Effect of the passivating coating type, particle size, and storage time on oxidation and nitridation of aluminum powders

2006 ◽  
Vol 42 (2) ◽  
pp. 177-184 ◽  
Author(s):  
A. A. Gromov ◽  
A. P. Il’in ◽  
U. Foerter-Barth ◽  
U. Teipel
Keyword(s):  
Particle Size ◽  
Storage Time ◽  
Aluminum Powders ◽  
Coating Type ◽  
Type Particle ◽  
And Storage

scholarly journals MODEL KINETIKA DEGRADASI CAPSAICIN CABAI MERAH GILING PADA BERBAGAI KONDISI SUHU PENYIMPANAN (Kinetic Model of Capsaicin Degradation on Red Chilli Paste at Various Storage Temperature)

2014 ◽  
Vol 34 (03) ◽  
pp. 330 ◽  
Author(s):  
Dharia Renate ◽  
Filli Pratama ◽  
Kiki Yuliati ◽  
Gatot Priyanto
Keyword(s):  
Activation Energy ◽  
Particle Size ◽  
Shelf Life ◽  
Storage Time ◽  
Arrhenius Equation ◽  
Storage Temperature ◽  
Hplc Method ◽  
Kinetic Reaction ◽  
C 30 ◽  
And Storage

The objective of this research was to asses relationship between temperature and storage time of capsaicin degradation of red chilli paste and to measure activation energy and shelf life using the Arrhenius model. The treatmens were storage temperature (20°C, 30°C, 40°C) and storage times (0, 2, 4, 6, 8, 10 weeks).  Parameters analyzed were capsaicin content using HPLC method, pH, and particle size.  The data was analyzed using linier regression and Arrhenius equation  The results showed that temperature condition and storage time affected capsaicin degradation of red chilli paste, unlike pH and particle size.  The longer storage time the lower capsaicin content.  The capsaicin content of red chilli paste storedat 30°C and 40°C in week-4 was 746,36 μg/g and 714,19 μg/g respectively, and it declined to 149,31 μg/g and 136,77 μg/g after being stored for ten weeks.  Research concluded that red chilli paste stored for 10 weeks at 20°C caused the lowest capsaicin degradation from   916.8029 μg/g  to 683.8097 μg/g. Degradation rate of capsaicin followed the first order reaction.  Arrhenius equation for capsaicin was  Y= -9356.3x + 27.836, (R=0.76), and activation energy was 18.581 kcal/mol.  Shelf life determination of capsaicin followed kinetic reaction equation of the fi rst order  i.e t = ln(Ao-At)/k.  The self life of red chilli paste stored at 20°C, 30°C and 40°C were 10.62 weeks, 8.62 weeks and 8.45 weeks respectively.Keywords: Red chilli paste, degradation, capsaicin, particle size, kinetic reaction ABSTRAKTujuan penelitian untuk mengkaji hubungan suhu dan lama penyimpanan terhadap degradasi capsaicin cabai merah giling serta menghitung energi aktivasi dan waktu simpan dengan pendekatan model persamaan Arrhenius. Perlakuan terdiri dari dua faktor yaitu suhu penyimpanan (20°C, 30°C, dan 40°C) serta lama penyimpanan (0, 2, 4, 6, 8 dan 10minggu). Metode analisis untuk kadar capsaicin menggunakan HPLC. Analisis pendukung yaitu pH dan ukuran partikel.  Data disajikan dengan grafi k persamaan regresi linier dan persamaan Arrhenius.  Hasil penelitian menunjukkan bahwa kondisi suhu dan lama penyimpanan berpengaruh terhadap degradasi capsaicin cabai merah giling, namun, pH dan ukuran partikel tidak berpengaruh secara signifi kan.  Semakin lama penyimpanan maka kandungan capsaicin semakin menurun.  Kadar capsaicin cabai giling yang disimpan pada suhu 30°C dan 40°C  pada minggu ke-empat masing masing sebesar 746,36 μg/g dan 714,19 μg/g menurun perlahan sampai pada  minggu ke-10 menjadi 149,31 μg/g dan 136,77 μg/g.  Dari hasil penelitian disimpulkan bahwa kadar capsaicin cabai giling yang disimpan pada suhu 20°C selama 10 minggu merupakan degradasi terendah dari 916,80 μg/g menjadi 683,81 μg/g.  Laju degradasi capsaicin mengikuti orde satu.  Persamaan Arrhenius untuk Capsaicin adalah Y= 27,836-9356,3x (R=0,76) dan energi aktivasisebesar 18581,65 kal/mol. Penentuan umur simpan capsaicin mengikuti persamaan kinetika reaksi orde satu yaitu t =ln(Ao-At)/k, maka umur simpan capsaicin cabai merah giling yang disimpan pada suhu 20°C, 30°C dan 40°C berturutturut sebesar 10,64 minggu; 8,62 minggu dan 8,45 minggu.Kata kunci: Cabai merah giling, degradasi, capsaicin, ukuran partikel, kinetika reaksi

