The retention and bioavailability of phytochemicals in the manufacturing of baked snacks

Figures & data

Table 1. Phytochemical health claims approved by FDA, EFSA and FSANZ.

	Phytochemical	Food source	Health benefit	Organization
Tyrosol	Tyrosol	Olive oil	Protection of LDL particles from oxidative damage	EFSA
Polyphenol	Olive oil polyphenols	Olive oil	Protection of LDL particles from oxidative damage	EFSA
Sterols and stanols	Phytostanol/phytosterol esters	Vegetable and seed oils, green and yellow vegetables, wheat, corn, soy	Helps to lower blood total and LDL cholesterol levels May reduce the risk of heart disease/CHD Lowering blood LDL-cholesterol and reduced risk of heart disease Maintenance of normal blood cholesterol concentrations Reduces dietary and biliary cholesterol absorption	FDA FDA EFSA EFSA FSANZ

Figure 1. The six main carotenoids and their structures.

Figure 2. Polyphenol main categories and their structure.

Figure 3. Reaction pathway of (a) alliinase and (b) myrosinase.

Table 2. Influence of drying technologies on carotenoid retention in vegetables, fruit, herbs, and spices.

	Pretreatment	Drying treatment	Phytochemical	Result	Reference
Vegetables
Carrot slices	Washed, peeled, sliced (4 mm) and water blanched (90 ° C, 7 min)	VMD: 3 kW for 19 min followed by 1.0 kW for 4 min and 0.5 kW for 10 min at a constant vacuum of 100 mm Hg	α-carotene β-carotene	−3.2%	Lin, Durance, and Scaman (1998)
		HAD: 70 °C	α-carotene β-carotene	−19.2%
		FD: 1.6 mm Hg with chamber temperature of 20 ° C and condenser temperature of −55 °C	α-carotene β-carotene	No significant loss
Lycopene-rich carrot	Blanched 95 °C for 65 s	HAD: 50–70 °C	Lycopene β-carotene Total carotenoids	No significant change in any	Regier et al. (2005)
		HAD: 90 °C	Lycopene β-carotene Total carotenoids	No significant change −20%
		VMD: 5 kPa, 400 W for 75 min combined with 240 W after	Lycopene β-carotene Total carotenoids	All Remained constant
		VMD: 5 kPa, 600 W for 75 min combined with 240 W after	Total carotenoids	−20%
		FD: −60 °C, plate temp 30 °C, pressure 6 Pa	Lycopene β-carotene Total carotenoids	Total retention
Carrot		Low pressure super-heated steam dryer: 7 kPa, fan 1100 rpm 60 °C, 420 min 70 °C, 330 min 80 °C, 210 min	β-carotene	−14% −19% −38%	Suvarnakuta, Devahastin, and Mujumdar (2005)
		VD: 7 kPa 60 °C, 300 min 70 °C, 250 min 80 °C, 180 min	β-carotene	−52% −53% −46%
		HAD: 60 °C, 420 min 70 °C, 300 min 80 °C, 240 min	β-carotene	−58% −54% −57%
Carrot		HAD: 60 °C	α-carotene β-carotene	−14% −15%	Zhao et al. (2014)
	HAD: 60 °C	MWD: 140 W	α-carotene β-carotene	−26% −29%
	MWD: 175 W	HAD: 60 °C	α-carotene β-carotene	−31% −15%
	MWD: 175 W	MWD: 140 W	α-carotene β-carotene	−63% −43%
		IM&AD: IM (5 s/15 s, ton/toff) and (5 s/20 s), AD 60 °C	α-carotene β-carotene	−11% −11%
Carrot		US + VD: 65 °C, 75 °C, 140 min	β-carotene	≈ −20% −11%	Chen, Guo, and Wu (2016)
		VD: 1. 65 °C, 2. 75 °C, 340 min	β-carotene	≈ −35% −25%
Sweet potato	Blanched 100 °C, 5 s Flour prepared by milling dried slices and sieved through 100-mesh screening size	HAD: 50 °C HAD: 60 °C HAD: 70 °C HAD: 80 °C (Until moisture of <6%)	β-carotene	−88% −90% −95% −96%	Ruttarattanamongkol et al. (2016)
