Sequential Inoculation Research Articles

PARP-inhibition with IFNg in the ovarian tumor microenvironment induces immunogenic cancer cell death for sustained anti-tumor immunity.

Abstract Poly(ADP-ribose) polymerase (PARP) inhibitors have been a remarkable breakthrough in the treatment of ovarian cancers with BRCA1/2 mutations. We have previously reported that PARP-inhibition with immune checkpoint blockade extended survival of BRCA1-deficient ovarian cancer (ov ca) preclinical models. A significant increase in IFNg producing effector T cells in the tumor environment promoted tumor cytotoxicity in a caspase-independent manner. In this study, we hypothesized that in the presence of IFNg, PARPi may induce immunogenic cell death (ICD) rather than apoptosis and promote immune-mediated tumor control. In vitro, PARPi+IFNg treatment induces hallmarks of ICD in BRCAmt ov ca; such as cell surface translocation of calreticulin, ATP and HMGB-1 release but not by PARPi or IFNg single treatment. Additionally, the PARPi+IFNg treated Ov ca cells induced maturation and activation of dendritic cells with enhanced antigen-presentation to stimulate anti-tumor T cells. Evidence of immunogenicity was confirmed by the benefit of vaccination with PARPi+IFNg treated Ov ca cells in vivo. The vaccination established the long-lasting protective anti-tumor immune responses to clear sequential tumor inoculations. T cell-depletion and adoptive transfer experiments showed the ICD-induced tumor immunity was surprisingly, both CD4 and CD8 T cell-mediated. Currently, we are addressing whether anti-tumor antibodies contribute to tumor control. Our results identified a novel mechanism by which PARP-inhibition with IFNg induces ICD in the ovarian tumor environment. These effects can be leveraged to enhance tumor clearance in the combination with immune therapies to modulate TME by stimulating tumor-immune cycles. Supported by grants from NCI (R37 CA229221)

Impact of Lachancea thermotolerans on Chemical Composition and Sensory Profiles of Viognier Wines.

Viognier is a warm climate grape variety prone to loss of acidity and accumulation of excessive sugars. The yeast Lachancea thermotolerans can improve the stability and balance of such wines due to the partial conversion of sugars to lactic acid during alcoholic fermentation. This study compared the performance of five L. thermotolerans strains in co-inoculations and sequential inoculations with Saccharomyces cerevisiae in high sugar/pH Viognier fermentations. The results highlighted the dichotomy between the non-acidified and the bio-acidified L. thermotolerans treatments, with either comparable or up to 0.5 units lower pH relative to the S. cerevisiae control. Significant differences were detected in a range of flavour-active yeast volatile metabolites. The perceived acidity mirrored the modulations in wine pH/TA, as confirmed via “Rate-All-That-Apply” sensory analysis. Despite major variations in the volatile composition and acidity alike, the varietal aromatic expression (i.e., stone fruit aroma/flavour) remained conserved between the treatments.

Preparation of instant dark tea by liquid-state fermentation using sequential inoculation with Eurotium cristatum and Aspergillus niger: Processes optimization, physiochemical characteristics and antioxidant activity

Preparation of instant dark tea (IDT) by liquid-state fermentation (LF) is an effective procedure, of which the process is more easily controlled than solid-state fermentation (SSF). The present study focused on developing a sequential inoculation liquid-state fermentation (SILF) procedure using the Eurotium cristatum and Aspergillus niger to prepare IDT. The key parameters (turbidity, redness, and tea pigments) were optimized by response surface methodology (RSM). Optimum conditions were modeled to be a water-tea ratio of 24.0 mL/g, inoculum size of 8.7% (v/v), and time of 9 d. The predicted and experimental values of redness, turbidity and tea pigments content were within a 5% difference using the optimized conditions. Bench scale was achieved in a 5-L fermenter, which generated IDT with a redness value of 43.50, a turbidity of 5.67 NTU and tea pigments content of 23.53%, w/w. The evaluation by E-nose and E-tongue showed that IDT had a similar aroma and mouthfeel with a commercial instant Fu-brick tea (IFT), and the antioxidant activities in vitro, color and clarity of tea infusion of IDT were higher than those of the IFT, respectively. These results indicate that preparation of IDT by SILF is feasible, this work expect to set up a new aspect for preparation of IDT.

