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Respiratory parameters of onion bulbs ( Allium cepa ) during storage. Effects of ionising radiation and temperature
Author(s) -
Benkeblia Noureddine,
Varoquaux Patrick,
Gouble Barbara,
SelseletAttou Ghalem
Publication year - 2000
Publication title -
journal of the science of food and agriculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 142
eISSN - 1097-0010
pISSN - 0022-5142
DOI - 10.1002/1097-0010(20000915)80:12<1772::aid-jsfa700>3.0.co;2-5
Subject(s) - allium , respiration , respirometer , chemistry , respiration rate , q10 , respiratory quotient , irradiation , horticulture , zoology , botany , biochemistry , biology , physics , nuclear physics
The O 2 and CO 2 respiration rates of untreated and irradiated onion bulbs ( Allium cepa ) at 0.15 and 0.30 kGy were measured at 4, 10 and 20 °C. The O 2 respiration rate increased for 24 h after treatment from 0.19 mmole kg −1 h −1 at 20 °C for control samples up to 0.26 and 0.39 mmole kg −1 h −1 for 0.15 and 0.3 kGy irradiated onions respectively. Respiratory quotient (RQ) increased with temperature. The Q 10 of the respiration of the control samples (1.61) was lower than that of any other plant tissue, but it increased with storage duration and irradiation dose. The respiration rate of control onions increased steadily over 25 weeks of storage at 4 °C, while that of the irradiated samples decreased during the same period after a peak observed after irradiation treatment. The apparent K m for the Menten–Michaelis equation was determined on a new respirometer and averaged 1.6 kPa at 10 °C and 6.3 kPa at 20 °C. However, at this higher temperature (20 °C) apparent K m varied with O 2 partial pressure, proving that the respiration of onion bulbs does not follow a Menten–Michaelis‐like process. The Fermentative Index (FI) of onions was measured under anoxic conditions as CO 2 production rates in mmole kg −1 h −1 at 4, 10 and 20 °C. © 2000 Society of Chemical Industry