Table 4.

Examples of US-innovative techniques combinations for the extraction of natural materials.

Technique	Matrix	Targeted compound	Type of combination	Device diagram	Combination impact	Ref
US combined with mechanical pressing	Sunflower seed	Oil	In line		US application improved extraction kinetics and oil diffusion from the mass of the cake to the extracting solvent, compared to conventional Soxhlet extraction.	[97]
Ultrasound-Microwave Assisted Extraction (UMAE)	Sorghum husk	Natural colorants	Direct in situ (DIS)		Significantly improved extraction yield and better dyeing properties of sorghum husk extracts.	[105]
	Sweet potatoes (Ipomoea batatas L.)	Prebiotic oligosaccharides	Direct in situ (DIS)		Higher extraction efficiency compared to theconventional hot-water extraction, microwave-assisted extraction (MAE), and ultrasound assisted extraction (UAE) methods.	[106]
	Lotus seed starch-green tea polyphenol complex	Preparation of starch-polyphenol complex	Direct in situ (DIS)		Increased extraction yield of the complex.	[107]
	Potato pulp	Pectin	Direct in situ (DIS)		Increased extraction efficiency of potato pectin.	[107]
Alternate Microwave/Ultrasound with DES	Schisandra Chinensis fruit	Polysaccharides and essential oil	Alternating US/MW digestion		Higher polysaccharide and essential oils yields.	[109]
Ultrasound Microwave- assisted enzymatic extraction (UMAEE)	Lentinus edodes	Polysaccharides	In line		Higher extraction yields of polysaccharides content compared to conventional techniques.	[110]
	Laminaria	Monoiodo-tyrosine (MIT) and Diiodo-tyrosine (DIT)	In line		An efficient method to extract MIT and DIT from Laminaria. Both US and MW radiation can destroy the laminaria cell walls which improves access and extractability of targeted compounds.	[111]
US combined with pressurized liquid	Sugar beet pulp	Pectin-enriched materials	In line		Higher extraction yield and improved functional properties obtained with subcritical water extraction.	[112]
	Pomegranate peel	Phenolic compounds	Direct in situ (DIS)		Higher extraction yield Reduced extraction time and temperature	[113]
	Fragrant oil from red pepper seed	Residual propane	In line		US was efficient in solvent residue removal. Treated oil presents good oxidation stability and quality.	[114]
US combined with supercritical CO2	Agave salmiana bagasse	Antioxidants and saponins	Direct in situ (DIS)		Increased extraction yield in terms of antioxidants and saponins contents.	[119]
	Ginger rhizomes	Pungent compounds	Direct in situ (DIS)		Improved extraction yield of pungent compounds from ginger.	[118]
	Iberis amara seeds	Cucurbitacin E (CuE)	Direct in situ (DIS)		The introduction of ultrasound to supercritical CO2 extraction enhanced CuE yield and reduced operation time as well as the amount of CO2 consumed.	[67]
Instant controlled pressure drop (DIC) combined with US	Orange peels	Antioxidants	In line		The highest yield of antioxidants with best kinetics is obtained by coupling both treatments.	[39]
	Steviarebaudiana bertoni leaves	Rebaudioside A, Vitamin B6 and vitamin B1.	In line		DIC pre-treatment has a significant positive effect on the extraction of Rebaudioside A, Vitamin B6 and vitamin B1.	[122]
Pulsed Electric Field (PEF) combined with US	Almond seeds	Phenolics, flavonoids, condensed tannins and anthocyanins, antioxidant activity and volatile compounds	In line		Combined treatment (PEF–US) has attained the highest value of total phenolics, total flavonoids, condense tannins, anthocyanin contents and antioxidant activity in DPPH, reducing power and metal chelating activity than all other treatments.	[124]
UV-C Radiation Combined with UAE	Cherry Tomato (Lycopersicon esculentum)	Lycopene	In line		Extracted obtained from the irradiated tomatoes presented 5.8 times more lycopene content.	[126]
	Tomatoes	Bioactive compounds	Direct in situ (DIS)		This postharvest non-thermal treatment resulted in increased lycopene, total phenols, vitamin C, hydrophilic and lipophilic antioxidant activities during storage.	[125]
US coupled with CCC and CPC	Paeonia lactiflora Pall roots	Albiflorin, benzoylpaeoniflorin, paeoniflorin, and galloylpaeoniflorin)	In line		The four targeted compounds were successfully extracted. Compared with conventional extraction methods, this combination offers the advantages of automationand systematic extraction and isolation of natural products.	[131]