scholarly journals Antioxidant Activity, and Volatile and Phytosterol Contents of Strobilanthes crispus Dehydrated Using Conventional and Vacuum Microwave Drying Methods

Molecules ◽  
2019 ◽  
Vol 24 (7) ◽  
pp. 1397 ◽  
Author(s):  
Chua ◽  
Chua ◽  
Figiel ◽  
Chong ◽  
Wojdyło ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Freeze Drying ◽  
Influencing Factor ◽  
Microwave Drying ◽  
Convective Drying ◽  
Drying Methods ◽  
Drying Method ◽  
Vacuum Microwave ◽  
Strobilanthes Crispus ◽  
C 50

The preservation of active constituents in fresh herbs is affected by drying methods. An effective drying method for Strobilanthes crispus which is increasingly marketed as an important herbal tea remains to be reported. This study evaluated the effects of conventional and new drying technologies, namely vacuum microwave drying methods, on the antioxidant activity and yield of essential oil volatiles and phytosterols. These drying methods included convective drying (CD) at 40 °C, 50 °C, and 60 °C; vacuum microwave drying (VMD) at 6, 9, and 12 W/g; convective pre-drying and vacuum microwave finish drying (CPD-VMFD) at 50 °C and 9 W/g; and freeze-drying (FD). GC–MS revealed 33 volatiles, and 2-hexen-1-ol, 2-hexenal, 1-octen-3-ol, linalool, and benzaldehyde were major constituents. The compounds β-sitosterol and α-linolenic acid were the most abundant phytosterol and fatty acid, respectively, in fresh S. crispus. The highest phenolic content was achieved with CD at 60 °C. The highest antioxidant activity was obtained with CD at 40 °C and VMD at 9 W/g. On the contrary, the highest total volatiles and phytosterols were detected with CD at 50 °C and VMD at 9 W/g, respectively. This study showed that CD and VMD were effective in producing highly bioactive S. crispus. A suitable drying parameter level, irrespective of the drying method used, was an important influencing factor.

scholarly journals The Influence of Drying Method on Volatile Composition and Sensory Profile of Boletus edulis

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Joanna Nöfer ◽  
Krzysztof Lech ◽  
Adam Figiel ◽  
Antoni Szumny ◽  
Ángel A. Carbonell-Barrachina
Keyword(s):  
Volatile Compounds ◽  
Freeze Drying ◽  
Sensory Profile ◽  
Microwave Drying ◽  
Convective Drying ◽  
Drying Methods ◽  
Drying Method ◽  
Volatile Composition ◽  
Boletus Edulis ◽  
Vacuum Microwave

The objective of this study was to evaluate the influence of different drying methods on aroma and sensory profile of Boletus edulis (cepe). The drying methods tested were convective drying (CD), freeze-drying (FD), vacuum microwave drying (VMD), and a combination of convective predrying and vacuum microwave finish-drying (CPD-VMFD). Fresh and dried cepe volatiles, analyzed by SPME and GC-MS, showed the presence of 53 volatile compounds, most of them present in all dried samples but with quantitative variation. The major volatile compounds in fresh and dried cepe were 1-octen-3-ol (3405 µg 100 g−1·db), 3-octanone (429 µg 100 g−1·db), and hexanal (355 µg 100 g−1·db). The results showed that drying of cepe mushrooms caused major losses of aroma compounds; however, the highest content of volatile compounds and the highest intensity of most of the key positive sensory attributes were found in samples after (i) CD at 80°C (3763 µg 100 g−1·db), (ii) CD at 70°C (3478 µg 100 g−1·db), and (iii) CPD at 60°C and VMFD at 480/240 W (2897 µg 100 g−1·db).

scholarly journals Characterisation of the Convective Hot-Air Drying and Vacuum Microwave Drying of Cassia alata: Antioxidant Activity, Essential Oil Volatile Composition and Quality Studies