	Blanched 100 °C, 5 s Flour prepared by milling dried slices and sieved through 100-mesh screening size	DD: 80 °C/3 rpm 80 °C/5 rpm 80 °C/7 rpm 95 °C/3 rpm 95 °C/5 rpm 95 °C/7 rpm 110 °C/3 rpm 110 °C/5 rpm 110 °C/7 rpm	β-carotene	−80% −74% −72% −80% −75% −77% −66% −75% −65%
Sweet potato	Steamed 100 °C, 10 min	HAD: 65 °C, 9 hr	β-carotene	≈ −62%	Yang et al. (2010)
	Steamed 100 °C, 10 min	MWD: 800 W, 5 min	β-carotene	≈ −50%
	Steamed 100 °C, 10 min	FD: 0.006 mbar, −50 °C, 36 hr	β-carotene	No significant difference
Tomato		HAD: 95 °C, 6–10 hr	Lycopene	−3.9% (84.4% cis, 16.6% trans)	Shi et al. (1999)
		VD: 55 °C, 4–8 hr	Lycopene	−3.2% (89.9% cis, 10.1% trans)
	Osmotic pretreatment (25 °C in 65 °Brix sucrose solution for 4 hr	VD: 55 °C, 4–8 hr	Lycopene	−2.4% (93.5% cis, 6.5% trans)
Tomato (Sheng-Neu)		HAD: 80 °C, 2 hr then 60 °C, 6 hr	Lycopene	+197%	Chang et al. (2006)
		FD: −50 °C, 5 Pa, 24 hr	Lycopene	−33%
Tomato (I-Tien-Hung)		HAD: 80 °C 2 hr, 60 °C, 6 hr	Lycopene	+152%	Chang et al. (2006)
		FD: −50 °C, 5 Pa 24 hr	Lycopene	−48%
Fruit
Apricot		HTST: 300 MPa, 5 min	β-carotene α-carotene β-cryptoxanthin Lutein	−10% +78% −26% −13%	Huang et al. (2013)
		HTST: 300 MPa, 20 min	β-carotene α-carotene β-cryptoxanthin Lutein	−11% +43% 0% +8%
		HTST: 400 MPa, 5 min	β-carotene α-carotene β-cryptoxanthin Lutein	−12% +71% −11% +9%
		HTST: 400 MPa, 20 min	β-carotene α-carotene β-cryptoxanthin Lutein	−7% −38% −10% −7%
		HTST: 500 MPa, 5 min	β-carotene α-carotene β-cryptoxanthin Lutein	−5% −56% 0% 0%
		HTST: 500 MPa, 20 min	β-carotene α-carotene β-cryptoxanthin Lutein	+19% −37% −5% +10%
Persimmon		HAD: 55 °C, air velocity 2 m s^−1: until ≈ 0.2 kg water/kg dw	β-carotene Lycopene	−33% −25%	Kayacan et al. (2020)
		IR, 88 W until ≈ 0.2 kg water/kg dw	β-carotene Lycopene	−12% −16%
		US vacuum: sonicated at 40 kHz in an US bath (amplitude 100%, power 590 W, volume: 10 L)Until ≈ 0.2 kg water/kg dw	β-carotene Lycopene	−21% −9%
		FD: until ≈ 0.2 kg water/kg dry matter	β-carotene Lycopene	−2% −4%
Herbs/spices
Lemon Thyme		VMD (4–6 kPa): 1. 240 W 2. 440 W	Total carotenoids	−85% −53%	Pasławska et al. (2020)
		MFBD: (4–10 m s^−1), 40 °C 1. 240 W 2. 440 W	Total carotenoids	−32% −29%
		Fluidized bed drying: (5–10 m s^−1) 70 °C 80 °C	Total carotenoids	−86% −37%
		HAD: (2 m s^−1) 70 °C 80 °C	Total carotenoids	−84% −70%
Paprika pericarp	Cutting	HAD: 60 °C, 1.25 m s^−1 Inert gas pilot dryer	Total carotenoids	−79%	Ramesh et al. (2001)
	Cutting	HAD: 60 °C, 1.25 m s^−1 Laboratory small scale inert gas dryer	Total carotenoids	−67%
	Steam blanch 3 min, then cut	HAD: 60 °C, 1.25 m s^−1 Inert gas pilot dryer	Total carotenoids	−69%
	Steam blanch 3 min, then cut	HAD: 60 °C, 1.25 m s^−1 Laboratory small scale inert gas dryer	Total carotenoids	−61%
Paprika	Pepper ground into fine puree in blender, then stored at −18 °C until use	FD: Stored at −70 °C then into FD −40 mm Hg for 8 days	Capsanthin Zeaxanthin β-cryptoxanthin β-carotene	−30% −27% −29% −28%	Topuz et al. (2011)
	"	HAD: 60 °C, 0.76 m s^−1, 7 hr	Capsanthin Zeaxanthin β-cryptoxanthin β-carotene	−35% −30% −23% −25%
		Refractance Window Drying: length 1.83 m, belt velocity 0.45–0.58 m/min, 94 °C	Capsanthin Zeaxanthin β-cryptoxanthin β-carotene	−32% −25% −18% −23%
		Natural Convective drying: paprika pods cut into two pieces, dried for 8–10 days	Capsanthin Zeaxanthin β-cryptoxanthin β-carotene	+15% +20% +19% +10%

