, oxidation and bacterial spoilage leading to post harvest food loses. Generally refrigeration preservation technology reasonably increases shelf life; however, the produce is very susceptible to chilling injury. Freezing causes irreversible damage to the tissues. Processing technology is an important option for preservation of fresh mushrooms. Sun drying preservation technology is a commonly used technology  in preservation of fresh mushrooms. 

Fresh straw mushrooms are cut longitudinally before drying.Another alternative is hot air drying  in an oven which can  be done at 40ºC then gradually increasing the temperature to 45ºC.Drying at 45ºC takes a period of 8 hours resulting to a product 10% of the original weight.Shiitake variety is usually sun dried gradually or in special driers with adjustable heat starting from 30ºC increasing gradually by 1-2ºC every hour, then 12 hours at 50ºC and 60ºC for 0ne hour to increase the luster of the cap.Canning is still considered the best technology for fresh mushrooms preservation. The procedure starts by sorting, trimming, washing of fresh produce, followed by blanching in boiling water for two minutes. Branched produce is then filled in cans and 2% brine solution added. The entrapped air is removed and the cans sealed. They are then sterilized or pasteurized for 30-60 minutes under pressure at 121ºC-130ºC, or one hour in boiling water. The cans are then cooled rapidly.

Pickling is yet another mushrooms preservation technology which involves sorting, washing, and blanching for 5 minutes in boiling water, then placing in cold water to cool.They are then transferred to a jar or wide mouthed bottle and brine, a little vinegar, vitamin C or citric acid added to give the product an appealing look. The jar is then closed loosely and steamed for one hour, and then the lid is tightened after cooling the contents. Last but not least, paste making preservation technology involves soaking fresh mushrooms in 40-50% brine solution for 10-15 days. The contents are then blended until there is liquid paste. The resulting paste is put in a cheese cloth to drain excess liquid, and then the paste is put in a wide mouthed bottle. Steam for one hour and the delicacy is ready to eat.