| Salt is one of the important and indispensable components in people's daily life.However,an excess intake of dietary salt is one of the highest dietary risk factors for diseases and deaths globally.Therefore,how to reduce salt in the processed food while maintaining the sensory quality of food is a major challenge.In this paper,gum arabic(GA),Water-extractable arabinoxylans(WEAX)and citrus fiber(CF)were taken as the objects.The corresponding salt reduction strategies in liquid food,semi-solid food and solid food were given based on food hydrocolloids.And the mechanism of enhancing saltiness perception in various types food was discussed.These findings would provide the theoretical supports for development of new technology of salt reduction and low-salt food in food industry,contributing to reduce people's salt intake and maintain their health.The main conclusions are as follows:1.The mucopenetration ability of gum arabic(GA)was discovered,and salt reduction 30%in liquid/semi-solid food(Yogurt drinks and mayonnaise)was achieved based on mucopenetration of GA.The mechanism of salt reduction of GA in liquid food had been studied in comparison with pectin.The results showed that the addition of GA enhanced the saltiness perception in the standard NaCl solution and yogurt drinks,achieving a salt reduction of 30%without saltiness loss.The results for sodium retention on vitro pig tongue and simulated tongue showed that the adhesion of GA was stronger than pectin,contributing to increase the saltiness perception.Compared to the pectin,GA exhibited the unique mucopenetration characteristics,which attributed to the screening effect of sodium ions on GA,masking the charged groups of GA,further led to a smaller size,lower viscosity,and thus improved diffusion rate of GA and sodium ions in the mucus.2.A salt reduction strategy for semi-solid food was developed based on the inhomogeneous distribution of protein/polysaccharide coacervate.Soy protein isolate(SPI)/GA coacervate containing sodium(Na+)was constructed,and SPI/GA coacervate system was dispersed in semi-solid starch gels,thus achieving the inhomogeneous distribution of salt.The results showed that the Na+preferentially partitioned in the coacervate phase during the formation of coacervate,contributing to form of sodium-rich spot in the semi-solid food.The sensory analysis revealed an enhanced saltiness of starch gels allowing a reduction in the salt content of 30%,while maintaining the taste and texture qualities.From the results of oral processing,the enhanced saltiness was attributed to a faster sodium release.Quartz crystal microbalance with dissipation(QCM-D)was used to reveal the mechanism of salt reduction,showing that GA that was screened by salt exhibited the mucopenetration ability and higher binding affinity with mucin layer,accelerating GA and sodium ions through the mucus layer and enhancing the saltiness perception.3.The GA and tannic acid(TA)complex system was constructed,and the interaction between flavor emulsion stabilized by GA-TA and mucin were manipulated to control the release of flavor components and oral perception,making a possible for odor induced saltiness enhancement in the liquid food.Results showed that the interaction of GA and TA was dominated mainly by the noncovalent interactions(hydrogen bound or hydrophobic interactions).Compared to the emulsions stabilized by GA or TA alone,the emulsions stabilized by GA-TA showed a smaller size and better physical stability.And the retention of flavor emulsions and release of flavor components in the vitro porcine tongue and model mouth were also evaluated.Results showed that the addition of TA delayed the release of flavor components,GA-TA complex enhanced the oral complexity of flavor emulsions,GA inhibit the interaction of TA and mucin,decreasing the astringency caused by the interaction between TA and mucin in oral cavity.4.The salt reduction strategy of bread based on dietary fiber enhancement was developed.Different mixing method of dietary fiber(WEAX)and wheat flour were used to achieve the inhomogeneous distribution of salt in bread in order to reduce the salt content of bread.The results showed that the pre-hydration of WEAX in the salt solution could achieve the inhomogeneous distribution of salt in bread and allow a reduction in the salt content of 20%while maintaining the saltiness perception.And it could achieve a reduction in the salt content of 30%with further adding a certain amount of calcium(1.0 wt%calcium chloride).The results showed that the addition of WEAX had no significant effect on the rheological properties of dough and bread quality.The results of Transwell?experiment proved that the presence of calcium ions significantly accelerated the penetration of sodium ions in the mucus layer,which was attributed to mucus aggregation induced by the calcium ion,manipulating the permeability of mucus layer,increasing the sodium ion diffusion and the saltiness perception.5.In this chapter,a salt reduction strategy of plant-based meat(or meat analogues)based on CF enhancement was constructed,achieving a salt reduction of 20%while maintaining the saltiness perception of meat analogues.The effect of CF addition on moisture content,water distribution and internal microstructure were investigated,and the mechanism of salt reduction via salt release in vitro and oral processing was evaluated.The results showed that the addition of CF affected the phase separation between protein phase and water phase and internal microstructure in the process of meat analogues formation.The release of salts in vitro revealed an increase in the rate of salt release for meat analogues,contributing to enhance the saltiness perception,which mainly attributed to higher moisture and porous microstructure of CF meat analogues.During the oral processing,CF meat analogues with high moisture were compressed,resulting in the water between the layers was expelled from the meat analogues matrix,which generated cracks and small fragments and enhance the salt release and saltiness perception. |
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