HAD, hot-air drying; VD, vacuum drying; MWD, microwave-drying; VMD, microwave-vacuum drying; DD, drum drying; FD, freeze-drying; US, ultrasound; IM&AD, intermittent microwave and couples hot air drying; IR, infrared; HTST, high temperature short time; dw, dry weight basis.

Table 3. Influence of drying technologies on polyphenol retention in vegetables, fruit, herbs, and spices.

Vegetable	Pre/post treatment	Drying treatment	Phytochemical	Result	Reference
Vegetables
Kale	Non-blanched	FD: −40 °C, 80 min	Quercetin Kaempferol Caffeic acid p-kumaric acid Sinapic acid Ferulic acid Total phenolics	−33% −45% −28% −33% −37% −60% −49%	Korus (2011)
	Non-blanched	HAD: 55 °C, 5.5 hr	Quercetin Kaempferol Caffeic acid p-kumaric acid Sinapic acid Ferulic acid Total phenolics	−50% −51% −73% −51% −56% −63% −60%
	Blanched	FD: −40 °C, 80 min	Quercetin Kaempferol Caffeic acid p-kumaric acid Sinapic acid Ferulic acid Total phenolics	−50% −54% −54% −56% −31% −56% −51%
	Blanched	HAD: 55 °C, 5.5 hr	Quercetin Kaempferol Caffeic acid p-kumaric acid Sinapic acid Ferulic acid Total phenolics	−58% −60% −56% −68% −51% −72% −65%
Sweet Potato Flour	Blanched 100 °C, 5 s	HAD: 50 °C HAD: 60 °C HAD: 70 °C HAD: 80 °C	Anthocyanin	+82% +247% +260% +217%	Ruttarattanamongkol et al. (2016)
	Blanched 100 °C, 5 s	DD: 80 °C/3 rpm 80 °C/5 rpm 80 °C/7 rpm 95 °C/ 3 rpm 95 °C/5 rpm 95 °C/7 rpm 110 °C/3 rpm 110 °C/5 rpm 110 °C/7 rpm	Anthocyanin	+231% +270% +262% +213% +280% +208% +243% +199% +178%
Sweet potato	Steamed 100 °C, 10 min	HAD: 65 °C, 9 hr	Total phenolics	+116%	Yang et al. (2010)
	Steamed 100 °C, 10 min	MWD: 800 W, 5 min	Total Phenolics	+225%
	Steamed 100 °C, 10 min	Vacuum FD: 0.006 mbar −50 °C, 36 hr	Total Phenolics	≈ +168
Broccoli		HAD: 60 °C, 5 hr to moisture 8.79% wb	Quercetin Isorhamnetin Trans-Ferulic acid p-Coumaric acid Chlorogenic acid Total phenols	−98% −98% −38% +89% −62% −61%	Yilmaz et al. (2019)
	HAD 60 °C to 1 kg water/1 kg dry matter	MWD: 54 W/g	Quercetin Isorhamnetin Trans-Ferulic acid p-Coumaric acid Chlorogenic acid Total phenols	−91% −61% +46% +380% −11% −8%
Tomato (Sheng-Neu)		HAD: 80 °C 2 hr, 60 °C, 6 hr	Total flavonoids Total phenolics	+89% +13%	Chang et al. (2006)
		FD: −50 °C, 5 Pa, 24 hr	Total flavonoids Total phenolics	+72% +2.6%
Tomato (I-Tien-Hung)		HAD: 80 °C 2 hr, 60 °C, 6 hr	Total flavonoids Total phenolics	+50% +29%	Chang et al. (2006)
		FD: −50 °C, 5 Pa, 24 hr	Total flavonoids Total phenolics	+23% +5.9%
Garlic	HAD: 60 °C to 60% wb	VMFD: 360 W, 4–6 kPa, fan with air steam 22 °C 1 m s^−1	Total phenolics (gallic acid)	−84%	Calín-Sánchez et al. (2014)
	HAD: 60 °C to 30% wb	VMFD: 480 W, 4–6 kPa, fan with air steam 22 °C 1 m s^−1	Total phenolics (gallic acid)	−71%
	HAD: 60 °C to 30% wb	VMFD: 360 W, 4–6 kPa, fan with air steam 22 °C 1 m s^−1	Total phenolics (gallic acid)	−79%
	HAD: 60 °C to 30% wb	VMFD: 240 W, 4–6 kPa, fan with air steam 22 °C 1 m s^−1	Total phenolics (gallic acid)	−69%
	HAD: 60 °C to 15% wb	VMFD: 360 W, 4–6 kPa, fan with air steam 22 °C 1 m s^−1	Total phenolics (gallic acid)	−65%
Herbs/spices
Ginger rhizomes		HAD: 60 °C	Total phenolic Total flavonoids	−19% −10%	An et al. (2016)
		IR: 3 × 225 W red glass lamps	Total phenolic Total flavonoids	−5% +8%
		FD: −40 °C for 12 hr, then 20 Pa, −58 °C	Total phenolic Total flavonoids	+16% −13%
