Fermentation of cacao (Theobroma cacaoL.) seeds with a hybridKluyveromyces marxianusstrain improved product quality attributes

Abstract

Fermentation of Theobroma cacao (cacao) seeds is an absolute requirement for the full development of chocolate flavor precursors. An adequate aeration of the fermenting cacao seed mass is a fundamental prerequisite for a satisfactory fermentation. Here, we evaluated whether a controlled inoculation of cacao seed fermentation using a Kluyveromyces marxianus hybrid yeast strain, with an increased pectinolytic activity, would improve an earlier liquid drainage ('sweatings') from the fermentation mass, developing a superior final product quality. Inoculation with K. marxianus increased by one third the volume of drained liquid and affected the microorganism population structure during fermentation, which was detectable up to the end of the process. Introduction of the hybrid yeast affected the profile of total seed protein degradation evaluated by polyacrylamide gel electrophoresis, with improved seed protein degradation, and reduction of titrable acidity. Sensorial evaluation of the chocolate obtained from beans fermented with the K. marxianus inoculation was more accepted by analysts in comparison with the one from cocoa obtained through natural fermentation. The increase in mass aeration during the first 24 h seemed to be fundamental for the improvement of fermentation quality, demonstrating the potential application of this improved hybrid yeast strain with superior exogenous pectinolytic activity.

Effect of Pectin Lyase Enzyme on Fermentation and Drying of Cocoa (<i>Theobroma cacao</i> L.): An Alternative to Improve Raw Material in the Industry of Chocolate

“…reported values of acidity, obtained at the end of the fermentation by different methods (plastic containers, wooden boxes and heaps), higher than the ones found in the present study, which may lead to a better quality by the absence of concentrated acids flavors before the drying process [22]. These results agree with the researches where the use of hybrids of yeast K. marxianus increased the activity of the enzyme pectin lyase during the fermentation process [29], producing a positive effect on the sensory quality of cocoa, which is related to the decrease in the acidity.…”

“…Both aspects should allow the free water migrate more easily on the surface. Leal et al, (2008) reported an increase for exudate in the presence of pectin lyase, which impacted the decrease of the fermentation time, without affecting the quality of the grain [29].…”

Postharvest practices and farmers’ perception of cocoa bean quality in Cameroon

“…It is white, juicy and rich in fermentable sugars such as glucose, fructose and sucrose. It also contains salts (8-10 %), pentosans (2-3 % pectin), organic acids (1-2 %) and 0.6 % proteins [3][4][5]. The pulp has a high concentration of acids, especially citric acid, 2.1-2.4 % (w/w), and also has smaller amounts of other organic acids present such as lactic acid, 0.03 % (w/w) and acetic acid, 0.04 % (w/w) [6,7].…”

“…The pulp has a high concentration of acids, especially citric acid, 2.1-2.4 % (w/w), and also has smaller amounts of other organic acids present such as lactic acid, 0.03 % (w/w) and acetic acid, 0.04 % (w/w) [6,7]. During on-farm processing, this mucilaginous pulp is degraded by microbial fermentation, producing a running liquid known in the industry as 'sweating' [5]. Fermentation, was considered as simply an easy way to remove the pulp to facilitate drying, but its importance to cocoa quality has been well established [4].…”

Cocoa Fermentation from Agnéby-Tiassa: Biochemical Study of Microflora

“…Based on halo diameter, pectinolytic strains were classified i groups: the first group concerned high strains producing 2 cm of halo diameter, second group comprised strains yielding 1.5-2 cm halo diameter corresponding to a middle pectinolytic activity and the last group of strains presented low pectinoly activity with halo diameter ranging in 1-1.4 cm (Figure Activity of pectinolytic yeast strains in cocoa fermen was also reported by some authors [17]. This technological property of yeasts strains is very important for cocoa fermentation process [2,45]. Indeed, according to pectinolytic activity of yeasts contributes to change aeration at the beginning of the cocoa fermentation and seemed to be more relevant to improve bean quality.…”