Respiratory losses in sugar beets as a function of storage temperature, field nitrogen application, sprouting incidence and handling severity

Abstract

Respiratory losses in sugar beets as a function of storage temperature, field nitrogen application, sprouting incidence and handling severity. The trend toward warmer temperatures in Michigan has lead to an increased risk of excessive temperatures in field piles of sugarbeets. In the 2004-2005 season, the Michigan industry is estimated to have lost approximately $25,000,000 to pile breakdown following an unusually warm winter and spring. Determination of optimal storage strategies requires knowing the effects of the major factors influencing respiratory activity. From 2005 to 2009, we evaluated the impact of storage temperature, nitrogen applied during the growing season, and handling severity on respiration after one and four months holding. In addition, the contribution of sprouts formed during storage to respiratory activity was estimated by harvesting sprouts and measuring their respiratory activity relative to the root. Field nitrogen application between 0 and 160 lb/acre did not influence respiratory activity. Commercial machine harvesting increased respiratory activity between 10 and 25% relative to handharvested controls and the impact of machine harvesting increased with storage duration. Beets collected after dropping into full, half-full and empty trailers all experienced enhanced respiration, with the greater respiratory activity induced by the most damaging treatment. The data collected will be used to model respiratory activity and pile temperature profiles for fieldstored sugarbeets in Michigan.

Glycolysis Is Dynamic and Relates Closely to Respiration Rate in Stored Sugarbeet Roots

“…Sucrose content decreased by approximately 3–4% in the 60 days after harvest under the favorable storage conditions used in this study. The quantity of sucrose lost in this study was similar to that reported by Beaudry et al (2011) who observed a 3–9% decline in sucrose content for roots stored for 100 days under ideal conditions. Although a decline in sucrose of this magnitude may not be important for many crop or horticultural products, such a loss is economically important for a crop that is grown solely for the sucrose contained within.…”

“…During this time, root sucrose content declines. Under ideal storage conditions, sugarbeet roots stored for 100 days lost 3–9% of the sugar present at harvest ( Beaudry et al, 2011 ). In commercial practice, ideal storage conditions are seldom achieved, and losses of 50% or more of the sucrose present at harvest have occurred in roots stored under unfavorable environmental conditions ( Kenter and Hoffmann, 2009 ).…”

Transcriptomic and metabolomic changes in postharvest sugarbeet roots reveal widespread metabolic changes in storage and identify genes potentially responsible for respiratory sucrose loss

“…Sugarbeet root sucrose content and processing quality decline during storage, reducing the quantity of sugar that can be recovered during processing and increasing production costs. Losses of 3 to 10% of the sucrose present at harvest are reported for roots stored up to 100 d under favorable temperature conditions, but these can escalate to 50% or more if optimal pile temperatures are not obtained or maintained ( Kenter and Hoffmann, 2009 ; Beaudry et al., 2011 ; English, 2020 ). Processing quality deteriorates due to the formation and accumulation of carbohydrate impurities, such as glucose, fructose and raffinose, and cell wall modifications, that combined with root dehydration, soften roots ( Vukov and Hangyál, 1985 ; Dutton and Huijbregts, 2006 ).…”