scholarly journals Growth Modeling Kinetics of Aspergillus flavus in Dried Jujube at Different Temperatures

2021 ◽  
Author(s):  
Yiming Guo ◽  
Hua Ji
Keyword(s):  
Growth Rate ◽  
Growth Kinetic ◽  
Lag Time ◽  
Growth Characteristics ◽  
Optimal Temperature ◽  
Different Temperatures ◽  
Lag Period ◽  
Storage Methods ◽  
Kinetics Of

Dried jujube is a characteristic fruit of Xinjiang. Aspergillus is one of the main pathogens that causes mold on dried jujube, and A. flavus is a toxin-producing species, the aflatoxin produced by A. flavus is extremely toxic and carcinogenic. In this study, the growth kinetic models of A. flavus isolated from red jujube at different temperatures and times were fitted to Huang model and linear equation respectively, the Cardinal model was used to describe the growth rate and lag time of A. flavus on dried jujube agar. It turned out that 30–35 °C was the optimal temperature for growing A. flavus, so dried jujube should avoid storing in this temperature range. The kinetic model established in this study will help to understand the growth characteristics of A. flavus, and lay a foundation for evaluating the quality of stored dried jujube and predictions of shelf life, which are conducive to optimizing storage methods for dried jujube. It can be judged according to the value of Af and Bf, the Huang model had a better fitting effect than the Baranyi model, The two models all had the highest growth rate at 35 °C, and A. flavus grew more vigorously and the lag period shortened as the temperature was increased. The secondary Cardinal model had a good fitting effect on the growth rate and lag time, and the secondary Ratkowsky model had a good fitting effect on the growth rate. This study may have theoretical and application value to strengthen the safety of jujube storage in the future.

Growth Kinetics of Salmonella Isolates in a Laboratory Medium as Affected by Isolate and Holding Temperature†

1998 ◽  
Vol 61 (8) ◽  
pp. 964-968 ◽  
Author(s):  
THOMAS P. OSCAR
Keyword(s):  
Growth Rate ◽  
Stationary Phase ◽  
Growth Kinetics ◽  
Brain Heart Infusion ◽  
Lag Time ◽  
Culture Collection ◽  
Subsequent Growth ◽  
Laboratory Medium ◽  
Different Temperatures ◽  
Holding Temperature

Salmonella isolates were surveyed for their growth kinetics in a laboratory medium for the purpose of identifying isolates suitable for modeling experiments. In addition, the effect of holding stationary phase Salmonella cultures at different temperatures on their subsequent growth kinetics was evaluated for the purpose of developing a protocol to prevent the need for midnight sampling in modeling experiments. In Experiment 1, 16 isolates of Salmonella, 2 from the American Type Culture Collection (ATCC) and 14 from broiler operations, were surveyed for their growth kinetics in brain heart infusion (BHI) broth at 40°C. Lag time (P = 0.005) and growth rate (P = 0.022) were affected by identity of the isolate. Lag time ranged from 0.73 to 1.38 h, whereas growth rate ranged from 0.78 to 0.94 log10 CFU/ml/h. Overall, isolate S1 (Salmonella infantis from ATCC) was the fastest growing. In Experiment 2, 4 isolates of Salmonella, 1 from ATCC and 3 from broiler operations, were used to determine whether holding temperature influences subsequent growth kinetics. Salmonella isolates were grown to stationary phase at 37°C in BHI and then held for 24 h at 5, 22, or 37°C before dilution and reinitiation of growth in BHI at 37°C. Holding temperature did not alter or interact with identity of the isolate to alter subsequent growth kinetics. From the latter finding, a protocol was devised in which a dual-flask system is used to prevent the need for midnight sampling in modeling experiments. Similar to the results obtained in Experiment 1, identity of the isolate had only minor effects on growth kinetics in Experiment 2 indicating that all isolates examined were suitable for modeling experiments.

scholarly journals DRYING KINETICS OF PEELED COFFEE SUBMITTED TO DIFFERENT TEMPERATURES AND RELATIVE HUMIDITY OF THE AIR OF DRYING AFTER PARTIAL DRYING

2020 ◽  
Vol 28 ◽  
pp. 460-476
Author(s):  
Rodrigo Victor Moreira ◽  
Jefferson Luiz Gomes Correa ◽  
Ednilton Tavares de Andrade ◽  
Roney Alves da Rocha
Keyword(s):  
Relative Humidity ◽  
Effective Diffusivity ◽  
Drying Kinetics ◽  
Dew Point ◽  
Diffusivity Coefficient ◽  
Point Temperature ◽  
Dew Point Temperature ◽  
Different Temperatures ◽  
Kinetics Of