		5 W/g until 50% wb, then 1 W/g	Total phenolic Total flavonoids	−30% −7%
		Intermittent MWD 700 W pulsed ratio: (5 s/5 s, ton/toff)) to 50% wb then (5 s, 25 s) to the end of drying, hot air 60 °C throughout	Total phenolic Total flavonoids	−6% +14%
Lemon thyme		VMD (4–6 kPa): 1. 240 W 2. 440 W	Total phenolics	−21% −18%	Pasławska et al. (2020)
		MFBD: (4–10 m s^−1), 40 °C 1. 240 W 2. 440 W	Total phenolics	−81% −57%
		Fluidized bed drying: (5–10 m s^−1) 1. 70 °C 2. 80 °C	Total phenolics	−73% −56%
		HAD: (2 m s^−1) 1. 70 °C 2. 80 °C	Total phenolics	−84% −75%
Fruit
Strawberry (kent)		FD: 65 Pa, −60 °C, heating plate 30 °C, until moisture content 0.05 kg kg^−1 dw	p-coumaroyl glycoside Ellagic acid glycoside Quercetin-3-O-glycoside Kaempherol 3-O glycoside (+)-Catechin Procyanidin B Procyanidin polymers Total polyphenols Total anthocyanins	+3% −34% +18% +14% +1% −26% −5% −5% +3%	Wojdyło, Figiel, and Oszmiański (2009)
		VD: 50 °C, 100 Pa, 24 hr	p-coumaroyl glycoside Ellagic acid glycoside Quercetin-3-O-glycoside Kaempherol 3-O glycoside (+)-Catechin Procyanidin B Procyanidin polymers Total polyphenols Total anthocyanins	−27% −43% −18% −14% −47% −47% −18% −30% −75%
		VMD: 240 W, 4 − 6 kPa, 33 min	p-coumaroyl glycoside Ellagic acid glycoside Quercetin-3-O-glycoside Kaempherol 3-O glycoside (+)-Catechin Procyanidin B Procyanidin polymers Total polyphenols Total anthocyanins	−24% −43% +5% −5% −15% −34% −5% −11% −23%
		VMD: 360 W, 4 − 6 kPa, 21.5 min	p-coumaroyl glycoside Ellagic acid glycoside Quercetin-3-O-glycoside Kaempherol 3-O glycoside (+)-Catechin Procyanidin B Procyanidin polymers Total polyphenols Total anthocyanins	−23% −7% +14% −2% +2% −29% −10% −13% −22%
		VMD: 480 W, 4 − 6 kPa, 16.5 min	p-coumaroyl glycoside Ellagic acid glycoside Quercetin-3-O-glycoside Kaempherol 3-O glycoside (+)-Catechin Procyanidin B Procyanidin polymers Total polyphenols Total anthocyanins	−12% −18% +84% 0 +4% −26% −10% −13% −28%
		HAD: 70 °C, 550 min	p-coumaroyl glycoside Ellagic acid glycoside Quercetin-3-O-glycoside Kaempherol 3-O glycoside (+)-Catechin Procyanidin B Procyanidin polymers Total polyphenols Total anthocyanins	−25% −24% −14% +7% −54% +5% −32% −36% −73%
Strawberry (Elsanta)		FD: 65 Pa, −60 °C, heating plate 30 °C, until moisture content 0.05 kg kg^−1 dw	p-coumaroyl glycoside Ellagic acid glycoside Quercetin-3-O-glycoside Kaempherol 3-O glycoside (+)-Catechin Procyanidin B Procyanidin polymers Total polyphenols Total anthocyanins	−4% −31% −17% +35% +16% −3% 0 0 −1%	Wojdyło, Figiel, and Oszmiański (2009)
		VD: 50 °C, 100 Pa, 24 hr	p-coumaroyl glycoside Ellagic acid glycoside Quercetin-3-O-glycoside Kaempherol 3-O glycoside (+)-Catechin Procyanidin B Procyanidin polymers Total polyphenols Total anthocyanins	−19% −4% −34% +58% −51% −54% −21% −31% −76%
		VMD: 240 W, 4–6 kPa, 33 min	p-coumaroyl glycoside Ellagic acid glycoside Quercetin-3-O-glycoside Kaempherol 3-O glycoside (+)-Catechin Procyanidin B Procyanidin polymers Total polyphenols Total anthocyanins	+9% −56% −28% +40% −9% −3% −2% −4% −18%
		VMD: 360 W, 4–6 kPa, 21.5 min	p-coumaroyl glycoside Ellagic acid glycoside Quercetin-3-O-glycoside Kaempherol 3-O glycoside (+)-Catechin Procyanidin B Procyanidin polymers Total polyphenols Total anthocyanins	−2% −28% −27% +44% +19% −10% −3% −5% −16%
