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

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.

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

Molecules ◽

10.3390/molecules24162900 ◽

2019 ◽

Vol 24 (16) ◽

pp. 2900 ◽

Cited By ~ 4

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.

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

Journal of Food Quality ◽

10.1155/2018/2158482 ◽

2018 ◽

Vol 2018 ◽

pp. 1-11 ◽

Cited By ~ 8

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).

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

Molecules ◽

10.3390/molecules24071397 ◽

2019 ◽

Vol 24 (7) ◽

pp. 1397 ◽

Cited By ~ 10

Author(s):

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.

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

Molecules ◽

10.3390/molecules24081625 ◽

2019 ◽

Vol 24 (8) ◽

pp. 1625 ◽

Cited By ~ 10

Author(s):

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.

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

Processes ◽

10.3390/pr7040210 ◽

2019 ◽

Vol 7 (4) ◽

pp. 210 ◽

Cited By ~ 7

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.

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Coriandrum sativum L.—Effect of Multiple Drying Techniques on Volatile and Sensory Profile

Foods ◽

10.3390/foods10020403 ◽

2021 ◽

Vol 10 (2) ◽

pp. 403

Author(s):

Jacek Łyczko ◽

Klaudia Masztalerz ◽

Leontina Lipan ◽

Hubert Iwiński ◽

Krzysztof Lech ◽

...

Keyword(s):

Solid Phase ◽

Coriandrum Sativum ◽

Sensory Profile ◽

Microwave Drying ◽

Convective Drying ◽

Drying Methods ◽

Vacuum Microwave ◽

Drying Procedures ◽

Drying Techniques ◽

Sensory Tests

Coriandrum sativum L. is a medicinal and aromatic plant spread around the world, with beneficial properties that are well recognized. Both coriander seeds and leaves are used for pharmaceutical and flavoring purposes. Even though coriander seeds tend to be more popular, the leaves are receiving a consistently growing interest, especially because of popularization of Mexican, Northern African, and Indian cuisines. This increased attention brings about the necessity for providing the product with guaranteed quality, which will retain its valuable characteristics, even after post-harvest treatment. For this reason, it is highly necessary to determine reliable protocols for cilantro preservation, which usually include drying procedures; in order to identify the optimal drying treatments, a spectrum of drying techniques—convective, vacuum-microwave, and a combination of convective and vacuum-microwave—were evaluated. Cilantro-based dried products were examined from the perspectives of volatile organic constituent composition and sensory quality. After headspace solid-phase microextraction-GC/MS analysis and sensory tests, the results demonstrate that convective drying at 70 °C for 120 min followed by vacuum-microwave drying at 360 W and convective drying at 70 °C were the optimal drying methods for preserving cilantro aroma quality, while convective drying at 70 °C for 120 min followed by convective finishing drying at 50 °C decreased cilantro aroma quality.

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HS-SPME Analysis of True Lavender (Lavandula angustifolia Mill.) Leaves Treated by Various Drying Methods

Molecules ◽

10.3390/molecules24040764 ◽

2019 ◽

Vol 24 (4) ◽

pp. 764 ◽

Cited By ~ 14

Author(s):

Jacek Łyczko ◽

Klaudiusz Jałoszyński ◽

Mariusz Surma ◽

Klaudia Masztalerz ◽

Antoni Szumny

Keyword(s):

Solid Phase ◽

Microwave Drying ◽

Convective Drying ◽

Drying Methods ◽

Linalyl Acetate ◽

Lavandula Angustifolia ◽

Optimal Method ◽

Volatile Constituents ◽

Vacuum Microwave

True lavender (Lavandula angustifolia Mill.) is a widely used flavoring and medicinal plant, which strong aroma is mainly composed of linalool and linalyl acetate. The most valuable parts of the plant are the flowers, however leaves are also abundant in volatile constituents. One of the main factors responsible for its quality is the preservation procedure, which usually comes down to a drying process. For this reason an attempt to verify the influence of various drying methods (convective drying, vacuum-microwave drying and combined convection pre-drying with vacuum-microwave finishing drying) on the quality of true lavender leaves was carried out by determination of the volatile constituents profile by solid-phase microextraction (SPME) coupled with GC-MS technique. Total essential oil (EO) content was also verified. The study has revealed that the optimal drying method is strongly dependent on the purpose of the product. For flavoring properties convective drying at 60 °C is the most optimal method, while the best for preserving the highest amount of EO is vacuum-microwave drying at 480 W. Furthermore, SPME analysis had shown that drying may increase the value of true lavender leaves by significantly affecting the linalool to linalyl acetate to camphor ratio in the volatile profile.

