The Effect Of Oligofructose And Inulin On The Flavor Of Fermented Sausage

Fructo-oligosaccharides and inulin have functions of dietary fiber and prebiotics.They have been used in many foods to improve the color,texture,texture and processing characteristics of products.Many experiments showed that fructo-oligosaccharides and inulin effected on the viability of lactic acid bacteria,and promoted the production of short chain fatty acids.Short chain fatty acids have important effects on flavor of fermented sausages.In light of the positive flavor impacts of fructo-oligosaccharides,inulin and lactic acid bacteria,there is sufficient evidence to warrant further exploration into the potential effects of a combined into fermented sausages.In this project,lactic acid bacteria degraded fructo-oligosaccharides and inulin efficiently were screened from Jinhua ham of which was rich in microbial resources.Then to investigate the changes of sugar composition of fructo-oligosaccharides and inulin,and the mechanism of the production of volatile compounds in lactic acid bacteria fermentation broth.In addition,the model sausages was used to study the effects of fructo-oligosaccharides and inulin on protein degradation and flavor production.On this basis,the fermented sausages was used to explore the effects of fructo-oligosaccharides and inulin on the quality of fermented sausages during drying process.It could be implied the regulation of improvement of quality of feremnted suasges by supplementing the combined fructo-oligosaccharides,inulin and lactic acid bacteria.The main results are as follows:1.A total of 135 strains of lactic acid bacteria were isolated and purified from Jinhua ham.22 strains of lactic acid bacteria were obtained according to the meat starter culture selection standard and a discoloration plate method.By activity screening on broth containing fructo-oligosaccharides or inulin as carbon source in the media and the activity of?-fructofuranosidase,strain L40 of which bacterial density and ?-fructofuranosidase activity were highest.The sequencing analysis results showed that the amplified 16S rDNA sequence of L40 had the highest homology(98%identity)with that of Lactobacillus curvatus.The morphological observation and chemotaxonomic assays showed that strain L40 had the diagnostic characteristics of Lactobacillus curvatus.Therefore,strain L40 was identified as Lactobacillus curvatus.2.Determinated of growth and acid production ability of Lactobacillus curvatus,the change of sugar composition and volatile flavor of Lactobacillus curvatus in fructo-oligosaccharide and inulin as carbon source fermentation broth to explore the mechanisms production of volatile flavor compounds.The results showed that fructo-oligosaccharide and inulin could promote the growth of Lactobacillus curvatus,and significantly reduced the pH of the fermentation broth.At the end of the fermentation,the contents of sucrose,1-kestose,and nystose in the fermentation broth with fructo-oligosaccharide decreased by 68.0%,93.1%,and 92.6%,respectively,the contents of fructose,sucrose,1-kestose,nystose,and 1 F-fructofuranosylnystose in the fermentation broth with inulin decreased by 61.6%,86.6%,90.9%,25.8%.Acids,aldehydes,ketones and alcohols in the fermentation broth with fructo-oligosaccharides arid with inulin were significantly higher than that of fermentation broth with glucose(P<0.05),mainly reflected in acetic acid,3-methyl-butanal,phenylacetaldehyde and 3-methyl-1-butanol.Results showed that the strain Lactobacillus curvatus mainly fermented the 1-kestose and nystose components in fructo-oligosaccharides or inulin to produce a large amount of volatile compounds.3.To evaluate the aroma produced by fructo-oligosaccharides or inulin combined with Lactobacillus curvatus in a model system with conditions resembling those used in fermented sausages by determining the the change of pH,total lactic acid bacteria,protein degradation,free amino acid and volatile flavor in the meat model system during the fermentation process.The results showed that the addition of fructo-oligosaccharide and inulin could significantly reduce the pH of model sausages,increased the total number of lactic acid bacteria significantly(P<0.05).In the model sausages with fructo-oligosaccharides and model sausages with inulin,paramyosin(97.2 kDa)and actin(45 kDa)in the myofibrillar protein were significantly degraded compared with the model suasages with sucrose,and the total amount of free amino acids were higher than that in the model suasages with sucrose,mainly reflected in the sweet and bitter amino acids.At the end of the fermentation(12 d),3-methyl-butanal,phenylacetaldehyde,hexanal,3-hydroxy-2-butanone,pentanol,2,3-butanediol,and the content of ethyl acetate and methyl isovalerate in the model sausages with fructo-oligosaccharides and model sausages with inulin were significantly higher than that of model suasages with sucrose(P<0.05).4.The effect of fructo-oligosaccharides and inulin combined with Lactobacillus curvatus on the quality of fermented sausages was investigated.The results showed that the addition of fructo-oligosaccharides and inulin could increase the sausages' safety by reducing the pH,and also reduced hardness and oxidation of sausages fat and made the sausages easier to chew.In addition,the addition of fructo-oligosaccharides significantly increased the L*of the sausages,and the addition of inulin significantly inhibited the increase of b*of sausages during air-drying(P<0.05).The volatiles content of the suasages with fructo-oligosaccharides were higher than other groups,mainly in ethyl acetate,phenylacetaldehyde,acetic acid,pentanol and 3-hydroxy-2-butanone.Sensory evaluation scores and overall acceptability were shown that the suasages with fructo-oligosaccharides was better than the suasages with sucrose.