Study On Drying Technology And Product Characteristics Of Abalone

Abalone is gastropods of mollusca, single shell, living in the shallow water, with abdominal foot adsorption in the rocks. Abalone only has a shell which has an oval, flats and fat abdominal foot. Processed dried abalone is delicious exception. Abalone is welcomed by the market and has wide market because of its taste and convenient storage. This paper took abalone n Australia as the raw material in order to study processing technology from salted to dry and dynamics, thermodynamics of the process, as well as compare the advantages of products and drying, natural dry through the electron microscope scanning, nutrition index, sensory index, finally obtains the best processing technology.1. Studied the effect of temperature, salt concentration on dehydrated abalone by apply comprehensive test of two factors 3 levels in order to obtain the best process of salted abalone. The results showed that: the best process: temperature: 20℃, salt concentration: 10% and salted time: 24 hours. In order to control the salt content of abalone to meet the needs of the market and control the moisture content of abalone to guide later drying production and shorten drying time. Establishing dynamic model, predict and control drying time and the internal salt content of abalone was to control the quality of dried abalone, and then promote large-scale production. Obtained the dynamic equations of water loss and sale content when the saline under different times are: wl = 9.2+1t /1009.32t and S tG =4.24t/100 +52t.56t, guided the actual production according to different process requirements.2. In order to study the effect temperature, humidity, wind speed on the quality of abalone in drying process, considered the effect of three factors on the sensory quality of abalone by single factor experiments. The results showed that: the effect order of three factors on the quality of dried abalone in the experimental range: humidity>temperature >wind speed, as well as the effect of three factors on sensory score increased at first then decreased and show a down parabola.In order to get the best drying technology of drying process, optimize operating parameters of cold-air drying of abalone, established a quadratic regression orthogonal rotational combing design which optimize technology taking temperature (x1), humidity (x2)and wind (x3)for dry conditions With sensory score as index, finally obtained the second response surface regression model: y = 68 .21-7.66x₁ -8.68x₂-2.05x₃-4.63x₁x₂+10.38x₂x₃-3.49x₁²-2.34x₃² and the optimum drying temperature: 16℃, humidity :70%, wind speed: 3m / s.3. In order to control product quality and characterize dynamics characteristic, studied dynamic characteristics of dry abalone and diffusion rate of internal moisture of abalone by diffusion coefficients during drying process. The results showed that: effective diffusion coefficients were in 2.833³.379×10^-10m²/s range, diffusion constant D0 = 5.886×10^-6m²/s, diffusion activation energy was 2.34kJ/mol, and the diffusion coefficient was the biggest at 16℃.4. Quoted unsteady Fick second law model to understand the transport process of material moisture with the changes of time, distance better, and did numerical calculation for model using Matlab by determining the initial and boundary conditions, and drew 2d and 3d images for mass transfer process, obtained reasonable drying technology by analyzing image to provide sufficient theoretical basis for improving the quality of product.5. To illustrate the superiority of the cold dry abalone, made drying treatment for abalone in cold dry, hot air drying, traditional natural air basks and finished chemical comparison parameters under the condition of different operating parameters. (1)By color analysis, showed that abalone which is larger red and yellow, Fully rosy, tan by cold-air dry meet the standard of superior abalone. (2) By different magnification electron microscopy scans, observed that abalone which has the larger gap of muscle fibers and connective tissue by cold-air dry is good to rehydration and taste. (3)By the sensory score of three drying methods, showed product by cold-air drying has the highest score (43.9) and was the best for color, shape, feel, smell, taste. (4)By the analysis of main component content, showed cold-air dried abalone: protein (61.83%), higher fat (15.65%), ash (4.92%), less water (12.6%). (5)By the comparison of shrinkage, showed the shrinkage of hot air drying was the biggest and 82% after 30 days, while the shrinkage of hot-air drying had little change and reach 78% after 32 days. (6)By the analysis of inorganic elements, showed inorganic elements had little change by three drying methods. The results showed that abalone was the best by cold-air drying.