Effects Of Flaxseed Gum On Water-Holding Capacities, Emulsion Capacities, Gelatinisation And Anti-Retrogradation Of Starch In Meat Product

Flaxseed gum (FG), one of the most potential hydrocolloid gums, contains mainly xylose, rhamnose, galactose, glucose, arabinose, fucose and galacturonic acid. It has been shown that flaxseed gum has a potential in water holding capacity, emulsion and anti-retrogradation of starch. In recent years, FG has been intensitively focused on its physichemical properties, especially in non-meat products. However, few data are available on its application to meat products. The objective of the present study is to explore the effect of FG on water-holding capacity, emulsion, gelatinisation and anti-retrogradation of starch. The whole study includes the following seven parts:1 Effect of flaxseed gum on water holding capacity of heat-induced gel of porcine myofibrillar proteinsWater holding capacity of heat-induced gel of porcine myofibrillar proteins increased (P<0.001) as FG concentration increased. Scanning electron microscopy (SEM) showed that WHC of protein gel was related to its microstructure. Distributed analysis of the T2 relaxation revealed that addition of FG significantly decreased water mobility of porcine myofibrillar protein (P<0.05). The fourier transform infrared spectroscopy (FT-IR) analysis suggested that FG strengthened electrostatic attraction of PMP system. Flaxseed gum improved WHC of heat-induced gel of PMP, which is concentration-dependent, by a finer gel network, lower relaxation time and stronger electrostatic attraction.2 Effect of flaxseed gum on emulsifying stability of lard Emulsifying stability of lard was investigated at different concentrations of lard (6%, 8%,10% w/w oil) and FG (0.1,0.3,0.5% w/w) and their ratio (60 to 20). Particle size, emulsion ability, emulsion stability, the mobility of oil droplets and the oil/protein interaction at the interface were measured. At a low concentration (0.1% w/w), the presence of flaxseed gum caused the aggregation of oil droplets in an emulsion by the formation of cross-links, which resulted in larger particles and thus poor emulsion ability, and emulsion stability. At a high concentration (0.5% w/w), the emulsion droplets were fully covered by flaxseed gum and showed good particle stability, emulsion ability, and emulsion stability. NMR was used to characterize the undiluted emulsion systems. Lower T2 values (by low-field 1H NMR) in the emulsions containing both high (0.75% w/w) and low (0.25% w/w) amounts of flaxseed gum, indicated increasingly restricted mobility of lard. The line broadening in lard signals in the NMR spectra (low-field 1H, high-field 1H,13C) indicated increased interaction between lard molecules and flaxseed gum at the interface with increasing flaxseed gum concentration in emulsions. The values of resonances of the individual groups on lard molecules, obtained by high-field 1H NMR, reflected their different environments within the lard droplets.3 Influence of flaxseed gum on the gelatinisation of maize starchDifferential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction(XRD) and scanning electron microscope(SEM) were used to investigate effect of flaxseed gum on the gelatinisation of maize starch. The DSC results showed that the addition of flaxseed gum to maize starch siginificantly increased the onset temperature and enthalpy of starch melting. The FT-IR spectra of the maize starch and maize starch-FG powders were very similar, indicating that the addition of FG did not change the chemical structure of maize starch. There was no interaction between flaxseed gum and maize starch at 65℃. However, FG can facilitate the combination of starch and water at 75℃. X-ray diffraction results showed that there was no significant change in relative crystallinity of maize starch before and after the addition of FG before gelatinization of maize starch, but relative crystallinity of maize starch was significantly decreased after gelatinization, which indicated that the addition of flaxseed gum delayed the maize starch gelatinization. Scanning electron microscopy confirmed it.4 Effect of flaxseed gum on the retrogradation of maize starchDSC, NMR, XRD and SEM were used to investigate effect of FG on the retrogradation of maize starch.The DSC results showed that the addition of FG siginificantly decreased maximum degree retrogradation (DR) of mazie starch gel at 7th, 14th and 21th day. NMR T2 distribution revealed two distinct water populations corresponding to intra-and extra-granular water, which significantly increased after FG was added. The results of DSC and NMR showed that with the increase in water content in maize starch gel, concentration of maize starchs was decreased and less cross-links were formed among starch molecules, and thus retrogradation degree was lower when FG was added to maize starch. However, recrystallization of maize starch could occur after FG addition under X-ray diffraction (XRD). However, the sensitivity of powder X-ray diffraction is relatively low compared with techniques with DSC which are able to detect even minor extents of recrystallization.Scanning electron microscopy showed that the addition of FG gum induced the formation of porous structure of maize starch, which increased the water holding capacity of starch gel.5 Interaction between Flaxseed Gum and other hydrocolloids in Meat ProductsFactorial design was applied to investigate the interaction among FG, carrageenan and xanthan gum, which are commonly added in meat products. Results indicated that the addition of FG had highly signifcant effect on water retention of sausage after drying for 20,40,60 and 80 min at 60℃(P<0.01). Carrageenan had no signifcant effect on water retention of sausage after drying for 20 and 40 min at 60℃(P>0.05). FG and xanthan gum had a signifcant interaction on water retention of sausage after drying for 20and 40 min at 60℃(P<0.05). FG, xanthan gum, carrageenan showed different water holding capacity, from high to low in order. FG had signifcant effect on oil retention of sausage after dipping into diethyl ether for 40 and 60 min (P<0.05) but rather not for xanthan gum and carrageenan. The oil holding capacity in order from high to low is flaxseed gum, xanthan gum, carrageenan.6 Interaction between Flaxseed Gum and non-meat proteins in Meat ProductsFactorial design was applied to investigate the interaction among FG, SPI and casein, which were also commonly added in meat product. The addition of FG had highly signifcant effect on water retention of sausage after drying for 20 min at 60℃(p<0.01) However, the addition of FG did not affect water retention of sausage after drying for 40 min at 60℃(P>0.05). The addition of casein also affected water retention of sausage after drying for 20 and 40 min at 60℃(P<0.01).The order for water holding capacity was casein,FG, SPI from high to low. The addition of FG had signifcant effect on oil retention of sausage after dipping into diethyl ether for 20,40 and 60 min (P<0.05) as did the addition of SPI and casein. The addition of SPI showed highly signifcant influence on oil retention of sausage after dipping into diethyl ether for 60 min (P<0.01) and there was signifcant interaction between FG and SPI on water retention of sausage after drying for 60 min at 60℃(P<0.05).The oil holding capacity of SPI is higher than that of casein.7 Effects of flaxseed gum, xanthan gum and soy protein on yield and textural properties of pork sausageA three-factor Central composite rotatable design was adopted for studying the simultaneous effects of processing variables such as FG (0.1-0.5%), xanthan gum (0.2-0.6%) and SPI (1.0-4.0%) on yield and textural properties of pork sausage. In addition, the ridge analysis was conducted to find the interactions of processing variables, i.e., yield and the texture profile analysis (TPA) parameters. Experimental design allowed for evaluation of potential interactive and quadratic effects between these variables. It was found that the addition of FG, xanthan gum and SPI increased the yield (p<0.05) as the amount of FG, xanthan gum and SPI increased. FG and SPI had interactive effect on yield and adhesiveness. There was signifcant increase on hardness of sausage with increasing SPI. The springiness of sausage decreased with increasing amount of xanthan gum and SPI, and there was signifcant interaction between xanthan gum and SPI. The cohesiveness of sausage significantly decreased with the increasing amount of FG, but increased with the increasing amounts of xanthan gum and SPI. There was signifcant interaction between xanthan gum and SPI on cohesiveness of sausage. Neither of FG, xanthan gum and SPI affected chewiness.