Study On The Preparation And Shelf-life Of Gelidium Amansii Yogurt Tablets

Gelidium amansii is an important wild deep-sea red algae,the agar extracted from it has good transparency,high gel strength,strong stability and water holding capacity,and rich in alginate substances,starch sulfate fat,minerals and vitamins,as well as other nutrients,so it has a high diet and economic value.It has antihypertensive,hypolipidemic effects.At present,for the development and utilization of Gelidium amansii products is insufficient,most of the resources have been wasted.Thus,it is of great significance to develop high value products.In this research,acid method was used to degrade Gelidium amansii agar,and the degradation processes were determined.The Gelidium amansii agar and its degradation products,combined with reconstituted milk,Bifidobacterium and sucrose was to ferment yogurt.Finally,the shelf-life of yogurt tablets was determined.The results were as follows:1.The single factor experiments suggested that the degradation time,solid-liquid ratio,degradation temperature has a significant effect on the degradation of agar.The response surface experimental design was used to determine the optimization of agar degradation process:34.28 min the degradation time,1:60 solid-liquid ratio,117.24 ?degradation temperature,243.50 mgreducing sugar content under this condition.TLC results showed that the degradation products contained agar oligosaccharides.Turbidimetric method showed that agar degradation products was able to promote the growth of bifidobacteria,and the best adding amount was 1.5%.2.The optimum formula of yoghurt was obtained by single factor and response surface:11.34%sucrose,20%Gelidium amansii agar,1.5%inoculum amount,5.93 h fermentation time.Under these conditions,the predicted sensory evaluation was 80.58 and the number of viable bacteria was 2.83 X 109CFU/mL.Compared Gelidium amansii yogurt with commercially available yogurt found that the field of number of live bacteria,water holding capacity,hardness,adhesion,recovery,chewiness and consistency were higher,while the sensory scores need to be improved.3.The NMR and magnetic resonance imaging(MRI)and environment scanning electron microscope(ESEM)were used to study the changes of water holding capacity and network structure during fermentation and ripening process.The results showed that the addition of Gelidium amansii agar was beneficial to improve the water holding capacity of yoghurt during fermentation and storage.The results showed that the optimal fermentation time and the post-ripening time were 6 h and 24 h,respectively.4.The sensory evaluation and texture technology were used to get the best process for Gelidium amansii yogurt tablet:15%maltodextrin,15%?-Cyclodextri,1.6%CMC-Na,1.2%magnesiumstearate.Pearson correlation analysis showed there was significant correlation between sensory scores and viscosity and there was positivecorrelation with hardness and chewiness.5.The effects of different storage conditions on shelf life of carnation yoghurt tablets were discussed.The results showed that with the extension of storage time,the hardness and chewiness,Bifidobacterium,and sensory scores were decreased in different degrees.Viscosity,total number of colonies wereincreased.The shelf life of PE plastic sealing packaging at room temperature is about 60 days.While aluminum foil packaging was at normal temperature and aluminum foil sealing packing was at 4 ?,the shelf life of PE plastic packaging was about 180 days.