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Estimation of moisture ratio for apple drying by convective and microwave methods using artificial neural network modeling

Scientific Reports ◽

10.1038/s41598-021-88270-z ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Vali Rasooli Sharabiani ◽

Mohammad Kaveh ◽

Roozbeh Abdi ◽

Mariusz Szymanek ◽

Wojciech Tanaś

Keyword(s):

Specific Energy Consumption ◽

Effective Diffusivity ◽

Moisture Ratio ◽

Microwave Drying ◽

Convective Drying ◽

Neural Network Modeling ◽

Drying Methods ◽

Apple Slices ◽

Artificial Neural ◽

Drying Technology

AbstractTwo different drying methods were applied for dehydration of apple, i.e., convective drying (CD) and microwave drying (MD). The process of convective drying through divergent temperatures; 50, 60 and 70 °C at 1.0 m/s air velocity and three different levels of microwave power (90, 180, and 360 W) were studied. In the analysis of the performance of our approach on moisture ratio (MR) of apple slices, artificial neural networks (ANNs) was used to provide with a background for further discussion and evaluation. In order to evaluate the models mentioned in the literature, the Midilli et al. model was proper for dehydrating of apple slices in both MD and CD. The MD drying technology enhanced the drying rate when compared with CD drying significantly. Effective diffusivity (Deff) of moisture in CD drying (1.95 × 10−7–4.09 × 10−7 m2/s) was found to be lower than that observed in MD (2.94 × 10−7–8.21 × 10−7 m2/s). The activation energy (Ea) values of CD drying and MD drying were 122.28–125 kJ/mol and 14.01–15.03 W/g respectively. The MD had the lowest specific energy consumption (SEC) as compared to CD drying methods. According to ANN results, the best R2 values for prediction of MR in CD and MD were 0.9993 and 0.9991, respectively.

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Impact of different factors on the yield and properties of fractions enriched in dietary fiber isolated from peach (Prunus persica L.) residues

Open Agriculture ◽

10.1515/opag-2016-0006 ◽

2016 ◽

Vol 1 (1) ◽

Author(s):

Paula Sette ◽

Jhon Edinson Nieto Calvache ◽

Marcelo Soria ◽

Marina de Escalada Pla ◽

Lía N. Gerschenson

Keyword(s):

Dietary Fiber ◽

Prunus Persica ◽

Orthogonal Design ◽

Raw Material ◽

Microwave Drying ◽

Convective Drying ◽

Plant Residues ◽

Ethanol Treatment ◽

Hydration Properties ◽

Sample Ratio

AbstractThe industrialization of peaches gives origin to leftover remaining from fruit canning, juice or jam production. The transformation of leftover to dietary fiber (DF) concentrates represents a strategy that can be incorporated in productive processes tending to optimize raw material use. In the present research, DF was obtained from peach (Prunus persica L.) using an ethanol treatment followed by dehydration. The influence of four factors: time and temperature of ethanol treatment prior to drying step, ratio of ethanol to sample and drying temperature using microwave or convective drying on different properties (yield, hydration properties, oil holding capacity and apparent density) of the concentrate obtained, were studied through a two level orthogonal design. Yield ranged between 4.38-7.27 g/100g for all the conditions explored. Time and temperature of the ethanol extraction affected properties when a subsequent convective drying was employed. The effect of the ethanol/sample ratio and of the temperature of drying on oil holding capacity and hydration properties was mainly detected on samples dried by microwave technique. The results obtained provide insight into the effect of processing of plant residues on the properties of DF concentrates obtained and on their potential performance as ingredients or additives for the food industry. It could be concluded that the drying technique is a key factor in relation to the properties of dietary fiber enriched fractions isolated from peach. Microwave drying allowed to produce fractions with functional properties that can be modulated through the use of different relations of ethanol to sample ratio and drying temperatures.

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Microwave Drying to Determine the Solids Content of Milk and Cottage and Cheddar Cheese

Journal of Food Protection ◽

10.4315/0362-028x-47.4.272 ◽

1984 ◽

Vol 47 (4) ◽

pp. 272-278 ◽

Cited By ~ 7

Author(s):

DAVID M. BARBANO ◽

MARY E. DELLA VALLE

Keyword(s):

Standard Method ◽

Rapid Determination ◽

Reference Method ◽

Cheddar Cheese ◽

Microwave Drying ◽

Cottage Cheese ◽

Drying Methods ◽

Test Results ◽

Conventional Drying ◽

Handling Methods

Microwave ovens have been used in quality control laboratories for rapid determination of moisture content of dairy products. Factors that influence sample drying rate and final test result for microwave drying are quite different than factors that influence conventional drying methods. Differences in dielectric properties of samples will have a significant influence on microwave drying, but may not influence conventional drying. Sample handling methods that reduce variability in test results for milk, cottage cheese, and Cheddar cheese are discussed. Preliminary investigations indicated that there are differences in results from one microwave oven to the next, even when the same sample material was dried under the same analysis conditions. This variations may be due to a combination of differences in sample positioning, differences in wave patterns in individual oven cavities, and differences in magnetron power output with age and heavy usage. Good correlations of microwave test results with those from the standard method were obtained for milk and cottage and Cheddar cheese. Statistically significant differences between microwave results and standard method results indicated that for best agreement between laboratories it would be necessary to calibrate individual microwave ovens against a standard reference method for each type of product.

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