Effect of inoculation strategy with autochthonous Oenococcus oeni strains on aroma development in Rioja Alavesa Tempranillo wines

The potential use as malolactic starters of four indigenous strains of Oenococcus oeni was evaluated under different inoculation regimes. Among others, the fermentative capacity of strains, their degree of implantation, the main oenological parameters as well as their ability to modulate the aromatic profile of wines, were analysed. Main results elucidated that co-inoculation led to the prompt consecution of malolactic fermentation (MLF), highlighting the performance of indigenous Oenococcus oeni P2A strain and commercial O. oeni Viniflora OENOS strain which finished the process 20–30 days earlier compared to batches that undergo sequential inoculation. Moreover, inoculation strategy did also have an important influence on the volatile profile of wines. Co-inoculated wines significantly showed less concentration of volatile compounds. Main reduction was detected in higher alcohols and acids. Lower concentration of acids and higher alcohols may prevent the masking of desired aroma attributes. Indeed, in co-inoculated wines, the perception of ripe fruit aroma was highlighted over the others, and was extensively perceived by panellists in comparison with their respective sequentially inoculated wines. Above all, it was elucidated the suitability of the strain P2A, resulting an advantageous alternative to significantly reduce the overall winemaking time as well as to better control the fermentative process.

Interaction effect of Root Lesion Nematodes and Fusarium culmorum Sacc. on disease complex in some wheat cultivars

The study was conducted to assess a possible interaction between fungal pathogen of Fusarium culmorum Sacc. and Root lesion nematodes at sequentially and simultaneously inoculation. Fusarium culmorum spore suspension effect evaluated on plant disease severity and nematode density on moderate resistant wheat line to F. culmorum (2-49) and susceptible wheat variety (İkizce) under controlled condition. The disease severity was higher on İkizce cv. than 2-49. This indicates that there is a considerable important pathogen resistance. Simultaneous and sequential inoculation of Pratylenchus thornei and F. culmorum reduced the final nematode density and reproduction rate more than inoculation with only nematode on İkizce cv. The simultaneously P. penetrans and F.culmorum inoculation (N+F) affected the positively of final density on İkizce cv. The N+ F treatment affected the positively of P. neglectus density on İkizce cv., whereas negative effect was found in pre or post inoculation of F. culmorum treatments. No synergistic interactions were detected on 2-49 when plants were co-infected by the root lesion nematode and fungus. It was determined that P. thornei had a positive effect on disease severity when it entered the plant simultaneously and before the F. culmorum on İkizce cv.. The disease severity decreased in F. culmorum was applied four weeks after the P. neglectus treatment on 2-49 wheat line and İkizce cv. In the interaction with F. culmorum on İkizce cv., differences were determined between the species of root lesion nematodes.

Technological Improvements on FML in the Chianti Classico Wine Production: Co-Inoculation or Sequential Inoculation?

Winemaking variables and techniques are known to affect the composition of wines. To obtain a rapid and safe fermentation course, with a reduced risk of proliferation of unwanted microbial species, frequent recourse is made to the use of selected microorganisms, which can greatly simplify the complex management of the fermentation process. In particular, selected strains of lactic acid bacteria are used, which are much more sensitive than yeasts to the operating conditions of the medium. In this regard, the overall aim of this research was to verify whether the early inoculation of homolactic acid bacteria for hexoses (Lactobacillus plantarum) carried out after 24 h, compared with that of saccharomycetes operating alcoholic fermentation, could be advantageous compared with a traditional innoculation with a different heterolactic bacterial strain for hexoses (Oenococcus oeni) operated at the end of alcoholic fermentation. The grape variety chosen was Sangiovese, the protagonist of Tuscan oenology. The evaluation focused on different aspects such as the management of winery operations, and the quality and longevity of the product; was carried out in all phases of winemaking; and analysed both from a chemical and sensory point of view.

