During bread making, the sugar content in dough changes continuously due to enzymatic starch degr... more During bread making, the sugar content in dough changes continuously due to enzymatic starch degradation. Despite its importance, the relation between amylase activity and sugar release in dough is ill documented. In this work, the relative importance of a-and b-amylase activity and substrate availability on the dynamics of sugar release in dough was studied. Analysis of non-yeasted dough samples from Bilux flour (Falling number [FN] 477 s) and Bison flour (332 s) revealed that maltose was released quickly during mixing (z1.0% dm) and reached z2.0% dm after resting (180 min). Inhibition of a-amylase in Bilux flour indicated that >85% of the maltose release during resting could be attributed to endogenous b-amylase activity. a-Amylase supplementation markedly increased maltose release from 2.0 to 4.7% dm after resting. Barley b-amylase addition, on the contrary, left maltose levels virtually unchanged. Maltose concentrations were also increased, up to 3.6% dm, by increasing the damaged starch content from 6.4 to 10.6% dm. In conclusion, this work shows that b-amylase can provide a relatively high amount of maltose in the absence of a-amylase. Higher maltose levels require either higher levels of endogenous or added a-amylases or increased damaged starch levels.
The fermentation of cocoa pulp is one of the few remaining large-scale spontaneous microbial proc... more The fermentation of cocoa pulp is one of the few remaining large-scale spontaneous microbial processes in today's food industry. The microbiota involved in cocoa pulp fermentations is complex and variable, which leads to inconsistent production efficiency and cocoa quality. Despite intensive research in the field, a detailed and comprehensive analysis of the microbiota is still lacking, especially for the expanding Asian production region. Here, we report a large-scale, comprehensive analysis of four spontaneous Malaysian cocoa pulp fermentations across two time points in the harvest season and two fermentation methods. Our results show that the cocoa microbiota consists of a ''core'' and a ''variable'' part. The bacterial populations show a remarkable consistency, with only two dominant species, Lactobacillus fermentum and Acetobacter pasteurianus. The fungal diversity is much larger, with four dominant species occurring in all fermentations (''core'' yeasts), and a large number of yeasts that only occur in lower numbers and specific fermentations (''variable'' yeasts). Despite this diversity, a clear pattern emerges, with early dominance of apiculate yeasts and late dominance of Saccharomyces cerevisiae. Our results provide new insights into the microbial diversity in Malaysian cocoa pulp fermentations and pave the way for the selection of starter cultures to increase efficiency and consistency.
During bread making, the sugar content in dough changes continuously due to enzymatic starch degr... more During bread making, the sugar content in dough changes continuously due to enzymatic starch degradation. Despite its importance, the relation between amylase activity and sugar release in dough is ill documented. In this work, the relative importance of a-and b-amylase activity and substrate availability on the dynamics of sugar release in dough was studied. Analysis of non-yeasted dough samples from Bilux flour (Falling number [FN] 477 s) and Bison flour (332 s) revealed that maltose was released quickly during mixing (z1.0% dm) and reached z2.0% dm after resting (180 min). Inhibition of a-amylase in Bilux flour indicated that >85% of the maltose release during resting could be attributed to endogenous b-amylase activity. a-Amylase supplementation markedly increased maltose release from 2.0 to 4.7% dm after resting. Barley b-amylase addition, on the contrary, left maltose levels virtually unchanged. Maltose concentrations were also increased, up to 3.6% dm, by increasing the damaged starch content from 6.4 to 10.6% dm. In conclusion, this work shows that b-amylase can provide a relatively high amount of maltose in the absence of a-amylase. Higher maltose levels require either higher levels of endogenous or added a-amylases or increased damaged starch levels.
The fermentation of cocoa pulp is one of the few remaining large-scale spontaneous microbial proc... more The fermentation of cocoa pulp is one of the few remaining large-scale spontaneous microbial processes in today's food industry. The microbiota involved in cocoa pulp fermentations is complex and variable, which leads to inconsistent production efficiency and cocoa quality. Despite intensive research in the field, a detailed and comprehensive analysis of the microbiota is still lacking, especially for the expanding Asian production region. Here, we report a large-scale, comprehensive analysis of four spontaneous Malaysian cocoa pulp fermentations across two time points in the harvest season and two fermentation methods. Our results show that the cocoa microbiota consists of a ''core'' and a ''variable'' part. The bacterial populations show a remarkable consistency, with only two dominant species, Lactobacillus fermentum and Acetobacter pasteurianus. The fungal diversity is much larger, with four dominant species occurring in all fermentations (''core'' yeasts), and a large number of yeasts that only occur in lower numbers and specific fermentations (''variable'' yeasts). Despite this diversity, a clear pattern emerges, with early dominance of apiculate yeasts and late dominance of Saccharomyces cerevisiae. Our results provide new insights into the microbial diversity in Malaysian cocoa pulp fermentations and pave the way for the selection of starter cultures to increase efficiency and consistency.
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