Drying methods differentially alter volatile profiles of edible locusts and silkworms

2020 ◽  
Vol 6 (4) ◽  
pp. 405-415
Author(s):  
M. Mishyna ◽  
M. Haber ◽  
O. Benjamin ◽  
J.J. Itzhak Martinez ◽  
J. Chen

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.

Molecules ◽  
2021 ◽  
Vol 26 (14) ◽  
pp. 4153
Author(s):  
Doaa Abouelenein ◽  
Ahmed M. Mustafa ◽  
Simone Angeloni ◽  
Germana Borsetta ◽  
Sauro Vittori ◽  
...  

Strawberry is the most consumed berry fruit worldwide due to its unique aroma and flavor. Drying fruits to produce a powder represents one of the possible conservation methods to extend their shelf-life. The aim of the present study was to compare the influence of freezing and different drying methods on the volatile profile of strawberry using the HS-SPME/GC–MS method, in addition to analysis of strawberry jam volatiles. A total of 165 compounds were identified, accounting for 85.03–96.88% of the total volatile compositions. Results and PCA showed that freezing and each drying process affected the volatile profile in a different way, and the most remarkable representative differential volatiles were ethyl hexanoate, hexyl acetate, (E)-2-hexenyl acetate, mesifurane, (E)-nerolidol, γ-decalactone, 1-hexanol, and acetoin. Shade air-dried, frozen, freeze-dried, and oven-dried 45 °C samples retained more of the fruity and sweet aromas of strawberry, representing more than 68% of the total aroma intensity according to the literature. In contrast, the microwave-drying method showed drastic loss of fruity esters. Strawberry jams demonstrated complete destruction of esters and alcohols in most jams, while terpenes were significantly increased. These findings help better understand the aroma of strawberry and provide a guide for the effects of drying, freezing, and jam processing.


2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Joanna Nöfer ◽  
Krzysztof Lech ◽  
Adam Figiel ◽  
Antoni Szumny ◽  
Ángel A. Carbonell-Barrachina

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).


Molecules ◽  
2019 ◽  
Vol 24 (7) ◽  
pp. 1397 ◽  
Author(s):  
Chua ◽  
Chua ◽  
Figiel ◽  
Chong ◽  
Wojdyło ◽  
...  

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.


2021 ◽  
Vol 251 ◽  
pp. 02049
Author(s):  
Li Qian ◽  
Lv Yongbin ◽  
Su Keying ◽  
Luo Simei ◽  
Zhao Shiming ◽  
...  

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.


Molecules ◽  
2021 ◽  
Vol 26 (9) ◽  
pp. 2644
Author(s):  
Jan Oszmiański ◽  
Sabina Lachowicz ◽  
Paulina Nowicka ◽  
Paweł Rubiński ◽  
Tomasz Cebulak

The present study aimed to evaluate the effect of Jerusalem artichoke processing methods and drying methods (freeze drying, sublimation drying, vacuum drying) on the basic physicochemical parameters, profiles and contents of sugars and polyphenolic compounds, and health-promoting properties (antioxidant activity, inhibition of the activities of α-amylase, α-glucosidase, and pancreatic lipase) of the produced purée. A total of 25 polyphenolic compounds belonging to hydroxycinnamic phenolic acids (LC-PDA-MS-QTof) were detected in Jerusalem artichoke purée. Their average content in the raw material was at 820 mg/100 g dm (UPLC-PDA-FL) and was 2.7 times higher than in the cooked material. The chemical composition and the health-promoting value of the purées were affected by the drying method, with the most beneficial values of the evaluated parameters obtained upon freeze drying. Vacuum drying could offer an alternative to freeze drying, as both methods ensured relatively comparable values of the assessed parameters.


2015 ◽  
Vol 1130 ◽  
pp. 577-580 ◽  
Author(s):  
Jeong Ae Kim ◽  
Myung Hee Song ◽  
Yeoung Sang Yun

Polyethylenimine (PEI)-coated biomass-chitosan composite fiber (PBCF) was fabricated to recover Ru from acetic acid waste solution. The present work aimed to understand the effects of molecular weight of chitosan and drying method on stability and sorption performance of the PBCF. For this, the PBCF was prepared by extruding the mixed solutions of chitosan and Corynebacteriumglutamicum to form the composite fibers which were modified with ionic polymer, PEI. The degree of swelling of PBCFs prepared by hot-air, natural, and freeze drying methods were 1.25, 1.34, and 1.07 %, respectively, indicating that the freeze-drying method was the best. Batch biosorption studies showed that the maximum Ru uptake could be achieved with PBCF prepared with medium molecular weight chitosan, and could reach 34.1 mg/g, which was 7.9 times higher than that of the commercial ion exchange resin, LEWATIT® MonoPlus M 500 (4.3 mg/g). Therefore, PBCF can be considered as an alternative sorbent to synthetic resin for recovery of Ru form industrial acetic acid waste solution.


