Issue |
OCL
Volume 27, 2020
|
|
---|---|---|
Article Number | 52 | |
Number of page(s) | 12 | |
Section | Agronomy | |
DOI | https://doi.org/10.1051/ocl/2020046 | |
Published online | 19 October 2020 |
Research Article
Impact of post-harvest storage and freezing of palm fruits on the extraction yield and quality of African crude palm oil extracted in the laboratory
Effet du stockage post-récolte et de la congélation des fruits de palme sur le rendement d’extraction et la qualité de l’huile de palme brute
1
INRAE, UR BIA,
44316
Nantes, France
2
University of Yaoundé I, Department of Biochemistry,
Yaoundé, Cameroon
3
CIRAD, UMR INNOVATION,
F-34398
Montpellier, France
4
INNOVATION, Univ. Montpellier, CIRAD, INRAE, Institut Agro,
Montpellier, France
5
INRAE, CIRAD, Montpellier SupAgro, Univ Montpellier, UMR IATE,
34398
Montpellier, France
6
IRAD, CEREPAH,
BP 243,
Douala, Cameroon
* Correspondence: claude.genot@inrae.fr
Received:
27
January
2020
Accepted:
1
September
2020
In the frame of African artisanal small-scale extraction of palm oil, the effects of post-harvest storage time and freezing of palm fruits on the extraction yield and quality of crude palm oil (CPO) were studied at laboratory scale using a process mimicking artisanal extraction. The extraction yield and free fatty acid (FFA) content of CPO increased with the length of fruit storage time at room temperature and freezing. FFA, total fatty acid and triacylglycerol profiles indicated a lack of specificity of the lipases at work. During post-harvest storage, the carotenoid content of CPO decreased slightly, tocopherols and tocotrienols (tocols) remained steady, while lipid oxidation remained at a very low level. For frozen fruits, carotene and tocol contents decreased sharply as a function of storage time, thought remaining quite high, but decreasing amounts of secondary oxidation products were detected. The FFA content and lipid oxidation level were highly correlated, indicating a pro-oxidant effect of FFAs. To conclude, three days of storage prior to artisanal extraction seemed the best trade-off between extraction yield and CPO quality. Combined storage at room temperature and freezing of palm fruits led to a large range of FFA contents in CPO. Optimization of the FFA contents of artisanal CPOs in line with local consumer’s demand calls for an assessment of their functional properties and sensory perception of foods formulated with CPOs.
Résumé
Dans le contexte africain de l’extraction artisanale d’huile de palme brute (HPB), cette étude s’intéressait aux effets du stockage post-récolte et de la congélation des fruits du palmier sur le rendement d’extraction et la qualité des HPB. Les résultats confirment que rendement d’extraction et teneur en acides gras libres (AGL) des HPB augmentent avec la durée de stockage et la congélation. Le niveau maximal de lipolyse s’observe pour des fruits congelés 1 ou 3 jours après récolte. Les profils d’AGL, d’acides gras totaux et de triglycérides ne montrent pas de spécificité des lipases. Une diminution modérée de la teneur en caroténoïdes accompagnée de teneurs en tocophérols et tocotriénols (tocols) stables et de faibles niveaux d’oxydation sont observés lors du stockage. La congélation provoque une forte diminution des teneurs en caroténoïdes et tocols. Niveau d’oxydation et teneurs en AGL des HPB, très fortement corrélés, montrent l’effet pro-oxydant des AGL. Le stockage à température ambiante combiné à la congélation des fruits produit donc des HPB avec des teneurs en AGL très contrastées, trois jours de stockage semblant le meilleur compromis entre rendement d’extraction et qualité des HPB. L’optimisation pour des consommateurs locaux des teneurs en AGL des HPB artisanales nécessite l’évaluation de leurs propriétés fonctionnelles et de leur acceptabilité sensorielle.
Key words: crude palm oil / extraction yield / post-harvest storage / freezing / lipolysis / oxidation
Mots clés : huile de palme brute / extraction / stockage post-récolte / congélation / lipolyse / oxydation
© D. Nanda et al., Hosted by EDP Sciences, 2020
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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