Effect of fat and salt reduction on the sensory quality of slow fermented sausages inoculated with Debaryomyces hansenii yeast

Construction of a synthetic microbial community and its application in salt-reduced soy sauce fermentation

High salt conditions negatively affect the fermentation efficiency of soy sauce and human health. This study aimed to construct a synthetic microbial community based on dominant functional microorganisms for salt-reduced soy sauce fermentation by investigating the succession and function of the microbial community during factory soy sauce fermentation. The findings revealed that the interplay between salinity and microorganisms influenced the dynamic changes of microbial communities. Furthermore, Aspergillus, Wickerhamomyces, Zygosaccharomyces, Staphylococcus, Weissella, and Tetragenococcus were analyzed to play key roles during soy sauce fermentation. Subsequently, the core strains were isolated and their strains and metabolic characteristics were evaluated. Finally, six strains (Aspergillus oryzae JQ09, Wickerhamomyces anomalus HJ07, Zygosaccharomyces rouxii JZ11, Staphylococcus carnosus QJ26, Weissella paramesenteroides ZJ19, and Tetragenococcus halophilus GY03) were employed to reconstruct the synthetic microbial community and conduct salt-reduced soy sauce fermentation. Biofortification increased the accumulation of metabolites in salt-reduced soy sauce. When the salt content was reduced to 14%, the sensory characteristics of soy sauce were closest to those of traditional soy sauce. Overall, this research presents a bottom-up approach to establish a simplified microbial community model with desired functions through deconstructing and reconstructing microbial structure and function. It has the potential to enhance the fermentation efficiency and realize the fermentation of salt-reduced traditional fermented food.

Flavour enhancement of dry fermented sausages by nitrite-degrading Levilactobacillus brevis CHOL1: Combining flavouromics and lipidomics to elucidate the mechanism of aroma formation

Levilactobacillus brevis CHOL1, exhibiting a nitrite degradation rate of 99.03 %, was added to dry fermented sausages to evaluate its effects on product quality, sensory and aroma properties. Lipidomics analysis was performed to explore the mechanism of aroma formation after inoculation. Results showed that Lev. brevis CHOL1 reduced the sausages' pH, water activity, and nitrite residues. Inoculation also imparted desirable texture and sensory characteristics to the sausages. Furthermore, significant increases in alcohol, acid and ester contents were observed, which enhanced the aroma of the sausages. Correlation analysis revealed that Lev. brevis CHOL1 promoted the hydrolysis of PC 36:2 and PC 35:2, thereby facilitating the production of key aroma compounds such as heptanol, hexanol and octanol. These components improved the aroma profile of the sausages. These findings indicate that Lev. brevis CHOL1 inoculation is a promising method to reduce the content of nitrite residues and improve the flavour of dry fermented sausages.

Characterizing flavor development in low-salt Chinese horse bean-chili paste through integrated metabolomics and metagenomics

This study utilized metabolomics and metagenomics to investigate the microbial composition and functions in low- and high-salt Chinese horse bean-chili pastes (CHCPs). The results showed that 25 key metabolites were identified to distinguish the flavor attributes between the two samples. Leuconostoc was identified as the dominant microbiota in low-salt CHCP, while Pantoea prevailed in the high-salt CHCP. Compared to traditional high-salt fermentation, low-salt and inoculated fermentation promoted the increase in the relative abundances of Companionlactobacillus, Levilactobacillus, Tetragenococcus, Zygosaccharomyces and Wickerhamiella as well as the enrichment of carbohydrate and amino acid metabolic pathways, which contributed to the enhancement of characteristic flavor compounds. Further metabolic pathway reconstruction elucidated 21 potential microbial genera associated with the formation of key metabolites, such as Leuconostoc, Levilactobacillus, Pantoea, and Pectobacterium. This study may provide insights for optimizing the fermentation process and improving the flavor quality of low-salt CHCP and similar fermentation products. KEYWORDS: Low-salt fermentation Hight-salt fermentation Chinese horse-bean chili paste Flavor formation Metabolomics Metagenomics.

