ABSTRACT
Objective: To shorten the drying time of Lycium barbarum, increase its shelf life, improve the quality of dried L. barbarum products, and provide technical support for the development of wolfberry drying industry. Methods: Using L. barbarum as experiment material, after being permeated, ultrasonic treating, blanching, ultrasonic treating + permeation and ultrasonic treating + blanchting, far infrared drying test was carried out. The effects of different pretreatment methods on the far-infrared drying characteristics of L. barbarum were studied. Weibull distribution function was used to fit the drying process. The quality and microstructure of dried L. barbarum products were analyzed. Results: After being pretreated, the drying time of L. barbarum was significantly reduced, the drying rate was increased; Compared with L. barbarum without pretreatment before pre-dried, drying time after blanching pretreatment shortened 27.5%, the moisture ratio of the material decreased fastest, and drying rate was the highest. Weibull distribution function can simulate the far infrared drying process of L. barbarum under different pretreatment conditions. The range of r2 and χ2 was 0.991 73-0.999 15 and 8.13 41 × 10-5-8.846 79 × 10-4. The drying characteristics described by scale parameter (α) and shape parameter (β) were consistent with those in the drying characteristic curve. The dried product pretreated with ultrasound + permeation had the smallest color difference (6.756 4) compared with the fresh sample. The polysaccharide content inside the material (991.27 mg/g•DW) was the highest; The microstructure of the dry product obtained by the ultrasound + penetration group had the most voids, and the drying treatment had the least damage to its surface. Conclusion: Ultrasonic and osmotic pretreatment of L. barbarum before drying can not only shorten the drying time, but also improve the quality of its dried products.
ABSTRACT
Objective: To investigate the effect of ultrasonic technology on the far infrared vacuum drying process by using Lycium barbarum as the test material. Methods: The far-infrared vacuum drying test of L. barbarum was performed by ultrasonic technology. Using the independently developed far-infrared vacuum radiation drying equipment to study the far-infrared vacuum drying characteristics and quality change law of L. barbarum under different ultrasonic frequency, ultrasonic power and ultrasonic treatment time; And the Weibull function was used to simulate the drying process dynamically. Results: With the increase of ultrasonic frequency, ultrasonic power and ultrasonic treatment time, the drying time was significantly shortened, and the drying rate was significantly increased. The Weibull distribution function could better simulate the far-infrared vacuum drying process of L. barbarum under different ultrasonic treatment conditions (r2 = 0.993 9-0.999 2, χ2 = 0.000 1-0.000 6), the scale parameter α generally increased with the increase of ultrasonic frequency, ultrasonic power and ultrasonic processing time, and the shape parameter β was greater than 1; Compared with far-infrared vacuum dried products, ultrasonic treatment can not only reduce the loss of active ingredients of L. barbarum, but also shorten its drying time. Among them, the polysaccharides (812.846 mg/g) of the dried products obtained by the single factor test under the condition of 40 kHz ultrasonic frequency was the highest. When the ultrasonic power was 80 W, the total flavone content of L. barbarum after drying increased up to 28.69% in the single factor test. When the ultrasonic frequency was 60 kHz, the total phenol content of the dried L. barbarum products obtained by the single factor test increased by 10.11%. When the ultrasonic treatment time was 25 min, the corresponding DPPH value of dried L. barbarum producta obtained by the single factor test increased by 14.33%; By comparing the microstructure diagrams under different processing conditions, it was found that ultrasonic waves can not only increase the number of micropores in the surface of materials, but also reduce the damage to L. barbarum epidermal cells. Conclusion: The application of ultrasonic technology to the far-infrared vacuum drying of L. barbarum strengthens the heat and mass transfer process inside and improves the quality of L. barbarum dried fruit, which can provide technical guidance for the development of L. barbarum drying technology.
