Effects of sugar concentration on mango wine composition fermented by Saccharomyces cerevisiae MERIT .ferm

Exogenous Mogroside V Drove Microbial Carbohydrate Metabolism and Consequently Enhanced Fruity Aroma in Greengage Wine

The microbial community is essential for the formation of aroma development in high-acidity greengage wine fermentation. Recent observations also highlight positive effects of mogroside V (MG V) on microorganisms in fermented foods, but the underlying chemical and biological mechanisms remain inadequate. The results indicated differences in the physicochemical properties among greengage wines, particularly a 50% increase in the ethanol conversion rate. Concurrently, GC-MS and sensory analyses demonstrated that MG V augmented carbohydrate conversion into ethyl esters (twice as much as in the control group), exhibiting tropical fruit and floral aroma profiles. The perceived intensity of these aromatic compounds increased by over 30%, thereby enriching the overall aromatic harmony of the wine. Integrated analysis of KEGG pathways and CAZymes annotations demonstrated that the enhancement of ethyl ester formation by MG V depends on improvement of the transport of carbohydrates and MG V, as well as accelerating the flux of pyruvate to acetyl-CoA in yeast. In conclusion, our study presents a targeted strategy for the high-acidity fruit wine industry of modulating this metabolic node in yeast, thereby achieving a focused enhancement of tropical fruit aroma characteristics in fruit wines.

Characterization of Red Dragon Fruit Wine Fermented with a Newly Identified Yeast Strain Saccharomyces cerevisiae M7

Research background

Dragon fruit (Hylocereus spp.) has been known to be a rich source of bioactive compounds, such as anthocyanins, betacyanin, betaxanthin and other phenolic substances, and it has a nutritional profile suitable to produce wine with functional properties. The aim of this study is to characterize the wine fermentation from red dragon fruit juice by a newly identified yeast strain.

Experimental approach

Yeast strains from banh men, a Vietnamese traditional alcoholic fermentation starter, were screened for ethanol production using thermally pretreated red dragon fruit juice. The most potent candidate was identified by the DNA sequencing method and subjected to an optimization study using a one-factor-at-a-time approach to optimize the conditions for red dragon fruit wine fermentation.

Results and conclusions

Results showed that thermal pretreatment of the red dragon fruit juice at 70 °C for 10 min resulted in a higher amount of phenols and antioxidants than at other pretreatment temperatures. Among the four isolates, M7 was the strongest alcohol fermenter, which was then identified as Saccharomyces cerevisiae using a DNA sequencing method. The optimal conditions for wine fermentation from red dragon fruit juice by S. cerevisiae M7 included a pitching rate of 108 CFU/mL, an initial sucrose content of 18 % (m/V), an initial pH=4.5, fermentation temperature of 30 °C and a fermentation time of 6 days. Under these conditions, the wine fermented by S. cerevisiae M7 had an ethanol volume fraction of (12.1±0.2) %, the concentration of total phenolics expressed as gallic acid equivalents (37.8±0.4), anthocyanins expressed as cyanidin 3-glucoside equivalents (11.2±0.3), betacyanin (65.2±0.8) and betaxanthin (60.5±1.3) mg/L and antioxidant activity measured by DPPH scavenging capacity of (65.4±0.4) %.

Novelty and scientific contribution

This study used a novel yeast strain Saccharomyces cerevisiae M7 for fermentation. In addition, the results of the study provide new data such as the optimal parameters and the accumulation of bioactive compounds (phenols, anthocyanins and betalains) related to the fermentation of red dragon fruit wine.

Simultaneous Content Determination of Mono-, Di-, and Fructo-oligosaccharides in Citrus Fruit Juices Using an FTIR-PLS Method Based on Selected Absorption Bands

A quantification method was developed to determine the sugar components, either following addition or enzymatic treatment, in citrus fruit juices containing additional fructo-oligosaccharides using midinfrared spectroscopy. For the quantification, we compared the results obtained by applying the simultaneous equation method, which uses very little wavenumber information, and the partial least squares (PLS) regression method, which requires a lot of wavenumber information. In order to prevent overfitting in the PLS method, we concentrated on reducing the amount of spectral data used in the analysis. The corresponding FTIR-PLS method led to an accurate quantification of the sugar contents, even in enzymatically treated orange juices with complicated compositions. The spectral data used for model calibration were significantly reduced by focusing on the absorption and assignment information of the sugar components. The RMSEs of Glc, Fru, Suc, GF2, and GF3 in enzyme-treated orange juice before and after spectral data reduction were 0.50, 0.46, 0.61, 0.74, and 0.61 g/L and 0.51, 0.49, 0.73, 0.86, and 0.61 g/L, respectively. The developed method could be easily implemented for practical applications, using a simple measuring instrument since only absorption information at the limited absorption bands is required.