Strategies to Reduce Salt Content: PDO and PGI Meat Products Case

The reduction of sodium chloride (NaCl) content, commonly known as salt, in processed meat products is one of the objectives of health organizations and government authorities to achieve healthier products. This reformulation of traditional meat products with protected designations poses more constraints, as they have a more consolidated quality image and less margin for change, since consumers appreciate the products for their unique sensory characteristics. The aim of this work is to present some of the strategies that have been explored to obtain meat products with low sodium content. Information related to the characteristics of traditional meat products with quality marks and geographical indications in different studies is discussed in opposition to the information recorded in their product specifications. It was found that the product specifications of meat products with Portuguese Protected Designation of Origin (PDO) and Protected Geographical Indication (PGI) show a wide variation in the NaCl content, much higher than the recommended values. Thus, one of the requirements to be implemented will be the parameterization of NaCl levels and their monitorization by control and certification organizations as a way to ensure product quality. It is also urgent to examine whether healthy innovation strategies may affect the quality of traditional PDO or PGI meat products and whether they can be included in the respective product specifications.

Dual Role of Yeasts and Filamentous Fungi in Fermented Sausages

This contribution aims to review the presence and the potential double role-positive or beneficial and negative or harmful-of fungi in fermented sausages as well as their use as starter cultures. Traditionally, studies have been focused on lactic acid bacteria; however, over the years, interest in the study of fungi has increased. The important contribution of yeasts and filamentous fungi to the quality and safety of fermented sausages has emerged from reviewing the literature regarding these fermented products. In conclusion, this review contributes to the existing literature by considering the double role of filamentous fungi and yeasts, the global fermented sausage market size, the role and use of starters, and the starters mainly present in the worldwide market, as well as the main factors to take into account to optimize production. Finally, some suggestions for future broadening of the sector are discussed.

Unveiling the aromatic differences of low-salt Chinese horse bean-chili-paste using metabolomics and sensomics approaches

To achieve salt reduction while ensuring flavor quality of Chinese horse bean-chili-paste (CHCP), we comprehensively explored the effect of indigenous strains Tetragenococcus halophilus and Candida versatilis on the aroma profiles of low-salt CHCP by metabolomics and sensomics analysis. A total of 129 volatiles and 34 aroma compounds were identified by GC × GC-MS and GC-O-MS, among which 29 and 20 volatiles were identified as significant difference compounds and aroma-active compounds, respectively. Inoculation with the two indigenous strains could effectively relieve the undesired acidic and irritative flavor brought by acetic acid and some aldehydes in salt-reduction samples. Meanwhile, inoculated fermentation provided more complex and richer volatiles in low-salt batches, especially for the accumulation of 3-methylbutanol, 1-octen-3-ol, benzeneacetaldehyde, phenylethyl alcohol, and 4-ethyl-phenol etc., which were confirmed as essential aroma compounds of CHCP by recombination and omission tests. The research elucidated the feasibility of bioturbation strategy to achieve salt-reducing fermentation of fermented foods.

Comprehensive investigation on volatile and non-volatile metabolites in low-salt doubanjiang with different fermentation methods

Doubanjiang is a well-known fermented condiment in China, but the high-salt concentration in its traditional manufacture process greatly lengthens the fermentation time, and leads to potential health risks. Here, the effects of salt reduction and co-inoculated starters (Tetragenococcus halophilus and Zygosaccharomyces rouxii) on the volatile metabolites (VMs) and non-volatile metabolites (NVMs) of doubanjiang were investigated using metabolomics technology and chemometrics analysis. Results showed that 75 VMs were identified, and 12 of them had significant aroma contribution (ROVAs ≥ 1). In addition, 106 NVMs were defined as significantly different metabolites (p < 0.05; VIP ≥ 1). Salt reduction could significantly increase the concentrations of VMs, but this strategy also promoted some undesirable odors like 2-phetylfuran and hexanoic acid, which could be totally suppressed by inoculation of starter. Moreover, the two starters improved amino acid, ester, and acid metabolites. This study provides a deeper insight into the development of low-salt fermented foods.