Use of Torulaspora delbrueckii and Hanseniaspora vineae co-fermentation with Saccharomyces cerevisiae to improve aroma profiles and safety quality of Petit Manseng wines

Nowadays, the inoculation of more than one non-Saccharomyces species in combination with S. cerevisiae was proposed to compensate the shortage of one non-Saccharomyces species and further enhance the wine quality. In this work, the fermentation performance of different co-inoculation ratios of Hanseniaspora vineae CVE-HV6 and Torulaspora delbrueckii CVE-TD20 sequential inoculation with S. cerevisiae was evaluated in Petit Manseng grape must. Results revealed that H. vineae and T. delbrueckii co-inoculation treatments increased the concentrations of desired aroma compounds, and decreased levels of acetic acid and biogenic amines compared to S. cerevisiae pure culture and the mixed cultures involved one non-Saccharomyces strain. The treatment of H. vineae and T. delbrueckii with a 2:8 inoculation ratio achieved the highest levels of major ethyl esters and the lowest level of acetic acid. Wines using co-inoculation of T. delbrueckii and H. vineae yeasts had less biogenic amines, especially tyramine, which was more pronounced with the increasing proportion of H. vineae. These results indicated that co-inoculating H. vineae and T. delbrueckii strains with the optimal ratio can make up some enological shortages of non-Saccharomyces species, and effectively improve the overall quality of wine products.

Effects of inoculation protocols on aroma profiles and quality of plum wine in mixed culture fermentation of Metschnikowia pulcherrima with Saccharomyces cerevisiae

This study describes the first report of application of Metschnikowia pulcherrima combined with Saccharomyces cerevisiae to ferment plum wine. Variable factors studied include inoculum ratio (M. pulcherrima: S. cerevisiae = 10:1, 1:1, and 1:10), as well as simultaneous versus sequential inoculation, with tested trials spanning 10:1sim, 1:1sim, 1:10sim, 10:1seq, 1:1seq, and 1:10seq, respectively. The yeast growth kinetics, physicochemical characteristics, organic acids, aroma profiles, and sensory evaluation were investigated. During fermentation, M. pulcherrima growth was inhibited by S. cerevisiae. Compared to each simultaneous analog, sequential fermentation which was inoculated with the same yeast ratio consumed less sugar and produced lower ethanol content. Organic acids in each sample varied with the use of different inoculation strategies. A total of 48 aroma compounds were quantified, and 1:1seq sample was observed to be abundant in esters and terpenes but relatively low in higher alcohols, fatty acids, and phenols. Sensory evaluation of the variously-prepared samples revealed that 1:1seq sample featured a highly intense ‘global aroma’, ‘fruity’, and ‘alcohol’ notes. PCA illustrated that different inoculation protocols of mixed culture fermentation influenced plum wine aroma except 1:10sim. Ultimately, 1:1seq was identified as a promising candidate for production of high-quality plum wine.

Interaction of Meloidogyne incognita (Kofoid & White, 1919) (Nemata: Meloidogynidae) and Fusarium oxysporum f. sp. radicis-lycopersici Jarvis & Shoemaker in tomato F1 hybrids with differing levels of resistance to these pathogens

The interaction of Meloidogyne incognita (Kofoid & White, 1919) (Rhabditida: Meloidogynidae) and Fusarium oxysporum f. sp. radicis-lycopersici Jarvis & Shoemaker (FORL) on nematode reproduction and wilt severity was investigated in tomato hybrids in this study. The study included with five combinations of individual, simultaneous and sequential inoculations of M. incognita and FORL to tomato F1 hybrids Adel, Alberty, Armstrong, Body, Gülizar and Kaplan in January-May 2021 under controlled conditions. The experiment was completed after 60 days. Simultaneous inoculation increased M. incognita galls and egg masses in Adel, Armstrong, Body, and Gülizar. The highest gall and egg mass numbers occurred with FORL inoculation 10 days after M. incognita inoculation (N+10 FORL) in Alberty and Kaplan. The highest disease incidence occurred in all tomato hybrids at the application of N+10 FORL and was followed by Gülizar, Kaplan, Body, Alberty, Armstrong and Adel. Meloidogyne incognita showed high reproductive rates in Alberty and Body, and FORL resistance was overcome with treatment N+10 FORL. Meloidogyne incognita was unable to reproduce in Adel and Armstrong and thus no disease was seen. The results indicated that the development of root-knot nematodes is a significant factor affecting the durability of FORL resistance.

