Research On The Composition,Functional Properties And Application Of Flaxseed Gum For Fat Reduction

Exogenous fats are often added during the production of surimi to compensate for the loss of the rinsing process and improve quality.Due to the impact of excessive fat intake on human health,researchers are now working on the development of a variety of lipid substitute products.As a hydrophilic polysaccharide,flaxseed gum has high water retention capacity,high viscosity and weak gelling properties.In this paper,flaxseed gum and grass carp surimi gel were used as research objects to characterize the characteristics of flaxseed gum prepared by different p H solutions,and the influencing factors of the functional properties of flaxseed gum were studied.On this basis,flaxseed gum was added to grass carp surimi gel in a certain proportion to replace part of the fat,and the effect of partial fat replacement of flaxseed gum on the characteristics and molecular structure of grass carp surimi gel was discussed,which laid a theoretical foundation for the development of healthy low-fat surimi,and the main research contents and results are as follows:1.The effect of the composition and functional properties of flaxseed gum prepared by different p H solutions was studied.The components,monosaccharide composition,physicochemical properties of FG extracted under acidic（p H 4.0）,neutral（p H6.5）and alkaline（p H10）solutions were compared,and the extraction conditions of FG with excellent functional characteristics were screened.The results showed that the intrinsic viscosities of FG（FG-4）extracted from p H4,FG（FG-6.5）extracted from p H6.5and FG（FG-10）extracted from p H10 were 692.1 ml/g,674.4 ml/g and 763.6 ml/g,respectively,and the corresponding weight average molecular weights were 6.996×10⁵g/mol,6.381×10⁵g/mol and 7.377×10⁵g/mol,respectively;The protein content in FG-4was slightly higher than that of FG-6.5 and FG-10,and the main monosaccharide components of FG were xylose（30.35%～31.19%）and rhamnose（24.65%～25.54%）,and the proportion of neutral polysaccharides in FG-10 was relatively low;The particle size of FG-10 was significantly greater than that of FG-4 and FG-6.5,while the electronegativity of FG-10 was significantly greater than that of FG-4 and FG-6.5,the emulsification,emulsification stability and gelling of FG-4 were better than FG-6.5 and FG-10,and the p H of the extraction solution had no significant effect on the foaming and foam stability of FG.Therefore,FG extracted under acidic conditions（p H 4.0）has better functional characteristics.2.To study the effects of different amounts of salt（Na Cl,Ca Cl₂）,sugar（sucrose,trehalose）and different p H and heating temperature on the emulsification and stability,micromorphology,foaming property and its stability and gelling characteristics of FG,and analyze the effects of different processing factors on the functional characteristics of FG.The results showed that the emulsifying activity of FG decreased with the increase of ionic strength(Na⁺and Ca²⁺),and showed a trend of increasing and then weakening with the increase of carbohydrate（trehalose and sucrose）,and the emulsifying activity was the highest at 2 g/L;With the increase of p H,the emulsification performance of FG was the worst,and the emulsifying activity of FG gradually decreased with the increase of temperature,and the emulsification performance of FG at 10°C-50°C was better.When the amount of Na Cl was 20 mmol/L,and the addition of Ca Cl₂was 20 mmol/L and 80 mmol/L,the foaming property of FG solution was strong,and the addition of different concentrations of Na Cl and Ca Cl₂reduced the foam stability to different degrees;When the concentration of trehalose was 2 g/L and 8g/L,and the concentration of sucrose was 8 g/L,the foaming property of FG solution was good.The foaming property of FG solution is the best at p H8,and the foam stability of FG solution is the best at p H10.When the temperature is 50°C,FG has good foaming performance.The addition of Na Cl to FG solution led to poor gelability,and the addition of Ca Cl₂led to the increase and then decrease of FG gelability,and the gel strength was the highest when the addition amount was 20 mmol/L.The amount of trehalose and sucrose added reached 10 g/L,and the FG gel strength reached the highest.With the increase of p H,the gel strength of FG showed a trend of increasing first and then decreasing,and the gel strength was the highest at p H6.FG gel strength increases with dissolution temperature,and gel strength is highest at 90°C.3.The effects of different amounts of FG instead of fat on the microstructure,intermolecular force,secondary structure,water holding capacity,gel characteristics and digestibility of grass carp surimi gel were studied,and the optimal proportion of FG instead of fat was screened.The results showed that the addition of FG made the surimi gel form a more dense and ordered three-dimensional network structure,significantly increase the hydrogen bond,hydrophobic interaction,ionic bond content in the system,reduce the non-specific binding effect,and strengthen the transformation ofα-helix toβ-fold.The different proportions of FG instead of oil in grass carp surimi gel significantly affected the gel characteristics,and when the FG substitution ratio was 80%,the water holding and oil holding properties of the gel were the most significant,and the centrifugation water loss rate increased by 2.2%and the cooking loss rate increased by 4.39%compared with the gel without added fat.Adding FG instead of 60%or 80%fat can significantly improve the texture properties of the gel,enhance the gel strength,and slightly reduce whiteness.The gel strength of the 60%FG replacement ratio was increased by 45.16%compared to the gel without FG.The whiteness of the gel with an FG replacement ratio of 80%was 1.53%lower than that of the gel without FG added.FG substitution ratio 60%and 80%gel can slow down the protein digestion rate,in the first 30 minutes of digestion,the protein digestibility of gel with 60%and 80%replacement ratio is 21.73%and 12.01%lower than that of surimi gel with only added fat,respectively.The addition of FG did not affect the final digestibility of protein,and the digestibility of all treatment groups reached 80%～90%after digestion for 3 h.After adding FG,the myosin denaturation temperature decreased from around50°C to around 40°C.