Molecules ◽  
2019 ◽  
Vol 24 (8) ◽  
pp. 1625 ◽  
Author(s):  
Chua ◽  
Chua ◽  
Figiel ◽  
Chong ◽  
Wojdyło ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Microwave Drying ◽  
Convective Drying ◽  
Drying Methods ◽  
Fresh Sample ◽  
Cassia Alata ◽  
Vacuum Microwave ◽  
High Antioxidant Activity ◽  
C 50 ◽  
Drying Conditions

The preservation of active constituents in Cassia alata through the removal of moisture is crucial in producing a final product with high antioxidant activity. This study aims to determine the influences of various drying methods and drying conditions on the antioxidant activity, volatiles and phytosterols content of C. alata. The drying methods used were convective drying (CD) at 40 °C, 50 °C and 60 °C; freeze drying; vacuum microwave drying (VMD) at 6, 9 and 12 W/g; and two-stage convective pre-drying followed by vacuum microwave finish drying (CPD-VMFD) at 50 °C and 9 W/g. The drying kinetics of C. alata are best described by the thin-layer model (modified Page model). The highest antioxidant activity, TPC and volatile concentration were achieved with CD at 40 °C. GC–MS analysis identified the presence of 51 volatiles, which were mostly present in all samples but with quantitative variation. The dominant volatiles in fresh C. alata are 2-hexenal (60.28 mg 100 g−1 db), 1-hexanol (18.70 mg 100 g−1 db) and salicylic acid (15.05 mg 100 g−1 db). The concentration of phytosterols in fresh sample was 3647.48 mg 100 g−1 db, and the major phytosterols present in fresh and dried samples were β-sitosterol (1162.24 mg 100 g−1 db). CPD-VMFD was effective in ensuring the preservation of higher phytosterol content in comparison with CD at 50 °C. The final recommendation of a suitable drying method to dehydrate C. alata leaves is CD at 40 °C.

scholarly journals Determination of Various Drying Methods’ Impact on Odour Quality of True Lavender (Lavandula angustifolia Mill.) Flowers

Molecules ◽  
2019 ◽  
Vol 24 (16) ◽  
pp. 2900 ◽  
Author(s):  
Łyczko ◽  
Jałoszyński ◽  
Surma ◽  
García-Garví ◽  
Carbonell-Barrachina ◽  
...  
Keyword(s):  
Solid Phase ◽  
Microwave Drying ◽  
Convective Drying ◽  
Drying Methods ◽  
Drying Method ◽  
Sensory Panel ◽  
Lavandula Angustifolia ◽  
Preservation Method ◽  
Vacuum Microwave

True lavender flowers (Lavandula angustifolia Mill.) is a critical source of essential oils and a flavouring agent used in numerous industries like foods, cosmetics and pharmaceuticals. Its main volatile constituents are linalool and linalyl acetate, which are commonly considered as main odour-active constituents (OACs). Nevertheless, the quality of true lavender flowers is highly dependent on its post-harvest treatment, mainly the preservation method. Recognising that drying is the most frequently used preservation method, the influence of various drying methods, including convective drying (CD) at 50, 60 and 70 °C, vacuum-microwave drying (VMD) with powers 240, 360 and 480 W and combined convective pre-drying at 60 °C followed by vacuum-microwave finish-drying with power 480 W (CPD-VMFD), on the quality of true lavender flowers was verified. The evaluation of influence was carried out by HS-SPME(HS, solid-phase microextraction), GC-MS, GC-MS-O (gas chromatography–mass spectrometry–olfactometry) techniques. Moreover, the sensory panel has assessed the sample odour quality. As a result, the optimal drying methods regarding the requirements for products were established. Overall, for total essential oil recovery, CD at 50 °C is the optimal drying method, while for odour quality concerning the sensory panel evaluation, VMD with power 360 W combined CPD-VMFD and CD at 50 °C is the optimal drying method.

scholarly journals Drying of Phyla nodiflora Leaves: Antioxidant Activity, Volatile and Phytosterol Content, Energy Consumption, and Quality Studies

