Physicochemical Properties of Enzymatically Modified Starches

The physicochemical properties of native, annealed and enzyme-treated chickpea (CP), corn (CS), Turkish bean (TB) and sweet potato (SPS) were investigated. Germinated sorghum extract (GSET) was used as the source of enzymes. Starches were annealed in excess water by holding the slurry at 60 °C for 60 min with or without GSET. The flow curves/rheological data were fitted to the power law, Casson and Herschel–Bulkley models. Starches exhibited shear thinning behavior and a variation in the flow behavior index (n) (0.34–0.82) as a function of the starch type. The consistency index (k) of CP and CS decreased with annealing and GSET treatment but increased for TB and SPS. Annealed and GSET-treated SPS exhibited the highest yield stress compared to the other starches, except for CP. The temperature dependency of all starches was well described by the Arrhenius model (r2 = 0.88–0.99). The activation energy (Ea) values were in the range of 660–5359 (J/mol). The TB exhibited the most Ea and SPS the least. With the exception of SPS, annealing appeared to increase the Ea of all tested starches, but the range of Ea was broader for SPS and CS. Annealed and GSET starches exhibited an increase in the gelatinization temperatures (onset and peak) and a decrease in gelatinization enthalpy (ΔH). The syneresis and water holding capacity decreased after annealing or GSET treatment.

Optimization, Kinetics, Thermodynamic and Arrhenius Model of the Removal of Ciprofloxacin by Internal Electrolysis with Fe-Cu and Fe-C Materials

The ciprofloxacin (CIP) removal ability of a Fe-Cu electrolytic material was examined with respect to pH (2–9), time (15–150 min), shaking speed (100–250 rpm), material mass (0.2–3 g/L), temperature (298, 308, 323) and initial CIP concentration (30–200 mg/L). The Fe-Cu electrolytic materials were fabricated by the chemical plating method, and Fe-C materials were mechanically mixed from iron powder and graphite. The results show that at a pH value of 3, shaking time 120 min, shaking speed 250 rpm, a mass of Fe-Cu, Fe-C material of 2 g/L and initial CIP concentration of 203.79 mg/L, the CIP removal efficiency of Fe-Cu material reached 90.25% and that of Fe-C material was 85.12%. The removal of CIP on Fe-Cu and Fe-C materials follows pseudo-first-order kinetics. The activation energy of CIP removal of Fe-Cu material is 14.93 KJ/mol and of Fe-C material is 16.87 KJ/mol. The positive ΔH proves that CIP removal is endothermic. A negative entropy of 0.239 kJ/mol and 0.235 kJ/mol (which is near zero and is also relatively positive) indicated the rapid removal of the CIP molecules into the removed products.

Estimasi Umur Simpan Pliek-U Berdasarkan Kadar Air Menggunakan Model Arrhenius dan Metode Q10

Abstrak. Penelitian ini bertujuan untuk menduga umur simpan Pliek-U menggunakan model Arrhenius dan metode Q10. Sebanyak 6 sampel Pliek-U yang sudah diketahui kadar air awalnya diberikan perlakuan suhu ekstrim 50, 60, dan 70˚C sampai kondisi Pliek-U mengalami penurunan mutu yang ditandai dengan perubahan warna dan bau. Perubahan berat sampel diamati dalam interval 30 menit. Selanjutya dilakukan perhitungan kadar air Pliek-U dan nilainya diplotkan dalam grafik di mana koordinat x nya sebagai waktu dan koordinat y nya sebagai kadar air. Gradien grafik adalah laju reaksi perubahan kadar air Pliek-U (k). Model Arrhenius adalah hasil plot nilai ln k terhadap 1/T dalam skala Kelvin. Selanjutnya dihitung nilai Q10 dan umur simpan Pliek-U dengan asumsi bahwa umur simpan sampel pada suhu ruang (30ºC) adalah 32 bulan. Hasil penelitian ini menunjukkan nilai k Pliek-U pada suhu 50ºC 0,0621 dan nilai R2 sebesar 15,52%. Nilai k Pliek-U pada suhu 60ºC adalah 0,0826 dan nilai R2 sebesar 67,9%, dan nilai k Pliek-U pada suhu 70ºC adalah 0,0877 dan nilai R2 sebesar 54,39%. Persamaan Arrhenius Pliek-U berdasarkan perubahan kadar air adalah k = 27,454 . e-1.925(1/T) dengan R2 sebesar 91,47%. Nilai faktor percepatan reaksi (Q10) Pliek-U adalah 1,214. Umur simpan Pliek-U dapat ditentukan dengan persamaan tT1=32 .1,214(∆T/10).Shelf-life estimation of Pliek-U based on moisture changes by using Arrhenius and Q10 approachAbstract. The study aimed to predict the shelf-life of Pliek-U by using Arrhenius and Q10 approach. About 6 samples of Pliek-U, already known its moisture, were exposed to high temperatures of 50, 60, dan 70ºC to reach degradation quality characterized by color and odor changes. The alteration of weight was also observed at interval of 30minutes. Based on these data, the changes of moisture were calculated and the trend was drawn on a XY scatter chart. The gradien of the chart was the reaction rate of quality degradation (k). Then, the Arrhenius model was constructed by plotting ln k and 1/T (K) into a graph. Lastly, the Q10 and shelf-life were calculated by using assumption that the shelf-life at room temperature was about 32 months. Results showed that the k-value and R-square of Pliek-U at 50˚C was 0.0621 and 15.52%, respectively. The k-value and R-square of Pliek-U at 60˚C was 0,0826 and 67,9%, whereas the k-value and R-square of Pliek-U at 70˚C was 0,0877 and 54,39%. The Arrhenius model of Pliek-U based on moisture changes was k = 27,454. e-1.925(1/T) and R-square was 91.47%. The Q10-value of Pliek-U was 1,214 and the shelf-life of Pliek-U can be adjusted by using the model tT1=32 .1,214(∆T/10).

