Using a metaproteomics approach, we showed that the initial milk quality impacts the proteome allocation of starter cultures used in cheese production and can be considered a fundamental source of ...cheese quality batch-to-batch variation. Raw milk was spiked with a highly proteolytic strain of Pseudomonas trivialis, previously isolated from raw milk, and incubated for 1, 3, and 6 days at refrigerated temperature. After incubation, the milk was heat-treated and then fermented with a mesophilic starter culture commonly used to produce Gouda-type cheeses. The development of metabolites was analyzed and a taxonomical and functional characterization of the starter culture was performed. Milk storage time impacted both the metaproteome of the starter culture, consequently affecting metabolite levels after fermentation and the level of protein expressed by the different taxa; Lactococcus protein was more abundant in samples made from milk stored longer with Pseudomonas while proteins expressed by Leuconostoc spp. decreased in abundance.
•The initial microbial quality of raw milk is important for a stable starter culture fermentation.•Milk quality impacted the metabolism of mesophilic starter cultures used in cheese manufacturing.•Different taxa responded differently depending on the initial quality of the raw milk.•Critical pathways, such as carbohydrate and citrate, were impacted by the raw milk quality.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Coffee is an important commercial product to Brazil with its consumption distributed globally. The aim of this work was to evaluate the potential of yeast strains as starter cultures for dry ...fermentation of washed and non-washed coffee beans. Four yeast strains (Saccharomyces cerevisiae UFLA YCN727, S. cerevisiae UFLA YCN724, Candida parapsilosis UFLA YCN448 and Pichia guilliermondii UFLA YCN731) were inoculated separately in washed and non washed coffee cherries and in the control was not added any of the starter cultures. The fruits inoculated were spread on trays and placed on a terrace until the coffee beans reached 11% of moisture. Samples were collected for evaluation of the persistence of the inoculum by PCR-DGGE, and for chemical composition by HPLC and GC-FID. Sensory analysis was performed using the Temporal Dominance of Sensations (TDS) methodology. In all tests the yeasts persisted until the end of fermentation. There was no propionic and butyric acid production in concentrations that could compromise the final quality of the beverage. Forty-eight volatile compounds were identified, some were similar for green and roasted coffee. The most abundant class of compounds was alcohols (11–27%) followed by furan in roasted grains (~27%), and aldehydes (~13%) in green grains. The coffee inoculated with yeast showed sensations of flavors higher than the control coffee indicating increased sensory quality. The treatment with C. parapsilosis UFLA YCN448 showed dominance rate higher (near 1) for the sensation of caramel. In non-washed coffee those sensations were not pleasant in relation to the washed coffee, except when P. guilliermondii UFLA YCN731 was inoculated, suggesting that washing the fruit before the fermentation process positively influenced the final product quality. A coffee with special aroma of caramel, herbs and fruits could be produced using the starter cultures C. parapsilosis UFLA YCN448 and S. cerevisiae UFLA YCN727 in coffee processed by the dry method.
•Yeast starters during fermentation improved coffee quality.•Coffee with special aroma was produced using C. parapsilosis and S. cerevisiae.•Alcohols, furan and aldehydes were the main compounds found in coffee grains.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Kimchi, a traditional Korean food made by the fermentation of vegetables, has become popular globally because of its organoleptic, beneficial, and nutritional properties. Spontaneous kimchi ...fermentation in unsterilized raw materials leads to the growth of various lactic acid bacteria (LAB), which results in variations in the taste and sensory qualities of kimchi products and difficulties in the standardized industrial production of kimchi. Raw materials, kimchi varieties, ingredients, and fermentation conditions have significant effects on the microbial communities and fermentative characteristics of kimchi during fermentation. Heterofermentative LAB belonging to the genera Leuconostoc, Lactobacillus, and Weissella are likely to be key players in kimchi fermentation and have been subjected to genomic and functional studies to gain a better understanding of the fermentation process and beneficial effects of kimchi. The use of starter cultures has been considered for the industrial production of high quality, standardized kimchi. Here, we review the composition and biochemistry of kimchi microflora communities, functional and genomic studies of kimchi LAB, and perspectives for industrial kimchi production.
