Clément Burgeon

This study investigated the influence of various fermentation supports on cocoa bean quality, aiming to identify alternatives to banana leaves, which are facing scarcity issues. Supports tested included banana leaves (support used as a reference), palm leaves, cocoa pods, jute bags, polypropylene tarpaulins and polypropylene bags. Key parameters monitored during fermentation included temperature, pH, microbial dynamics and concentrations of reducing sugars and organic acids. The beans underwent physicochemical characterisation and market value evaluation after fermentation and drying. The results revealed that fermentation in cocoa pods and polypropylene bags was suboptimal. Cocoa pods exhibited low fermentation temperatures, delayed microbial activity, high pH and increased mould proliferation, leading to poor marketability with low cut‐test scores. Polypropylene bags retained higher humidity levels, posing a risk for mould contamination, although they showed higher phenolic compound content. By contrast, beans fermented on jute bags, palm leaves and reusable polypropylene tarpaulins displayed fermentation profiles and final product characteristics similar to banana leaves, making them viable alternatives for local producers. Further analysis of the aromatic characteristics of beans fermented on these supports is needed to provide a holistic evaluation. This study offers valuable insights into identifying sustainable alternatives for cocoa fermentation and serves as a reference for resource optimisation in other food production systems.

Anthropogenic activities have denatured aquatic, terrestrial, and aerial environments throughout the world in general, and in Lubumbashi in particular, where market garden soils have become uncultivable for many plants. Thus, bioponics could be an effective means of producing uncontaminated vegetables in soilless cultivation, not only reducing the amount of fertilizer used and limiting contamination of agricultural produce but also achieving higher yields than in open-ground cultivation. The overall objective of this study was to implement a new bioponic technique for producing liquid fertilizer from chicken manure and utilize it in the organic hydroponic cultivation of lettuce (Lactuca sativa var. Lucrecia) installed on floating raft systems. To achieve this, two types of trials were conducted. The first was aimed at determining the quantities of organic matter to be used in the formulation of nutrient solutions. The second trial aimed to determine the optimal nitrogen concentration to be provided for hydroponic plant growth. Mineralization and/or anaerobic digestion of chicken manure were conducted for 7 days in 200 L barrels. For the first trial, nutrient solutions were created from three different concentrations of chicken manure (0.35%, 3.5%, and 7% dry matter—D.M.). These solutions were then used in bioponic rafts where total ammonia nitrogen (TAN) concentrations were fixed at 150 mg/L. For the second trial, D.M. was fixed at 2.5% for each tested modality, but TAN concentrations varied among them (i.e., 60, 90, and 120 mg/L TAN concentration). Modalities with low D.M. concentration (0.35%) and those with low TAN concentration (60 mg/L) resulted in higher yields than bioponic modalities receiving high concentrations of dry matter or TAN, respectively, for trials 1 and 2. Although the reference chemical solutions generate the greatest yields, bioponic systems operating with chicken manure present a good alternative for the cultivation of vegetables in developing countries with heavily contaminated soils. Indeed, bioponics allows for the production of vegetables in large quantities from animal waste, which does not pose health risks for human consumption. Local vegetable species commonly grown in Lubumbashi should be tested under hydroponic conditions.

The extraction of boar taint compounds from pork fat samples was performed under various temperature (150, 300 and 450 °C) and atmosphere (air, nitrogen and reduced pressure) conditions. This aimed at understanding which conditions allow the greatest extractions of indole, skatole and androstenone (present in backfat in low concentrations) while limiting the presence of other VOCs in the headspace of heated fat (interfering with correct VOC-based detection of boar taint compounds). Indole and skatole were extracted in the greatest concentrations when heating backfat at 450 °C under reduced pressure, while androstenone was highest when heating at 300 °C under reduced pressure. Oxidation products were most abundant under air conditions, nitrogenated products appeared in the presence of a nitrogen-enriched atmosphere, and lastly, molecules intrinsic to boar fat saw their headspace concentration increase with reduced pressure. The combination of 450 °C and reduced pressure atmosphere was suggested for the heating of backfat prior to detection with analytical methods and to complement the current sensory analysis.

Boar taint detection is a major concern for the pork industry. Currently, this taint is mainly detected through a sensory evaluation. However, little is known about the entire volatile organic compounds (VOCs) profile perceived by the assessor. Additionally, many research groups are working on the development of new rapid and reliable detection methods, which include the VOCs sensor-based methods. The latter are susceptible to sensor poisoning by interfering molecules produced during high-temperature heating of fat. Analyzing the VOC profiles obtained by solid phase microextraction gas chromatography–mass spectrometry (SPME-GC-MS) after incubation at 150 and 180 °C helps in the comprehension of the environment in which boar taint is perceived. Many similarities were observed between these temperatures; both profiles were rich in carboxylic acids and aldehydes. Through a principal component analysis (PCA) and analyses of variance (ANOVAs), differences were highlighted. Aldehydes such as (E,E)-nona-2,4-dienal exhibited higher concentrations at 150 °C, while heating at 180 °C resulted in significantly higher concentrations in fatty acids, several amide derivatives, and squalene. These differences stress the need for standardized parameters for sensory evaluation. Lastly, skatole and androstenone, the main compounds involved in boar taint, were perceived in the headspace at these temperatures but remained low (below 1 ppm). Higher temperature should be investigated to increase headspace concentrations provided that rigorous analyses of total VOC profiles are performed.