Agro-industrial wastes are suitable as cost-effective sources of various health-promoting molecules at significant concentrations. lnvestigating new methods for converting them into high-value-added compounds is crucial for the sustainable development goals.
Compound | Source | Properties and Functions | References |
---|---|---|---|
Bioactive Peptides | Cakes, meals, and plant by-products | Protein fragments (<20 amino acid residues) with diverse impacts on body functions. Antioxidant, antihypertensive, anti-inflammatory activities, and immune-modulating functions. When applied directly to food, they mitigate oxidation reactions, resulting in a safer alternative to synthetic antioxidants. |
Velliquette et al. [16][11] Hemker et al. [17][12] |
Phenolic Compounds | Cereal bran, fruit and vegetable waste, complex carbohydrates | Antioxidant, antihypertensive, antimicrobial, and anti-carcinogenic effects. Widely used in the food industry to control lipid oxidation and microbial growth. Used in pharmaceutical and cosmetic industries, including mouthwashes, eye creams, and herbal cosmetics. They enhance the shelf-life of food products. |
Huang et al. [18][13] |
Carbohydrates: Lignocellulose, β-glucans |
Starch, oat bran, and other cereal waste | Vital energy sources. Starch has widespread industrial applications. Lignocellulose (cellulose, hemicellulose, and lignin) can be converted into high-value products, contributing to waste reduction. β-Glucans, found in cereal waste, have scientifically proven health benefits with cholesterol-lowering and immune-modulating properties. |
Lovegrove et al. [19][14] Fortunati et al. [20][15] Tosh et al. [21][16] |
Lycopene (Carotenoids) |
Tomato and by-products (skin and seeds) Carrots |
Natural pigment and antioxidant, suitable for food coloration and cellular protection. It prevents cellular components’ degradation, including DNA. β-Carotenoids are antioxidants and anti-inflammatory. |
Anarjan and Jouyban [22][17] Caseiro et al. [23][18] |
Poly-unsaturated fatty acids (PUFAs): omega-3 and omega-6 | Vegetable oils, nuts, and their by-products | Anti-inflammatory agents. | Dave and Routray [24][19] |
Category | Traditional Approaches | Advanced Approaches | Target Bioactive Compounds | References |
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Solvent Extraction | Maceration | Supercritical CO2 Extraction | Phenolic compounds from grape pomace (resveratrol) | Carrasco-Sandoval et al. [25][24] |
Soxhlet Extraction | Subcritical Water Extraction using pressurized hot water | Flavonoids from citrus peels (hesperidin) | Carrasco-Sandoval et al. [25][24] | |
Hydro-distillation by steam | Ionic Liquid Extraction | Volatile compounds such as essential oils from aromatic herbs | Hikal et al. [26][25] | |
Maceration | Graphene Oxide-Based Extraction to adsorbs compounds | Oligosaccharides from fruit peels (inositol) | Ranjha et al. [27][26] | |
Mechanical Methods | Physical pressure | |||
Heat-sensitive food granule powder extraction | ||||
Kainat et al. | ||||
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Solid-Phase Microextraction | Enzyme-Assisted Extraction | Active compounds from plant matter | Yang et al. [38][37] and Reshmitha et al. [39][38] | |
Pressurized Liquid Extraction | Supercritical Fluids | Replacing organic solvents in various procedures | Kainat et al. [37][36] and Begić et al. [40][39] |
Bioactive Compound | Substrate | Microorganism | Fermentation Process 1 | References | ||||
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Phenolic Compounds | Black rice bran | Aspergillus awamori and Aspergillus oryzae | SSF | Shin et al. [48][47] | ||||
Apple peels | Aspergillus spp. (A. niger ZDM2 and A. tubingensis ZDM1) | SSF | Gulsunoglu et al. [44][43] | |||||
Cauliflower | Bacillus subtilis | SmF | Doria et al. [49][48] | |||||
Prebiotic Oligomers | Brewer’s spent grain | Trichoderma reesei B. subtilis (engineered strain) |
SmF | Amorim et al. [50,51][49][50] | ||||
Ultrasound-Assisted Extraction | Essential oils from citrus peels (limonene) | Chen et al. | ||||||
Pectin | [ | 28 | ] | [27] | ||||
Citrus peel waste | Pichia pastoris | (engineered strain) |
SmF | Yang et al. [52][51] | Grinding/Milling | Pulsed Electric Field Extraction | Antioxidants from fruit peels (quercetin) | Kaleem et al. [29][28] |
β-Glucan | Sugarcane straw | Lasiodiplodia Theobromae CCT 3966 | SmF | Abdeshahian et al. [53][52] | Shaking during maceration to boost extraction yield | Subcritical Water Extraction | Phenolic compounds from various food sources | Gbashi et al. [ |
Soybean molasses | Lasiodiplodia theobromae MMPI | 30 | SmF][29], Beya et al. [ | Acosta et al. [5431][30] and Kathiman et al. [32]][53][31] |
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Heat-Based Methods | Heat Soxhlet Extraction by combining heat with solvents | Microwave-Assisted Extraction (Heating) | Carotenoids from vegetable waste (lycopene) | Anton et al. [33][32] and Vinatoru et al. [34][33] | ||||
Steam Distillation | Ohmic Heating Extraction | Volatile compounds Capsaicinoids from pepper waste (capsaicin) |
Hikal et al. [26][25] | |||||
Chemical Methods | Acid/Base Hydrolysis | Enzyme-Assisted Extraction | Peptides (antioxidant peptides) | Costa et al. [35][34] and Prokopov et al. [36][35] | ||||
Aqueous Two-Phase for two immiscible liquids | Ionic Liquid Extraction | Alkaloids from agricultural waste (caffeine) | Costa et al. [35][34] | |||||
Solid-Phase Methods | Solid-Phase Microextraction to absorbs compounds | Molecularly Imprinted Polymers (MIPs) for selective binding. | Polysaccharides from plant residues (β-glucans) | Gbashi et al. [30][29], Beya et al. [31][30] and Kathiman et al. [32][31] | ||||
Solid-Phase Extraction for compound adsorption | Graphene Oxide-Based Extraction for compound adsorption | Oligosaccharides from fruit peels (inositol) | Ranjha et al. [27][26] | |||||
Other Methods | Steam Distillation and condensation | Supercritical Fluid Extraction (SFE) | Essential oils from various plant sources | Hikal et al. [26][25] and Kainat et al. [37][36] | ||||
Pressurized Liquid Extraction (PLE) or Accelerated Solvent Extraction (ASE) Combines solvent, high pressure, and temperature |
Enzyme-Assisted Extraction | Proteins and enzymes from agricultural waste | Costa et al. [35][34] | |||||
Liquid–liquid extraction Separation of immiscible liquids | Instant Controlled Pressure Drop Technology for auto-vaporization and organic product development |