		VMD: 480 W, 4–6 kPa, 16.5 min	p-coumaroyl glycoside Ellagic acid glycoside Quercetin-3-O-glycoside Kaempherol 3-O glycoside (+)-Catechin Procyanidin B Procyanidin polymers Total polyphenols Total anthocyanins	−14% −1% −27% +48% +28% −17% −5% −6% −15%
		HAD: 70 °C, 550 min	p-coumaroyl glycoside Ellagic acid glycoside Quercetin-3-O-glycoside Kaempherol 3-O glycoside (+)-Catechin Procyanidin B Procyanidin polymers Total polyphenols Total anthocyanins	−16% −32% −2% +65% +30% −27% −33% −36% −64%
Sour cherry		FD: 0.96 kPa pressure, −60 °C hot plate: 26 °C, 24 hr	Catechin Polymeric procyanidins Chlorogenic acid Quercetin-3-0-glucoside Cyanidin-3-glucosyl-rutinoside	−41% −38% −1% −11% −9%	Wojdyło et al. (2014)
		HAD: 70 °C, 14 hr	Catechin Polymeric procyanidins Chlorogenic acid Quercetin-3-0-glucoside Cyanidin-3-glucosyl-rutinoside	−84% −60% −23% +17% −41%
		VMD: 240 W, 4–6 kPa, 28 min	Catechin Polymeric procyanidins Chlorogenic acid Quercetin-3-0-glucoside Cyanidin-3-glucosyl-rutinoside	−26% −46% −8% +25% −30%
		VMD: 360 W then 120 W, 4–6 kPa, 44 min	Catechin Polymeric procyanidins Chlorogenic acid Quercetin-3-0-glucoside Cyanidin-3-glucosyl-rutinoside	−39% −33% 0% +32% −9%
		VMD: 480 W then 120 W, 4–6 kPa, 40 min	Catechin Polymeric procyanidins Chlorogenic acid Quercetin-3-0-glucoside Cyanidin-3-glucosyl-rutinoside	−38% −33% −1% +46% −1%
Apple		Air dry: 47 °C, 7 hr	Catechin Epicatechin Chlorogenic acid Quercetin-3-0-glucoside	−31% −23% −4% +2%	Joshi, Rupasinghe, and Khanizadeh (2011)
		HAD: 70 °C, 10 hr	Catechin Epicatechin Chlorogenic acid Quercetin-3-0-glucoside	−17% −22% −18% −35%
		VD: 20 °C, 24 hr	Catechin Epicatechin Chlorogenic acid Quercetin-3-0-glucoside	−2% −3% +1% −13%
		VD: 50 °C, 24 hr	Catechin Epicatechin Chlorogenic acid Quercetin-3-0-glucoside	0% −18% −3% +52%
Blueberries		HAD: 76.6 °C, 4.5 hr	Total phenolics glycosides Total phenolics aglycones Total anthocyanins glycosides Total anthocyanins aglycones	−88% +72% +337% −40%	Mejia-Meza et al. (2008)
		VMD: 65.5 °C, 90 min, 300 W, 2.6 kPa	Total phenolics glycosides Total phenolics aglycones Total anthocyanins glycosides Total anthocyanins aglycones	−72% +57% +153% +55%
	Samples treated with calcium chloride at −23 °C, 1 hr	FD: −60 °C, 72 hr	Total phenolics glycosides Total phenolics aglycones Total anthocyanins glycosides Total anthocyanins aglycones	−49% +61% +1270% +157%
	HAD: 45 min, 98.8 °C	VMD: 71.1 °C, 60 min, 2.6 kPa	Total phenolics glycosides Total phenolics aglycones Total anthocyanins glycosides Total anthocyanins aglycones	−65% +63% +500% +30%
Persimmon		HAD: 55 °C, 2 m s^−1 Until ≈ 0.2 kg water/kg dw	Gallic acid Catechin Epigallocatechin Epi-catechin Total Phenolics Total flavonoid	N/A N/A −49% −60% −71% −58%	Kayacan et al. (2020)
		IR: 88 W Until ≈ 0.2 kg water/kg dw	Gallic acid Catechin Epigallocatechin Epi-catechin Total Phenolics Total flavonoid	−34% N/A −78% −54% −58% −38%
		US vacuum: sonicated at 40 kHz in an ultrasonic bath (amplitude 100%, power 590 W, volume: 10 L) Until ≈ 0.2 kg water/kg dw	Gallic acid Catechin Epigallocatechin Epin-catechin Total Phenolics Total flavonoid	−88% N/A −9% −49% −53% −29%
		FD: Until ≈ 0.2 kg water/kg dw	Gallic acid Catechin Epigallocatechin Epi-catechin Total Phenolics Total flavonoid	−22% −49% −4% −25% −1% −3%

