Ethanolic fermentation of Bartlett pears as influenced by ripening stage and atmospheric composition

Journal Article · Thu Sep 01 00:00:00 EDT 1994 · Journal of the American Society for Horticultural Science; (United States)

OSTI ID:6808879

Ke, D; Yahia, E; Mateos, M; Kader, A A ^[1]

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1. Univ. of California, Davis, CA (United States). Dept. of Pomology

Changes in fermentation volatiles and enzymes were studied in preclimacteric and postclimacteric Bartlett pears (Pyrus communis L.) kept in air, 0.25% O[sub 2], 20% O[sub 2] + 80% CO[sub 2], or 0.25% O[sub 2] + 80% CO[sub 2] at 20 C for 1, 2, or 3 days. All three atmospheres resulted in accumulation of acetaldehyde, ethanol, and ethyl acetate. The postclimacteric pears had higher activity of pyruvate decarboxylase (PDC) and higher concentrations of fermentation volatiles than those of the preclimacteric fruit. For the preclimacteric pears, the 0.25% O[sub 2] treatment dramatically increased alcohol dehydrogenase (ADH) activity, which was largely due to the enhancement of one ADH isozyme. Exposure to 20% O[sub 2] + 80% CO[sub 2] slightly increased ADH activity, but the combination of 0.25% O[sub 2] + 80% CO[sub 2] resulted in lower ADH activity than 0.25% O[sub 2] alone. Ethanolic fermentation in Bartlett pears could be induced by low O[sub 2] and/or high CO[sub 2] via (1) increased amounts of PDC and ADH; (2) PDC and ADH activation caused by decreased cytoplasmic pH; or (3) PDC and ADH activation or more rapid fermentation due to increased concentrations of their substrates (pyruvate, acetaldehyde, or NADH).

• OSTI ID: 6808879
• Journal Information: Journal of the American Society for Horticultural Science; (United States), Vol. 119:5; ISSN 0003-1062
• Country of Publication: United States
• Language: English

Related Subjects

63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
CARBON DIOXIDE
BIOLOGICAL EFFECTS
ETHANOL
FERMENTATION
OXYGEN
PEARS
CELL DIFFERENTIATION
CONTROLLED ATMOSPHERES
ALCOHOLS
ATMOSPHERES
BIOCONVERSION
CARBON COMPOUNDS
CARBON OXIDES
CHALCOGENIDES
ELEMENTS
FOOD
FRUITS
HYDROXY COMPOUNDS
NONMETALS
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
560300* - Chemicals Metabolism & Toxicology