Study On Preparation Process Of High Transparency Agar

Agar is a polysaccharide extracted from Gracilariaand Gelidium,and is widely used in food,biology,and medical fields.Transparency is an important quality indicator of agar products,which directly affects the application in actual production.This paper first compared the quality differences between domestic agar and imported agar,and found the difference between domestic and imported agar in terms of transparency,gel strength and other indicators.On this basis,according to relevant literature reports,the effects of washing and carboxymethylation reaction processes on agar transparency and related quality indicators were studied.The main results are as follows:(1)Comparing the quality of three domestic Gracilaria agars and two imported agars,it was found that the melting temperature and melting point of Gracilaria agar were higher than that of imported agar,and the transparency and whiteness were lower than that of imported agar,and the turbidity was higher than that of imported agar.(2)Research of the Gracilaria agar washing process was optimized to obtain ethanol washing conditions:ethanol concentration 80%,washing time 1.5 h,cleaning temperature 30℃,The sodium hypochlorite cleaning conditions were sodium hypochlorite concentration 0.08%,cleaning time 1 h,and cleaning temperature 30℃.With this technology,the transparency of Gracilaria agar reached 88.9%.(3)Transparency and gel strength were used as indicators,the optimum conditions for carboxymethyl reaction of gracilaria were:the amount of chloroacetic acid added was 0.38 g/g,and the reaction is carried out in two portions,reaction temperature is 50℃,reaction time is 50 min,pH=5.0.Agar prepared by this process,it’s transparency is 96.5%,the gel strength is 1095.2 g/cm2,and the turbidity is 8.9 NTU.The transparency of the pilot test sample was 96.7%,the gel strength is 834.2 g/cm2,and the turbidity is 8.5 NTU.All meet the technical requirements of imported similar agar products.This paper developed a preparation process of high transparent agar.The transparency quality index meets or exceeds the foreign similar products and maintains a high gel strength.It provides a technical basis for domestically produced high transparency agar products.