A. Effect of Processing on Tocopherol Content of Peppers
VI. Carotenoids
Varying composition and concentration of carotenoids in capsicum are responsible for diversely colored fruit. Common carotenoids in capsicum fruits are shown in Figure 9.2. Capsicum species
New Mexico 6-4 Green 6 40 80 22
New Mexico 6-4 Breaker 6 40 80 22
New Mexico 6-4 Red succulent 16 107 200 22
New Mexico 6-4 Red-partially dry 12 80 150 22
New Mexico 6-4 Red-dried 7 47 90 22
Nu-Mex R-Naky Green 3 20 40 22
Nu-Mex R-Naky Breaker 8 53 100 22
Nu-Mex R-Naky Red succulent 13 87 160 22
Nu-Mex R-Naky Red-partially dry 11 73 140 22
Nu-Mex R-Naky Red-dried 21 140 260 22
B-18 Green 2 13 30 22
B-18 Breaker 8 53 100 22
B-18 Red succulent 24 160 300 22
B-18 Red-partially dry 15 100 190 22
B-18 Red-dried 31 207 390 22
a α-Tocopherol = 1.0 mg αTE.
bRecommended daily intakes, adult males and females = 15 mg αTE.
c Fruit harvested and analyzed in 1994.
dFruit harvested and analyzed in 1995.
TABLE 9.3 (Continued)
Tocopherol Content of Fresh Capsicum Fruit
Species Type Cultivar Maturity
α-Tocopherola
Ref.
Pericarp (mg/100 g DW)
%RDIb
M F
Antioxidant Vitamin and Phytochemical Content of Fresh and Processed Pepper Fruit 177
have been selectively bred to obtain fruit with various colors including white, green, yellow, orange, brown, black, and purple. The ketocarotenoids capsanthin and capsorubin contribute to red color, while α- and β-carotene, zeaxanthin, lutein, and β-cryptoxanthin are responsible for yellow-orange color. The carotenoids and additional pigments responsible for exotic colored brown and purple fruit have not been characterized.
The pepper carotenoids α- and β-carotene and β-cryptoxanthin contribute to provitamin A activity. However, pepper fruit are also a good source of oxygenated carotenoids, or xanthophylls, which vary considerably in composition and concentration due to differences in genetics and fruit maturation.46,73 Oxygenated carotenoids, which do not possess provitamin A activity, have been FIGURE 9.2 Major carotenoids in Capsicum fruit.
HO Capsanthin OH
O O
HO Capsorubin
HO β-Cryptoxanthin
HO
O
OH O
HO
OH Violaxanthin
α-Carotene OH
HO Lutein
Zeaxanthin γ-Carotene β-Carotene
O HO OH
O
OH
Antheraxanthin 6409_book.fm Page 177 Saturday, September 16, 2006 9:54 AM
shown to be effective free radical scavengers,74 and may be important for prevention of advanced age-related macular degeneration and cataracts.75 In addition to antioxidant activity, carotenoids may play a role in cancer chemoprevention through their ability to act as antimutagens,76 enhance cell-to-cell communication,77 act as anti-inflammatory and antitumor agents, and induce detoxifi-cation of enzyme systems.78 Carotenoids present in pepper fruit may also be important in retarding changes associated with aging. Incorporation of a capsanthin-rich red bell pepper extract in the diet of senescence-accelerated mice resulted in amelioration of learning impairment.79
The provitamin A content (α- and β-carotene and β-cryptoxanthin) of fresh pepper cultivars is shown in Table 9.4.80 Provitamin A values range from nondetectible to 502 retinal equivalents (RE)/100 g. The wide range of provitamin A carotenoids in the cultivars referenced is not surprising, as the cultivars vary greatly in visual color. Cultivars that terminally ripen at the green, light-yellow, or yellow stages typically have less provitamin A activity due to reduced genetic capacity to synthesize α- and β-carotene and β-cryptoxanthin.73,81,82 Many studies have demonstrated that the β-, ε-series carotenoids in capsicum fruit, including lutein, decline during ripening, whereas α- and β-carotene increase, and other pigments, β-cryptoxanthin, capsanthin, and zeaxanthin are formed de novo.46,73,82,83 However, some exceptions are notable. The bell cv. Yellow Bell contains 257 RE/100 g and the yellow wax cv. Rio Grande Gold contains 502 RE/100 g. These yellow cultivars apparently contain the genetic capacity to synthesize provitamin A carotenoids.
Pepper fruit that ripen to orange and red stages contain high levels of provitamin A carotenoids, contributing 3 to 52% of the RDI (900 μg RE/100 g) for adult males and 4 to 67% of the RDI (700 μg RE/100 g) for adult females. Pepper cultivars that contain >25% of the RDI of provitamin A for both males and females include bell cv. Grande Rio 66 (red), bell cv. Yellow Bell (yellow), chile cv. Tam Mild Chile (red), chile cv. New Mexico-6 (red), jalapeno cv. Tam Veracruz (red), serrano cv. TAES Hidalgo (red), yellow wax cv. Rio Grande Gold (yellow), and tabasco cv.