Effect of sequential fermentation with four non-Saccharomyces and Saccharomyces cerevisiae on nutritional characteristics and flavor profiles of kiwi wines

To improve the functional properties and flavor complexity of kiwi wine using different non-Saccharomyces cerevisiae, Wickeramomyces anomala (Wa), Zygosaccharomyces rouxii (Zr), ZygoSaccharomyces bailii (Zb) and Schizosaccharomyces pombe (Sp) were inoculated sequentially with S. cerevisiae (Sc). The physicochemical and sensorial profiles of the wines were evaluated. The evolution of cells showed that non-Saccharomyces exhibited varying degrees of fermentation vigor and only acted during the first vinification stage. Ethanol content, pH, ΔE and organic acids in the wines varied according to the yeasts used. Compared with the pure Sc fermentation, the sequential fermentations of Wa-Sc and Sp-Sc significantly increased the production of polyphenols. Fifteen volatile compounds with relative odor activity values (rOAV) ≥ 1.0 were identified. Furthermore, principal component analysis (PCA) revealed that Zr-Sc and Sp-Sc were correlated with higher levels of ethyl esters (ethyl hexanoate, ethyl heptanoate, ethyl decanoate), isoamyl acetate and 2-phenyl-1-ethanol in the wines, improving the flower and sweet notes. Zr-Sc also enhanced the tropical fruity aroma. Sequential inoculation with Zb was related to the contents of acetate esters, ethyl butyrate, methyl butyrate and cineole, triggering the tropical fruity odor. In addition, the partial least-squares regression (PLSR) revealed that acetate esters contributed greatly to the tropical fruity note.

Ethyl esters enhancement of Jinchuan pear wine studied by coculturing Saccharomyces bayanus with Torulaspora delbrueckii and their community and interaction characteristics

To enhance the fruity flavour of pear wine by coculturing Saccharomyces yeasts with non-Saccharomyces, the coculture patterns were optimised based on the effect of different strains on the physicochemical properties and metabolites, and the interaction relationship in the coculture fermentation was also studied. These results showed that total volatiles of S. bayanus were higher than those of S. cerevisiae, especially esters, acids and phenols. The contents of total volatiles and esters were enhanced by sequential inoculation. The effect of coculturing S. bayanus Y4 with T. delbrueckii Y7 or Pichia sp. was better than that of coculturing with them with S. cerevisiae Y1, enhancing the contents of phenylethanol, acetate and ethyl esters. Furthermore, the esters (mainly ethyl esters) content was increased by 53.30%, and the acids content was decreased by 32.82% when S. bayanus Y4 was cocultured with T. delbrueckii Y7 by sequential inoculation compared with S. bayanus Y4 single inoculation. Their coculture increased the α-diversity of the fungal community and changed the correlation network between the microbiota. Redundancy analysis showed that Torulaspora was closely correlated to ethyl hexanoate, ethyl decanoate and ethyl 9-decenoate, while Saccharomyces was associated with hexanoic acid and octanoic acid. PICRUSt2 prediction revealed that Torulaspora may utilize the fatty acids produced by Saccharomyces to synthesize fatty acid ethyl esters.

Impact of chemoprophylaxis immunisation under halofantrine (CPS-HF) drug cover in Plasmodium yoelii Swiss mice malaria model.

