Freeze–thaw cycles characterize varietal aroma of Vidal blanc grape during late harvest by shaping self-assembled microeukaryotic communities

Fungal Community Composition and Its Relationship with Volatile Compounds during Spontaneous Fermentation of Cabernet Sauvignon from Two Chinese Wine-Growing Regions

“…After cold soaking at 4 °C, dimethyl ecarbonate (DMDC) (Aladdin Chemistry Co., Ltd., Shanghai, China) was added to the grape juice at a concentration of 400 μL/L, which was then incubated overnight at 25 °C with agitation at 100 rpm for chemical sterilization, according to the method described by Pinu et al [ 25 ]. Microorganisms on the surface of grape berries were collected following Chen’s method with modifications [ 26 ]. Using the five-point sampling method, 400 g of cabernet sauvignon grapes were randomly sampled from Bolongbao Chateau in Beijing (B) and Yuanshi Chateau in Ningxia (Z).…”

Characteristic metabolites drive the self-assembly of microeukaryotic communities during spontaneous fermentation of icewine

“…The application of commercial yeast in an incompatible fermentation scenario potentially causes the risk of stuck and sluggish fermentation and product homogenization. It even has a detrimental effect on the composition of regional microbiota [1], which play important roles in characterizing aroma profile and wine quality [2]. Currently, more and more researchers and wineries have realized the limitations of commercial yeasts and are gradually turning their attention to the study of non-Saccharomyces strains and the interactions between local microbiota and environmental factors [3][4][5].…”

“…With the development of high-throughput sequencing technology, researchers can conduct parallel analyses of the epiphytic microorganisms from vineyards and wines. It is effective to acquire an overview of microbial structure and position the pathogenic factors [2,9,10]. Therefore, the prerequisite for a well-controlled spontaneous fermentation is to identify the characteristic microbial resources in the production area, reduce the ecological dimension of the microeukaryotes community using self-assembled yeast communities, and establish a proper fermentation condition according to regional characteristics.…”

“…In our previous study, two main environmental factors have been determined, namely, initial abiotic factors around vineyards and initial microbial community on the grape skin. Through the 'top-down' approach, we specially designed a self-assembled non-Saccharomyces yeasts group, which was composed of six selected yeast strains and highly expresses carbohydrate-active enzymes [2,5]. The yeast group was first used to obtain a predictable and controllable fermentation mode during the spontaneous fermentation of icewine.…”

“…Fully ripe grapes hang on the vines for several months to suffer natural freeze-thaw cycles and be desiccated for the concentration of sugar (>35°Brix) [12]. This period has been proven to be effective for the accumulation of varietal aroma in grapes [2,5]. For instance, high-odor-active compounds, such as terpenes and phenylalanine-derivates, can be largely developed during late harvest through a series of interactions between epiphytic microeukaryotes and grapes [2,5].…”