Effect of storage time on the quality of olive oil mill wastewaters obtained from the cold extraction of olive oil in the region of Khenchela and their biological properties
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Date
2022
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Abbes Laghrour University- Khenchela
Abstract
The objective of this work is to evaluate the effect of storage time on the quality of olive oil mill
wastewater (OMW) obtained from the cold extraction of olive oil in the region of Khenchela, Eastern Algeria, and
their biological properties. The physicochemical quality of OMW from two types of separated and mixed showed
that the OMW storing could help decrease the pollution produced by this waste over time. During one year of
storage, the reduction rate of chemical oxygen demand, biological oxygen demand, total oxidizable matter, and
biodegradability index is correspondingly (29.4%), (54.8%), (39.16%), and (54.2%); however, C/N, BOD
5
/COD,
and pH continue to decrease. The highest phenolic concentration (961.11 ± 65.95 µg GAE/mL) was recorded in
OMW of Abani variety after 12 months of storage. The highest concentration of flavonoids (27.96 ± 3.71 µg
QE/mL) was recorded in OMW of Zlitni, just after olive oil extraction. The highest concentration of total tannin
(90.47 ± 21.24 µg CAE/mL) was recorded in Zlitni after 1 month of storage. For condensed tannin, the highest
concentration (8.66 ± 3.22 µg TAE/mL) was recorded in Abani after 6 months of storage. Qualitative analysis by
LC-MS revealed the presence of 28 constituents, of which kampherol was the major constituent and rosmarinic
acid was detected for the first time in OMW. The analysis of the antioxidant activity showed a very highly
significant difference for DPPH, ABTS, FRAP, and H
2
O
2
. The best results were obtained in OMW of Abani after
12 months of storage for the four tests; DPPH (IC
50
= 151.12 ± 0.22 µg/mL), ABTS (IC
50
= 129.32 ± 26.09 µg/mL),
FRAP (IC
50
= 72.42 ± 8.59 µg/mL) and H
2
O
2
(IC
50
= 75.52 ± 0.85 µg/mL). The anti-inflammatory activity of the
phenolic compounds showed a very highly significant difference between the two tests, IPD and MSP. The best
value obtained for the IPD test (IC
50
= 25.47 ± 1.50 µg/mL) was recorded after 1 month of storage of OMW from
the Abani variety. The best value obtained for the MSP test (IC
50
= 16.11 ± 0.10 µg/mL) was recorded in OMW
from Abani after 12 months of storage. For the anticoagulant activity, the finding showed, for the time effect, a
very highly significant difference, as regards APTT and PT. The best values obtained for APTT (80.07 ± 0.15 s)
and PT (37.13 ± 0.31 s) were recorded in Zlitni OMW just after olive oil extraction. It concluded that the storage
time affects the physicochemical and biological properties of OMW. In addition, OMWs are a source of molecules
with biological activity, and their extraction can constitute one of the strategies for recovering this waste.