In the present study, we have investigated the role of antimalarial drug halofantrine (HF) in inducing the sterile protection against challenges with sporozoites of the live infectious Plasmodium yoelii (Killick-Kendrick, 1967) in Swiss mice malaria model. We observed that during the first to third sequential sporozoite inoculation cycles, blood-stage patency remains the same in the control and chemoprophylaxis under HF drug cover (CPS-HF) groups. However, a delayed blood-stage infection was observed during the fourth and fifth sporozoite challenges and complete sterile protection was produced following the sixth sporozoite challenge in CPS-HF mice. We also noticed a steady decline in liver stage parasite load after 3th to 6th sporozoite challenge cycle in CPS-HF mice. CPS-HF immunisation results in a significant up-regulation of pro-inflammatory cytokines (IFN-γ, TNF-α, IL-12 and iNOS) and down-regulation of anti-inflammatory cytokines (IL-10 and TGF-β) mRNA expression in hepatic mononuclear cells (HMNC) and spleen cells in the immunised CPS-HF mice (after 6th sporozoite challenge) compared to control. Overall, our study suggests that the repetitive sporozoite inoculation under HF drug treatment develops a strong immune response that confers protection against subsequent challenges with sporozoites of P. yoelii.

Use of Non-Saccharomyces Yeast Co-Fermentation with Saccharomyces cerevisiae to Improve the Polyphenol and Volatile Aroma Compound Contents in Nanfeng Tangerine Wines.

This study attempted to improve the polyphenol and volatile aroma compound contents in Nanfeng tangerine wines using non-Saccharomyces yeast and Saccharomyces cerevisiae. The effects of fermentation with pure cultures of Candida ethanolica, Hanseniaspora guilliermondii and Hanseniaspora thailandica, as well as in sequential and mixed inoculations (1:1 or 1:100 ratio) with S. cerevisiae in Nanfeng tangerine wines were evaluated. C. ethanolica was found to produce the most polyphenols (138.78 mg/L) during pure fermentation, while H. guilliermondii produced the most volatile aroma compounds (442.34 mg/L). The polyphenol content produced during sequential fermentation with S. cerevisiae and H. guilliermondii (140.24 mg/L) or C. ethanolica (140.21 mg/L) was significantly higher than other co-fermentations. Meanwhile, the volatile aroma compounds were found to be more abundant in S. cerevisiae/H. guilliermondii mixed fermentation (1:1 ratio) (588.35 mg/L) or S. cerevisiae/H. guilliermondii sequential fermentation (549.31 mg/L). Thus, S. cerevisiae/H. guilliermondii sequential fermentation could considerably boost the polyphenol and volatile aroma component contents in Nanfeng tangerine wines. The findings of this study can be used to drive strategies to increase the polyphenol content and sensory quality of tangerine wines and provide a reference for selecting the co-fermentation styles for non-Saccharomyces yeast and S. cerevisiae in fruit wine fermentation.

Effect of inoculation method on the quality and nutritional characteristics of low-alcohol kiwi wine

In order to prepare the kiwi wine with high nutritional characteristics and low alcohol content, the physicochemical properties, organic acids, monomer phenols, water-soluble vitamins and aroma of kiwi wine fermented by Saccharomyces cerevisiae and Wickerhamomyces anomalus in different inoculation method were analyzed. The results showed that the alcohol content of the three kiwi wines ranged from 5.3 to 5.5% (v/v). The lactic acid content of COF (inoculated with a mix of S. cerevisiae and W. anomalus) low-alcohol kiwi wine was 10.99 mg/mL. The quercetin and catechin contents of WSF (sequential inoculation with W. anomalus followed by S. cerevisiae) low-alcohol kiwi wine were significantly lower than those in the other kiwi wines. The aroma in COF and WSF low-alcohol kiwi wines were predominately from W. anomalus, while those in SWF (sequential inoculation with S. cerevisiae followed by W. anomalus) low-alcohol kiwi wine were predominately from S. cerevisiae.

