Rencontres Caraibes en lutte biologique

National audienc

Les nematodes de la canne a sucre dans les Antilles francaises. I : donnees sur les peuplements. II : premiers essais nematicides

National audienc

Mise en evidence et etude des bacteries symbiotiques chez deux charancons parasites du bananier : Cosmopolites sordidus (Germar) et Metamasius hemipterus (L.) (Col.Curculionidae)

National audienc

Ectoparasitic nematodes (Aphelenchoidoidea: Acugutturidae) of Lepidoptera and Blattodea in Guadeloupe

International audienc

Effect of some local plant extracts on fatty acid composition of fish (Alestes baremoze) during smoking and sun drying in the Far‐North region of Cameroon

Abstract The objective of this study was to assess the antioxidant activities of three plant extracts (Moringa oleifera leaves, Xylopia aethiopica fruits, and Allium cepa leaves) and to evaluate their effects on the preservation of fish polyunsaturated fatty acids (PUFAs) during smoking and sun‐drying processes. PUFAs are highly prone to oxidation during fish processing. The plant extracts were analyzed for their polyphenol contents and were evaluated for their total antiradical capacity. The polyphenol components of each plant were characterized. The hydroethanolic and aqueous extracts were added to the fish at concentrations of 3, 6, 9, and 12 g/L and 10, 20, 30, and 40 g/L, respectively. Butylated hydroxytoluene (BHT) was used as a positive control at a concentration of 2 g/L to compare the antioxidant effects of the plant extracts. The treated fish was subjected to smoking or sun drying and the fatty acid composition of the fish lipid extract was assessed. The results showed that the total polyphenolic, flavonoid, and tannin contents varied significantly from one plant extract to the other (p < .05). The radical scavenging and FRAP increased significantly with the concentration of the plant extracts (p < .05). An HPLC analysis of the extracts led to the preliminary identification of four hydroxycinnamic acids in M. oleifera and X. aethiopica, one anthocyanin and one flavone glycoside in M. oleifera, and four flavan‐3‐ols in X. aethiopica. Moreover, eight flavonols were preliminarily identified in the three plants. Compared to the control product, these plant extracts significantly protected fish PUFAs from oxidation (p < .05). The aqueous extract of A. cepa at 40 g/L better preserved omega‐3 in fish during smoking and sun drying than the control product. Incorporating the three plant extracts during smoking and sun‐drying processes can effectively preserve the PUFAs in fish. Therefore, these plants are viable sources of natural antioxidants in the preservation of fish products

Pea and lupin protein ingredients : New insights into endogenous lipids and the key effect of high-pressure homogenization on their aqueous suspensions

The incorporation of plant protein ingredients in foods is a means to promote the transition to vegetable proteins. Pea and lupin meet sustainability demands and their protein ingredients display promising technological properties, yet sometimes poor functionalities. However, the involved mechanisms are still unclear, partly because comprehensive and systematic characterization of those ingredients in terms of composition and physicochemical properties is still lacking. In this work, commercial protein fractions of pea and lupin (one isolate and one concentrate for each) were thoroughly characterized. A high-pressure homogenization (HPH) treatment was applied to their aqueous suspensions (pH 7.0) to improve their dispersibility. Although isolates displayed a higher protein content (up to 72 g/100 g (d.m.) against 39 g/100 g (d.m.) for the concentrates, with respective specific N factors), their solubility (i.e., the proteins remaining in the supernatant after centrifugation) was lower than for the concentrates (15–49 wt% of the total proteins, against 65 wt%). Substantial amounts of endogenous lipids in the powders were measured after chloroform/methanol extraction (3.4–10.3 g/100 g (d.m.)), of which about half were phospholipids. For all ingredients, detailed microscopic investigations (including confocal fluorescence microscopy), and light scattering measurements showed that HPH was useful to break down large powder grains. Thus, it altered the colloidal structures present, released endogenous lipid assemblies and enhanced protein solubility. Those new insights into the non-protein composition of plant protein fractions and their behaviour in aqueous media are key for improving their functionalities and facilitating food products’ rational formulation

Rapid assessment of fatty acyls chains of phospholipids and plasmalogens by atmospheric pressure chemical ionization in positive mode and high-resolution mass spectrometry using in-source generated monoacylglycerol like fragments intensities

International audienceWe recently published a new concept using monoacylglycerol-like fragments [MG+H-H2O]+ (ions B) pro-duced in-source by atmospheric pressure photoionization in positive mode and high-resolution massspectrometry for the determination of the fatty acyl (FA) composition of triacylglycerols (TGs) from plantoils. This study extends the concept to the phospholipids (PLs) category and shows that the APCI+ sourcecan also be used. Moreover, the coupling with NP-LC allows to simultaneously analyze different PLsclasses in the same sample. We compared the relative intensities of the ions B produced in-source tothe % composition of FAs determined by GC-FID. In the case of PLs from natural extracts composed ex-clusively of diacyl-PLs, the relative intensities of ions B are close to the % of the FAs obtained by GC-FID.This approach is not directly useable for extracts containing plasmalogens (P-PLs). For these PLs, acidichydrolysis by HCl fumes allows hydrolyzing selectively vinyl ether functions to form lyso-PLs. The analy-sis of hydrolyzed extracts makes it possible to obtain the composition of P-PLs FAs thanks to the lyso-PLsthus formed, while the diacyl-PLs composition remains unchanged. Unlike GC-FID FAs determination, thisapproach allows a distinction between the diacyl-PLs and P-PLs FAs composition. We also found that theion B intensities were consistent among the PL classes (PG, PE, PA, PI, CL, PS and PC) and lyso- forms(LPE and LPC). In the case of the diacyl-PLs extracts analyzed, no statistically significant differences werefound between the PLs FAs compositions calculated from ion B intensities and the corresponding GC-FIDdata. A weighting coefficient was applied to correct ion B intensities issued from polyunsaturated FAswith three or more double bonds. The fatty alkenyls composition of P-PLs could also be calculated fromthe % intensities of specific ions

Membrane lipid composition of Carnobacterium maltaromaticum CNCM I-3298, a highly cryoresistant lactic acid bacterium

The growing consumption of fermented products has led to an increasing demand for lactic acid bacteria (LAB), especially for LAB tolerant to freezing/thawing conditions. Carnobacterium maltaromaticum is a psychrotrophic and freeze-thawing resistant lactic acid bacterium. The membrane is the primary site of damage during the cryo-preservation process and requires modulation to improve cryoresistance. However, knowledge about the membrane structure of this LAB genus is limited. We presented here the first study of the membrane lipid composition of C. maltaromaticum CNCM I-3298 including the polar heads and the fatty acid compositions of each lipid family (neutral lipids, glycolipids, phospholipids). The strain CNCM I-3298 is principally composed of glycolipids (32%) and phospholipids (55%). About 95% of glycolipids are dihexaosyldiglyceride while less than 5% are monohexaosyldiglyceride. The disaccharide chain of dihexaosyldiglyceride is composed of α-Gal(1-2)-α-Glc chain, evidenced for the first time in a LAB strain other than lactobacillus strains. Phosphatidylglycerol is the main phospholipid (94%). All polar lipids are exceptionally rich in C18:1 (from 70 to 80%). Regarding the fatty acid composition, C. maltaromaticum CNCM I-3298 is an atypical bacterium within the genus Carnobacterium due to its high C18:1 proportion but resemble the other Carnobacterium strains as they mostly do not contain cyclic fatty acids