Development Of Parfait Food Based On Kelp And Study On The Technology Of Preservation During Storage

Kelp (Laminaria japonica Aresch), is a very important economic algae withabundant nutrient. At present, traditional processing techniques are still dominantmethods for producing kelp products in our country, and the resulting products arerough and lack of market competitiveness. In this thesis, based on the nutritionalcharacteristics and properties of the kelp, a new snack kelp-parfait was developed, andPCR technique was used to detect and identify dominant spoilage bacteria in theproduct during storage. According to the result of PCR determination, anti-spoilagemeasures were take to and inhibit the dominant bacteria flora and extend shelf life ofthe kelp-parfait. A new way was exploited for full utilization and ehancingadded-value of kelp resources by this reserch. The major achievements and resultswere concluded as follows:1. Effect of deodorization agent including licorice, green tea, citric acid, andacetic acid was investigated. According to L9(34) orthogonal experiment protocol,the effect of concentration of deodorization agent, deodorization temperature, anddeodorization time. By intuitive analysis and comprehensive consideration, it wasshowed that deodorization effect of green tea was best, and the optimum conditionswere: concentration of deodorization agent2%, deodorization temperature30°C, anddeodorization time20min.2. Polyphosphates was used as kelp softener. According to the quadraticorthogonal rotation combination experiment design, the mathematical regressionmodel for kelp pulp yield (Y) and softener concentration (X1), reaction temperature(X2), reaction time (X3) was established. The resulted regression equation was listedas follows:Y=84.13835+1.00581X1+0.61241X2+2.60440X3-0.83790X12-0.90861X22-1.17378X32-0.10000X1X2-0.35000X1X3-0.42500X2X3,The regression model fitted with the actual practice can be used to reflect therelationship between the production of softener concentration,reaction temperature,reaction time and seaweed pulp yield. The optimal parameters were: concentration of polyphosphate0.08%, the reaction temperature60°C, and reaction time6h. Under thisexperiment condition, seaweed pulp yield was85.7%.3. EZ-TEST texture analyzer was used to analyze the kelp-parfait texturecharacteristics, factors effecting on the texture characteristics were invesitigated,including dosage of seaweed pulp, carrageenan, ansd konjac gum. It was showed thatthe hardness, elasticity, viscosity and chewiness can be effectively improved while thekelp-parfait was made of30%kelp pulp,0.09%-0.12%carrageenan, and0.09%-0.12%konjac gum.4. Fuzzy comprehensive evaluation method was used to describe the sensorycharacteristics of nine kelp-parfait samples made by different recipes throughmodulation membership, and a fuzzy comprehensive evaluation system was builtfirstly to determine the domain of the sensory evaluation and of commnet rating; thensingle sensory index was evaluated in order to determine the fuzzy weight vector.Finally, the fuzzy comprehensive evaluation model was established; According to theresult of the fuzzy comprehensive evaluation and verfication test, the optimal recipewas the addition of seaweed pulp, carrageenan, konjac gum, water, sugar was35%,0.1%,0.1%,48%and14%respectively. According to this formulations, thekelp-parfait’s shape, color, organization, taste are best.5. PCR technique was used to analyze spoilage bacteria of Kelp-parfait duringstorage. It was revealed that Acinetobacter baumannii, Leclercia adecarboxylata, andBacillus subtilis are donminant spoilage bacteria in the kelp-parfait.6. After treated by UV for15min, the original carrier bacterial colonies inkelp-parfait were dropped from the122cfu/g to10cfu/g, It was suggesting that UVsterilization was a viable non-thermal pre-sterilization technology for this products7. It was showed that the storage temperature has a significant impact on thekelp-parfait’s sensory score and on the total number of bacterial colonies, the lowerthe storage temperature was set, the slower the kelp-parfait’s sensory score wasdecreased, and the total number of bacterial colonies was also increase more slowly atlow temperature. the shelf life of the kelp-parfait can be prolonged to7~8days attemperature of5°C~10°C. 8. The test results was showed that the ratio of gas in the package had asignificant impact on the kelp-parfait’s sensory score and on the total number ofbacterial colonies, too high or too low O2content was detrimental for the storage ofkelp-parfait. Microbial’s growth and reproduction was inhibited when O2contentmwas decreased to about10%; CO2dissolved in the surface of the kelp-parfait coulddecrease of pH of the product, It beneficial to curb the growth of microorganisms.But if the content of CO2was increased to more than50%, the kelp-parfait’s waterholding capacity would be decreased, thereby the sensory score of the kelp-parfaitwould be reduced. Therefore, the shelf life of kelp-parfait could be extended to12days with a gas ratio about10%O2,+50%CO2+40%N2in storage packaging.9. Under the conditions of storage temperature is10°C, the gas composition is10%O2+50%CO2+40%N2, the dominant bacteria in kelp-parfait samples storage for12days is Lactococcus. Acinetobacter baumannii, Leclercia adecarboxylata, andBacillus subtilis are no detection.