Effects of sequential inoculation of Lachancea thermotolerans and Oenococcus oeni on chemical composition of spent coffee grounds hydrolysates

Spent coffee grounds (SCG) disposal is an environmental problem. These residues from coffee brewing and instant coffee production have potential to produce novel alcoholic beverages. SCG valorization through sequential alcoholic and malolactic fermentation was investigated using a yeast, Lachancea thermotolerans Concerto and a lactic acid bacterium (LAB), Oenococcus oeni Lalvin 31 in this study. Our results showed that sequential inoculation prevented early death of yeast confronted when simultaneous inoculation was adopted, allowing for growth and persistence of both yeast and LAB till the end of fermentation. Adequate ethanol production (4.91 ± 0.13 %, v/v) with low residual sugar content was also attained. In addition, relatively lower levels of acetic, lactic, and succinic acids were produced by sequential inoculation than that of simultaneous inoculation. Furthermore, SCG hydrolysates fermented via sequential inoculation had the widest variety of volatiles (e.g. esters and ketones). Overall, our results indicated that sequential inoculation of L. thermotolerans and O. oeni in SCG hydrolysates might be a way to develop novel beverages with pleasant flavor profiles.

Sequential infections by 32 isolates of

Context Studies of Phoma black stem and leaf spot disease (caused by Phoma medicaginis) in annual medics (Medicago spp.) normally involve a ‘once-only’ inoculation not reflecting multiple pathogen infection and phytoestrogen production cycles in the field. Phytoestrogen production by plants can result in lower ovulation rates in grazing animals. Aims We aimed to determine whether sequential infections by P. medicaginis increase production of phytoestrogens in annual medics, and to measure the genetic diversity of isolates. Methods In a greenhouse experiment, pathogenicity and virulence were investigated across 32 isolates of P. medicaginis following one, two or three rounds of inoculation of M. polymorpha var. brevispina. Production of the phytoestrogens coumestrol and 4′-O-methyl coumestrol was measured, and correlation with disease parameters assessed. DNA sequencing using ITS, β-tubulin, calmodulin and P. medicaginis-specific EFNI-1α was applied for phylogenetic analysis of isolates from Western Australia and elsewhere. Key results Across isolates, highest leaf disease incidence was 76%, petiole disease incidence 61%, leaf disease severity 52% and petiole disease severity 53%. Stem coumestrol content range was 45–1247 mg kg−1, and 4′-O-methyl coumestrol 0–344 mg kg−1. All measures were highest after three rounds of inoculation. Overall, there was a positive correlation of leaf disease incidence with coumestrol content (P < 0.05) and of both leaf and petiole disease incidence with 4′-O-methylcoumestrol content (P < 0.01, P < 0.05, respectively). Phylogenetic analysis revealed a high degree of genetic similarity among Western Australian isolates, generally grouping into a single separate cluster across the four markers, and genetically distinct from isolates sourced outside Australia. Conclusions Leaf disease incidence was the best discriminating disease parameter for coumestrol and 4′-O-methylcoumestrol content. Western Australian isolates of P. medicaginis were genetically similar and unique, possibly due to geographic separation. Implications The study emphasised the importance of sequential inoculations when screening annual Medicago genotypes towards developing cultivars with superior disease resistance and enhanced animal reproductive outcomes.

Schizosaccharomyces japonicus/Saccharomyces cerevisiae mixed starter cultures: New perspectives for the improvement of Sangiovese aroma, taste, and color stability

Schizosaccharomyces japonicus and Saccharomyces cerevisiae were inoculated in Sangiovese grape must and the impact of simultaneous (co-inoculation) and sequential inoculation protocols on growth and fermentation kinetics, and on the analytical and sensory profiles of the experimental wines, was evaluated at the end of the alcoholic fermentation and after aging in bottle.While Sch. japonicus proved to affect S. cerevisiae growth and fermentative performances solely in sequential inoculation, the combined activity of the two yeasts always resulted in significantly higher total polysaccharides concentrations (p < 0.05), no matter the inoculation protocol utilized. Moreover, Sch. japonicus modulated the concentration of some volatile compounds when in mixed culture. In particular, ethyl acetate, that reached high levels at the end of alcoholic fermentation, showed a significant decrease after twenty-four months of bottle aging (p < 0.05), when the occurrence of hydrolysis/esterification reactions led to a significant increase of other acetate esters (p < 0.05). As a result, sensory analyses showed no significant differences for the ethyl acetate perception in mixed fermentation and control aged wines. Moreover, sequentially inoculated wines showed significantly higher sweetness compared to control wines, possibly due to the higher glycerol and polysaccharide content.