McIlhenny tabasco (red).
Carotenoids in paprika cultivars have been studied extensively, because they are used in the form of powders and oleoresins as spices and food colorants. Dried paprika products are excep-tionally rich in carotenoids, including the ketocarotenoids capsanthin and capsorubin, which occur only in red Capsicum fruit, and contribute to the red color and quality of paprika oleoresin and powder. Numerous studies have documented the composition and concentration of carotenoids in dried paprika products that vary greatly in color.71,84–88
Efforts have been made to increase the carotenoid content of dried paprika through plant-breeding programs. The total carotenoid content of C. annuum plant-breeding lines ranged from 390 to 16,600 μg/g.86 Most of the red pigments were esterified, and diesters were present at higher concentrations than monoesters. An important observation was that a narrow range of variation existed among the ratios of carotenoids present in the breeding lines. This indicates that the levels of synthesis and accumulation of various carotenoid pigments are controlled genetically by common regulatory genes. Plant breeders may take advantage of this genetic trait in breeding and developing new paprika cultivars with elevated levels of carotenoids, including the red pigments capsanthin and capsorubin, which affect the color and quality of paprika oleoresin and powder. One breeding line 4126 was identified,86 which contained 240 mg of total carotenoids/100 g fresh weight, of which 20 mg was β-carotene. This level of β-carotene is comparable to levels found in carrots, but the total carotenoid content of this paprika breeding line is sixfold higher than levels found in carrots. Thus, breeding new pepper cultivars for elevated total carotenoid content appears to be feasible and may be beneficial for improving human health and nutrition.
In addition to genetics, the carotenoid content of peppers may be influenced significantly by environmental growing conditions. In a study involving five cultivars each of nonpungent and pungent pepper cultivars, grown in the field and a glasshouse, it was found that glasshouse grown peppers had much higher levels of carotenoids than those grown in the field.83 The authors suggested that the more consistent and protected conditions in the glasshouse may have caused carotenoid levels to be increased, especially at the red stage.
Antioxidant Vitamin and Phytochemical Content of Fresh and Processed Pepper Fruit 179
TABLE 9.4
Provitamin A Content of Fresh Capsicum Fruit
Species Type Cultivar Maturity
RE (μg)/100 g Fresh Weight
%RDIa
Ref.
Male Female
C. annuum Bell Dove White 16 2 2 19
Dove Light Orange 29 3 4 19
Ivory White 14 2 2 19
Ivory Light Yellow 46 5 7 19
Blue Jay White 22 2 3 19
Blue Jay Orange 59 7 8 19
Lilac Purple 17 2 2 19
Lilac Orange 86 10 12 19
Valencia Green 25 3 4 19
Valencia Orange 26 3 4 19
Oriole Green 37 4 5 19
Oriole Orange 99 11 14 19
Black Bird Green 32 4 5 19
Black Bird Black 41 5 6 19
Chocolate Beauty Green 38 4 5 19
Chocolate Beauty Brown 108 12 15 19
Cardinal Green 33 4 5 19
Cardinal Red 110 12 16 19
King Arthur Green 33 4 5 19
King Arthur Red 127 14 18 19
Var. 862R Green 38 4 5 19
Var. 862R Red 119 13 17 19
Red Bell G Green 44 5 6 19
Red Bell G Red 80 9 11 19
Red Bell C Green 35 4 5 19
Red Bell C Red 52 6 7 19
Klondike Bell Green 40 4 6 19
Klondike Bell Yellow 31 3 4 19
Canary Green 31 3 4 19
Canary Yellow 31 3 4 19
Orobelle Green 49 5 7 19
Orobelle Yellow 36 4 5 19
Golden Bell Green 37 4 5 19
Golden Bell Yellow 32 4 5 19
Tam Bel 2 Green 33 4 5 19
Tam Bel 2 Red 64 7 9 19
Grande Rio-66 Green 81 9 12 19
Grande Rio-66 Red 253 28 36 19
Yellow Bell Green 31 3 4 21
Yellow Bell Yellow 257 29 37 21
Caribe Caloro Green 2 <1 <1 80
Cascabella Peto Cascabella Yellow 4 <1 <1 21
Peto Cascabella Red 137 15 20 21
Cayenne Mesilla Green 42 5 6 21
Mesilla Red 214 24 31 21
Chile New Mexico-6 Green 79 9 11 20
Continued.
6409_book.fm Page 179 Saturday, September 16, 2006 9:54 AM
Dried paprika is an excellent source of vitamin A. A 1-g serving of freshly ground paprika provides 13 to 24% and 17 to 31% of the RDI for males and females, respectively.45 Thus, dried paprika is an excellent source of various carotenoid pigments that may be important for prevention of chronic diseases.
The carotenoid content of fresh and dried paprika fruit is also affected by the ripening stage.
The β-carotene content of the fresh paprika fruit cv. Mihalyteleki increased from 419 μg/g dry matter at the green stage to 468 μg/g at the deep red stage, whereas the β-carotene content of dried fruit increased from 610 μg/g at the green stage to 652 μg/g at the deep red stage.45