The Identification,Removal Method Of Kelp Fishy Smell Ingredients And Application

Kelp (Laminaria japonica) also named Kunbu or river cabbage, is a kind of edible and medicinal large algae plants, which contains many kinds of nutrients that human body need, so kelp is very beneficial to human health. Because of it’s fishy smell, the application of kelp in food industry was inhibited. In this thesis, the identification, removal for the fishy smell of kelp and it’s application was studied. The chemical components of the fishy smell was identified through the electronic nose and HS-SPME-GC-MS, and the fermentation method was employed to remove the fishy smell of kelp and then a kind of kelp-fruit compound beverage was developed. The results were as follows:(1) Through the sensory evaluation with electronic nose, the volatile components of kelp were analyzed at 10℃,20℃,30℃,40℃,50℃,60℃, and then the HS-SPME-GC-MS was used to analyze the detail at 30℃. The results showed that there were 45 kinds of volatile components in kelp, mainly including alcohols, 20.89%; aldehydes,33.48%; ketones,21.7%; carboxylic acids,4.95%; hydrocarbon and ramification,15.15%; and small amounts of aromatic compounds and esters. It is possible that it is the interaction among these organic ingredients, which leads to the special fishy smell of kelp.(2) To remove the fishy smell of kelp, through the sensory evaluation with electronic nose, lactic acid bacteria and yeast were used to ferment the kelp. The optimal technological parameters for yeast fermentation were determined by the single factor test and the orthogonal test as follows:the temperature 33℃, the bacteria addition 0.70×108cfu/g, the time 2 h; The best technological parameters for lactic acid bacteria were:the temperature 39℃, the bacteria addition 1.00×109cfu/g, the time 7 h. Then the combined fermentation was used to optimize the fermentation. The results showed that the kind of volatile components of kelp is less 12 kinds than that of the control group. The fishy flavor disappeared after the combined fermentation.(3) Use the iodine dissolution rate as the index, the components of kelp was extracted in the compound phosphate solution, based on the single factor experiments and the response surface methodology, a regression model equation was obtained: Y=1153.20+12.13A+5.38B+1.00C-0.50AB+3.75AC+10.75BC-8.85A2-29.35B2-35.1 OC2, the optimal extraction parameters were proved according to the equation:the time 1.85 h, the temperature 41℃, and the pH 9.12. According to the verification, the average iodine dissolution rate was 1152.3 mg/kg, the relative error was 0.47%.(4) Pectinase was used to clarify the grape juice under different conditions, the results of the single factor experiments and orthogonal tests showed that the optimal parameters of clarification were:the amount of the pectinase 1.0 g/mL, the time 35 min, the temperature 55℃,and the pH 4.4.(5) Through the sensory evaluation, according to the single factor experiments and orthogonal tests, the formula of the kelp-fruit compound beverage was optimized as follows:the grape juice 40%, the kelp juice 30%, the sugar 6%, the citric acid 0.15%. Under this technology condition, a kind of beverage with yellowish color, clear and special flavor of grape and kelp was developed.