Mass Transfer Kinetics of Nonvolatile Compounds into Coffee Beans during Wet Processing: Study at the Laboratory Scale and in Real Conditions Using Two Yeast Strains

International audienceThe transfer kinetics of four labeled aroma precursors were studied from a liquid medium into the coffee beans during a simulated wet treatment using four media (compositions of M1: dehulled beans, M2: demucilaged beans, M3: depulped beans, and M4: depulped beans with yeast) and then verified via fermentations in real conditions using two strains of Saccharomyces cerevisiae yeast (LSCC2 and LSCC3). Lactic acid, alanine, and glutamic acid were transferred continuously in M1 media, reaching, respectively, 4.8 ± 0.43, 6.4 ± 0.63, and 4.1 ± 0.34 mg/g of coffee in 48 h. Parchment resistance reduced the transfer of these precursors by up to 60%. Fructose underwent germination-related metabolic reactions, reducing its amount in the beans and reaching 1.9 ± 0.62 mg/g in 48 h. During fermentation in real conditions, lactic acid and alanine were produced and transferred into the coffee beans after a 12 h latency phase. The LSCC2 strain produced significantly more lactic acid and alanine and consumed fructose more slowly than LSCC3

Cassava foliage affects the microbial diversity of Chinese indigenous geese caecum using 16S rRNA sequencing

Geese are extremely adept in utilizing plant-derived roughage within their diet. However, the intestinal microbiome of geese remains limited, especially the dietary effect on microbial diversity. Cassava foliage was widely used in animal feed, but little information is available for geese. In this study, the geese were fed with control diet (CK), experimental diet supplemented with 5% cassava foliage (CF5) or 10% (CF10) for 42 days, respectively. The cecal samples were collected after animals were killed. High-throughput sequencing technology was used to investigate the microbial diversity in the caecum of geese with different dietary supplements. Taxonomic analysis indicated that the predominant phyla were distinct with different dietary treatments. The phyla Firmicutes (51.4%), Bacteroidetes (29.55%) and Proteobacteria (7.90%) were dominant in the CK group, but Bacteroidetes (65.19% and 67.29%,) Firmicutes (18.01% and 17.39%), Proteobacteria (8.72% and 10.18%), Synergistete (2.51% and 1.76%) and Spirochaetes (2.60% and 1.46%) were dominant in CF5 and CF10 groups. The abundance of Firmicutes was negatively correlated with the supplementation of cassava foliage. However, the abundance of Bacteroidetes and Proteobacteria were positively correlated with the supplementation of cassava foliage. Our study also revealed that the microbial communities were significantly different at genus levels. Genes related to nutrient and energy metabolism, immunity and signal transduction pathways were primarily enriched by the microbiome