Date of Award

1999

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Plant, Environmental Management and Soil Sciences

First Advisor

David H. Picha

Abstract

The applicability of using shrink-wrap films in sweetpotato storage was investigated. 'Beauregard' sweetpotatoes were individually wrapped in either Cryovac D955, Clysar EHC50, Clysar EHC60 or Clysar EHC75 shrink-wrap film and a nonwrapped control. Roots were also overwrapped in 2.3-kg packages using Cryovac D955 or Clysar EHC75 films. Wrapped and nonwrapped roots were stored at either 7°C, 15.6°C or 22°C for five weeks followed by one week at 22°C. Shrink-wrapped roots exhibited increased sprouting. Roots wrapped in EHC75 film had less weight loss and increased sucrose compared to the other films. Shrink-wrapped roots were higher in sucrose content but were not different in reducing sugars, dry matter content or alcohol-insoluble solids than the nonwrapped controls. In another study, roots were dipped in 35, 45, 65, or 75°C water for 2, 5, 8, or 11 min to determine the effect of hot water treatment on root quality and composition. Higher water temperatures caused increased rate of respiration, weight loss, and reducing sugars (fructose and glucose), but a decreased sucrose concentration. The 55°C treatment for 5 min provided the most superior root appearance. Another study was conducted to investigate the applicability of hot water treatment to control decay in shrink-wrapped sweetpotatoes. Roots were dipped in 2,6,-dichloro-4-nitroaniline, hot water (55°C for 5 min), a combination of the two treatments, or untreated before placing in 2.3-kg consumer packages overwrapped with Clysar D955 film. Hot water and fungicide treatments reduced root decay and maintained a superior root appearance. Hot water treatment also inhibited sprouting. To investigate the effect of low-oxygen on sweetpotatoes, roots were held under 0, 1, 1.5, 2, 5, 10 or 21% O2 (balance N2) for 14 days at room temperature. Storage at 1.5, 2, 5, and 10% O2 resulted in a reduced root respiration rate compared with 0, 1, and 21% O 2. Ethanol and acetaldehyde accumulated at 0% and 1% O2, corresponding to increased alcohol dehydrogenase (ADH) and pyruvate decarboxylase (PDC) activities. Sucrose and total sugar concentration increased under low-oxygen while reducing sugars (fructose and glucose) and pH decreased.

ISBN

9780599636095

Pages

95

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