| As the primary process of black tea processing, the optimization of withering process parameters has a great influence on tea quality. At present, compared with temperature and humidity, research on the relation of light condition (including light quality, light intensity, light hours, etc.) and withering leaf quality is less. This paper attempts to combine light condition parameters with the traditional parameters (i.e. temperature and humidity) and explore how these combination impact the changes of physical and chemical properties of withering leaves. The method of response surface design is adopted to obtain the the corresponding withering optimization parameters for the best sensory quality of tea. On the basis of the above verified parameters, a digital device with function of visual inspection to monitor the degree of withering is designed and tentatively applied in practice.The main results are as follows:(1) During the withering process, the water content as a whole decreases with the passage of time. The bulk density and softness of the products are the signs of the degree of withering. The turning point is the best time to enter the rolling stage. The activities of polyphenol, soluble sugar and PPO decreased,while the activities of POD, amino acids and water-soluble flavonoids were increased.(2) Under the different withering temperature (20 ?,25 ?,30 ?,35 ?,etc.),25-30 ?treatment bulk density, softness is more peace, and PPO, POD enzyme activity is the highest, sensory review Good; and 35 ? treatment group, the sensory evaluation of tea in the performance of the more well(3) Under different wilting relative humidity (RH50%, RH60%, RH70%, RH80%), the wet weight and softness of RH60% -70% wilted samples were the best, and the activities of PPO and POD were the highest, Review is better(4) Under different light intensity (3001x, 6001x, 9001x, 12001x), the light intensity of 9001x was moderate, the bulk density, softness and other properties, polyphenols, amino acids, POD activity and sensory The total score of the best quality; and 12001x score in the aroma better(5) The Box-Behnken design was applied to optimize the wilting process of black tea. Three factors,such as withering temperature, relative humidity, and red light intensity, were selected as the index of tea sensory quality. Find the regression equation and the optimal parameters:Aroma score = 90 + 1.63 * A-2.12 * B-0.75 * C + 0.25 * AB + 0.5 * AC-1 * BC + 0.87 * A2-1.13 *B2-0.87 * C2When the temperature was 22 ?, light intensity was 13001x and humidity was 64.3%, the maximum score of sensory evaluation was 93.4.The results are shown in Table 1. The results are shown in Table 2. The results are shown in Table 1.The results are as follows:When the temperature is 31.6 ?, the light intensity is 13001x and the humidity is 61.5%, the sensory evaluation has the maximum value of 93.4.taste score = 91 + 0.12 * A + 1.00 * B + 0.63 * C-1.00 * AB + 0.25 * AC-2.37 * A2-2.62 * B2-0.38 *C2Temperature of 27.9 ?, light intensity of 7201x, humidity 68.4% of the sensory evaluation of taste when the maximum score of 91.3 points;sensory evaluation score = 89.70 + 0.30 * A+ 0.52 * B-0.33 * C-0.25 * AB + 0.40 * AC-0.15 *BC-0.2 * A2-1.35 * B2-0.7 * C2Temperature 27.7 ?, light intensity 10461x, humidity 59.2% when the sensory evaluation of the maximum score of 89.8 points(6) The computer vision technology is used to detect and control the degree of withering. The system consists of a data collector and corresponding professional software. By converting rgb and other photoelectric data into digital format data, the degree of withering is monitored in real time. Through the computer terminal, To meet the different needs of the product. At present, the experiment has achieved initial results, and computer vision technology and optical composite technology in the practical production of tentative promotion. |
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