The mathematical modelling is fundamental for the understanding of the related processes the drying, that influences the quality of the coffee drink. The objective of this study was to evaluate the influence of different relative humidity of the drying air after partial drying on drying kinetics of peeled coffees. Coffee fruits were harvested in the cherry stage and processed by wet, resulting in the portion of peeled coffee. Eleven treatments of drying were accomplished, being nine results of the combination of three dry bulb temperatures and three dew point temperatures, more two treatments without the control of the dew point temperatures. The control of the relative humidity by the dew point temperature was made after the grains reached the partial drying. Among the studied models, those of Diffusion Approximation and Modified Midilli were the most adequate for describing the drying process of the first and second part of drying respectively. The effective diffusivity coefficient of water in coffee grains ranged from 0.81 x 10-11 to 1.84 x 10-11 m² .s-1 during the first part of the drying and ranged from 1.49 x 10-11 to 3.29 x 10-11 m² .s-1 during the second part of the drying, increasing significantly with the reduction of the dew point temperature and increase of the dry bulb temperature.

scholarly journals Influence of abiotic factors on seed quality of maize hybrids in the process of its storage

2021 ◽  
Vol 5 (1) ◽  
pp. 30-37
Author(s):  
M. Ya. Kyrpa ◽  
Yu. S. Bazilieva ◽  
O. F. Stasiv
Keyword(s):  
Growth Rate ◽  
Moisture Content ◽  
Chemical Treatment ◽  
Seed Quality ◽  
Abiotic Factors ◽  
Seed Mass ◽  
Seed Storage ◽  
Maize Hybrids ◽  
Storage Methods

The research results of influence of various abiotic factors on seed quality of maize hybrids during long storage are given. The most effective of them are: temperature regime, seed moisture content and oxygen access. The storage methods (dry and cold, and controlled atmosphere storage) that have the greatest impact on the seed quality were established. It was found that the optimal moisture content of seed depends on the storage duration, if for 1–2 years – 10–11 %, 3 years and more – 7–8 %. In order to stabilize the moisture content, it is recommended to store the seeds in airtight containers, limiting the humidity access from the outside. During the long-term seed storage, particularly for the breeding purposes, the temperature range should advisably maintain within 8–10 °C in seed storage place. With that the laboratory germination of seeds increased by 3–5 %, field germination – by 6–8 %, growth rate by number of sprouts– by 5–9 % and by the weight of sprouts – by 2–5 g compared to the 18–20 °C temperature in a typical storage. Methods of pre-sowing improvement of seed quality were established – it is separation and chemical treatment (seed dressing). Separation is the sifting of the seed mass through sieves with round holes in order to divide from the smallest fraction, the content of which was 15–23 % depending on the seed uniformity of maize hybrids. It was found that in order to assess objectively the effectiveness of different chemicals and establish their suitability for presowing seed treatment, it is necessary to determine laboratory germination, especially the growth rate by the number of sprouts and weight of 100 sprouts. Premature chemical treatment of seed should be avoided. Key words: maize hybrids, storage methods, abiotic factors, seed quality, presowing treatment.

scholarly journals Study of Recrystallization Kinetics of 1565ch Aluminum Alloy during hot deformation

2020 ◽  
Vol 326 ◽  
pp. 05001
Author(s):  
Vasiliy Yashin ◽  
Alexander Drits ◽  
Evgenii Aryshenskii ◽  
Ilya Latushkin ◽  
Ekaterina Chitnaeva
Keyword(s):  
Growth Rate ◽  
Aluminum Alloy ◽  
Optical Microscope ◽  
Recrystallization Process ◽  
System Alloy ◽  
Industrial Practice ◽  
Cast Ingot ◽  
Recrystallization Kinetics ◽  
Different Temperatures ◽  
Kinetics Of

The present study addresses recrystallization process in Al-Mg-Mn-Zn-Zr system alloy samples. The samples are collected from cast ingot, produced by casting to industrial DC mold, and homogenized based on standard industrial practice. After that the samples were rolled with different hot rolling schedules. Rolled samples were annealed at different temperatures and their resultant microstructure was examined using optical microscope. During the study new grains nuclei generation rate and their growth rate were determined, analytical records, describing recrystallization kinetics, were obtained, main differences, specific to this alloy recrystallization in 350 ºС-450 ºС temperature range, were identified.

