scholarly journals DEGRADATION KINETICS OF ANTIOXIDANTS IN DEHYDRATED MATRIX OF INDIAN GOOSEBERRY AND GUAVA POWDER

2020 ◽  
Vol 21 (supplement 1) ◽  
Author(s):  
Mudita Verma ◽  
Radha Kushwaha ◽  
GK Rai ◽  
Devinder Kaur
Keyword(s):  
Ascorbic Acid ◽  
Degradation Kinetics ◽  
Ascorbic Acid Content ◽  
Reaction Model ◽  
Activation Energies ◽  
Breakfast Cereal ◽  
First Order ◽  
Indian Gooseberry ◽  
Freeze Dried ◽  
Nutritional Enhancement

The stability of antioxidants in any material is essential for delivering health benefits even after their additional thermal processing for their preparation itself, for example, their incorporation in biscuits, cookies, bread, breakfast cereal mixes or many other functional foods for the end product’s nutritional enhancement and value addition. In this study degradation of antioxidants were studied in Indian gooseberry and guava powder prepared by the cabinet and freeze-dried techniques at temperature 65 to 850C for 8 hours in the hot air oven. Polyphenolics, flavonoids, ascorbic acid content decreases in both the fruits as the temperature increased. Degradation of polyphenolics, flavonoids and ascorbic acid during processing, followed first-order degradation kinetics. Rate constants increased with increase in the temperature range. Activation energies calculated for cabinet dried Indian gooseberry powders were 31.04, 41.87 and 44.55 kJ/mol and 36.13, 45.23.48.65 kJ/mol while in case of guava, activation energies found to be 34.15, 74.62 and 42.78 for cabinet dried and 38.42,79.11, 52.47 for freeze-dried powder for total phenolics, flavonoids and ascorbic acid. The degradation followed first-order reaction model with the higher value of R2>0.927. The Arrhenius law was used to relate the coefficient k (drying rate constant) with the air drying temperature

Über die quantitative Verteilung der Ascorbinsäure innerhalb der Pflanzenzelle

1964 ◽  
Vol 19 (12) ◽  
pp. 1146-1149 ◽  
Author(s):  
Wolfgang Franke ◽  
Ulrich Heber
Keyword(s):  
Ascorbic Acid ◽  
Acid Content ◽  
Cell Walls ◽  
Direct Evidence ◽  
Ascorbic Acid Content ◽  
The Other ◽  
Leaf Cell ◽  
Unequal Distribution ◽  
Freeze Dried ◽  
High Figure

Leaves, which had been killed in liquid air, were freeze dried and then fractionated by a nonaqueous method. Two fractions were obtained, one consisting of chloroplasts and the other of cytoplasm, vacuolar constituents, cell walls and residual chloroplasts. Calculation of the intracellular distribution of ascorbic acid based on the analysis of the two fractions revealed that 40 to 50% of the total ascorbic acid content of the cells is located within the chloroplasts. Since chloroplasts occupy less than 10% of the total volume of the cells, this high figure is direct evidence of an unequal distribution of ascorbic acid within the leaf cell.

scholarly journals The Link between Polyphenol Structure, Antioxidant Capacity and Shelf-Life Stability in the Presence of Fructose and Ascorbic Acid

Molecules ◽  
2020 ◽  
Vol 25 (1) ◽  
pp. 225 ◽  
Author(s):  
Inbal Hanuka Katz ◽  
Eden Eran Nagar ◽  
Zoya Okun ◽  
Avi Shpigelman
Keyword(s):  
Ascorbic Acid ◽  
Antioxidant Capacity ◽  
Shelf Life ◽  
High Performance ◽  
Degradation Kinetics ◽  
Model System ◽  
Absorption Capacity ◽  
Component Model ◽  
Freeze Dried ◽  
The Stability