Processes ◽  
2019 ◽  
Vol 7 (4) ◽  
pp. 210 ◽  
Author(s):  
Lisa Yen Wen Chua ◽  
Bee Lin Chua ◽  
Adam Figiel ◽  
Chien Hwa Chong ◽  
Aneta Wojdyło ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Energy Consumption ◽  
Drying Kinetics ◽  
Microwave Drying ◽  
Convective Drying ◽  
Total Phenolic ◽  
Drying Methods ◽  
Drying Time ◽  
Antioxidant Power ◽  
Vacuum Microwave

Drying is an important process in the preservation of antioxidants in medicinal plants. In this study, leaves of Phyla nodiflora, or commonly known as frog fruit, were dried using convective drying (CD) at 40, 50, and 60 °C; vacuum-microwave drying (VMD) at 6, 9, and 12 W/g; and convective pre-drying followed by vacuum-microwave finish drying (CPD–VMFD) at 50 °C and 9 W/g. Drying kinetics of P. nodiflora leaves was modelled, and the influences of drying methods on the antioxidant activity, total phenolic content, volatile and phytosterol contents, energy consumption, water activity, and color properties were determined. Results showed that drying kinetics was best described by modified Page model. VMD achieved highest drying rate, whereas VMFD considerably reduced the drying time of CD from 240 min to 105 min. CPD–VMFD was the best option to dry P. nodiflora in terms of retaining volatiles and phytosterols, with lower energy consumption than CD. Meanwhile, VMD at 6 W/g produced samples with the highest antioxidant activity with 2,2′-Azinobis (3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) and ferric reducing antioxidant power (FRAP) value of 11.00 and 15.99 µM Trolox/100 g dw, respectively.

The Effectiveness of Vacuum-microwave Drying Methods in the Preservation of Amelanchier Berries (Amelanchier canadensis L. Medik.)

2017 ◽  
Vol 13 (6) ◽  
Author(s):  
Jan Piecko ◽  
Dorota Konopacka ◽  
Monika Mieszczakowska-Frąc ◽  
Dorota Kruczyńska
Keyword(s):  
Reference Method ◽  
Raw Material ◽  
Microwave Drying ◽  
Convective Drying ◽  
Drying Methods ◽  
Microwave Method ◽  
Nutritional Values ◽  
Vacuum Microwave ◽  
Challenges And Opportunities ◽  
Dried Fruit

Abstract In Poland, Amelanchier berries are of considerable interest to both consumers and potential producers, which presents marketing challenges and opportunities. An attempt was made to preserve Amelanchier berries using a vacuum-microwave method of drying in order to determine its usefulness for producing microbiologically stable dried fruit with a high nutritional values. The berry variety “Prince William” (Amelanchier canadensis) was chosen as the experimental material. Vacuum-microwave drying was performed in two variants: (convective drying [CD] + vacuum microwave method [VMW]) after convective pre-drying of fruit and (VMW) without pre-drying. Unassisted CD was used as the reference method. Application of a vacuum-microwave drying method to Amelanchier berries makes it possible to obtain a stable preserved product of high-quality, yielding moderate shrinkage and good retention of bioactive compounds. An optimized method of vacuum-microwave drying, applied directly to frozen fruit, allows the retention of 70 % of cyanidin glycosides present in the raw material.

scholarly journals The Influence of Different Drying Methods on Constituents and Antioxidant Activity of Saffron from China

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Yingpeng Tong ◽  
Xingyi Zhu ◽  
Yongqiu Yan ◽  
Ruoxi Liu ◽  
Feng Gong ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Microwave Drying ◽  
Drying Methods ◽  
Drying Method ◽  
Vacuum Oven ◽  
Oven Drying ◽  
Electric Oven ◽  
Long Time ◽  
Spectrum Effect

More and more saffron has been cultivated in China because of the increasing saffron demand, but no paper has studied the influence of drying methods on the quality of Chinese saffron. In this paper, three different dehydration treatments applied in actual production were evaluated: dehydration with electric oven, vacuum oven, and microwave. We determined that the highest quality of saffron will be obtained when fresh saffron is treated at higher temperatures (no more than 70°C) for a long time by electric oven drying and vacuum oven drying. In microwave drying, treatments at lower microwave power and longer time benefit the quality of saffron. In addition, the influence of the drying method on antioxidants in saffron is discussed. The correlation between individual saffron profiles and the antioxidant value was estimated by spectrum-effect relationships analysis.

