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The traditional dry sausage is highly appreciated in China because of its unique quality characteristics, but it contains high salt content. Hence, this study aimed to evaluate the effects of lactic acid bacteria (LAB) comprising Lactobacillus sakei (LS), Lactobacillus curvatus (LC), Lactobacillus plantarum (LP), and Weissella hellenica (WH) on the quality attributes of the reduced-salt dry fermented sausages. The results indicated that the LP sausage showed higher (P < 0.05) shear force value compared to the other sausages, while the LP, LC, and WH sausages had higher (P < 0.05) lightness values than the control sausages. Seventy-six volatile compounds were detected, and nine compounds were identified as the key differential volatile compounds among the sausages based on partial least squares discriminant analysis. Clustering analysis of electronic nose results corresponded well to the volatile compound results. The sensory evaluation confirmed that the inoculation with LC and LP had a positive impact on the aroma, color, and hardness attributes of the reduced-salt sausages. Besides, partial least squares regression analysis further indicated that L. curvatus and L. plantarum could be used as the potential starter cultures to manufacture reduced-salt dry fermented sausage having improved texture, color, and flavor. [Display omitted] • The LP sausage shows higher shear force value compared to the other sausages. • The LP, LC, and WH sausages have higher lightness values than the control sausages. • Seventy-six volatile compounds are detected in dry fermented sausage. • Sensory attributes correlate with the key volatile compounds using PLSR analysis. • L. curvatus and L. plantarum can improve the quality of reduced-salt dry sausage. [ABSTRACT FROM AUTHOR]

This study evaluated the effect of different sugar smoking times on the flavour profiles of chicken drumsticks using an electronic nose (E-nose), electronic tongue (E-tongue), and headspace solid-phase microextraction gas chromatography-mass spectrometry (HS-SPME/GC-MS). The moisture content, water activity, pH, and L *-value decreased from 71.26% to 65.23%, 0.987 to 0.979, 6.66 to 5.36, and 61.84 to 52.34, respectively (P < 0.05). The a *-value and b *-value increased from 4.96 to 9.65 and 16.61 to 26.45, respectively (P < 0.05) with the increase in smoking times. Seventy-five volatile compounds were identified, and 18 volatile compounds were identified as key odour compounds and among them seven key volatile compounds with variable importance in projection (VIP) > 1 were detected. Principal component analysis of E-nose, E-tongue, and HS-SPME/GC-MS indicated that 3-, 4-, and 5-min smoking samples had similar odour and taste profiles. Sensory analysis indicated that the 4-min sample had increased overall acceptability. The correlation analysis of E-nose and key volatile compounds with odour activity value > 1 and VIP >1 confirmed that W1C, W3C, and W5C sensors were sensitive to aromatic compounds, and W2S sensor was sensitive to ketones. These results may provide guidance for smoked chicken producers to reasonably control flavour formation. • A total of 75 volatile compounds were detected in smoked chicken drumsticks. • Eighteen key volatile compounds were identified. • The 3-, 4-, and 5-min smoked samples had similar odour and taste profiles. • The 4-min smoked chicken drumsticks had increased sensory acceptability. [ABSTRACT FROM AUTHOR]

This study was to investigate the succession of the bacterial community in Harbin dry sausages during fermentation and its correlation to the sausage flavour. The results showed that Staphylococcus count increased but the moisture content and water activity decreased (P < 0.05). The lactic acid bacteria count first increased and then decreased, while the pH showed an opposite trend during a twelve-day fermentation (P < 0.05). According to a single molecule real time sequencing analysis, Lactobacillus sakei and Staphylococcus xylosus were the predominant bacterial species over the entire fermentation period. A total of 79 volatile compounds were detected using the headspace solid phase microextraction gas chromatography-mass spectrometry. Furthermore, the correlation between the core bacteria (top 30) and the major volatile compounds was explored, which highlighted that three bacterial species (Lb. sakei , S. xylosus and Weissella hellenica) were significantly correlated with the major volatile compounds, such as 2,3-butanediol, ethanol, 3-hydroxy-2-butanone, ethyl hexanoate and ethyl lactate. The results may provide a theoretical basis for improving the flavour and overall quality of dry sausage. • Lactobacillus sakei and Staphylococcus xylosus were the dominant bacterial species. • Seventy-nine volatile compounds were detected in Harbin dry sausages. • L. sakei , S. xylosus and W. hellenica were correlated with the volatile compounds. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate the effects of NaCl reduction (2.5% 2.0%, 1.5% and 1.0%) on the bacterial growth, physicochemical characteristics, flavour profile and sensory traits of fermented dry sausage. The moisture content, water activity and lactic acid bacteria count increased as the NaCl level decreased (P < 0.05), contributing to decreases in pH (P < 0.05). A total of 50 volatile compounds were identified, and increases in volatile compounds, such as acetone, 3-hydroxy-2-butanone, with high odour activity values derived from carbohydrate metabolism and lipid oxidation may contribute to flavour development (P < 0.05). Additionally, the increased Staphylococcus spp. counts in sausages with 2.0% and 2.5% NaCl contributed to the increased contents of ethyl octanoate, ethyl butyrate and ethyl acetate (P < 0.05). Sensory evaluation showed higher scores for taste, chewiness and aroma in sausages with 2.0% and 2.5% NaCl. Therefore, it can be concluded that 2.0% NaCl can be employed as the desired addition level in fermented sausage to achieve better quality and flavour. • Sausages with reduction in NaCl level had higher moisture content and water activity. • The reduction of NaCl level increased lactic acid bacteria population. • Volatile compounds in fermented sausage during fermentation were identified. • 2.0% NaCl can be employed as the desired addition level in fermented sausage. [ABSTRACT FROM AUTHOR]