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CEKLJ, DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NUK, OBVAL, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
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•Bacterial diversity of dry sausages was analysed by high-throughput sequencing.•L. plantarum and S. xylosus promoted the proteolysis and lipolysis in the sausages.•The inoculation ...with mixed strains improved the flavour of the sausages.•Growth of unwanted bacteria was inhibited in the inoculated sausages.•Flavour development was attributed to the improved microbiological quality.
The use of starter cultures helps to improve the quality and safety of traditional meat products. In this study, the effects of Lactobacillus plantarum R2 and Staphylococcus xylosus A2 inoculation on microbial community, lipolysis, proteolysis, and volatile compounds in Chinese dry fermented sausages were investigated. Culture-dependent and culture-independent high-throughput sequencing) methods were employed to evaluate the bacterial communities. Results showed that the total contents of free fatty acids (FFAs) and free amino acids (FAAs) were increased by inoculating the starter cultures, especially a mixed culture. A significant decrease in pH and water activity was observed in the inoculated sausages (p < 0.05). Moreover, the inoculation treatment enhanced the competitiveness of dominant bacteria and inhibited the growth of unwanted bacteria. This was beneficial to promote the release of FFAs and FAAs and to prevent the formation of off-flavours and rancidity. Thus, the flavour development in the inoculated dry fermented sausages was attributed to the improvements in microbiological quality.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
The microbiota of ripening cheese is dominated by lactic acid bacteria, which are either added as starters and adjunct cultures or originate from the production and processing environments ...(nonstarter or NSLAB). After curd formation and pressing, starters reach high numbers, but their viability then decreases due to lactose depletion, salt addition, and low pH and temperature. Starter autolysis releases cellular contents, including nutrients and enzymes, into the cheese matrix. During ripening, NSLAB may attain cell densities up to 8 log cfu per g after 3 to 9 mo. Depending on the species and strain, their metabolic activity may contribute to defects or inconsistency in cheese quality and to the development of typical cheese flavor. The availability of gene and genome sequences has enabled targeted detection of specific cheese microbes and their gene expression over the ripening period. Integrated systems biology is needed to combine the multiple perspectives of post-genomics technologies to elucidate the metabolic interactions among microorganisms. Future research should delve into the variation in cell physiology within the microbial populations, because spatial distribution within the cheese matrix will lead to microenvironments that could affect localized interactions of starters and NSLAB. Microbial community modeling can contribute to improving the efficiency and reduce the cost of food processes such as cheese ripening.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
This study was designed to investigate the effect of starter culture on the improvement of physicochemical and sensory properties of dry-aged beef. Penicillium nalgiovense and Penicillium candidum ...were used as single starter cultures and mixed suspensions (1:1) to determine the effect of mixed starter culture. Starter cultures were spray-inoculated on the surface of beef samples, and samples were dry-aged for 0, 7, 10, 14, and 21 days. Dry-aged samples were then analyzed for microbial population, physicochemical properties (pH, water content, and color), proteolytic activity on sarcoplasmic and myofibrillar proteins, and flavor compounds (free amino acids, nucleotides, and volatile compounds). The microbial activities of starter cultures affected the physicochemical traits and enhanced sensory quality. Penicillium candidum particularly influenced proteolytic activity and volatile compounds, whereas P. nalgiovense affected free amino acid and nucleotide content, with the most significant effect on day 7. Combination of the two strains resulted in different patterns when compared to the single strains. Therefore, the inoculation of mold starter cultures significantly affected the physicochemical properties and improved the sensory qualities of dry-aged beef, and the effect differed between single and mixed strains.
•Starter culture can affect physicochemical and sensory properties of dry-aged beef.•Penicillium candidum promoted proteolysis of dry-aged beef and its volatile compounds.•Penicillium nalgiovense increased the production of taste compounds in dry-aged beef.•Mixed strains can work differently on the dry-aged beef.•The application of starter culture could shorten the dry aging period with better quality.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The development of standardized and safe food products with the typical characteristics of each region is highly desirable and can be obtained by using native starter cultures that influence the ...flavor, texture, and color of fermented foods. Therefore, scientists have been employing various techniques for screening and characterizing native bacteria (lactic acid bacteria and Gram-positive catalase-positive cocci) for application in fermented meat sausage. The present review outlines in vitro assays that evaluate the potential application and safety aspects of native isolates and introduces emerging omics technologies applied to the microbiology of fermented meat sausage. Results from current research are presented, and the strengths and limitations of each assay are provided, with references indicating where further details can be obtained. In choosing the most appropriate in vitro method, it is necessary to consider the available analytical infrastructure, the sensitivity and selectivity of the assay, the time it takes to get the results, the ease of the assay, and the costs involved.
