Influence of the starter culture on the volatile profile of processed cocoa beans by gas chromatography–mass spectrometry in high resolution mode

Cocoa is the main component of chocolate.It is widely accepted that cocoa quality largely depends on the processing,especially the fermentation step.Traditionally,fermentation takes place spontaneously by the endogenous microbiota;however,the process can lead to poor quality and heterogeneity of the final product.In this study,we evaluated the influence of the starter culture on the profile of volatiles during fermentation of commercial volumes of Mexican cocoa.Volatiles were also analyzed in post-fermented cocoa samples obtained after drying,roasting,and conching.Our results revealed a most desirable volatile profile in cocoa fermented with starter culture,mainly due to the higher relative content of alcohols(40%)and aldehydes(3.5%),but also due to a lower acidity(<1%)as compared to endogenous fermentation(acids,65%;alcohols,2%;and aldehydes<0.5%).Additionally,it is remarkable,the higher content of pyrazines in the inoculated samples after processing.

Comparison of the Performance of Three Cocoa Bean Drying Techniques in Bafia, Southwest Region, Cameroon

This research compares the performance of a wood-fuelled oven,a greenhouse solar dryer and open sun drying techniques for drying of fermented cocoa beans,under the same weather conditions.The tests were implemented in Bafia,in the Southwest Region of Cameroon,during the month of November 2017.Performance in drying time(number of days)and quality of the resulting beans were measured(determined using sensory measurements,sight,smell and taste).Data were also collected on the progression of weight and moisture loss in the beans during the drying process,and the ambient temperatures and relative humidity levels of the environment.Also,solar radiation levels were measured for the greenhouse solar dryer and open sun drying techniques.Results showed that during dry weather conditions the wood-fuelled oven was the fastest drying method(1 day),followed by open sun drying(4 days)and the greenhouse solar dryer(5 days).The quality of beans produced through open sun drying and in the greenhouse solar dryer had a good colour,and a pleasant chocolate smell and taste.However,the beans from the wood-fuelled oven had an overly dark colour and their smell and taste were smoky due to contamination by smoke from the oven.

Use of the ¹³C/¹²C, ¹⁵N/¹⁴N and ¹⁸O/¹⁶O Isotopic Ratios of Theobromine and Caffeine in the Characterization of Geographic Origin

The aim of this work is to characterize the geographical origin of cocoa beans and coffee beans. This study aims to contribute to the traceability of raw materials in order to fight against falsification. For this purpose, we based our work on the measurement of isotope ratios in 13C, 15N and 18O. The multi-element isotope ratios have been evaluated as a means to distinguish fermented cocoa beans of different geographic and varietal origins. The isotopic ratios of 13C, 15N and 18O were measured in theobromine obtained from samples of fermented cocoa beans. Twenty-two (22) samples of different geographical origins covering the four mainland cocoa producing areas were analyzed on the one hand and on the other hand, 16 caffeine samples from various origins were also analyzed. The treatment of the values resulting from these isotopic analyzes by statistical methods, namely the principal component analysis (PCA) makes it possible to visualize the discriminations between the different origins. The most discriminating variables identified as responsible for the geographic and varietal differences were the δ15N, δ13C and δ18O values of cocoa beans and certain extracts and tissues. We have shown that the isotope ratios are correlated with the altitude and precipitation conditions encountered in the different cocoa growing regions.

Investigation of the structural changes of cocoa bean (with and without seed coat) during convective drying

The influence of seed coat on the behaviour of heterogeneous structure of cocoa bean(frosteros sp.)during convective drying with tempering period was investigated in an isothermal condition.It was found that the removal rate of moisture and air diffusion between the cocoa kernel and seed coat is not the same especially at the temperature of 55℃and initial drying time for all temperatures used.When the drying temperature increased to 70℃and 81℃,the cocoa kernel and the seed coat shrinks simultaneously,indicating that the rate of moisture and air removal from the kernel through the seed coat are the same.Change in sphericity of the bean was more pronounced at the temperature of 55℃for the seeds with seed coat while for all other drying conditions it remains fairly constant after one-hour drying.