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ABSTRACT: Drying of thin layer tomato was studied using a solar tunnel dryer under the ecological conditions of Isparta, Turkey. During drying process, solar irradiation, drying air temperature, relative humidity, and air velocity were measured constantly in different parts of the dryer. Drying runs were performed using plum tomatoes, characterized by an oval shape, intense red color. The change of tomatoes mass was measured daily. The color measurements of dried products were determined at the beginning and end of experiment. In this study, the fresh tomato samples were sorted, graded, washed in water and then sliced into quarters and halves before pretreated. Sun drying behavior of half and quarter sliced tomatoes pretreated with 10% NaCl solution and non-pretreated was investigated. Results showed that the drying time for pretreated and non-pretreated samples was not significantly different. However, drying time and drying rates were affected by number of tomato slices (quarter and half). Drying characteristic curves were evaluated against thirteen mathematical models and the Midilli et al model was the best descriptive model for solar tunnel drying of thin layer tomato. Color analysis emphasized that if tomatoes are pretreated with 10% NaCl solution, they should be sliced in quarter for better quality.
RESUMO: A secagem do tomate de camada fina foi estudada usando um secador de túnel solar sob as condições ecológicas de Isparta, na Turquia. Durante o processo de secagem, a irradiação solar, a temperatura do ar de secagem, a umidade relativa e a velocidade do ar foram medidas constantemente em diferentes partes do secador. As operações de secagem foram realizadas com tomates ameixa, caracterizados por uma forma oval, cor vermelha intensa. A mudança de massa de tomates foi medida diariamente. As medidas de cor dos produtos secos foram determinadas no início e no final da experiência. Neste estudo, as amostras de tomate fresco foram classificadas, lavadas em água e depois cortadas em quartos e metades antes do pré-tratamento. O comportamento de secagem ao sol do tomate em fatias de meio e quarto pré-tratadas com solução de NaCl a 10% e sem pré-tratamento foi investigado. Os resultados mostraram que o tempo de secagem para amostras pré-tratadas e não pré-tratadas não foram significativamente diferentes. No entanto, o tempo de secagem e as taxas de secagem foram afetadas pelo número de fatias de tomate (trimestre e meio). As curvas características de secagem foram avaliadas contra treze modelos matemáticos, sendo que o modelo de Midilli et al foi o melhor modelo descritivo para secagem em túnel solar de tomate de camada fina. A análise de cores enfatizou que se os tomates forem pré-tratados com solução de NaCl a 10%, eles devem ser cortados em fatias para melhor qualidade.
ABSTRACT
Objective: Taking Angelicae Sinensis Radix (ASR) slices as the research object, the far infrared drying characteristics and kinetic model of ASR slice were explored, which provided a theoretical basis for improving the quality of dry products and establishing a suitable processing method. Methods: The far-infrared drying technique was applied to the drying of ASR. The far-infrared drying characteristics and dry product quality of ASR were studied under different drying temperature, slice thickness and irradiation height, and the Weibull function was used to fit the drying curve. The quantitative relationship between test factors and model parameters were established. Results: With the increase of drying temperature and the decrease of the slice thickness and the irradiation height, the water ratio was decreased significantly, and the drying rate was increased significantly. The far-infrared drying process of the ASR slice obeyed the Weibull distribution function (R2 = 0.983 34-0.999 34, χ2 = 0.001 3-0.006 5), both the size parameter and the shape parameter were related to the drying temperature, slice thickness and irradiation height; The interval for estimating the water diffusion coefficient (Dcal) was 4.698 × 10-11-2.084 × 10-10 m2/s. The effective moisture diffusion coefficient (Deff) was in the range of 3.891 × 10-9-2.179 2 × 10-8 m2/s, both of which tended to increase with the increase of drying temperature, slice thickness and irradiation height. Compared with dry products from hot-hair drying, the color difference and water activity of far infrared drying were smaller, and it was easier to retain ferulic acid and volatile oil in ASR. Scanning electron microscopy analysis of the microstructure of dry products under different drying conditions showed that far infrared increased the interior of ASR slices. The number of micropores was increased, the cells were arranged more neatly, so as to increase the rate of thermal mass migration during the drying process and reduce the drying time. Conclusion: The Weibull distribution function can predict the water migration law of the drying process of ASR. It is of great significance for the prediction of the drying process of ASR and the process optimization.
ABSTRACT
Study on drying quality of pill (false drying, surface crust, and cracks) is the difficulty in pharmaceutic research of Chinese materia medica (CMM). The influence mechanism and relationship of quality of CMM pill during drying and storage are still in the experimental stage, and there is no more appropriate theory to explain and research. This paper attempts to use glass transition theory to explore drying characteristics and physical state change process and mechanism of quality change and to control the quality change of strategy of CMM pill during drying and storage.