Drying of Food Waste for Potential Use as Animal Feed
Abstract
:1. Introduction
2. Materials and Methods
2.1. Food Waste Source Identification
2.2. Sample Preparation
2.3. Solar Drying System
2.4. Convective Batch Drying System
2.5. Experimental Procedure
2.6. Dried Product Analysis
2.6.1. Protein Determination
2.6.2. Fat Determination
2.6.3. Ash Determination
2.6.4. Moisture Determination
2.6.5. Carbohydrate Determination
2.7. Microbial Analysis
2.8. Effective Diffusion Coefficient Determination
3. Results
3.1. Effect of Drying Conditions on Drying Rate and Product Water Activity
Reproducibility Test (R-Test) of Solar Drying Experiments
3.2. Effective Diffusion Coefficient
3.3. Nutritional and Microbial Analysis
3.4. Potential Impact of the Study Results on Sustainable Food Waste Management and Circular Economy in the Region
4. Conclusions
Author Contributions
Funding
Informed Consent Statement
Data Availability Statement
Acknowledgments
Conflicts of Interest
References
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Time/h | Ambient Temperature (°C) | Collector Outlet Temperature (°C) | ||||||
R-test | Day 2 | Difference | RSD (%) | R-test | Day 2 | Difference | RSD (%) | |
0 | 35.5 | 32.5 | 3.00 | 4.41 | 52.2 | 50.4 | 1.80 | 1.75 |
1 | 37.5 | 32.8 | 4.70 | 6.69 | 60.9 | 59.2 | 1.70 | 1.42 |
2 | 37.1 | 34.7 | 2.40 | 3.34 | 61.1 | 63.7 | −2.60 | 2.08 |
3 | 34.2 | 36.2 | −2.00 | 2.84 | 63.2 | 66.5 | −3.30 | 2.54 |
4 | 37.2 | 33.2 | 4.00 | 5.68 | 69.8 | 59.2 | 10.60 | 8.22 |
5 | 38.4 | 37.4 | 1.00 | 1.32 | 66.9 | 61.9 | 5.00 | 3.88 |
6 | 37.7 | 30.8 | 6.90 | 10.07 | 62.4 | 59.6 | 2.80 | 2.30 |
7 | 34.8 | 29 | 5.80 | 9.09 | 53.8 | 37.2 | 16.60 | 18.24 |
Average | 3.23 | 5.43 | 4.08 | 5.05 | ||||
Time/h | Ambient Air Relative Humidity (%) | Chamber Outlet Air Relative Humidity (%) | ||||||
R-test | Day2 | Difference | RSD (%) | R-test | Day2 | Difference | RSD (%) | |
0 | 22.5 | 26.6 | −4.10 | 4.18 | 26.8 | 29.8 | −3.00 | 5.30 |
1 | 19.1 | 26.5 | −7.40 | 8.11 | 20.5 | 22.7 | −2.20 | 5.09 |
2 | 15.4 | 20.4 | −5.00 | 6.98 | 15.6 | 16.8 | −1.20 | 3.70 |
3 | 14.5 | 19.1 | −4.60 | 6.85 | 10.7 | 14.2 | −3.50 | 14.06 |
4 | 12.9 | 17.4 | −4.50 | 7.43 | 9.4 | 11.7 | −2.30 | 10.90 |
5 | 13.4 | 15.8 | −2.40 | 4.11 | 10.1 | 11.2 | −1.10 | 5.16 |
6 | 13.8 | 14.9 | −1.10 | 1.92 | 10.4 | 11.5 | −1.10 | 5.02 |
7 | 16 | 19.3 | −3.30 | 4.67 | 11.6 | 16.6 | −5.00 | 17.73 |
Average | −4.05 | 5.53 | −2.43 | 8.37 | ||||
Time/h | Moisture Content (%) | Product Water Activity (aw) | ||||||
