Postharvest practices

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After harvesting, the storage roots are sorted  to remove the diseased and damaged ones as well as to separate them into different sizes. Root classification into different grades vary among places but  generally, this practice is done to separate the rejects  from the marketable roots. The reject is composed of oversized, undersized, and damaged roots. The rejected roots can be sold at lower price, kept for home use, fed to the animals, given or thrown away. The final grading is done by the assembler/wholesaler.

Roots are sometimes classified into sizes based on their diameter but this was found to be accurate only when roots are roundish in shape. When roots are elliptical to cylindrical in shape or otherwise irregular, a classification based on weight is better.

Roots are cleaned by washing or by simply removing the adhering soil without washing. Washing is done depending on market requirement. 

Curing, a recommended postharvest practice to promote hardening of the skin in preparation for a long storage period or rough handling, is not commonly practised in areas where roots are immediately sold after harvesting.

The packaging materials for sweetpotato differ among places and countries. In some Asian countries wooden crates/boxes, large baskets (made of rattan or bamboo), synthetic sacks and jute or burlap sacks are used.

Comparison of roots transported in three types of containers showed that storage roots transported in sacks had the least damage during transport for four hours. During longer transport period, however, roots in wooden crates had the least damage.

Cultivars differ in storability. Some can be stored beyond 60 days after harvest (DAH) and even until 90 DAH without losing marketability while others show shriveling, sprouting and decay even at less than 30 DAH depending on the storage condition. Comparison of the storability of some cultivars under upland and postrice Philippine conditions showed that roots stored in the upland had lower rotting, sprouting and shriveling (Amante, et. al,1992). Lower temperature and higher relative humidity characterised this condition. The data also showed cultivar differences in storability.

Reference

Rasco, E.T., Jr. and Amante, V. 2000. Sweetpotato in Tropical Asia. SAPPRAD-PCARRD. 230 p.

 

Contributed by: Vilma Amante  

Land preparation

Planting material preparation

Planting

Soil management

Water management

Vine lifting

Integrated pest management

Harvesting


Storage roots are sorted and packed in sacks in the Philippines (F. Villamayor).


Storage roots ready for transport in Malaysia (E.T. Rasco).