As the primary by‐product of pea processing industry, pea pods represent a rich source of various high-value molecules. The aim of this work is to investigate the effect of nine different microwave output powers (200 to 1000 W) and five different ventilated oven temperatures (40, 60, 80, 100 and 120 °C) on the quality of pea pod such as physical-chemical (water activity, total color change), functional properties (water retention capacities and swelling capacity) and bioactive properties (total phenolic content, total flavonoid content and antioxidant capacity). The results show that microwave drying reduced significantly the drying time. Convective drying led to a greater color change than microwave drying. Convective drying at 80 °C for 135.33 min appeared the best process in terms of functional properties giving the highest values of water retention capacity and swelling capacity. Both microwave and convective drying methods could increase phenolic and antioxidant compounds content of pea pods. It was suggested that the microwave method can be a promising technology for drying the pea pods due to the shorter drying time, and higher product quality.
Research Article
Physicochemical, Functional and Bioactive Properties of Pea (Pisum sativum L.) Pods Microwave and Convective Dried Powders
https://doi.org/10.21203/rs.3.rs-951507/v1
This work is licensed under a CC BY 4.0 License
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Pea pods powders
microwave drying
Convective drying
color
functional properties
bioactive compounds
Table 1. Drying time and water activity of pea pods drying at different oven temperatures and microwave powers.
|
Drying conditions |
Drying time (min) |
Water activity |
|
Oven drying temperature(°C) |
|
|
|
40 |
850±22.91A |
0.364±0.020A |
|
60 |
206.33±4.61B |
0.309±0.014A,B,C |
|
80 |
135.33±6.42C |
0.266±0.003B,C,D,E |
|
100 |
86.33±5.68D,E |
0.260±0.012B,C,D,E |
|
120 |
50.16±1.25G,H |
0.244±0.036C,D,E |
|
Microwave drying power (W) |
|
|
|
200 |
217.11±0.67B |
0.324±0.057A,B |
|
300 |
99.05±2.04D |
0.305±0.006A,B,C |
|
400 |
72.91±0.79E,F |
0.297±0.010A,B,C,D |
|
500 |
53.88±0.29F,G |
0.276±0.040B,C,D,E |
|
600 |
44±0.94G,H,I |
0.274±0.020B,C,D,E |
|
700 |
37.55±0.34G,H,I,J |
0.266±0.016B,C,D,E |
|
800 |
32.16±0.36 H,I,J |
0.226±0.013D,E |
|
900 |
27.38±0.39I,J |
0.211±0.034E |
|
1000 |
22.36±0.42J |
0.205±0.020E |
Assays are performed in triplicate (n = 3) and data are expressed as mean ± standard deviation.
Table 2. Color parameters of fresh and dried pea pods at different oven temperatures and microwave powers.
Assays are performed in triplicate (n = 3) and data are expressed as mean ± standard deviation.
Table 3. Functional properties of fresh and dried pea pods at different oven temperatures and microwave powers.
|
Drying conditions |
Functional properties |
||
|
SW (ml/gDW) |
WRC (gwater/gDW) |
||
|
Fresh |
8.97± 0.12A |
8.17± 0.22A |
|
|
Oven drying temperature (°C) |
|
||
|
40 |
6.97 ± 0.06B,C |
4.45 ± 0.24D,E |
|
|
60 |
7.53 ± 0.15B |
5.68 ± 0.16B |
|
|
80 |
8.73 ± 0.12A |
5.88 ± 0.21B |
|
|
100 |
6.60 ± 0.17C,D |
4.68 ± 0.22C,D |
|
|
120 |
4.60 ± 0.35F |
3.58 ± 0.36E |
|
|
Microwave drying power (W) |
|
||
|
200 |
4.90 ± 0.20F |
5.51 ± 0.47B,C |
|
|
300 |
4.80 ± 0.36F |
4.09 ± 0.21D,E |
|
|
400 |
3.43 ± 0.12G |
3.97 ± 0.27D,E |
|
|
500 |
4.53 ± 0.21F |
4.23 ± 0.79D,E |
|
|
600 |
4.80 ± 0.10F |
4.58 ± 0.06C,D |
|
|
700 |
5.83 ± 0.25E |
4.69 ± 0.29C,D |
|
|
800 |
6.33 ± 0.06D,E |
4.49 ± 0.20D,E |
|
|
900 |
6.77 ± 0.15C,D |
4.01 ± 0.00D,E |
|
|
1000 |
6.80 ± 0.17C,D |
3.74 ± 0.27D,E |
|
Assays are performed in triplicate (n = 3) and data are expressed as mean ± standard deviation.
Table 4. Contents of total phenolics (as gallic acid equivalents, GAE), total flavonoids (as quercetin equivalents, QE) and antioxidant activity (determined by DPPH and reducing power method) in fresh and dried pea pods at different oven temperatures and microwave powers.
Assays are performed in triplicate (n = 3) and data are expressed as mean ± standard deviation