Compendium of sodium reduction strategies in foods: A scoping review

In response to health concerns generated by increased sodium intake, many new approaches have been studied to reduce the sodium content in processed food. It has been suggested that reducing sodium in the food supply may be the most appropriate solution. The aim of this scoping review was to establish what sodium reduction strategies are effective in maintaining acceptable sensory qualities for various food industry applications. Studies that evaluate and report on the effectiveness of a sodium reduction strategy relevant to food and included outcomes detailing how the strategies were received by human subjects using sensory data are included, as well as book chapters, literature reviews, and patents focusing on sodium reduction strategies. Only those published in English and since 1970 were included. Literature was obtained through Scopus, PubMed, EBSCOhost, and ScienceDirect databases, whereas patents were obtained through US Patent Trademark Office, Google Patents, and PATENTSCOPE databases. Two-hundred and seventy-seven primary studies, 27 literature reviews, 10 book chapters, and 143 patents were selected for inclusion. Data extracted included details such as analytical methods, broad and specific treatment categories, significant outcomes, and limitations among other material. Sodium reduction methods were categorized as either salt removal, salt replacement, flavor modification, functional modification, or physical modification. Although salt removal and salt replacement were the majority of included studies, future research would benefit from combining methods from other categories while investigating the impact on sensory characteristics, technological aspects, and consumer perception of the strategy.

Effects of Autochthonous Yeast Cultures on Some Quality Characteristics of Traditional Turkish Fermented Sausage "Sucuk"

The objective of this study was to determine the effects of yeast cultures (Candida zeylanoides and Debaryomyces hansenii) isolated from traditionally dry fermented Turkish sucuks, on some physicochemical and microbiological properties of the product. Eight different batches of the sucuks were produced by the inoculation of yeast and lactic acid bacteria (LAB) cultures (Lactobacillus curvatus, Lactobacillus plantarum and Lactobacillus sakei) in different combinations. The sucuks were ripened for 12 days and analyzed at 1^st, 6^th, and 12^th days of ripening. Percent moisture content, pH, water activity (a_w) and residual nitrite values of the sucuk inoculated with the yeast cultures were higher at the end of the ripening. The use of yeast cultures decreased hardness, gumminess, and chewiness values of the sucuk while increased adhesiveness values. Major volatile groups were aldehydes, terpenes, and sulphur compounds in the sucuk samples. The most noticeable results were for sensory properties of the sucuk that were positively improved by the yeast cultures.

Indigenous Microbiota to Leverage Traditional Dry Sausage Production

The main issue addressed in this review is the need for innovation in the artisanal production of dry fermented sausages-leveraging rather than discarding tradition, together with some practical strategies available to achieve it. Throughout the text, emphasis is placed on the autochthonous microbiota responsible for the identity and unique sensory characteristics of these products. The available strategies to introduce innovation in this manufacturing process rely on metabolic flexibility of microbial strains. In this sense, this review evaluates the application of several tools aimed at improving the quality and safety of artisanal dry fermented sausages focusing on the microbial community role. The most studied alternatives to enhance dry sausage production comprise the use of autochthonous starter cultures-including functional and/or probiotic strains, the production of bacteriocins, and the generation of bioactive peptides, which have been thoroughly covered herein. The purpose of this work is to review recent research about novel different strategies available for food technologists to improve safety and quality in the manufacture of dry fermented sausages. Additional support strategies-quality product registers and innovation through tradition-have been suggested as complementary actions towards a successful introduction of indigenous microbial communities into traditional dry sausage production.

Impact of a 25% Salt Reduction on the Microbial Load, Texture, and Sensory Attributes of a Traditional Dry-Cured Sausage

Catalão is a Portuguese dry-cured traditional sausage, highly appreciated for its distinctive sensory properties. The aim of this study was to evaluate the impact of a 25% salt reduction on Catalão manufactured with either purebred Alentejano (Al) or crossbred Iberian × Duroc (IDr) pork meat, on its physicochemical and microbiological stability, texture parameters, and sensory attributes. No significant effect of salt reduction or genotype was observed for pH, aW, and microbiological parameters. PUFA content was significantly higher for Al Catalão, particularly due to the content in linoleic and linolenic fatty acids. IDr 3% NaCl samples had the highest mean n6/n3 PUFA ratio, and the highest mean values for the atherogenicity and thrombogenicity indices, showing that both genotype and salt content influence these nutritional indices. Texture profile of Catalão was significantly influenced by salt content and genotype. Al samples were less adhesive, cohesive, and easier to chew. Low-salt Catalão was harder, more adhesive, and less cohesive, with lower resilience and higher chewiness values. Regarding sensory attributes, salt content influenced the product aroma, with reduced-salt sausages being evaluated as significantly less aromatic. Overall, a 25% salt reduction did not have a significant impact on the quality, stability, and sensory evaluation of Catalão.