Is the Consumer Ready for Innovative Fruit Wines? Perception and Acceptability of Young Consumers

The consumption of traditional wine has decreased in Europe during the last fifteen years. In parallel, new wine alternatives obtained by blending wines and fruit juices or by flavoring wines with artificial or natural flavors have appeared on the market. Recently, an innovative fruit wine obtained by co-fermentation of grape must and kiwi juice has been proposed and its potential of attraction for consumers should be exploited. To assess the potential consumer acceptability and expectations towards this new product, an online choice experiment has been conducted involving a consumer group of young adults (18–35 years old; n = 373). After the data collection, participants were divided into two groups according to whether they had already tasted a fruit wine (neophiles) or had never tasted it (new entries). For each group, the individual’s responses (on wine consumption habits, expectations and willingness to consume and pay a fruit wine) were analyzed through Principal Component Analysis. Different consumption styles and expectation patterns were defined in the two groups. However, in general, neophiles showed consumption patterns based on the evaluation of fruit quality, sales format, alcoholic content and the presence or not of bubbles, not giving importance to the brand. In contrast, new entries’ responses identified consumption patterns driven by the willingness to pay for a new product, the product value for money and packaging features. Differences between the two groups in expectations about the product sensory characteristics also emerged. These findings should contribute to this area of study by integrating environmental, economic and social dimensions and addressing food innovation and sustainability in the fruit and wine chains.

Coffee flavour modification through controlled fermentation of green coffee beans by Saccharomyces cerevisiae and Pichia kluyveri: Part II. Mixed cultures with or without lactic acid bacteria

This study attempted to achieve coffee flavour biotransformation through controlled fermentation of sterilsed green coffee beans with a coculture of Saccharomyces cerevisiae and Pichia kluyveri (FYco) and a sequential inoculation of Lc. lactis subsp. cremoris and the yeast coculture (FLYco). Isoamyl acetate, 2-phenylethyl acetate, and ethyl octanoate were produced by 5.76, 1.35 and 0.54 mg/kg, respectively, in FYco fermented green coffee beans. Compared to the green coffee bean fermented by the yeast monocultures in previous study, FYco led to a 1.2- and 4.1-times elevation in production of isoamyl acetate and 2-phenylethyl acetate, respectively. FLYco further increased acetate ester production by more than 2 times relative to FYco. The esters produced in FYco and FLYco partially survived the roasting process and imparted the roasted coffees with considerable fruity and winey aromas. The lactic acid fermentation in FLYco increased the acidity in green coffee beans, which promoted the formation of caramel-smelling furfurals and preservation of acidity and sweetness in the roasted coffees. Apart from the mere additions of flavour modification from individual strains, the proper combination of multiple strains can result in synergistic effects that enhanced the modulating activities of individual strains and further enhance flavour complexity of the resulted coffee.

Dominant yeasts associated to mango (Mangifera indica) and rose apple (Syzygium malaccense) fruit pulps investigated by culture-based methods

The biotechnological potential of yeasts associated to different habitats in Colombia has been poorly studied, especially the yeasts associated with different plant structures. Fruit pulps are interesting substrates mainly for the growth of yeast species, that can positively affect the productivity and quality of some bioeconomic species. Therefore, the objective of this study was to identify the dominant yeast species associated with mango and rose apple fruit pulps in Cali, Colombia. A total of 90 isolates were obtained, which were grouped considering their colony morphology. The D1/D2 domain of the large ribosomal RNA gene (LSU rRNA gene) or internal transcribed spacer (ITS) 1, ribosomal gene 5.8S and ITS 2 (ITS) regions of one to several representative isolates from each group was sequenced and compared with type strains for identification. The species Hanseniaspora thailandica, H. opuntiae and Clavispora lusitaniae were reported as shared by both fruits, specific for rose apple (H. uvarum, Pichia terricola, Rhodosporidiobolus ruineniae and Candida albicans), or for Mango (Meyerozyma caribbica, M. guilliermondii, C. natalensis, Aureobasidium pullulans, Pichia sp., Saturnispora diversa and C. jaroonii). Two morphotypes were not identified at the taxonomic level of species and were reported as candidates for new species, belonging to the genera Wickerhamomyces and Pichia.

Dynamic effects of fermentation on phytochemical composition and antioxidant properties of wampee (Clausena lansium (Lour.) Skeel) leaves

Variations in the phytochemical composition and antioxidant properties were studied in the wine of wampee leaves obtained at different stages of fermentation process. The highest concentrations of total phenolic and flavonoid contents were attained at Day 12 and Day 21 of fermentation, respectively. In addition, five phytochemical compounds including vanillic acid, p-coumaric acid, rutin, ferulic acid, and 7-hydroxycoumarin were identified and quantified by HPLC in fermented wampee products. The strongest antioxidant activity in wine was monitored on Day 12. Furthermore, total antioxidant activity was significantly correlated with vanillic acid, p-coumaric acid, ferulic acid, and 7-hydroxycoumarin compared with rutin. The obtained results suggested that 12-day fermentation could be an optimal process for excavation of applying wampee leaves into food and wine industries.