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Ensuring Quality in Fresh-Cut Fruits and VeggiesBy Doris Stanley
May 6, 1998
Fresh-cut fruit and vegetable quality can be maintained by selecting produce with proper maturity, controlling defects and disorders, and maintaining temperature, atmosphere and relative humidity in packaging, a scientist with the Agricultural Research Service reports today.
These fruits and vegetables deteriorate rapidly because cutting plant tissue leaves it unprotected by skin, exposing it to dehydration, discoloration and attack by pathogens. According to Alley Watada, a food technologist at the ARS Horticultural Crops Quality Laboratory, Beltsville, Md., shelf life of fresh-cuts differs widely among produce types, ranging from seven to 20 days. Watada will report this and related findings at the ARS Symposium on the Quality and Safety of Fresh Fruits and Vegetables, held May 3-6 at the agencys Beltsville (Md.) Agricultural Research Center.
Cutting or slicing with a very sharp blade reduces the amount of damaged cells, thereby slowing dehydration, Watada found. In lab tests, treating cut carrots with calcium and subjecting them to very high relative humidity kept them from turning white, a condition that turns off consumers.
For most produce, degree of browning or discoloration differs widely among varieties. Of 25 cabbage cultivars tested, eight browned slightly and two minimally after storage at 68 degrees F for 24 hours. Of 12 apple varieties tested, slices of five showed the least browning after storage at 36 degrees F for three days.
Since immature fruit lacks taste and over-mature fruit has limited shelf life, proper maturity is vital. Quality is judged by appearance, firmness or texture and vitamin content. Temperature is the most important factor in all these attributes because as storage temperature increases, so does respiration. Deterioration increases at a comparable rate with respiration, so low packaging temperatures are essential. Many fresh-cut fruits and vegetables are also sensitive to chilling injury, meaning they suffer damage when stored below 50 degrees F, with more severe damage as temperature drops to 32 degrees F.