scholarly journals Effect of temperature and speed of air dryer on drying kinetic and phenolic compounds of stevia leaf

2021 ◽  
Vol 18 (115) ◽  
pp. 259-271
Author(s):  
leila Nateghi ◽  
Foods ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 2924
Author(s):  
Daniel Rico ◽  
Elena Peñas ◽  
María del Carmen García ◽  
Dilip K. Rai ◽  
Cristina Martínez-Villaluenga ◽  
...  

Germination is an efficient and natural strategy that allows the modification of the nutritional value and the nutraceutical properties of seeds, enabling one to tailor the process according to its final use. This study aimed at optimization of germination conditions to produce novel lentil flours with improved nutritional and functional features. Response Surface Methodology (RSM) was applied to model the effect of temperature (15–27 °C) and time (1–5 days) on different nutritional and quality parameters of lentil flours including proximate composition, content and profile of fatty acids, content of phytic acid, ascorbic acid and γ-aminobutyric acid (GABA), content and profile of phenolic compounds, antioxidant activity, expected glycemic index (GI) and color during germination. As shown by RSM polynomial models, sprouting promoted the reduction of phytic acid content and enhanced the levels of ascorbic acid, GABA, insoluble phenolic compounds, antioxidant activity and expected GI, and modified the color of the resultant lentil flours. RSM optimization of germination temperature and time using desirability function revealed that the optimal process conditions to maximize the nutritional, bioactive and quality properties of sprouted lentil flours were 21 °C for 3.5 days.


2019 ◽  
Vol 7 (3) ◽  
pp. 417
Author(s):  
Anak Agung Gede Rai Giri Natha ◽  
A.A.P. Agung Suryawan Wiranatha ◽  
Sri Mulyani

The aims of this study were: 1) to determine the effect of temperature and the addition of abrasive ingredients on the epidermis of cocoa beans to the characteristics of body scrub creams, and  2) to obtain temperature and the addition of abrasive ingredients to the epidermis of cocoa beans to produce the best characteristic body scrub cream, and 3)  how the quality of body scrub cream changes during storage. The experimental design used in this study was a factorial randomized block design, which consisted of 2 factors. The first factor was the heating temperature which consists of two levels, namely temperature of 65 °C and 75 °C. The second factor was the addition of abrasive materials which consists of three levels namely 3 percent, 6 percent and 9 percent. All treatments were grouped into 3 groups to obtain 18 experimental units. The data obtained were analyzed by variance and  the Duncan test. The best result of body scrub cream is the treatment of heating temperature 65°C and the addition of powder epidermis of cocoa beans 9 percent  with the characteristics of pH 5.53, viscosity of 36,627 cp, content of phenolic compounds 21.631 mg GAE/g, aroma 5.85 and passions 5.55. pH, viscosity and total phenolic compounds are stable up to 6 weeks of storage. Keywords : epidermis of cocoa beans, body scrub, characteristic, temperature, addition of abrasives


Author(s):  
Francislaine Suelia dos Santos ◽  
Rossana Maria Feitosa de Figueirêdo ◽  
Alexandre José de Melo Queiroz ◽  
Ana Raquel Carmo de Lima ◽  
Thalis Leandro Bezerra de Lima

This study aimed to evaluate the effect of drying temperature (50, 60, 70 and 80 °C) on okra dehydration by comparing its powder’s physical properties obtained from a sample produced by a lyophilization process. Ten drying models were adjusted to the experimental data of the drying kinetics. As a result, effective diffusivity and activation energy were determined in addition to thermodynamic parameters: entropy, enthalpy and Gibbs free energy. A physical characterization, as well as the pigments and colorimetry analyses of the aforementioned powders were made, by comparing them with samples produced by lyophilization. The powders were characterized for hygroscopicity, solubility, wettability, apparent and compacted density, fluidity and cohesiveness, pigments, colorimetric, morphological analysis (SEM) and X-ray diffraction. Midilli model was the one that best adjusted to the drying kinetic curves. There was a booster in the effective diffusion coefficient with the increase of temperature. Enthalpy and entropy were reduced with the increase of both drying temperature and Gibbs free energy. The powders presented high luminosity, and the lyophilized powder had higher pigments retention and greater solubility. All powders presented poor fluidity and intermediate cohesiveness, with amorphous, irregular and asymmetric particles. Thus, from the present study it was possible to evaluate the best drying method, the one that should be applied for the drying of okra, considering the costs involved, its quality and the final application of the product, meeting the specific needs of each consumer