Screening and Identification of Yeasts from Fruits and Their Coculture for Cider Production

Coculturing non-Saccharomyces yeasts with Saccharomyces cerevisiae could enrich the aromatic complexity of alcoholic beverages during cider brewing. Therefore, the present study performed rapid strain screening via selective culture medium and aroma analysis and adopted a response surface methodology to optimize fermentation conditions to produce 2-phenylethyl acetate (PEA), which presents a rose and honey scent. The effects of coculturing yeasts on cider quality were evaluated through hedonic sensory analysis and the check-all-that-apply (CATA) method. Hanseniaspora vineae P5 and S. cerevisiae P1 produced ciders with high levels of PEA and 2-phenylethanol, respectively. The optimal fermentation process consisted of sequential inoculation with a 31 h delay between inoculations, followed by fermentation for 14.5 d at 18.7 °C, yielding 17.41 ± 0.51 mg/L of PEA, which was 4.6-fold higher than that obtained through the unoptimized fermentation process. Additionally, the CATA results revealed that the cider produced through coculturing was associated with descriptors such as “smooth taste”, “honey”, “pineapple”, and “fruity”, which can be attributed to the high ethyl acetate and PEA levels in the cider.

Enhancement of the aroma in low-alcohol apple-blended pear wine mixed fermented with Saccharomyces cerevisiae and non-Saccharomyces yeasts

Zaosu pear has a high yield and is widely planted in Northwest China. Recently, a large number of ripe fruits are spoiled in the orchards due to poor market. This cultivar has the potential to produce perry, so a novel fermentation strategy for Zaosu pear wine has been explored to reduce these huge losses. The mixed inoculation of M. pulcherrima 346 and S. cerevisiae ES488 allowed higher concentrations of aromatic esters and alcohols in pear wine than that involving pure S. cerevisiae culture. When Zaosu pear juice and apple juice were blended in a 60:40 ratio, the total content of aroma compounds increased by 18% compared with that in pure pear wine due to the increase in the ethyl esters, higher alcohols and terpenoids concentration. The optimum mixed fermentation parameters obtained using a single-factor test coupled with a Box–Behnken design were an initial pH of 3.7, 1.5:1 inoculation ratio of M. pulcherrima 346 and S. cerevisiae ES488, sequential inoculation time 45 h and making temperature 18 °C. The optimized wine sample was characterized by floral and fruity aromas, and more complex and rounded flavors. Overall, our study provides support for aroma enhancement of pear-apple wines.

Influence of Kazachstania spp. on the chemical and sensory profile of red wines

We report the fermentative traits of two Kazachstania species (K. aerobia and K. servazzii) in non-sterile red wine and the resulting chemical and sensory properties. This builds on our previous work which revealed that Kazachstania spp. increased acetate esters in sterilised white wine. In this study Kazachstania spp. were initially evaluated in laboratory-scale fermentations (500 mL) in Merlot must to assess whether similar increases in chemical/volatile compounds would occur. The impact of malolactic fermentation (MLF) by Oenococcus oeni (VP41) on aroma composition was considered and found to reduce ester profiles in Merlot wines. The sensory implications of sequential inoculation with Kazachstania spp., followed by Saccharomyces cerevisiae, were then evaluated in small-lot fermentations (7 kg) of Shiraz must. Fungal diversity was monitored during early fermentation stages and was influenced by the early implantation of Kazachstania spp., followed by the dominance of S. cerevisiae. The effect of MLF in Shiraz wines was inconclusive due to high ethanol levels providing an inhospitable environment for lactic acid bacteria. When compared to S. cerevisiae alone, Kazachstania spp. significantly increased acetate esters, particularly phenylethyl acetate and isoamyl acetate, in both Merlot and Shiraz. The Shiraz wines fermented with Kazachstania spp. had higher jammy and red fruit aroma/flavour compared to S. cerevisiae (monoculture) wines. No influence was observed on colour one-year post-bottling. Results from this study show the contribution of Kazachstania spp. to the aroma profile of red wines and demonstrate their potential as starter cultures for improving the aromatic complexity of wines.