Post harvest Management of Horticultural Crops (2+1)

Introduction

Storing produce at low temperature is generally beneficial because the overall rate of metabolism (e.g. respiration, ethylene production) is reduced. However, low storage temperatures do not suppress all cellular processes to the same extent. Some processes are especially sensitive to low temperature, and may cease completely below a critical temperature. Several cold-labile enzyme systems have been identified in plant tissues. Metabolic imbalance as a consequence of low temperature can lead to accumulation of reaction products and a shortage of reactants. If the imbalance becomes serious, essential substrates may not be produced and toxic products can accumulate. Consequently, cells will cease to operate properly and will lose their function and structure. Damaged cells often appear as discoloured areas (usually brown or black). Ethylene may be involved in low-temperature injury, since treatment with the ethylene binding site blocker 1-MCP can reduce discoloration symptoms associated with low-temperature disorders in some fruit (e.g. apple, pineapple).