The life and times of yeasts in traditional food fermentations

Yeasts are eukaryotic microorganisms which have a long history in the biotechnology of food production, as they have been used since centuries in bread-making or in the production of alcoholic beverages such as wines or beers. Relative to this importance, a lot of research has been devoted to the study of yeasts involved in making these important products. The role of yeasts in other fermentations in association with other microorganisms - mainly lactic acid bacteria - has been relatively less studied, and often it is not clear if yeasts occurring in such fermentations are contaminants with no role in the fermentation, spoilage microorganisms or whether they actually serve a technological or functional purpose. Some knowledge is available for yeasts used as starter cultures in fermented raw sausages or in the production of acid curd cheeses. This review aimed to summarize the current knowledge on the taxonomy, the presence and potential functional or technological roles of yeasts in traditional fermented plant, dairy, fish and meat fermentations.

Unraveling microbial community diversity and succession of Chinese Sichuan sausages during spontaneous fermentation by high-throughput sequencing

The microbial community diversity and succession of Chinese Sichuan sausages during the spontaneous fermentation were demonstrated using high-throughput sequencing technology. The bacterial diversity was abundant and the succession of bacterial community along the direction of Lactobacillus spp. increased and Weissella spp. decreased. While fungal diversity was single and trace fungal population was detected. The core functional microbiota were lactic acid bacteria, including Lactobacillus spp., Weissella spp. and Pediococcus spp. In initial fermentation, Weissella spp. was the dominant bacteria and its relative abundance was 49.84%, but then its relative abundance decreased to 11.96% during fermentation before recovering to 26.74% at the end of fermentation. Meanwhile, Lactobacillus spp. rose from 24.70 to 55.74% and became the dominant genus. Moreover, Pediococcus spp. increased from 0.06 to 18.05% on day 20 but then decreased to 1.89% on day 30. These results revealed that the primary microorganisms contributing to spontaneous fermentation of Chinese Sichuan sausages were bacteria, while eukaryotic microorganisms such as yeast scarcely contributed to fermentation.

Analyses of microbial community of naturally homemade soybean pastes in Liaoning Province of China by Illumina Miseq Sequencing

Traditional Chinese soybean pastes are homemade using natural fermentation and are quite common and popular in Liaoning Province. In this study, we investigated microbial diversity by collecting 23 samples from 10 cities and sequenced them using 2 × 300 bp Illumina Miseq Sequencing. 16S and ITS primers were used to amplify the V3-V4 region of the bacterial 16S rRNA gene and the ITS1 region of the fungal ITS rDNA gene, respectively. In total, 687,888 filtered bacterial sequences were obtained from nineteen samples and 1,091,649 filtered fungal sequences were obtained from twenty samples. Among the bacterial sequences, Firmicutes (74.77%), Proteobacteria (22.61%), and Actinobacteria (2.55%) were the predominant phyla, with Staphylococcus making up most of the Firmicutes. Among the fungal sequences, Ascomycota, Basidiomycota and Zygomycota accounted for 94.88%, 3.29% and 1.77%, respectively, while Glomeromycota and Chytridiomycota accounted for the remaining 0.06%. Most of the species from Ascomycota were unclassified Trichocomaceae and Debaryomyces, including 404578 and 187827 sequences, respectively. The microbial community in each sample was unique, most likely due to the geographical differences and external factors including the environment and manufacturing process during the fermentation. Soybean paste is the result of fermentation involving a great diversity of microorganisms, which include not only bacteria but also fungi.