Molecules ◽  
2020 ◽  
Vol 25 (22) ◽  
pp. 5274
Author(s):  
Ewa Olechno ◽  
Anna Puścion-Jakubik ◽  
Renata Markiewicz-Żukowska ◽  
Katarzyna Socha

Coffee is a widely consumed beverage, both in Europe, where its consumption is highest, and on other continents. It provides many compounds, including phenolic compounds. The aim of the study was to assess the effect of various brewing methods on the total phenolic content (TPC) in the infusion. Research material comprised commercially available coffees: Instant Arabica and Robusta, freshly ground Arabica and Robusta (immediately prior to the analysis), ground Arabica and Robusta, decaffeinated Arabica, and green Arabica and Robusta. The following preparation methods were used: Pouring hot water over coffee grounds or instant coffee, preparing coffee in a percolator and using a coffee machine. Additional variables which were employed were water temperature (90 or 100 °C) and its type (filtered or unfiltered). In order to determine the impact of examined factors, 225 infusion were prepared. Total phenolic content was determined by the spectrophotometric method using the Folin-Ciocalteu reagent and the obtained results were expressed in mg gallic acid (GAE) per 100 g of brewed coffee. The highest value was obtained for 100% Arabica ground coffee prepared in a coffee percolator using unfiltered water at a temperature of 100 °C: 657.3 ± 23 mg GAE/100 g of infusion. High values were also observed for infusions prepared in a coffee machine, where the highest TPC value was 363.8 ± 28 mg GAE/100 g for ground Arabica. In turn, the lowest TPC was obtained for Arabica green coffee in opaque packaging, brewed with filtered water at a temperature of 100 °C: 19.5 ± 1 mg GAE/100 g of infusion. No significant effect of temperature and water type on the TPC within one type of coffee was observed. Due to its high content of phenolic compounds, Arabica coffee brewed in a coffee percolator should be the most popular choice for coffee drinkers.


DYNA ◽  
2019 ◽  
Vol 86 (210) ◽  
pp. 211-215
Author(s):  
Luis Eduardo Ordoñez S. ◽  
Oswaldo Osorio Mora ◽  
Yamid Alexis Pinchao P.

The pea pod is a by-product that possesses several bioactive compounds. The effect of temperature, time, solid-liquid ratio and ethanol concentration on the ultrasonic assisted extraction of phenolic compounds were studied. A 2K factorial design was used and through ANOVA analysis the effect of each process variable was determined. Total phenols were analyzed by the Folin Ciocalteu method. The results showed that the temperature did not affect significantly the extraction of total phenols, however extraction time, ethanol concentration and solid-liquid ratio affected the extraction yield. The maximum concentration of the total phenols for each of the factors was recorded at 20 minutes, a 50% ethanol concentration and a liquid solid ratio of 1:40. These results provide useful information to optimize the ultrasound-assisted extraction process of the phenolic compounds of the pea pod according to the factors studied.


Molecules ◽  
2018 ◽  
Vol 23 (10) ◽  
pp. 2641 ◽  
Author(s):  
Juan Escobar ◽  
Cristina Prieto ◽  
Maria Pardo-Figuerez ◽  
José Lagaron

Currently, consumers are demanding additive-free, fresher, and more-natural products. Dragon’s Blood Sap (DBS), the deep red latex of the specie of tree Croton lechleri (Müll. Arg.), contains a high concentration of phenolic compounds of great interest for the food, pharmaceutical, and cosmetic industries. These chemical compounds are highly susceptible to degradation. Therefore, DBS storage stability and its photo-oxidation was studied by Fourier transform infrared spectroscopy (FT-IR) and UV-Vis spectrophotometry for 39 days at different temperatures (4–21 °C) and relative humidities (0–56%), as well as under UV light exposure. It was observed that the degradation of phenolic compounds was reduced at 0% relative humidity (RH), not showing a significant effect of temperature in the range studied. UV light irradiation degraded DBS in a 20%. DBS has an exceptional high and stable antioxidant content (≥93% inhibition percentage of DPPH), which makes it a unique property to consider the DBS as an antioxidant agent or ingredient for consumer products formulations.


Molecules ◽  
2019 ◽  
Vol 24 (4) ◽  
pp. 797 ◽  
Author(s):  
Elena Roselló-Soto ◽  
Francisco Martí-Quijal ◽  
Antonio Cilla ◽  
Paulo Munekata ◽  
Jose Lorenzo ◽  
...  

