Effect And Mechanism Of Flaxseed Gum On Starch Retrogradation And Its Application In Pork Sausage

Starch,as a kind of indispensable energy source in our daily diet,has been widely used in food industry.However,the gelatinized starch is easy to retrogradate during storage,leading to the quality deterioration of foods,such as hardening of tissue amd shorting shelf-life.Recently,researchers have found that many hydrocolliods had the ability to inhibit the retrogradation of starch.Flaxseed gum(FG),extracted from flaxseed or flaxseed hull,is a kind of natural hydrocolloid.It has been found that FG not only had excellent"weak gel" properties,emulsification ability and thickening function,but also had the ability to inhibit starch retrogradation.Currently,the effect of FG on starch retrogradation under different storage conditions and its mechanism ere needed for further investigation.In order to investigate the mechanism of the retardation effect of FG on starch retrogradation under different storage conditions and promote the industrialized application of flaxseed gum in starchy foods,especially the meat products containing starch,this study explored the retardation effect of FG on the retrogradation of starch under different storage temperatures and times,as well as the application of FG in pork sausage.This study contains three parts,the contents and results are as follows:1 Effects of flaxseed gum on starch retrogradation under different storage temperaturesThe MS-FG gels were stored under different temperatures(-20,4,20 ?)for 12 days to analyze the retrogradation of starch gels.When the storage temperature was set at-20 ?,there was almost no starch retrogradated.When its temperature reach room temperature,the water mobility was the highest but the moisture loss and hardness of gels were the largest.When the gels were stored at 4?,the starch retrogradation was the most serious,the relative crystallinity was the largest and the water mobility was the lowest.Besides,when the gels were stored at 20 ?,the aging of starch gels was slowly,the water hold capacity(WHC)was the largest and the hardness was the lowest.The addition of FG could reduce the growth rate of crystal and the moisture loss during storage,improve the texture of the gels and inhibit the retrogradation of starch efficiently(P<0.05).FG has a significant retardation effect on the retrogradation of starch under different storage temperatures(P<0.05).2 Effects of flaxseed gum starch retrogradation at different storage timesThe MS-FG gels were stored at 4 ? and then the retrogradation of starch was measured at different storage times.As time goes by,aging of starch is more and more serious.FG has a significant retardation effect on the retrogradation of starch(P<0.05).With the addition increasing,the retardation effect tended to be more significant.However,when the concentration of FG was up to 0.4%,the change of retrogradation ratio showed no significant difference.The results of X-ray diffrication showed that FG could inhibit the recrystallization of starch.As the concentration of FG increased from 0 to 0.4%,the corresponding values of relative crystallinity of MS-FG mixtures decreased from 6.9%to 5.1%.Besides,the results of 1H NMR indicated that FG could increase the water mobility.With increasing amounts of FG,the water loss caused by starch retrogradation was dramatically reduced.The scanning electron micrographs showed that the structure of retrograded starch was improved by FG,the network tended to be neat.FG has a significant retardation effect on the retrogradation of starch at different storage times(P<0.05).3 Effects evaluation of starch,flaxseed gum and storage temperature on pork sausage using factorial designThe effects of starch,flaxseed gum(FG),storage temperature and their interaction on the quality of pork sausage were investigated using factorial design.The results revealed that after long-term storage,the WHC decreased with increasing amounts of starch significantly(P<0.05),while increased with increasing amounts of starch and temperature rising significantly(P<0.05).The interaction between starch and storage temperature had significant influences on WHC(P<0.05).Results of texture profile analysis(TPA)indicated that thedifferent mixing ratio of starch and FG had different effect on the hardness and chewiness,but had the ability to increase the springiness.The rise in storage temperature led to an increase of hardness and chewiness and a decrease of the springiness.The interaction between starch and FG could significantly decrease the hardness and chewiness while the springiness decreased significantly due to the interaction between starch and storage temperature.From the results of sensory evaluation,the sensory quality of pork sausage,which was closely related to the interaction between starch and FG,could be improved by decreasing the amount of starch,increasing the amount of FG and lowering storage temperature.