408 Atmospheric Oxygen Level Affects `Beauregard' Sweetpotato Respiration Rate, Fermentation Products, and Sugar Composition

Abstract

<jats:p>`Beauregard' sweetpotatoes (<jats:italic>Ipomoea batatas</jats:italic> L. Lam) were stored under a continuous flow of 0%, 1%, 1.5%, 2%, 5%, 10%, or 21% O<jats:sub>2</jats:sub> (balance N<jats:sub>2</jats:sub>) for 14 days. Respiration rate was significantly lower at 1.5%, 2%, 5%, and 10% O<jats:sub>2</jats:sub> compared with 21% O<jats:sub>2</jats:sub>, while respiration at 0% and 1% O<jats:sub>2</jats:sub> was higher than at 1.5%, 2%, 5%, and 10% O<jats:sub>2</jats:sub>. Respiration rate at 0% O<jats:sub>2</jats:sub> remained high for several days after exposure to air while that at 1.5%, 2%, 5%, and 10% O<jats:sub>2</jats:sub> increased rapidly to equal that of 21% O<jats:sub>2</jats:sub>. Ethanol and acetaldehyde accumulated rapidly at 0% and 1% O<jats:sub>2</jats:sub> but were lower at the other O<jats:sub>2</jats:sub> levels. Ethanol increased 16- and 4-fold after 14 days of storage at 0% and 1% O<jats:sub>2</jats:sub>, respectively, compared to 21% O<jats:sub>2</jats:sub>. In addition, acetaldehyde increased 11- and 8-fold at 0% and 1% O<jats:sub>2</jats:sub> respectively, compared to 21% O<jats:sub>2</jats:sub>. Sucrose and total sugar concentration increased under low O<jats:sub>2</jats:sub> concentration while reducing sugars (fructose and glucose) and pH decreased.</jats:p>