HAD, hot-air drying; VD, vacuum drying; MWD, microwave-drying; VMD, microwave-vacuum drying; DD, drum drying; FD, freeze-drying; US, ultrasound; IR, infrared; VMFD, vacuum microwave finishing drying; HP, heat pump; MFBD, microwave assisted fluidized bed drying; dw, dry weight basis; wb, wet weight basis.

Table 4. Influence of drying technologies on organosulphur compound in vegetables, fruit, herbs, and spices.

Vegetable	Pretreatment	Drying treatment	Phytochemical	Result	Reference
Broccoli		HAD: 70 °C, 2 m s^−1 371 min	Glucoraphanin Gluconapin 4-hydroxyglucobrassicin Glucobrassicin 4-methoxyglucobrassicin Sulforaphane	−62% −6% −79% +20% −68% −53%	Cao et al. (2019)
		MWD: 500 W, 32 min	Glucoraphanin Gluconapin 4-hydroxyglucobrassicin Glucobrassicin 4-methoxyglucobrassicin Sulforaphane	−68% +32% −79% −7% −73% −70%
		MWD: 900 W, 42 min	Glucoraphanin Gluconapin 4-hydroxyglucobrassicin Glucobrassicin 4-methoxyglucobrassicinSulforaphane	−68% +76% −76% −5% −74% −76%
		USHA: 70 °C, 2 m s^−1, 271 min Sonification 5 s on 5 s off, 125.2 W/dm^2	Glucoraphanin Gluconapin 4-hydroxyglucobrassicin Glucobrassicin 4-methoxyglucobrassicin Sulforaphane	−64% −6% −81% −24% −70% −55%
		USHA: 70 °C, 2 m s^−1, 232 min Sonification 5 s on 5 s off, 180.1 W/dm^2	Glucoraphanin Gluconapin 4-hydroxyglucobrassicin Glucobrassicin 4-methoxyglucobrassicin Sulforaphane	−63% −6% −79% −26% −65% −49%
Broccoli	Water blanch: 3 min, 100 °C		4-hydroxyglucobrassicin Glucobrassicin 4-methoxyglucobrassicin Neoglucobrassicin Total glucosinolates	−10% −64% −51% −80% −64%	Mrkic et al. (2010)
	Water blanch: 3 min, 100 °C	HAD: 50 °C, 1.2 m s^−1	4-hydroxyglucobrassicin Glucobrassicin 4-methoxyglucobrassicin Neoglucobrassicin Total glucosinolates	−23% −67% −54% −83% −68%
	Water blanch: 3 min, 100 °C	HAD: 50 °C, 1.75 m s^−1	4-hydroxyglucobrassicin Glucobrassicin 4-methoxyglucobrassicin Neoglucobrassicin Total glucosinolates	−52% −67% −60% −83% −69%
	Water blanch: 3 min, 100 °C	HAD: 50 °C, 2.25 m s^−1	4-hydroxyglucobrassicin Glucobrassicin 4-methoxyglucobrassicin Neoglucobrassicin Total glucosinolates	−65% −67% −66% −82% −70%
	Water blanch: 3 min, 100 °C	HAD: 60 °C, 1.2 m s^−1	4-hydroxyglucobrassicin Glucobrassicin 4-methoxyglucobrassicin Neoglucobrassicin Total glucosinolates	−23% −67% −63% −86% −69%
	Water blanch: 3 min, 100 °C	HAD: 60 °C, 1.75 m s^−1	4-hydroxyglucobrassicin Glucobrassicin 4-methoxyglucobrassicin Neoglucobrassicin Total glucosinolates	−32% −68% −63% −84% −69%
	Water blanch: 3 min, 100 °C	HAD: 60 °C, 2.25 m s^−1	4-hydroxyglucobrassicin Glucobrassicin 4-methoxyglucobrassicin Neoglucobrassicin Total glucosinolates	−32% −67% −60% −83% −68%