Pediococcus pentosaceus (Pp) , Lactobacillus curvatus (Lc) , Lactobacillus sakei (Ls) and Staphylococcus xylosus (Sx) were evaluated to determine their roles in the quality characteristics and flavor formation in Harbin dry sausage. The inoculation of dry sausages with bacterial strains, especially mixed strains (Pp + Sx + Lc and Pp + Sx + Ls), significantly decreased the moisture content and water activity. Compared with the sausages inoculated with a single strain and non-inoculated, those inoculated with mixed strains had shorter transverse relaxation time T 21 that represents the immobilized water (P < 0.05) after a nine-day fermentation. The texture profile analysis showed that inoculation with bacterial strains increased the hardness and springiness of sausages. The sausages inoculated with mixed strains showed higher a *-values (P < 0.05). Furthermore, the percentages of some aldehydes, ketones, alcohols, acids and esters in the sausage inoculated with Pp + Sx + Lc were significant higher than that in control sausages (P < 0.05), which may be derived from carbohydrate catabolism (such as 3-hydroxy-2-butanone), amino acid metabolism (such as 3-phenylpropanol, 2,3-butanediol, phenylethyl alcohol, 2-methyl-propanal, 2-methyl-butanal and 3-methyl-butanal), β-lipid oxidation (such as 2-pentanone, 2-heptanone and 2-nonanone) and esterification (such as ethyl esters). • Bacterial fermentation promoted the decrease in moisture content and water activity. • Bacterial fermentation improved the hardness and springiness of sausage. • The fermentation with multiple bacterial strains had higher percentages of favorable volatile compounds. [ABSTRACT FROM AUTHOR]

The technological properties and flavour formation potential of yeast strains isolated from traditional dry fermented sausages were evaluated. A total of 46 yeast strains were isolated and characterized at the strain level by genotyping. Among them, 34 strains were selected for evaluation of technological properties (tolerance to acid, salt, and sodium nitrite stresses; proteolytic and lipolytic activities; and biogenic amine formation capacity) based on their genetic profiles. Then, seven strains (Debaryomyces hansenii HRB2, SH4, and HG2; Torulaspora delbrueckii DQ3 and HG7; Pichia kudriavzevii MDJ1; and Candida zeylanoides DQ7) were selected to investigate their flavour formation potential in a fermented sausage model. A total of 56 volatile compounds were detected in all models, of which 17 volatile compounds were the most important flavour contributors with an odour activity value (OAV) > 1. The most remarkable result was the significant production of acid, alcohol, and esters in the inoculated models, such as acetic acid, hexanoic acid, ethanol, phenethyl alcohol, ethyl acetate, and ethyl hexanoate. Of all the strains, D. hansenii SH4 was considered to be the best flavour producer because it produced multiple compounds with the highest OAVs, which are associated with the development of desirable sensory characteristics in dry sausages. • A total of 46 yeast strains were isolated from traditional dry fermented sausages. • Intraspecific genetic diversity of yeast strains was explored using ISSR-PCR. • Eight strains exhibited high tolerance to acid, salt, and sodium nitrite stresses. • Seven strains showed specific capacities to produce acids, alcohols, and esters. • Debaryomyces hansenii SH4 produced multiple compounds with high odour activity value. [ABSTRACT FROM AUTHOR]