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Cocoa quality depends on several parameters, such as cocoa variety, environmental growth conditions, cultivation technique, and post-harvest treatments applied to coca beans. In this work, we studied the impact of cocoa post-harvest processing on both microbial communities structure and volatile composition. Cocoa beans samples were fermented in wooden boxes in Ivory Coast at different time intervals with turning and without turning, and derived from pods stored for two different duration times. Cocoa beans were analyzed using a molecular fingerprinting method (PCR-DGGE) in order to detect variations in microbial communities' structure; this global analysis was coupled to SPME-GC-MS for assessing cocoa volatile profiles. The results showed that the main parameter that influenced microbial communities structure was fermentation time, followed by turning, whereas, pods storage duration had a minor impact. Similar results were obtained for aromatic profile, except for pods storage duration that significantly affected volatile compound production. Global statistical analysis using Canonical Correspondence Analysis (CCA), showed the relationship between microbial communities and volatile composition. Furthermore, this study allowed the identification of discriminating microbial and chemical markers of cocoa post-harvest processing.

This research describes on-farm-inoculated cocoa bean fermentation with two selected strains of high aroma-producing Saccharomyces cerevisiae isolated from wine fermentation and their effects on volatile profile of resulted raw cocoa material and sensory characteristics of chocolates produced. Both strains produced suitably flavour-active esters, aldehydes, ketones and pyrazines in raw cocoa. Inoculation of S. cerevisiae at 0.5 g kg−1 significantly improved the volatile profile of raw cocoa beans and enabled production of chocolate with enhanced intense fresh fruits and floral notes. Chocolate produced thereof presented better overall quality attributed whatever the fermentation time in comparison to the chocolate issued from spontaneous fermentation. Our results suggested the ways of using selected enhanced yeasts as S. cerevisiae for on-farm implementation of bean fermentation as promising alternative possibilities to improve the cocoa fermentation process, desirable flavourful raw cocoa material and high-aroma-quality chocolates produced.

International audience; Soumbala is made from African locust bean seeds (Parkia biglobosa), a legume widely spread in west Africa. It is a lipid and protein-rich condiment obtained by three main steps: cooking, fermentation and drying. Ten different analysis were made on AFLBS samples at each step with a particular focus on protein and lipid fates. Results showed that cooking decreased markedly the carbohydrate content leaving mainly proteins and lipids as substrates for fermentation. During this step, 20% of the proteins were converted into free amino acids, mainly glutamic acid and tyrosine. Significant biogenic amines release occurred and reached 50 mg per 100 g of dried ALBS. Di-glycerides and fatty acids increased markedly and represented 11% and 7% of the total lipids of dried ALBS. These results give a complete view of the nutritional characteristics of dried ALBS, its benefit but also its defects that arise during fermentation and not suppressed by the subsequent processing steps.

A simple, fast and ecological analytical method using a semi-automatic fat extractor and HPLC-FLD (fluorescence detection) for determination of polycyclic aromatic hydrocarbon markers i.e. benzo(a)anthracene (BaA), chrysene (Chr), benzo(a)pyrene (BaP) and benzo(b)fluoranthene (BbF) in cocoa butter has been validated. Validation's procedure performed out in concordance with French standard NF V03-110 (2010) was based on existing polycyclic aromatic hydrocarbon (PAH) determination methods in various smoked foodstuffs and edible vegetable oils. Determination of correlation coefficients for specific PAHs ranged from 0.9992 to 0.9998. Respective values of limits of detection were 0.010, 0.011, 0.033 and 0.029 μg kg−1 and those of quantification were 0.035, 0.038, 0.111 and 0.098 μg kg−1 for BaA, Chr, BbF and BaP. Both values of repeatability and intermediary precision tests coefficients of variation were less than 5%. Recovery scores of four PAH markers matched EU standard 836/2011 recommendations. Sum of four PAH markers (BaA, Chr, BbF, BaP) contents varied from 5.42 ± 0.58 to 11.37 ± 0.01 μg kg−1 whereas those of BaP was comprised between 0.26 ± 0.00 and 1.75 ± 0.13 μg kg−1 in 20 cocoa butter samples extracted from raw cocoa bean stored at Ivorian cocoa farmer levels.