Polyphenols play an important role in the sensorial and health-promoting properties of fruits and vegetables and display varying structure-dependent stability during processing and shelf-life. The current work aimed to increase the fundamental understanding of the link between the stability of polyphenols as a function of their structure, presence of ascorbic acid and fructose and total antioxidant capacity (TAC), using a multi-component model system. Polyphenol extract, used as the multi-component model system, was obtained from freeze-dried, high polyphenol content strawberry (Fragaria × ananassa ‘Nerina’) and twenty-one compounds were identified using high-performance liquid chromatography-mass spectrometry (HPLC-MS). The TAC and the first-order degradation kinetics were obtained, linking the polyphenol stability to its chemical structure, with and without the presence of fructose and ascorbic acid. The TAC (measured by oxygen radical absorption capacity (ORAC) and ferric reducing antioxidant potential (FRAP) assays) was not dramatically affected by storage temperatures and formulation, while polyphenol stability was significantly and structure dependently affected by temperature and the presence of ascorbic acid and fructose. Anthocyanins and phenolic acids were more unstable in the presence of ascorbic acid, while flavonol stability was enhanced by its presence. Shelf life study performed at 37 °C revealed significantly higher stability of purified polyphenols vs. the stability of the same polyphenols in the strawberry extract (multi-component system).

scholarly journals Degradation kinetics and in vitro digestive stability of selected bioactive compounds from a beverage formulated with butterfly pea flowers

2022 ◽  
Vol 52 (5) ◽  
Author(s):  
Renata Oliveira Santos ◽  
Laura Monteiro Keller ◽  
Vanessa Sales de Oliveira ◽  
Carlos Alberto Bucher ◽  
José Lucena Barbosa Junior ◽  
...  
Keyword(s):  
Ascorbic Acid ◽  
Degradation Rate ◽  
Degradation Kinetics ◽  
Model Systems ◽  
First Order ◽  
Ph Values ◽  
First Order Kinetics ◽  
Butterfly Pea ◽  
Effects Of Temperature

ABSTRACT: This study evaluated the effects of temperature on the pH of extracts of ascorbic acid and anthocyanins from petals of butterfly pea, as well as their in vitro digestive stability in model systems at 60, 70, and 80 °C. The pH values significantly decreased with an increase in the temperature (P < 0.05). The findings were similar for the degradation of anthocyanins and ascorbic acid, which followed first-order kinetics in all the systems. The samples heated at 80 °C presented the highest degradation rate (kobs), as well as higher percentages of degradation at the end of digestive stability in vitro.

scholarly journals Convective Drying of Fresh and Frozen Raspberries and Change of Their Physical and Nutritive Properties

Foods ◽  
2019 ◽  
Vol 8 (7) ◽  
pp. 251 ◽  
Author(s):  
Zoran Stamenković ◽  
Ivan Pavkov ◽  
Milivoj Radojčin ◽  
Aleksandra Tepić Horecki ◽  
Krstan Kešelj ◽  
...  
Keyword(s):  
Ascorbic Acid ◽  
Freeze Drying ◽  
Color Change ◽  
Quality Criteria ◽  
Ascorbic Acid Content ◽  
Biologically Active ◽  
Convective Drying ◽  
Total Phenolic ◽  
Anthocyanin Content ◽  
Freeze Dried

Raspberries are one of Serbia’s best-known and most widely exported fruits. Due to market fluctuation, producers are looking for ways to preserve this fresh product. Drying is a widely accepted method for preserving berries, as is the case with freeze-drying. Hence, the aim was to evaluate convective drying as an alternative to freeze-drying due to better accessibility, simplicity, and cost-effectiveness of Polana raspberries and compare it to a freeze-drying. Three factors were in experimental design: air temperature (60, 70, and 80 °C), air velocity (0,5 and 1,5 m · s−1), and state of a product (fresh and frozen). Success of drying was evaluated with several quality criteria: shrinkage (change of volume), color change, shape, content of L-ascorbic acid, total phenolic content, flavonoid content, anthocyanin content, and antioxidant activity. A considerable influence of convective drying on color changes was not observed, as ΔE was low for all samples. It was obvious that fresh raspberries had less physical changes than frozen ones. On average, convective drying reduced L–ascorbic acid content by 80.00–99.99%, but less than 60% for other biologically active compounds as compared to fresh raspberries. Convective dried Polana raspberry may be considered as a viable replacement for freeze-dried raspberries.