Phase Formation and Growth Kinetics of an Interface Layer in Ni/SiC

2008 ◽  
Vol 600-603 ◽  
pp. 631-634
Author(s):  
Kenichiro Terui ◽  
Atsuko Sekiguchi ◽  
Hiroshi Yoshizaki ◽  
Junichi Koike
Keyword(s):  
Growth Rate ◽  
Late Stage ◽  
Growth Kinetic ◽  
Early Stage ◽  
Interface Reaction ◽  
Interface Layer ◽  
Nickel Silicide ◽  
Composition And Structure ◽  
The Difference ◽  
Kinetics Of

The reaction behavior and growth kinetic of reaction layer were investigated in the Ni contact to n-type 6H-SiC. Annealing was performed at temperature in the range between 800 and 1000 °C for 1 to 240 minutes in Ar atmosphere. The interface reaction of Ni/SiC starts with Ni diffusion into SiC. Ni3Si is initially precipitated and subsequently forms the continuous layer of d-Ni2Si. Kirkendall voids are formed at the reaction front. Carbon is segregated in the interface layer of nickel silicide. The growth rate of the interface layer follows a parabolic law, meaning that the growth rate is controlled by diffusion. The growth occurs in two steps at all examined temperatures: a fast growth is followed by a slow growth. In addition, in the late stage, the growth rate changes dramatically below and above 850°C. The observed growth kinetic can be explained by the difference of Ni diffusivity and the required concentration change for phase transition depending on the phase composition and structure. The d-Ni2Si is formed in the early stage, while the e-Ni3Si2 and q-Ni2Si are formed in the late stage below and above 850°C, respectively.

scholarly journals Quality and Drying Kinetics of Moringa (Moringa oleifera Lam.) Seed Flour After Drying Process

2020 ◽  
Vol 8 (2) ◽  
pp. 380
Author(s):  
Francisco Marto De Souza ◽  
Emmanuel Moreira Pereira ◽  
Jackson Silva Nóbrega ◽  
Rosilene Agra Da Silva ◽  
Adriana Da Silva Santos ◽  
...  
Keyword(s):  
Nutritional Value ◽  
Drying Process ◽  
Constant Weight ◽  
Seed Flour ◽  
Peleg Model ◽  
Different Temperatures ◽  
Kinetics Of ◽  
Best Fit ◽  
Moringa Oleifera Lam

The moringa presents great nutritional value thanks to its bioactive compounds, providing many benefits to human health. Therefore, this plant has been studied with the aim of being used as a food fortifier. The objective of this work was to describe the technological process in the production of moringa seed flour at different temperatures through numerical and analytical solutions and assess its final chemical quality. Moringa pods were obtained in experimental area and were treated by removing their seeds. A drying process was performed at different temperatures (40, 50, 60 °C) with progressive weighing on a semi-analytical scale until constant weight which was obtained after 2 hours of drying. The flour was obtained with the use of a knife mill. Empirical models of Lewis, Herdenson and Pabis, Peleg and Page were used to describe the dehydration curve of moringa seeds. Protein, lipid, carbohydrate, ash and moisture contents were determined in the flours obtained at different temperatures. We verified that best fit model was Page’s, representing the best coefficients of determination and chi-squares. The Peleg model showed incoherent behavior, indicating that it is not ideal for simulating the drying process of moringa seeds at the studied temperatures. The temperature influenced the quality of the flour. The flour obtained at a temperature of 40 °C showed the best percentages of protein, ash, moisture and carbohydrates. For the lipid content, the best flour results was obtained at temperatures of 50 and 60 °C.

Diffusion of Water in Chestnut Fruits during Drying and Rehydration Processes at Different Temperatures

2008 ◽  
Vol 273-276 ◽  
pp. 758-763
Author(s):  
Ramón Moreira ◽  
Francisco Chenlo ◽  
L. Chaguri ◽  
Christiana Fernandes
Keyword(s):  
Moisture Content ◽  
Initial Moisture Content ◽  
Convective Drying ◽  
Transfer Processes ◽  
Hot Air ◽  
Mass Transfer Processes ◽  
Different Temperatures ◽  
Diffusional Model ◽  
Kinetics Of

Many food materials must be dried in order to decrease its water activity and to increase the shelf-life. Also, rehydration operation must be carried out as previous step before consumption. Both operations are commonly employed in some industrial chestnut processing. These processes can be carried out at different temperatures and in all cases the quality of the final product can be affected. In this work, convective drying with hot air is the employed method for water removal and rehydration is carried out by immersion of chestnut in water. In both cases, mass transfer processes are governed by water diffusion in the bulk of the solid. The aim of this work is to determine experimentally the drying and rehydration kinetics of chestnut samples at different conditions of temperature and moisture content. Obtained data are modeled with a diffusional model taking into account volume variations and the corresponding values of the coefficients of diffusion of water are obtained. Analysis of the results indicates that drying/rehydration rates increase with temperature and rehydration kinetics are also depending on the initial moisture content of chestnut. Finally, leaching flow during rehydration is only important at high temperature due to starch gelatinization processes.

