Biochemical changes during storage of sweet potato roots differing in dry matter content

Zhitian Zhang, Christopher C. Wheatley, Harold Corke*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

84 Scopus citations

Abstract

Changes during storage were investigated in carbohydrate level, digestibility, α-amylase, trypsin inhibitor activity and pasting properties of roots of six genotypes of sweet potato (Ipomoea batatas (L.) Lam) differing in dry matter content. Most genotypes showed a slight decrease in starch content during 0-180 days of storage, but in the genotype Hi-dry, it decreased substantially. Alpha-amylase activity increased during the first 2 months of storage, followed by a decrease with continued storage to a level similar to that at harvest. The decline in starch content was correlated with α-amylase activity in the first 60 days storage (r = 0.80, P = 0.06). Trypsin inhibitor activity (TIA) in the fresh roots varied among genotypes from 3.90 to 21.83 U/mg. Storage had little influence on TIA level. There was considerable genotypic variation in digestibility, with up to 27% reduction in digestibility after 120 days in storage. Glucose and sucrose concentration increased early in storage and then remained fairly constant. Storage reduced flour pasting viscosities, with up to nearly a 30% decline in peak viscosity.

Original languageEnglish
Pages (from-to)317-325
Number of pages9
JournalPostharvest Biology and Technology
Volume24
Issue number3
DOIs
StatePublished - 2002
Externally publishedYes

Keywords

  • α-amylase
  • Digestibility
  • Free sugars
  • Pasting viscosity
  • Postharvest storage
  • Sweet potato
  • Trypsin inhibitor activity

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