The aim of this study was to assess the effect of temperature, solvent (hydroethanolic mixtures) and pH on the recovery of individual phenolic compounds from “horchata” by-products. These parameters were optimized by response surface methodology and triple-TOF-LC-MS-MS was selected as the analytical tool to identify and quantify the individual compounds. The optimum extraction conditions were 50% ethanol, 35 °C and pH 2.5, which resulted in values of 222.6 mg gallic acid equivalents (GAE)/100 g dry matter and 1948.1 µM trolox equivalent (TE)/g of dry matter for total phenolic content (TPC) and trolox equivalent antioxidant capacity (TEAC), respectively. The extraction of phenolic compounds by the conventional solvent method with agitation was influenced by temperature (p = 0.0073), and more strongly, by the content of ethanol in the extraction solution (p = 0.0007) while the pH did not show a great impact (p = 0.7961). On the other hand, the extraction of phenolic acids was affected by temperature (p = 0.0003) and by ethanol amount (p < 0.0001) but not by the pH values (p = 0.53). In addition, the percentage of ethanol influenced notably the extraction of both 4-vinylphenol (p = 0.0002) and the hydroxycinnamic acids (p = 0.0039). Finally, the main individual phenolic extracted with hydroethanolic mixtures was 4-vinylphenol (303.3 μg/kg DW) followed by spinacetin3-O-glucosyl-(1→6)-glucoside (86.2 μg/kg DW) and sinensetin (77.8 μg/kg DW).


2020 ◽  
Vol 8 (2) ◽  
pp. 90-100 ◽  
Author(s):  
Dewi Selvia Fardhyanti ◽  
Achmad Chafidz ◽  
Bayu Triwibowo ◽  
Haniif Prasetiawan ◽  
Novia Noor Cahyani ◽  
...  

Rice husk is an agricultural waste which contains 50% cellulose, 25%-30% lignin and 15%-20% silica. It can be used as raw material of bio-oil. Bio-oil is liquid which produced by pyrolysis process. Bio-oil can be produced from the rice husk at 773 and 873 K. The main component of Bio-oil from rice husk pyrolysis at 773 and 873 K is phenolic compounds about 47.98% and 62.65%, respectively. It causes corrosive, low heating value, high acidity, high viscosity and unstable that causing an engine damage. The presence of phenolic compound decreases the quality of bio-oil. Therefore, it needs a process such as liquid-liquid extraction to reduce the phenolic compound using 80% methanol and 80% chloroform as a solvent. The extract and raffinate phase were analyzed using UV-Vis spectrophotometer. The aim of this research determine the effect of temperature pyrolysis for the characterization of bio-oil, the stirring speed and the temperature of the extraction for the distribution coefficient and the yield of phenolic compound. The results showed that the characterization of bio-oil produced from rice husk pyrolysis at 773 and 873 K are densities 1,040 and 1,042 Kg/m3; viscosities 9.3488 and 9.5007 cSt; acid numbers 46.75 and 52.45 mg KOH/g; pH 2.5 and 3; flash points 426 and 423 K and heating values 3.229 and 3.339 MJ/kg, respectively. The highest distribution coefficient and yield were obtained at 323 K and a stirring speed of 250 rpm. The distribution coefficient of bio-oil produced by pyrolysis at 773 and 873 K is 1.504, and 1.528, respectively. The yields of bio-oil produced by pyrolysis at 773 and 873 K are 58.885%, and 48.429%, respectively.  


2021 ◽  
Vol 8 (2) ◽  
pp. 108-113
Author(s):  
Syaliza Omar ◽  
Noor Marinah Sahri ◽  
Hafizah Abd. Aziz ◽  
Maimunah Sanny

The effect of temperature at 50°C, 70°C and 100°C for up to 120 min on the content of phenolic compounds and antioxidant activity of Tualang honey and Kelulut honey was studied. Unheated honey samples for both varieties were used as control. The total phenolic content and antioxidant activity were examined using Folin-Ciocalteau and DPPH assays, respectively. Both honeys vary widely in the total phenolic content as well as antioxidant activity upon heating and time of heating. The total phenolic content in both honeys showed fluctuations at all temperatures throughout 120 min. In comparison to controls for both honeys, heating at 100°C for 10 min demonstrated a drop in total phenolic content in Tualang honey (13%) and Kelulut honey (29%), but the antioxidant activity increased 29% and 57% in Tualang and Kelulut honey, respectively. The study generates information on the characteristics of components in both honeys which react differently to heat and time of heating, therefore this will help the honey manufacturers or public to optimize the processing protocols and later to preserve the quality of honey.


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