scholarly journals Design of Healthy Snack Based on Kiwifruit

Molecules ◽  
2020 ◽  
Vol 25 (14) ◽  
pp. 3309 ◽  
Author(s):  
Urszula Tylewicz ◽  
Malgorzata Nowacka ◽  
Katarzyna Rybak ◽  
Kinga Drozdzal ◽  
Marco Dalla Rosa ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Vitamin C ◽  
Bioactive Compounds ◽  
Freeze Drying ◽  
Bioactive Compound ◽  
Convective Drying ◽  
Drying Methods ◽  
Hot Air ◽  
Sugar Addition ◽  
High Antioxidant Activity

Kiwifruit is an excellent source of vitamin C and other bioactive compounds, which contribute to its high antioxidant activity. However, the fruits with small size and low weight are considered waste and are unprofitable; therefore, the production of healthy kiwifruit-based dried snacks, which contain a lot of health-beneficial ingredients, could be a viable alternative for their use. The aim of this study was to develop formulations and methods to produce attractive and nutritionally valuable dried snacks based on yellow kiwifruit. Three different puree formulations (kiwifruit; fennel; and strawberry, lemon, or spinach) with or without addition of sugar were subjected to two drying methods: freeze-drying (fruit bars) and conventional hot air drying (fruit leathers). The obtained products were analysed for their content of total polyphenols (TPs), flavonoids, and vitamin C, as well as their antioxidant activity. The results showed that snacks prepared by freeze-drying (fruit bars) presented higher TP, vitamin C, and flavonoids content than those prepared by convective drying; however, the antioxidant activity did not always follow this trend. The amount of bioactive compounds depended on the formulation used for the preparation of snacks. The effect of the sugar addition seems to be strictly related to the mix used and specific bioactive compound investigated.

scholarly journals Characterization of pseudo-fruits of Hovenia dulcis T. at different maturation stages and drying methods

2021 ◽  
Vol 43 ◽  
pp. e50571
Author(s):  
Georgia Ane Raquel Sehn ◽  
Sabrina Vicentini Schaefer ◽  
Marcio Schmiele ◽  
Bibiana Paim da Silva ◽  
Milene Teixeira Barcia ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Phenolic Compounds ◽  
Shelf Life ◽  
Freeze Drying ◽  
Raw Material ◽  
Maturation Stage ◽  
Drying Methods ◽  
Drying Method ◽  
Maturation Stages ◽  
Hovenia Dulcis

The vast majority of fruits and unprocessed vegetables, have a very short shelf life, mainly due to its high-water activity. Drying technology is an effective process, used to increase the shelf life of these products. It also can provide an effective method of consumption of fruits in food products. In this study, the influence of the maturation stage and drying method on the phenolic compounds and antioxidant activities of Japanese grape pseudo-fruits (Hovenia dulcis T.) were studied. The centesimal composition, reducing sugars and nonreducing sugars, ratio, color, phenolic compounds and antioxidant activity by oxygen radical absorbance capacity (ORAC) of the unprocessed pseudo-fruits, at different maturation stages (immature, in maturation and mature), were analyzed. Two drying methods were employed in the pseudo-fruits (oven with air circulation and freeze drying) obtaining flour from which moisture content, instrumental color, phenolic compounds and antioxidant activity were determined. The unprocessed pseudo-fruits of Japanese grape showed significant content of phenolic compounds at the early stages of maturation and high antioxidant capacity when mature (at the final stages of maturation). In addition, they showed a high content of fibers and sugars, and can be used as raw material in the food industry. After dehydration, the freeze-drying process provided a more stable color, because this process minimizes the enzymatic browning reactions, and preserved a greater number of phenolic compounds. The antioxidant activity, however, showed to be associated with the drying method, being higher in the flour obtained from lyophilized immature pseudo-fruits.

scholarly journals Changes in the Content of Phenolic Compounds and Biological Activity in Traditional Mexican Herbal Infusions with Different Drying Methods