scholarly journals Changes in Particle Size, Sedimentation, and Protein Microstructure of Ultra-High-Temperature Skim Milk Considering Plasmin Concentration and Storage Temperature

Molecules ◽  
2021 ◽  
Vol 26 (8) ◽  
pp. 2339
Author(s):  
So-Yul Yun ◽  
Jee-Young Imm
Keyword(s):  
Particle Size ◽  
High Temperature ◽  
Storage Temperature ◽  
Whey Proteins ◽  
Skim Milk ◽  
Storage Period ◽  
Sediment Analysis ◽  
Sediment Formation ◽  
And Storage ◽  
Ultra High Temperature

Age gelation is a major quality defect in ultra-high-temperature (UHT) pasteurized milk during extended storage. Changes in plasmin (PL)-induced sedimentation were investigated during storage (23 °C and 37 °C, four weeks) of UHT skim milk treated with PL (2.5, 10, and 15 U/L). The increase in particle size and broadening of the particle size distribution of samples during storage were dependent on the PL concentration, storage period, and storage temperature. Sediment analysis indicated that elevated storage temperature accelerated protein sedimentation. The initial PL concentration was positively correlated with the amount of protein sediment in samples stored at 23 °C for four weeks (r = 0.615; p < 0.01), whereas this correlation was negative in samples stored at 37 °C for the same time (r = −0.358; p < 0.01) due to extensive proteolysis. SDS-PAGE revealed that whey proteins remained soluble over storage at 23 °C for four weeks, but they mostly disappeared from the soluble phase of PL-added samples after two weeks’ storage at 37 °C. Transmission electron micrographs of PL-containing UHT skim milk during storage at different temperatures supported the trend of sediment analysis well. Based on the Fourier transform infrared spectra of UHT skim milk stored at 23 °C for three weeks, PL-induced particle size enlargement was due to protein aggregation and the formation of intermolecular β-sheet structures, which contributed to casein destabilization, leading to sediment formation.

scholarly journals Wheat Grinding Process with Low Moisture Content: A New Approach for Wholemeal Flour Production

Processes ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 32
Author(s):  
Waleed H. Hassoon ◽  
Dariusz Dziki ◽  
Antoni Miś ◽  
Beata Biernacka
Keyword(s):  
Particle Size ◽  
Moisture Content ◽  
Average Particle Size ◽  
Average Particle ◽  
Grinding Process ◽  
Mixing Properties ◽  
New Approach ◽  
Grain Moisture ◽  
Flour Production ◽  
And Storage

The objective of this study was to determine the grinding characteristics of wheat with a low moisture content. Two kinds of wheat—soft spelt wheat and hard Khorasan wheat—were dried at 45 °C to reduce the moisture content from 12% to 5% (wet basis). Air drying at 45 °C and storage in a climatic chamber (45 °C, 10% relative humidity) were the methods used for grain dehydration. The grinding process was carried out using a knife mill. After grinding, the particle size distribution, average particle size and grinding energy indices were determined. In addition, the dough mixing properties of wholemeal flour dough were studied using a farinograph. It was observed that decreasing the moisture content in wheat grains from 12% to 5% made the grinding process more effective. As a result, the average particle size of the ground material was decreased. This effect was found in both soft and hard wheat. Importantly, lowering the grain moisture led to about a twofold decrease in the required grinding energy. Moreover, the flour obtained from the dried grains showed higher water absorption and higher dough stability during mixing. However, the method of grain dehydration had little or no effect on the results of the grinding process or dough properties.

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