	Water blanch: 3 min, 100 °C	HAD: 75 °C, 1.2 m s^−1	4-hydroxyglucobrassicin Glucobrassicin 4-methoxyglucobrassicin Neoglucobrassicin Total glucosinolates	−39% −76% −66% −87% −76%
	Water blanch: 3 min, 100 °C	HAD: 75 °C, 1.75 m s^−1	4-hydroxyglucobrassicin Glucobrassicin 4-methoxyglucobrassicin Neoglucobrassicin Total glucosinolates	−52% −74% −71% −87% −75%
	Water blanch: 3 min, 100 °C	HAD: 75 °C, 2.25 m s^−1	4-hydroxyglucobrassicin Glucobrassicin 4-methoxyglucobrassicin Neoglucobrassicin Total glucosinolates	−58% −76% −66% −87% −77%
	Water blanch: 3 min, 100 °C	HAD: 75–60–50 °C, 1.75 m s^−1	4-hydroxyglucobrassicin Glucobrassicin 4-methoxyglucobrassicin Neoglucobrassicin Total glucosinolates	−29% −70% −71% −82% −71%
	Water blanch: 3 min, 100 °C	HAD: 100 °C, 1.75 m s^−1	4-hydroxyglucobrassicin Glucobrassicin 4-methoxyglucobrassicin Neoglucobrassicin Total glucosinolates	−71% −77% −86% −93% −80%
Cabbage		HAD: 60 °C, 145 min	Glucoraphanin Sinigrin Glucobrassicin Gluconasturtiin 4-methoxyglucobrassicin	−61% +18% −6% −27% −51%	Tao et al. (2019)
		HAD + US: Surface contacting sonication (492.3 W/m^2), 120 min	Glucoraphanin Sinigrin Glucobrassicin Gluconasturtiin 4-methoxyglucobrassicin	−69% −5% −46% −21% −44%
		HAD + US: Surface contacting sonication (1131.1 W/m^2), 60 °C, 105 min	Glucoraphanin Sinigrin Glucobrassicin Gluconasturtiin 4-methoxyglucobrassicin	−51% +97% +25% −18% −11%
	Water blanch: 100 °C, 30 s	HAD: 60 °C, 47 min	Glucoraphanin Sinigrin Glucobrassicin Gluconasturtiin 4-methoxyglucobrassicin	−58% +47% −30% −15% −9%
	Water blanch: 100 °C, 30 s	HAD + US: surface contacting sonication (492.3 W/m^2), 60 °C, 33 min	Glucoraphanin Sinigrin Glucobrassicin Gluconasturtiin 4-methoxyglucobrassicin	−70% −18% −7% −19% −16%
	Water blanch: 100 °C, 30 s	HAD + US: Surface contacting sonication (1131.1 W/m^2), 60 °C, 24 min	Glucoraphanin Sinigrin Glucobrassicin Gluconasturtiin 4-methoxyglucobrassicin	−68% −7% −5% −17% −11%
Cabbage leaves		HAD: 45 °C, 105 min 60 °C, 15 min 60 °C, 10 min followed by 45 °C, 65 min	Sulforaphane	+34% +17% +47%	Lekcharoenkul et al. (2014)
		VD: 5 kPa, 60 °C, 15 min	Sulforaphane	+30%
	LPSSD 5 kPa 60 °C, 10 min	VD: 5 kPa, 45 °C 20 min	Sulforaphane	+88%
Garlic		HAD: 40 °C 50 °C 60 °C Until MC 0.3 g water/g dw	Allicin	+3% −3% −16%	Ratti et al. (2007)
		FD: 72 hr, heating plate: 20 °C 40 °C 60 °C	Allicin	+16% −14% −42%
Garlic		HAD: 50 °C, 7 hr 60 °C, 6 hr 80 °C, 4 hr 90 °C, 3 hr	Allicin	−29.5% −39% −50% −50%	Rahman et al. (2009)
		VD: 80 kPa 50 °C, 8 hr 60 °C, 7 hr 90 °C, 4 hr	Allicin	−36% −35% −61%
		Nitrogen atmosphere 40 °C, 15–21 hr 60 °C, 6 hr	Allicin	−36% −49%