Molecules ◽  
2020 ◽  
Vol 25 (7) ◽  
pp. 1601
Author(s):  
Sandra N. Jimenez-Garcia ◽  
Moisés A. Vazquez-Cruz ◽  
Xóchitl S. Ramirez-Gomez ◽  
Vicente Beltran-Campos ◽  
Luis M. Contreras-Medina ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Phenolic Compounds ◽  
Enzymatic Activity ◽  
Freeze Drying ◽  
Antioxidant Properties ◽  
Microwave Drying ◽  
Drying Methods ◽  
Antioxidant Power ◽  
Cold Temperatures

Mexican spices are used in the supplementation of the human diet and as medicinal herbs for the particularly high amounts of compounds capable of deactivating free radicals. In addition, these spices can have beneficial effects on chronic, no-transmissible diseases such as type II diabetes and hypertension arterial. The objective of this study is to determine the content of phenolic compounds on the antioxidant activity and inhibitory enzymes of α-amylase, α-glucosidase and angiotensin-converting enzyme in melissa, peppermint, thyme and mint, which are subjected to microwave drying, conventional and freeze-drying to be used as alternative treatments. Spices were evaluated to determine total phenols, flavonoids, tannins, 2,2-Diphenyl-1-picrylhydrazyl (DPPH), (2,2′-azino-bis- (3-ethyl benzothiazolin-6-ammonium sulphonate) (ABTS) and Ferric Reducing/Antioxidant Power (FRAP), enzymatic activity. The investigation showed that conventional drying caused a decrease in antioxidant properties and inhibitory activity, in some species, while remained preserved in microwave drying and freeze-drying. The activity of polyphenol oxides and peroxidase decreases with high temperatures and these increase with the use of cold temperatures. This study aims to determine the extent of optimal drying required to preserve phenolic compounds, and the positive effect on antioxidant activity and enzymatic activity in in vitro models, which will produce benefits for the infusion processing industry and the pharmaceutical industry.

scholarly journals Influence of Drying Method on Some Bioactive Compounds and the Composition of Volatile Components in Dried Pink Rock Rose (Cistus creticus L.)

Molecules ◽  
2020 ◽  
Vol 25 (11) ◽  
pp. 2596 ◽  
Author(s):  
Natalia Matłok ◽  
Sabina Lachowicz ◽  
Józef Gorzelany ◽  
Maciej Balawejder
Keyword(s):  
Solid Phase ◽  
Volatile Fraction ◽  
Volatile Components ◽  
Drying Methods ◽  
Drying Method ◽  
Flight Mass Spectrometry ◽  
Vacuum Microwave ◽  
Odoriferous Substances ◽  
C 50 ◽  
Cistus Creticus

This study investigates the effects of various drying methods applied to leaves of Cistus creticus L. on the contents of polyphenols and the composition of the volatile fraction. The following four drying methods were used: convection drying at a temperature of 40 °C (CD 40 °C), 50 °C (CD 50 °C), and 60 °C (CD 60 °C); vacuum-microwave (VMD 240 W); combined drying, involving convection pre-drying (50 °C) and vacuum-microwave (240 W) finish drying (CPD-VMFD) as well as freeze-drying (FD). Polyphenols in the dried leaves were determined using chromatography-photodiode detector-quadrupole/time of flight-mass spectrometry (UPLC-PDA-Q/TOF-MS). The contents of odoriferous substances in the dry material were determined by means of head space-solid phase microextraction (HS-SPME) with the use of a gas chromatograph (GC). Thirty-seven polyphenol components including 21 flavonols, eight flavan-3-ols, and eight hydrolyzed tannins in dry Pink Rock Rose material were found for the first time. The highest contents of polyphenols, totaling 2.8 g 100 g−1 dry matter (d.m.), were found in the samples subjected to the CPD/VMFD drying method. Pink Rock Rose subjected to this drying method was characterized by large quantities of odoriferous compounds, mainly eugenol, thymol, and carvacrol, which contribute to its antiseptic properties. By using CPD/VMFD methods, it is possible to obtain fine quality dry material from the leaves of C. creticus.

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