Parallel reaction kinetics of smectite to illite conversion

Clay Minerals ◽  
1996 ◽  
Vol 31 (3) ◽  
pp. 365-376 ◽  
Author(s):  
H. Wei ◽  
E. Roaldset ◽  
M. Bjorøy
Keyword(s):  
Electrostatic Interactions ◽  
Gulf Coast ◽  
Sedimentary Basins ◽  
Frequency Factor ◽  
Reaction Model ◽  
Activation Energies ◽  
Parallel Reaction ◽  
First Order ◽  
Maximum Reaction ◽  
Kinetics Of

AbstractA parallel reaction model is developed for describing the conversion of smectite to illite. Each reaction represents a group of similar smectite layers that require the same activation energy and have the same illitization rate. The model considers that the rate-determining reactant is smectite itself which follows first-order Arrhenius kinetics. By modelling the data from hydrothermal illitization experiments and from a Gulf Coast well, the activation energies are found to be distributed in the range of 11–24 kcal/mol with a maximum reaction at 18 kcal/mol, which involves 65% of reactive smectite. A frequency factor in the order of 10−3–10−4/s, obtained from the data fitting, appears to be adequate for modelling natural diagenesis in sedimentary basins. The distribution pattern of activation energies is considered to be controlled by the degree of heterogeneity of the initial smectite and the degree of electrostatic interactions between smectite layers and the newly formed illite layers during reaction.

scholarly journals Drying Characteristics of Jackfruit and Snake Fruit using Freeze Dryer

2021 ◽  
Vol 29 (1) ◽  
Author(s):  
Joko Nugroho Wahyu Karyadi ◽  
Siti Rahma ◽  
Ronal Sitindaon ◽  
Dionisia Gusda Primadita Putri ◽  
Dwi Ayuni
Keyword(s):  
Ascorbic Acid ◽  
Moisture Content ◽  
Acid Content ◽  
Heating Temperature ◽  
Ascorbic Acid Content ◽  
Drying Rate ◽  
Order Kinetic ◽  
Drying Time ◽  
Freeze Dried ◽  
Freeze Dryer

Jackfruit (Artocarpus heterophyllus Lam.) and snake fruit [Salacca zalacca (Gaert.) Voss] are tropical fruits that are rich in vitamins and minerals. Due to their specific aroma and unique taste, jackfruit and snake fruit have great potential to be processed into dried fruits and healthy snacks. In this work, jackfruit and snake fruit were freeze-dried using a self-designed laboratory-scale freeze dryer. The freeze dryer was constructed with a stainless-steel plate (3 mm thickness). The drying rates were determined with three different heating temperatures: 50, 60, and 70ºC. This study also investigated the effect of the freeze-drying process on the characteristics of dried fruit such as moisture content, texture, color, ascorbic acid content, and morphological of dried samples. Results showed that the heating temperatures were revealed to affect characteristics such as drying rate, final moisture content, texture, and ascorbic acid content. Increased drying rate and decreased drying time were observed with an increase in the dryer temperature. The sample resulted from 70ºC of heating temperature exhibited the optimum results in terms of hardness and ascorbic content preservation. The first-order kinetic model was the best fit for the prediction of drying kinetics of all materials.

Analysis of ascorbic acid content in various fruits and vegetables by spectrofluorimetric methods

Planta Medica ◽  
2011 ◽  
Vol 77 (12) ◽  
Author(s):  
A Haskovic ◽  
A Copra Janicijevic ◽  
A Topcagic ◽  
L Klepo ◽  
A Kapur ◽  
...  
Keyword(s):  
Ascorbic Acid ◽  
Acid Content ◽  
Fruits And Vegetables ◽  
Ascorbic Acid Content
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