No abstract

Forastero hybrid cocoa bean fermentations have been carried out in a box (B) and in a heap (H), with or without the inoculation of and as starter cultures. The bacteria, yeasts, and microbial metabolites (volatile and nonvolatile organic compounds) were monitored during fermentation to assess the connection between microbiota and the release of metabolites during this process. The presence of starter cultures was detected, by means of culture-dependent analysis, during the first 2 days of both fermentations. However, no statistical difference was observed in any of the physicochemical or microbiological analyses. Plate counts revealed the dominance of yeasts at the beginning of both fermentations, and these were followed by acetic acid bacteria (AAB) and lactic acid bacteria (LAB). ,, ,, and were the most abundant operational taxonomic units (OTUs) during both fermentation processes (B and H), although different relative abundances were observed. Only the diversity of the fungal species indicated a higher level of complexity in the B fermentations than in the H fermentations ( < 0.05), as well as a statistically significant difference between the initially inoculated starter cultures ( < 0.01). However, the microbial metabolite analysis indicated different distributions of the volatile and nonvolatile compounds between the two procedures, that is, B and H ( < 0.05), rather than between the inoculated and noninoculated fermentations. The box fermentations showed faster carbohydrate metabolism and greater production of organic acid compounds, which boosted the formation of alcohols and esters, than did the heap fermentations. Overall, the microbial dynamics and associations between the bacteria, yeasts, and metabolites were found to depend on the type of fermentation. In spite of the limited effectiveness of the considered inoculated starter strains, this study provides new information on the microbial development of box and heap cocoa fermentations, under inoculated and noninoculated conditions, as we coupled yeast/bacterial amplicon-based sequencing data with microbial metabolite detection. The information so far available suggests that microbial communities have played an important role in the evolution of aroma compounds. Understanding the pathways that microorganisms follow during the formation of aromas could be used to improve the fermentation processes and to enhance chocolate quality.

Grape skin flours obtained from grape pomace of Chardonnay, Moscato and Pinot noir varieties were used as sources of polyphenolic compounds in yogurt formulation during 3 weeks of storage. Yogurt containing grape skin flour presented significantly higher total phenolic content (+55%), antioxidant activity (+80%) and acidity (+25%) whereas lower pH, syneresis (−10%) and fat (−20%) than control. Procyanidin B1 and vanillic acids were detected only in the yogurt added of Pinot noir flour while gallic acid, catechin and quercitrin were the major phenolic compounds found in the yogurts with Moscato or Chardonnay grape skins. Significant differences were highlighted for acidity and lactose content while total phenolic content, antioxidant activity and lactic acid bacteria trend were stable after production and storage. The liking test performed with consumers showed a loss of textural quality for yogurts fortified with grape skin flours. PRACTICAL APPLICATIONSGrape skin is a nutritious, but underused, by-product of winemaking containing fiber and antioxidants. Using a suitable production design, a new fortified yogurt formulation with grape by-product could be optimized for enhance antioxidant consumers' daily intake. The use of grape skin flour in the development of valueadded food products will be a step toward making new functional foods, and partially solving waste management problem from wine production. The results of this study would provide an opportunity of dairy producer to develop a novel product in agreement with consumers' preferences. This research represents a new approach in the development of novel dairy foods with high nutritional quality and with great potential applications on food industry.

Changes in the microbial gene content and abundance can be analyzed to detect shifts in the microbiota composition due to the use of a starter culture in the food fermentation process, with the consequent shift of key metabolic pathways directly connected with product acceptance. Meat fermentation is a complex process involving microbes that metabolize the main components in meat. The breakdown of carbohydrates, proteins, and lipids can lead to the formation of volatile organic compounds (VOCs) that can drastically affect the organoleptic characteristics of the final products. The present meta-analysis, performed with the shotgun DNA metagenomic approach, focuses on studying the microbiota and its gene content in an Italian fermented sausage produced by using a commercial starter culture (a mix of and), with the aim to discover the connections between the microbiota, microbiome, and the release of volatile metabolites during ripening. The inoculated fermentation with the starter culture limited the development of and reduced the microbial diversity compared to that from spontaneous fermentation. KEGG database genes associated with the reduction of acetaldehyde to ethanol (EC 1.1.1.1), acetyl phosphate to acetate (EC 2.7.2.1), and 2,3-butanediol to acetoin (EC 1.1.1.4) were most abundant in inoculated samples (I) compared to those in spontaneous fermentation samples (S). The volatilome profiles were highly consistent with the abundance of the genes; elevated acetic acid (1,173.85 μg/kg), ethyl acetate (251.58 μg/kg), and acetoin (1,100.19 μg/kg) were observed in the presence of the starters at the end of fermentation. Significant differences were found in the liking of samples based on flavor and odor, suggesting a higher preference by consumers for the spontaneous fermentation samples. Inoculated samples exhibited the lowest scores for the liking data, which were clearly associated with the highest concentration of acetic acid. We present an advance in the understanding of meat fermentation by coupling DNA sequencing metagenomics and metabolomics approaches to describe the microbial function during this process. Very few studies using this global approach have been dedicated to food, and none have examined sausage fermentation, underlying the originality of the study. The starter culture drastically affected the organoleptic properties of the products. This finding underlines the importance of starter culture selection that takes into consideration the functional characteristics of the microorganism to optimize production efficiency and product quality.

<p style="text-align: justify;"><strong>Aims</strong>: This study was designed to gain knowledge of three Controlled Denomination of Origin (DOC) Italian sweet white Passito wines (Caluso Passito DOC, Cinque Terre Sciacchetrà DOC and Passito di Pantelleria DOC) produced in several areas of Italy from grapes dried with different systems and vinification techniques.</p><p style="text-align: justify;"><strong>Methods and results</strong>: Physico-chemical and chromatic characteristics, sodium, potassium, gluconic acid, glucono-γ-lactone, acetaldehyde, sorbitol, laccase, organic acids and semi-quantitative free volatile profile were determined on these wines. Caluso Passito DOC wines presented higher contents of organic acids (above all, malic acid), main metabolites from noble Botrytis cinerea (laccase, glycerol, gluconic acid and benzaldehyde) and low contents of total polyphenols. Among the volatile components, normal fatty acid ethyl esters (ethyl hexanoate and ethyl octanoate), branched-chain esters (ethyl 2-methylpropanoate, ethyl 2-methylbutyrate, ethyl 3-methylbutyrate) and benzaldeyde characterized this Passito wine. Cinque Terre Sciacchetrà DOC wines showed the lowest total acidity with a lower amount of malic acid and a higher content of polyphenols. This wine was characterized by some predominant acetates (isoamyl acetate), alcohols, benzaldehyde and an isoprenoid, ß-damascenone. Passito di Pantelleria DOC wines presented higher amounts of ashes resulting in higher pH values compared to the other two Passito typologies. Due to its production from aromatic grapes, it showed several varietal components such as terpenes, while ethyl esters/acetates and alcohols were less represented.</p><p style="text-align: justify;"><strong>Conclusion</strong>: This survey provides information allowing the characterisation of three Passito dessert wines at high commercial value.</p><p style="text-align: justify;"><strong>Significance and impact of the study</strong>: This study provides oenological information to be utilised to protect and valorise the Controlled Denomination of Origin sweet wine production and contributes to the preservation of traditional and terroir productions and their commercialization.</p>