Industrial applications of kale (Brassica oleracea var. sabellica) as a functional ingredient: a review

Figures & data

Table 1. Eating behavior of different types of kale.

Kale Types	Color, Size and Shape	Consume	Composition	Authors
Winterbor Kale	Thick leaves Bluish-green Height (3 feet)	Winterbor kale is typically cooked due to its thicker leaves, but it can also be eaten raw.	It is a popular type of curly kale that is favored by both commercial growers and home gardeners due to its high antioxidant activity. It is one of the cold-hardiest kales, meaning it can withstand freezing temperatures.	^[Citation13,Citation14]
Lacinato Kale	Dark green and blade-shaped leaves Height (3 feet)	Lacinato is tender, making it ideal for use in salads. It’s also delicious in soups, frittatas, and other cooked dishes.	Lacinato is high in minerals that most Americans do not consume, such as and zinc. It’s also contain fiber, vitamins C and K.	^[Citation13,Citation15]
Scarlet Kale	Purple leaves and stalks	Young, tender leaves can be eaten raw in salads, while mature leaves can be cooked and added to soups or grain dishes.	Scarlet kale had the highest amount of total tocopherols and alpha tocopherols in a study that compared eight kale cultivars.	^[Citation13,Citation16]
Red Russian Kale	Height (2–3 feet)	Baby leaf kale is especially tasty raw in salads.	Its contain minerals (manganese, copper, calcium, and magnesium) and vitamins (A, K, C, and B6).	^[Citation13,Citation17]
RedBor Kale	Deep reddish-purple leaves Height (2–3 feet)	Its leaves are crisp when raw but tender when cooked, making it an excellent addition to stews and pastas. Its leaves can also be finely shredded to make a bright and crisp raw salad.	Redbor kale contains a lot of nutrients (vitamins A and C, as well as Fe^2+, Ca^2+, Mg^2+, K^+, protein, polysaccharides, and dietary fiber).	^[Citation13,Citation18]
Beira Kale	Thick stems Green Height (2 feet)	Beira has green leaves that are used in a traditional dish called Portuguese kale soup.	It is rich source of antioxidants (glucosinolates).	^[Citation13,Citation19]
Darkibor Kale	Thick stems Height (2 feet)	It is used in raw and cooked form	It is good source of antioxidants	^[Citation13,Citation20]
Walking Stick Kale	Walking stick kale Massive leafy green.	Because of their tender texture, most people prefer to eat the younger leaves. The tougher, older leaves make excellent animal feed.	It is rich source of nutrients and antioxidants.	^[Citation13,Citation21]
Japanese Flowering Kale	Rosette Fuschia center and green outer leaves	The frilly leaves add to the overall visual appeal. It also makes great kale chips.	The iron-rich flat leaves are easy to chop and high in vitamins A, C, and E. It is also a natural breath sweetener due to its high chlorophyll content.	^[Citation13,Citation22]
Thousandhead Kale	Height 6 feet Massive leaves	The leaves are only slightly curled at the tips, making pests like caterpillars easier to spot.	Its contain carotene which can help prevent in different diseases.	^[Citation13,Citation23]

Table 2. Different processing methods of kale.

Kale part	Processing Method	Conditions	Preservation	Changes	Authors
Raw kale	Drying	Thermal energy and humidity	Increase shelf life of food products by reduce humidity and water activity	During the drying processing of kale minimum changes occurred in polyphenols and vitamin C	^[Citation26]
Raw Kale	High-pressure Processing (HPP)	Pressure and time	The results suggested that HPP was confirmed as a gentle treatment technique for lipophilic micronutrients in kale	Carotenoids contents had been found to be decreased. HPP had been found to be effective for kale lipophilic nutrients	^[Citation27]
Kale raw leaves and blanched	Blanching, cooking, freezing, canning or drying	Temperature. time, freezing and humidity	The average levels of chlorophylls and carotenoids in freeze-dried products were higher.	Minimal changes occurred in chlorophylls and carotenoids values of kale	^[Citation28]
Fresh kale leaves	Blanching and cooking	Position of sieves, time and temperature	The preliminary use of blanching as a treatment improved GLS retention in dried leaves due to the inactivation of myrosinase.	The minimal GLS losses were in frozen kale leaves whereas the highest loss was in sterilized and dried.	^[Citation29]
Fresh and frozen kale leaves	Blanching or cooking	Temperature and time	Frozen products from blanched raw material contained the highest amounts of antioxidants, total polyphenols and vitamin C	Frozen products retains the highest phenolic contents	^[Citation26]
Fresh and processed	Blanching	Temperature and time	Both fresh and processed leaves of kale were a good source of amino acids	In kale leaves, both fresh and processed, minimum changes were observed in amino acid contents.	^[Citation30]

Figure 1. Nutritional composition of kale.

Figure 2. Anti-nutritional/bioactive compounds in kale.

Table 3. Therapeutic potential of kale.

Kale Raw and Processed	Bioactive compounds	Disease	Improvements	Authors
Leaves and stem	Phenolic compounds, glucosinolates and carotenoids	Cancer, cardiovascular and gastrointestinal system	Leaves and stems contain macronutrient and phytochemical that play an essential role in the prevention of different diseases	^[Citation51]
Kale	Phenolics, carotenoids, and glucosinolates	Chronic and degenerative diseases	This review discussed the effects of abiotically stressed kale on the prevention and treatment of chronic and degenerative diseases.	^[Citation52]
Kale	Prebiotic carbohydrates, unsaturated fatty acids and different vitamins	Coronary artery disease, inflammatory, genotoxic and gastrointestinal diseases	kale plays a protective role in rent diseases	^[Citation53]
Curly kale juice	Phenolic, vitamin C and minerals	Antimicrobial and antioxidant activity	The study indicated that fermented curly kale juice may become popular in the functional food sector	^[Citation54]
Kale juice	Protein, carbohydrate, vitamins and minerals	Coronary heart disease	The study suggested that kale juice reduces the risks of coronary artery disease in male	^[Citation55]
Kale and papaya	Prebiotic	Inflammation	The study suggested that both vegetables showed prebiotic and anti-inflammatory effects in the TNBS model of rat colitis	^[Citation56]
Kale extract	Raw kale plant	kaempferol-glucosides	The outcomes suggest that Lactobacillus paracasei A221 is effective in enhancing the anti-aging properties of kaempferol-glucosides	^[Citation57]

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