Consumer sensory and hedonic perception of sheep meat coppa under blind and informed conditions

The development of air-dried cured sheep meat products represents an interesting option to add value to the meat of adult animals. In this context, the aim of the present study was to evaluate consumer sensory and hedonic perception of sheep meat coppa, an innovative product. Four sheep meat coppa samples were formulated by varying smoking (smoked vs. non-smoked) and salt content (4.5% vs. 3.4%), and compared with two commercial samples of regular pork meat coppa. Samples were evaluated under blind or informed conditions by 202 consumers, who had to rate their liking and to answer a check-all-that-apply question. Sheep and pork meat coppa samples did not largely differ in their overall liking in both experimental conditions. Smoking and high salt content significantly increased consumers' hedonic perception of sheep meat coppa. The information included in the labels did not modify consumer hedonic perception but influenced their sensory description, particularly for the terms related to the type of meat used in their manufacture. Results indicate positive market opportunities for sheep meat coppa in the Brazilian market.

Yeast inoculation as a strategy to improve the physico-chemical and sensory properties of reduced salt fermented sausages produced with entire male fat

Yeast inoculation of dry fermented sausages manufactured with entire male fat was evaluated as a strategy to improve sausage quality. Four different formulations with entire male/gilt back fat and inoculated/non-inoculated with Debaryomyces hansenii were manufactured. The use of entire male back fat produced the highest weight losses, hardness and chewiness in dry sausages. Consumers clearly distinguished samples according to drying time and D. hansenii inoculation while the use of entire/gilt back fat was not highly perceived. The presence of androstenone and skatole was close to their sensory thresholds. Androstenone was not degraded during the process but skatole was affected by yeast inoculation. D. hansenii growth on the surface regulated water release during ripening, reduced hardness and chewiness in entire male sausages and resulted with similar texture to gilt sausages. Yeast inoculation inhibited lipid oxidation providing fruity odours and less oxidized fatty sausages in the sensory analysis. The effectiveness of yeast to mask boar taint was demonstrated by sensory analysis.

Beneficial Effects of Traditional Seasonings on Quality Characteristics of Fermented Sausages

Though traditional seasonings are widely used in many dishes, however, no attention has been paid to the investigation of their effects on quality characteristics of food products. The present investigation was undertaken to study the effects of incorporating several traditional seasonings including doenjang (fermented soybean paste), gochu-jang (red pepper paste), fresh medium-hot, and hot peppers, and fresh garlic on the lipid oxidation, cholesterol content and sensory characteristics of fermented sausages. Six fermented sausage treatments (5 with 1% (w/w) each test seasoning and 1 without added test seasoning (control) were prepared. The addition of seasonings generally had beneficial effects on the improvement of fermented sausage's quality however the effects differed depending on the each type of seasonings added. Significant lower pH values were found in all fermented sausages made with the seasonings while, lower levels of lipid oxidation were found in the treatments with hot peppers and garlic as compared with the control (p<0.05). The treatment with seasonings did not cause color or texture defects in the products whereas the sausages made with gochu-jang had significantly higher Commission International de l'Eclairagea* (redness) value in comparison with the control. Noticeably, incorporating doenjang, medium-hot peppers, hot peppers and garlic resulted in reduction of 26.50, 32.54, 47.04, and 48.54 mg cholesterol/100 g samples, respectively (p<0.05). Higher scores for the sensory traits such as aroma, taste, color and acceptability were also given for the sausages made with seasonings. The current work demonstrates that the test seasonings represent potentially natural ingredients to be used for producing healthier fermented sausages.

Characterisation of "Catalão" and "Salsichão" Portuguese traditional sausages with salt reduction

The present study evaluated the effect of salt reduction on traditional dry-cured sausages' safety, quality and product acceptance, comprising physicochemical and microbiological parameters, biogenic amines, fatty acids, texture profile and sensory analysis. According to our results, salt content had a major effect on microbiological counts, although not compromising the products' safety. Marked differences were identified regarding biogenic amines, in particular for histamine, tyramine and cadaverine, which were detected in larger amounts in products with 3%. Moreover, significant differences in the fatty acids profile have also been found, but only in less abundant components such as linoleic, lauric and heneicosanoic acids. Texture profile analysis of low-salt products, revealed a decrease in hardness and chewiness, along with an increase in adhesiveness values. Sensory evaluations revealed that despite the less intense aroma, products with 3% salt, had a more balanced salt perception. Our results suggest that salt content may be reduced to 50% in dry-cured products, with the obvious health-related advantages.