R-test | Day 2 | Difference | RSD (%) | R-test | Day 2 | Difference | RSD (%) | |
0 | 68.11 | 68.94 | −0.83 | 0.30 | 0.951 | 0.96 | −0.01 | 0.47 |
1 | 54.37 | 59.3 | −4.93 | 2.17 | 0.935 | 0.944 | −0.01 | 0.48 |
2 | 42.93 | 49.26 | −6.33 | 3.43 | 0.911 | 0.916 | −0.01 | 0.27 |
3 | 24.45 | 28.74 | −4.29 | 4.03 | 0.877 | 0.78 | 0.10 | 5.85 |
4 | 13.2 | 15.27 | −2.07 | 3.64 | 0.797 | 0.599 | 0.20 | 14.18 |
5 | 8.86 | 8.68 | 0.18 | −0.51 | 0.225 | 0.226 | 0.00 | 0.22 |
6 | 8.29 | 7.64 | 0.65 | −2.04 | 0.216 | 0.129 | 0.09 | 25.22 |
7 | 7.85 | 7.52 | 0.33 | −1.07 | 0.208 | 0.123 | 0.09 | 25.68 |
Average | −2.16 | 1.24 | 0.06 | 9.04 |
Deff (m2 s−1) | Non-Optimized | Optimized Shrinkage Not Considered | Optimized Shrinkage Considered |
---|---|---|---|
Day 1 | 6.10 × 10−10 | 3.30 × 10−10 | 2.33 × 10−10 |
Day 2 | 8.92 × 10−10 | 3.75 × 10−10 | 2.56 × 10−10 |
Day 3 | 7.20 × 10−10 | 4.12 × 10−10 | 2.81 × 10−10 |
Lab. Batch | 5.69 × 10−10 | 2.93 × 10−10 | 1.88 × 10−10 |
Components | Research Data | Literature Data (for Poultry) | Reference |
---|---|---|---|
Value [g/kg] | Value [g/kg] | ||
Protein | 51.76 ± 6.0 | 153.4 | [59] |
Fat | 45.26 ± 0.9 | 50.09 | |
Ash | 39.90 ± 0.6 | 46.5 | |
Moisture | 81.15 ± 5.9 | - | |
Carbohydrates | 781.19 ± 13.14 | 668.86 |
Non-Autoclaved | Autoclaved | |||
---|---|---|---|---|
Lab. Batch | Solar | Lab. Batch | Solar | |
CFU g−1 | CFU g−1 | CFU g−1 | CFU g−1 | |
Total counts | 4.40 × 105 | 2.10 × 107 | 1.20 × 104 | 2.30 × 104 |
Total aerobic spores | 1.40 × 105 | 1.90 × 106 | 9.50 × 103 | 2.20 × 104 |
Coliforms | 8.00 × 102 | 2.60 × 103 | 2.50 × 101 | 1.00 × 101 |
E. coli | 7.50 × 102 | <10 | 2.50 × 101 | <10 |
S. aureus | 3.00 × 102 | <10 | 7.50 × 102 | <10 |
Yeast | 3.50 × 101 | 1.50 × 101 | <10 | <10 |
Molds | 7.50 × 101 | 1.30 × 102 | <10 | <10 |
Water activity | 0.303 | 0.336 | 0.314 | 0.428 |
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Noori, A.W.; Royen, M.J.; Medveďová, A.; Haydary, J. Drying of Food Waste for Potential Use as Animal Feed. Sustainability 2022, 14, 5849. https://doi.org/10.3390/su14105849
Noori AW, Royen MJ, Medveďová A, Haydary J. Drying of Food Waste for Potential Use as Animal Feed. Sustainability. 2022; 14(10):5849. https://doi.org/10.3390/su14105849
Chicago/Turabian StyleNoori, Abdul Wasim, Mohammad Jafar Royen, Alžbeta Medveďová, and Juma Haydary. 2022. "Drying of Food Waste for Potential Use as Animal Feed" Sustainability 14, no. 10: 5849. https://doi.org/10.3390/su14105849