Author(s):  
Sonia Singh ◽  
Neetu Agrawal

The herbs, Chenopodium album Linn. and Spinacia oleracea Linn. belongs to Chenopodiaceae family, are the two nutritious and edible green leafy food crops, abundantly found especially in the northern-west region of India. These plants have gained renown popularity, because of their high nutritional content including protein, amino acids, carbohydrate, and even the presence of phenolic components, which ultimately may get affected with drying and storage techniques. Impact of different drying methods (microwave drying at 4 minutes, hot air oven drying at 5 hours and sun drying at 8-10 hours) on nutrient quality and antioxidant property of Chenopodium album Linn. and Spinacia oleracea Linn. leaves were evaluated by using UV spectrophotometritc assay, total phenolic content and DPPH free radical scavenger method. Drying treatments were significantly decreased the moisture, carbohydrate and protein content present in C.album and S. oleracea. Hot air oven drying method produced dried samples of C.album and S. oleracea had significantly similar antioxidant activity when compared with the samples obtained from sun drying method. The dried samples obtained from hot air oven drying technique showed significant presence of total phenolic content in C. album and S. oleracea (6.44±0.12 mg/g, 6.69±0.40 mg/g) whilst the traditional sun drying method produced 8.00±0.02 mg/g and 7.89±0.37 mg/g). It is concluded that microwave drying and hot air oven drying were the methods to preserve appreciable percentage of nutrient components compared to the fresh samples. On other hand, the traditional method produced substantial reduction of nutrient quality. From statistical analysis, hot air oven drying technique was considered as optimum method which showed satisfactory % retention of protein (65.86%) and carbohydrate (85.95%) at 5 hours (shorter time than sun drying time period) along with significant antioxidant activity (34.89 μg/mL and 35.60 μg/mL) similar as obtained from the traditional technique (32.00 μg/mL).


Molecules ◽  
2019 ◽  
Vol 24 (16) ◽  
pp. 2900 ◽  
Author(s):  
Łyczko ◽  
Jałoszyński ◽  
Surma ◽  
García-Garví ◽  
Carbonell-Barrachina ◽  
...  

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.


2018 ◽  
Vol 12 (02) ◽  
pp. 158 ◽  
Author(s):  
A. Alhanannasir ◽  
Amin Rejo ◽  
Daniel Saputra ◽  
Gatot Priyanto

Pempek is a typical food of Palembang, South Sumatra, Indonesia, mostly processed in the form of wet with a moisture content of 50-60%, so that it only lasts for 3-4 days. In order for pempek to long last, it was processed into instant pempek using the freeze drying method. Pempek had tube form with a size of 3 cm in high and 4 cm in diameter. This study was aimed to see the freeze drying pressure and time to length of cooking, density, and lightness of instant pempek. Stored pempek at temperature of -50° C was carried out freeze drying with a pressure of 0.002 bar, 004 bar, 0.006 bar, and 0.008 bar for 38 hours, 40 hours, 42 hours, and 44 hours with a methodology of Split the Duncan Real Distance Difference Test Plot Design. The result showed that the pressure and time had very significant effect on the length of cooking, density and lightness of pempek. P3 (0.006 bar) pressure treatment affected shorter cooking time of pempek about 10.83 minutes, L2 treatment has 14.17 minutes for cooking times and the P3L2 treatment combination has low density of 0.71 g / cm3 and color brightness (lightness) about 85.38, almost resemble with white color. Making instant pempek with freeze drying method gave better results in ways of shorter and faster cooking time than instant pempek by other drying methods. Keywords: cooking length, freeze drying, instant pempek


Nutrients ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 4365
Author(s):  
Anna Jakubczyk ◽  
Urszula Złotek ◽  
Kamila Rybczyńska-Tkaczyk

This research aims to investigate the influence of elicitation and drying methods (natural, convection, microwave, and freeze-drying), with jasmonic acid (JA) and yeast extract (YE) on the biological activity of extracts and hydrolysates from lovage (Levisticum officinale Koch) leaves. The results indicate that the highest TPC was determined for hydrolysates obtained from JA-elicited microwave-dried lovage (24.96 mg/gDW). The highest ACE and lipase inhibitory activity was noted for PBS extract obtained from JA-elicited lovage after microwave drying (EC50 = 0.16 and 0.12 mg/mL, respectively). Ethanolic extract from JA-elicited lovage after freeze-drying was characterized by the highest α-amylase inhibitory activity (EC50 = 3.92 mg/mL) and the highest α-glucosidase inhibitory activity (EC50 = 1.43 mg/mL) was noted for hydrolysates from control plants subjected to freeze-drying. The highest antimicrobial activity towards C. albicans yeasts was observed for microwave ethanolic extracts with minimal inhibition (MIC) and lethal (MLC) concentrations of 0.625 and 1.25 mg/mL, respectively.


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