HAD, hot-air drying; VD, vacuum drying; MWD, microwave-drying; FD, freeze-drying; US, ultrasound; LPSSD, low pressure superheated steam drying; USHA, ultrasound-hot air drying; MC, moisture content; dw, dry weight.

Table 5. Comparison between different dehydration technologies applied to snack form.

Technology	Capital cost	Running cost	Batch size	Time	Heat transfer	Final product attributes				Equipment footprint
						Color retention	Flavor development/retention	Phytochemical retention	Texture
Radiative
Microwave drying	- -	+	+	++	++	0	–	0	–	- -
Radio frequency	–	+	–	+	++	+	+	+	0	- -
Infrared drying	+	+	+	++	+	–	+	+	0	0
Hybrid
Convective microwave drying	–	0	++	++	++	0	0	0	+	+
Ultrasound assisted convective drying	++	0	- -	++	++	+	+	0	–	- -
Vacuum microwave drying	- -	0	–	++	++	0	+	++	0	- -
Heat
Hot air convective drying	+	–	++	+	0	–	0	- -	–	–
Hot air impingement drying	+	–	++	+	+	–	0	- -	0	–
Vacuum drying	- -	- -	–	–	–	–	0	+	+	–
Freeze-drying	- -	- -	- -	- -	- -	++	0	++	++	–
Osmotic dehydration	++	++	–	–	- -	+	+	+	+	+
Frying	++	++	++	++	++	–	++	- -	++	+
Solar drying	++	++	++	- -	- -	- -	–	- -	0	++

++ = great advantage; + = advantage; 0 = neutral; - disadvantage; - - = great disadvantage.

Table 6. Estimation of the quantity of polyphenols in an average 5-a-day.

	Banana	Apple	Grapes	Tomato	Red onion
Polyphenols (mg/80 g FW)
Flavanones	0	0	0	0.11	0
Flavanols	1.16	7.67	9.93	0	0
Flavonols	0	5.49	2.46	0.11	102.8
Procyanidins	3.04	81.12	48.32	0	0
Anthocyanins	0	0.74	57.68	0	7.2
Lignans	0	0	0	0	0
Dihydrochalcones	0	4.3	0	0	0
Stilbenes	0	0	0.26	0	0
Phenolic acids	0.8	15.2	1.35	1.69	1.6
Total polyphenols*	5	114.52	120	1.91	111.6	353.03

* Calculated from the sum of polyphenols determined by chromatography on Phenol-Explorer database.

Table 7. Example zero-base recipe for a polyphenol dense snack.

Ingredient	Recipe quantity (g)	Moisture content (%)	Quantity after moisture loss (g)	Dietary fiber (g/100 g FW)	Dietary fiber in recipe (g)	TPC (mg/100 g FW)	TPC in recipe (mg)
Refined flour	50	11.9	44	2.7	1.35	0	0
Corn starch	32.9	10	29.7	0	0	0	0
Sugar	25	1	24.8	0	0	0	0
Lecithin	2.5	1	2.5	0	0	0	0
HOSO	2	0	2	0	0	0	0
Dark chocolate	50	0.6	49.7	11.5	5.8	1860	930
Strawberries	200	91	18.1	2	4	235	470
Plum	250	87.2	31.9	1.4	3.5	377	943
Blueberries	300	84.2	47.4	2.4	7.2	836	2508
Chestnut	50	40.5	29.8	5.1	2.6	1215	608
Batch weight	962		278	25	24	4523	5459
Per portion (28.5 g)					0.7		556

TPC, total polyphenol content.

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