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- Bengtsson, Anton, 1979, et al.
(författare)
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In vitro bioaccessibility of beta-carotene from heat-processed orange-fleshed sweet potato
- 2009
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Ingår i: Journal of Agricultural and Food Chemistry. - : American Chemical Society (ACS). - 0021-8561 .- 1520-5118. ; 57:20, s. 9693-9698
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Tidskriftsartikel (refereegranskat)abstract
- Orange-fleshed sweet potato (OFSP) is currently promoted in parts of sub-Saharan Africa as a biofortified staple food with large potential to provide considerable amounts of provitamin A carotenoids. However, the bioaccessibility of provitamin A carotenoids from OFSP has not been widely investigated, especially not as an effect of different preparation methods. In this study, we used an in vitro digestion model to assess the bioaccessibility of beta-carotene from differently heat-processed OFSP. The fraction of carotenoids transferred from the food matrix to a micellar phase obtained after microfiltration and to a supernatant obtained after low-speed centrifugation was investigated. The percentage of accessible all-trans-beta-carotene in the micellar phase varied between 0.5 and 1.1% in the heat-processed OFSP without fat and between 11 and 22% with the addition of 2.5% (w/w) cooking oil. In comparison with the micellar phase, the percentage of accessible all-trans-beta-carotene in the supernatant phase was significantly higher (P
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- Chandrika, UG, et al.
(författare)
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Content and in vitro accessibility of Β-carotene from cooked Sri Lankan green vegetable and their estimated contribution to vitamin A requirements
- 2006
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Ingår i: Journal of the Science of Food and Agriculture. - : Wiley. - 1097-0010 .- 0022-5142. ; 86:1, s. 54-61
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Tidskriftsartikel (refereegranskat)abstract
- Vitamin A deficiency is an important issue for public health in Sri Lanka, where pro-vitamin A carotenoids from green leafy vegetables provide most of the dietary vitamin A. The objective of this study was to analyse the beta-carotene content of seven types of green leafy vegetables and calculate the contribution of one traditionally cooked portion to the recommended daily allowance (RDA) of retinol. The total amount and in vitro accessibility of beta-carotene were determined using HPLC. The in vitro method simulates the conditions in the human intestinal tract. The all-trans-beta-carotene content in the fresh blanched vegetables ranged from 149 mu g g(-1) dry weight (DW) in leaves of Alternanthera sessilis (mukunuwanna) to 565 mu g g(-1) DW in Amaranthus caudatus (thampala). One portion (100g) of green leaves cooked without fat (coconut) only contributed from 140 to 180 mu g mg(-1) of the recommended daily allowance. A. sessilis, Centella asiatica (gotukola), Spinacea oleracea (nivithi) and A. caudatus, cooked with coconut fat contributed 140-680 mu g mg(-1). However, stir-fried or 'malluma' preparations (with coconut products) of Sesbania grandiflora (kathurumurunga) and Manihot esculenta (manioc) may provide more than 1.59-4.37 times the RDA of retinol. These results show that not only the choice of green leaves used but also the addition of fat while cooking is of great importance.
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- Matuschek, Erika, 1974, et al.
(författare)
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The effect of fruit extracts with polyphenol oxidase (PPO) activity on the in vitro accessibility of iron in high-tannin sorghum
- 2005
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Ingår i: Food Chemistry. - : Elsevier BV. - 0308-8146 .- 1873-7072. ; 90:4, s. 765-771
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Tidskriftsartikel (refereegranskat)abstract
- Dephytinized high-tannin sorghum flour was incubated with crude extracts from pear, banana or avocado, respectively, followed by investigation of the effects on the phenolic content and on in vitro accessible iron. All fruits contained polyphenol oxidase (PPO) activity and incubation resulted in significant reduction of phenolic compounds. Incubation with avocado extract resulted in the lowest levels of phenolic compounds, as well as the highest amount of in vitro accessible iron. Peroxidase activity and some organic acids in the fruit extracts might also have contributed to the positive effect on iron accessibility. Nevertheless, incubation of the sorghum flour with the fruit extracts under conditions enabling the PPO to oxidize phenolic compounds, resulted in the highest accessibility of iron. The results from this study suggest that the PPO activity in simple fruit extracts can be utilized to increase the accessibility of iron in dephytinized polyphenol-containing cereal foods.
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- Towo, Elifatio, 1962, et al.
(författare)
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Fermentation and enzyme treatment of tannin sorghum gruels: Effects on phenolic compounds, phytate and Fermentation and enzyme treatment of tannin sorghum gruels: Effects on phenolic compounds, phytate and in vitro accessible iron
- 2006
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Ingår i: Food Chemistry. - : Elsevier BV. - 0308-8146 .- 1873-7072. ; 94:3, s. 369-376
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Tidskriftsartikel (refereegranskat)abstract
- The presence of polyphenols and phytate in cereal products has been. shown to interfere with the bioavailability of minerals such as iron. In the present study, we added enzymes (wheat phytase and mushroom polyphenol oxidase) during fermentation of tannin sorghum gruels prepared from flour with or without addition of 5% flour of germinated tannin-free sorghum grains (power flour), and investigated the effects on phenolic compounds, phytate and in vitro accessible iron. Assayable phenolic compounds were significantly reduced by fermentation, with high reductions observed in gruels with added enzymes. Fermentation of the gruels with addition of enzymes reduced (on average) total phenols by 57%, catechols by 59%, galloyls by 70% and resorcinols by 73%. The phytate content was significantly reduced by fermentation (39%), with an even greater effect after addition of power, flour, (72%). The largest reduction of phytate (88%) was, however, obtained after addition of phytase. The in vitro accessible iron was 1.0% in the sorghum flour and it increased after fermentation with power flour and/or with enzymes. The highest in vitro accessibility of iron (3.1%) was obtained when sorghum was fermented with addition of power flour and incubated with phytase and polyphenol oxidase after the fermentation process.
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- Vasco, Catalina, et al.
(författare)
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Physical and chemical characteristics of golden-yellow and purple-red varieties of tamarillo fruit (Solanum betaceum Cav.)
- 2009
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Ingår i: International Journal of Food Sciences and Nutrition. - : Informa UK Limited. - 0963-7486 .- 1465-3478. ; 60:SUPPL. 7, s. 278-288
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Tidskriftsartikel (refereegranskat)abstract
- Golden-yellow and purple-red tamarillos (Solanum betaceum Cav.) cultivated in Ecuador were studied for their physical properties, proximate composition, pH, degrees Brix, acidity, sugars, organic acids, minerals, vitamin C and beta-carotene content in the edible part. Results were compared with those for Spanish fruits. The golden-yellow and purple-red Ecuadorian fruits were larger (107 and 188 g) than the respective Spanish fruits (43 and 63 g), softer but generally similar in chemical composition except for fat (0.72 and 0.6%) and malic acid (0.32 and 0.53%) contents in the golden-yellow and purple-red Ecuadorian fruits. Tamarillo fruits are a good source of potassium (similar to 400 mg/100 g fresh weight). Total phenolics in the golden-yellow and purple-red varieties were 125 and 187 mg gallic acid equivalents/100 g fresh weight, respectively. The golden-yellow variety had weaker anti-DPPH radical activity than the purple-red variety. Flavonols were only found in the peel of both varieties, while hydroxycinnamic acid derivatives were found in peel and pulp.
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