Shelf-Life Prediction of Glazed Large Yellow Croaker (Pseudosciaena crocea) during Frozen Storage Based on Arrhenius Model and Long-Short-Term Memory Neural Networks Model

In this study, the changes in centrifugal loss, TVB-N, K-value, whiteness and sensory evaluation of glazed large yellow croaker were analyzed at −10, −20, −30 and −40 °C storage. The Arrhenius prediction model and long-short-term memory neural networks (LSTM-NN) prediction model were developed to predict the shelf-life of the glazed large yellow croaker. The results showed that the quality of glazed large yellow croaker gradually decreased with the extension of frozen storage time, and the decrease in quality slowed down at lower temperatures. Both the Arrhenius model and the LSTM-NN prediction model were good tools for predicting the shelf-life of glazed large yellow croaker. However, for the relative error, the prediction accuracy of LSTM-NN (with a mean value of 7.78%) was higher than that of Arrhenius model (with a mean value of 11.90%). Moreover, the LSTM-NN model had a more intelligent, convenient and fast data processing capability, so the new LSTM-NN model provided a better choice for predicting the shelf-life of glazed large yellow croaker.

Does the Modified Arrhenius Model Reliably Predict Area of Tissue Ablation After Magnetic Resonance-Guided Laser Interstitial Thermal Therapy for Pediatric Lesional Epilepsy?

BACKGROUND Commercial magnetic resonance-guided laser interstitial thermal therapy (MRgLITT) systems utilize a generalized Arrhenius model to estimate the area of tissue damage based on the power and time of ablation. However, the reliability of these estimates in Vivo remains unclear. OBJECTIVE To determine the accuracy and precision of the thermal damage estimate (TDE) calculated by commercially available MRgLITT systems using the generalized Arrhenius model. METHODS A single-center retrospective review of pediatric patients undergoing MRgLITT for lesional epilepsy was performed. The area of each lesion was measured on both TDE and intraoperative postablation, postcontrast T1 magnetic resonance images using ImageJ. Lesions requiring multiple ablations were excluded. The strength of the correlation between TDE and postlesioning measurements was assessed via linear regression. RESULTS A total of 32 lesions were identified in 19 patients. After exclusion, 13 pairs were available for analysis. Linear regression demonstrated a strong correlation between estimated and actual ablation areas (R2 = .97, P < .00001). The TDE underestimated the area of ablation by an average of 3.92% overall (standard error (SE) = 4.57%), but this varied depending on the type of pathologic tissue involved. TDE accuracy and precision were highest in tubers (n = 3), with average underestimation of 2.33% (SE = 0.33%). TDE underestimated the lesioning of the single hypothalamic hamartoma in our series by 52%. In periventricular nodular heterotopias, TDE overestimated ablation areas by an average of 13% (n = 2). CONCLUSION TDE reliability is variably consistent across tissue types, particularly in smaller or periventricular lesions. Further investigation is needed to understand the accuracy of this emerging minimally invasive technique.

Assessment of the Accelerated Shelf Life of Human Milk Dehydrated by Aspersion and Treated by UV, High Pressures, and Pasteurization

Human milk banks pasteurize and freeze the milk in order to conserve it, but thawing and prolonged storage cause loss of nutritional components. The aim of this work was to evaluate the effect of pasteurization, high hydrostatic pressures, UV radiation, and spray drying in human milk packed and stored at 25 to 40°C by a period of 14 weeks, using an accelerated shelf life method with Arrhenius model. Effectiveness of packaging, microbiological viability, and deterioration of carbohydrates, lipids, and proteins was evaluated. The results showed that proteins and carbohydrates in powdered human milk with different treatments did not show significant changes during storage at 25 to 40°C and without the growth of microorganisms. However, 33.3% deterioration of lipid oxidation was observed up at 40°C. We predict with the applied model that, at 18°C, the human milk powder will be preserved for approximately one year without significant changes in its composition.

Masa simpan tempe dalam pengemas edible film tapioka termodifikasi [Shelf life of tempe wrapped by modified-tapioca edible film]

Edible film made up of modified tapioca was used to wrap tempeh and its shelf life estimation was determined. The edible films must be capable of evenly aerating and maintaining moisture without causing condensation in order mycelium to be able to grow and produce high-quality tempeh. The experiment was carried out in completely randomized design with two main factors of storage temperature and time. An accelerated shelf life test at 17oC, 27oC, and 37oC with an Arrhenius model was used to calculate the shelf life, and water content was used as quality parameter indicator. The result showed that modified-tapioca based edible film made from fermentation of tapioca by Saccharomyces cerevisiae was characterized as having elongation of 11.40 %, tensile strength of 408.37 MPa, thickness of 0.88 mm and WVTR of 12.60 g/m2/h. Rate constant of water content decrease in edible film wrapped tempeh based on Arrhenius model was 0.3832 % day-1 and Ea was 10.296 kkal/gmol, while that of in PP-plastic wrapped tempeh was 0.3831% day-1 and Ea was 9.998 kkal/gmol. The shelf life of edible film wrapped tempeh was 9.39 days at 27oC, 5.18 days at 27oC, and 2.96 days at 37oC, while shelf life of PP-plastic wrapped tempeh was 8.64 days at 17oC, 4.85 days at 27 oC, and 2.82 days at 37oC. Therefore, it can be concluded that modified tapioca based edible film increased the shelf life of tempeh.