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•Review of in vitro assays for testing native bacterial starter culture•Advantages and disadvantages of in vitro assays•Stress tolerance and enzyme activity of native bacterial isolates•Safety aspects of native bacterial isolates•NGS and omics applied to the microbiology of fermented meat sausage
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
To satisfy the demand of industrial production, selecting strains suitable for fermentation initiation is necessary. In this study, the effects of mixed‐starter culture including Leuconostoc, ...Lactobacillus, and Weissella on the quality of Sichuan pickle were discussed. Results showed that mixed‐starter culture can accelerate fermentation and had the highest efficiency for nitrite degradation, that is, the maximum nitrite concentration was 8.97 g/kg on day 1 and decreased to 1.88 mg/kg after 3 days. The mixed‐starter culture improved the sensory properties of pickles, which easily produced acids but had reduced amounts of total acids. The pickle products fermented by the mixed‐starter culture contained increased lactic acid (17.52 g/kg), mannitol (0.62%), umami (35.85), and sweet (11.36) amino acids on day 4. The strains Weissella paramesenteroides C2‐2 and Lactobacillus brevis ZP11‐2 grew well in the mixed‐starter culture fermentation.
This is the first report about three LAB strains' application on Brassicaceae pickle. Also, the fermentation characteristics of five treatments are analyzed, including single‐starter culture fermentation, mixed‐starter culture fermentation, and spontaneous fermentation.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Kimchi fermentation usually relies upon the growth of naturally-occurring various heterofermentative lactic acid bacteria (LAB). This sometimes makes it difficult to produce kimchi with uniform ...quality. The use of Leuconostoc mesenteroides as a starter has been considered to produce commercial fermented kimchi with uniform and good quality in Korea. In this study, a combination of a barcoded pyrosequencing strategy and a 1H NMR technique was used to investigate the effects of Leu. mesenteroides strain B1 as a starter culture for kimchi fermentation. Baechu (Chinese cabbage) and Chonggak (radish) kimchi with and without Leu. mesenteroides inoculation were prepared, respectively and their characteristics that included pH, cell number, bacterial community, and metabolites were monitored periodically for 40days. Barcoded pyrosequencing analysis showed that the numbers of bacterial operational taxonomic units (OTU) in starter kimchi decreased more quickly than that in non-starter kimchi. Members of the genera Leuconostoc, Lactobacillus, and Weissella were dominant LAB regardless of the kimchi type or starter inoculation. Among the three genera, Leuconostoc was the most abundant, followed by Lactobacillus and Weissella. The use of Leu. mesenteroides as a starter increased the Leuconostoc proportions and decreased the Lactobacillus proportions in both type of kimchi during kimchi fermentation. However, interestingly, the use of the kimchi starter more highly maintained the Weissella proportions of starter kimchi compared to that in the non-starter kimchi until fermentation was complete. Metabolite analysis using the 1H NMR technique showed that both Baechu and Chonggak kimchi with the starter culture began to consume free sugars earlier and produced a little greater amounts of lactic and acetic acids and mannitol. Metabolite analysis demonstrated that kimchi fermentation using Leu. mesenteroides as a starter was completed earlier with more production of kimchi metabolites compared to that not using a starter, which coincided with the decreases in pH and the increases in bacterial cell number. The PCA strategy using all kimchi components including carbohydrates, amino acids, organic acids, and others also showed that starter kimchi fermented faster with more organic acid and mannitol production. In conclusion, the combination of the barcoded pyrosequencing strategy and the 1H NMR technique was used to effectively monitor microbial succession and metabolite production and allowed for a greater understanding of the relationships between the microbial community and metabolite production in kimchi fermentation.
► The use of Leuconostoc mesenteroides as a starter in kimchi fermentation. ► Analysis of microbial succession and metabolites during kimchi fermentation. ► The genera Leuconostoc, Lactobacillus, and Weissella were dominant LAB in kimchi. ► Starter kimchi fermented faster with more metabolite production.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
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