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

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

International Journal of Food Engineering ◽

10.1515/ijfe-2016-0346 ◽

2017 ◽

Vol 13 (6) ◽

Cited By ~ 1

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.

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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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Drying methods differentially alter volatile profiles of edible locusts and silkworms

Journal of Insects as Food and Feed ◽

10.3920/jiff2019.0046 ◽

2020 ◽

Vol 6 (4) ◽

pp. 405-415

Author(s):

M. Mishyna ◽

M. Haber ◽

O. Benjamin ◽

J.J. Itzhak Martinez ◽

J. Chen

Keyword(s):

Freeze Drying ◽

Oxidation Process ◽

Microwave Drying ◽

Insect Species ◽

Drying Methods ◽

Drying Method ◽

Headspace Volatiles ◽

Volatile Profiles ◽

Maillard Products ◽

Different Levels

In this study, the effect of freeze-drying, oven- and microwave-drying on the volatile profiles and sensory properties of edible locust and silkworm was studied. Fifty-five headspace volatiles were detected, including alkanes, alcohols, aldehydes, esters, and ketones, with variations in intensity depending on the insect species and drying method. Volatiles from microwave-dried locusts and silkworms were typical for the Maillard reaction, that is in accordance with the significant increase of fluorescence of advanced Maillard products (2.9 and 5.5 times higher than in raw silkworms and locusts, respectively). Comparison of fatty acid composition and Fourier transform infrared spectra revealed signs of oxidation process at different levels depending on the insect. Changes in aroma and its intensity caused by different drying methods were also detected by sensory panellists who rated the samples of oven-dried locusts (2.4) and microwave-dried silkworms (1.9) with the lowest scores. An addition 15% of dried insects to cookies decreased the diversity of the volatiles, changed their intensity and lessened the dissimilarities between cookies with differently dried insect powders. Sensory panellists determined the presence of additional ingredients by higher odour intensity and general changes in overall liking scores of the insect-based cookies. Thus, drying can modify odour and sensory characteristics of locusts and silkworms and, consequently, cookies with these insect species, that should be considered in the processing of insects and formulation of novel insect-based foods.

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Effect of drying methods on the texture properties and active ingredients in Longan flesh

E3S Web of Conferences ◽

10.1051/e3sconf/202125102049 ◽

2021 ◽

Vol 251 ◽

pp. 02049

Author(s):

Li Qian ◽

Lv Yongbin ◽

Su Keying ◽

Luo Simei ◽

Zhao Shiming ◽

...

Keyword(s):

Vitamin C ◽

Freeze Drying ◽

Microwave Drying ◽

Drying Methods ◽

Drying Method ◽

Active Ingredients ◽

Texture Properties ◽

Texture Characteristics ◽

Active Substances

In order to determine the best drying method of longan flesh, the effects of different drying method (microwave drying, blast drying,vacuum freeze-drying) on the texture characteristics and active ingredients were compared. The results show that different drying methods will increase the hardness, cohesion and chewiness of longan flesh, and decrease the viscosity and elasticity to varying degrees. For active substances, the content of flavonoids and polyphenols is the largest under vacuum freeze-drying, followed by microwave drying and blast drying, but the loss of vitamin C is the opposite. On the whole, vacuum freeze-drying does not cause shrinkage of the flesh, and maintains good hardness, cohesion, chewiness and active ingredients. Comprehensive texture characteristics and changes in active ingredients, vacuum freeze drying is more suitable for drying and processing longan flesh.

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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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Effects of Different Drying Methods on the Retention of Bioactive Compounds, On-Line Antioxidant Capacity and Color of the Novel Snack from Red-Fleshed Apples

Molecules ◽

10.3390/molecules25235521 ◽

2020 ◽

Vol 25 (23) ◽

pp. 5521

Author(s):

Aneta Wojdyło ◽

Krzysztof Lech ◽

Paulina Nowicka

Keyword(s):

Antioxidant Capacity ◽

Bioactive Compounds ◽

Freeze Drying ◽

Control Method ◽

Food Product ◽

Quality Parameters ◽

Microwave Drying ◽

Drying Methods ◽

Vacuum Microwave ◽

On Line

The aim of this study was to determine the effect of different drying methods: convective (at 50, 60, 70 °C), vacuum-microwave (at 120, 240, 360, 480 W and 360 W with reduction to 120 W) and hybrid (convective pre-drying at 50, 60, 70 °C followed by vacuum-microwave drying at 120 W) on the quality parameters of novel red-fleshed apple fruit snacks (RFAs), such as phenolics, on-line antioxidant capacity, water activity and color. Drying kinetics, including a temperature profile of dried material, and modified Page model were determined. Freeze-drying was used as a control method. The highest content of bioactive compounds in the samples was retained following freeze-drying, then hybrid, vacuum-microwave and finally convection drying. The antioxidant capacity measured by on-line 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS), identified anthocyanins, flavan-3-ols and phenolic acid as the main compounds responsible for this activity. Unfavorable changes in color, formation of hydroxymethylfurfural (HMF) and degradation of polyphenolics were noted along with increasing drying temperature and magnetron power. The red-fleshed apple snacks are a promising high-quality dehydrated food product belonging to functional foods category.

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