Development and Validation of Growth Model for Yersinia enterocolitica in Cooked Chicken Meats Packaged under Various Atmosphere Packaging and Stored at Different Temperatures

2001 ◽  
Vol 64 (7) ◽  
pp. 987-993 ◽  
Author(s):  
Q. K. WEI ◽  
T. J. FANG ◽  
W. C. CHEN
Keyword(s):  
Growth Rate ◽  
Specific Growth Rate ◽  
Yersinia Enterocolitica ◽  
Specific Growth ◽  
Modified Atmosphere Packaging ◽  
Growth Curves ◽  
Gompertz Model ◽  
Lag Time ◽  
Bias Factor ◽  
Different Temperatures

Mathematical models that can predict the growth of Yersinia enterocolitica in chicken meats were evaluated in this study. The growth curves for Y. enterocolitica in chicken meats variously packaged (air, vacuum, and modified atmosphere packaging [MAP]) and stored at various temperatures (4, 10, 16, 22, 28, and 34°C) were constructed. The Gompertz model was applied to fit each of the experimental curves for the conditions mentioned above. The variations in the parameters, including lag time (λ) and specific growth rate (μ), at various temperatures were then described by the following models: the variations in lag time were described by the Adair and Smith models and the variations in the specific growth rate were described by the Ratkowsky and Zwietering models. The various models were then compared using graphical and mathematical analyses such as mean square error (MSE), regression coefficient (r2), bias factor, and accuracy factor. The results indicate that the mean r values in the Gompertz model for chicken meats packaged in air, vacuum, and MAP were 0.99, 0.99, and 0.95, respectively. The lag time modeled with the Adair and Smith functions exhibited a greater variance and demonstrated larger errors. The MSEs were 0.0015 and 0.0017 for Ratkowsky and Zwietering models, respectively. The r2 values in the Ratkowsky and Zwietering models were both 0.99. The bias factor was 1.017 for the Ratkowsky model and 1.096 for the Zwietering model. The accuracy factor of the Zwietering model was 1.174, which was lower than that in the Ratkowsky model (1.275), indicating that the former model was more accurate than the latter in predicting the specific growth rate of Y. enterocolitica in chicken meats.

Study of drying kinetics of salmon processing by-products at different temperatures and the quality of extracted fish oil

2017 ◽  
Vol 35 (16) ◽  
pp. 1981-1993 ◽  
Author(s):  
Winny Routray ◽  
Deepika Dave ◽  
Vegneshwaran V. Ramakrishnan ◽  
Wade Murphy
Keyword(s):  
Fish Oil ◽  
Drying Kinetics ◽  
Different Temperatures ◽  
Kinetics Of ◽  
By Products

scholarly journals On the Path to Thermo-Stable Collagen: Culturing the Versatile Sponge Chondrosia reniformis

Marine Drugs ◽  
2021 ◽  
Vol 19 (12) ◽  
pp. 669
Author(s):  
Boaz Orel ◽  
Marco Giovine ◽  
Micha Ilan
Keyword(s):  
Growth Rate ◽  
Disease Transmission ◽  
Marine Invertebrates ◽  
Biotechnological Applications ◽  
Optimal Temperature ◽  
Alternative Source ◽  
Controlled System ◽  
Food Industries ◽  
Different Temperatures ◽  
The Difference

The collagen proteins family is sought-after in the pharmaceuticals, cosmetics, and food industries for various biotechnological applications. The most abundant sources of collagen are pigs and cows, but due to religious restrictions and possible disease transmission, they became less attractive. An alternative source can be found in marine invertebrates, specifically in sponges. Alas, two problems arise: (1). Growing sponges is complicated. (2). Sponge collagen has low heat tolerance, which can impose a problem for human biotechnological usage. To fill these gaps, we studied the collagen-abundant sponge Chondrosia reniformis. Two culture experiments were conducted: (1). A sea-based system examined the difference in growth rates of C. reniformis from different habitats, growing under natural seasonal conditions; (2). A land-based controlled system, which assessed the growth-rate of C. reniformis at different temperatures. The results reveal that C. reniformis from shallow habitats are growing larger and faster than individuals from colder, deeper habitats, and that the optimal temperature for C. reniformis growth is 25 °C. The results demonstrate that C. reniformis is highly fit for culture and can produce thermally stable collagen. Further research is needed to determine the best conditions for C. reniformis culture for collagen extract and other exciting materials for bioprospecting.

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