| 1. |
- Eduardo, Maria, 1965, et al.
(författare)
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Effect of hydrocolloids and emulsifiers on the shelf-life of composite cassava-maize-wheat bread after storage
- 2016
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Ingår i: Food Science and Nutrition. - : Wiley. - 2048-7177. ; 4:4, s. 636-644
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Tidskriftsartikel (refereegranskat)abstract
- The objective of this study was to evaluate the effect of hydrocolloids and/or emulsifiers on the shelf-life of composite cassava-maize-wheat (ratio 40: 10: 50) reference bread during storage. Added hydrocolloids were carboxymethylcellulose (CMC) and high methoxyl pectin (HM pectin) at a 3% level (w/w) and/or the emulsifiers diacetyl tartaric acid esters of monoglycerides (DATEM), lecithin (LC), and monoglycerides (MG) at a 0.3% level (w/w). After 4 days of storage, composite breads with MG had comparatively lower crumb moisture while crumb density was similar in all breads. The reference bread crumb firmness was 33.4 N, which was reduced with an addition of DATEM (23.0 N), MG (29.8 N), CMC (24.6 N) or HM pectin (22.4 N). However, the CMC/DATEM, CMC/LC, and HM pectin/DATEM combinations further reduced crumb firmness to
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| 2. |
- Guiamba, Isabel, 1963, et al.
(författare)
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Effect of Infrared Blanching on Enzyme Activity and Retention of β-Carotene and Vitamin C in Dried Mango
- 2015
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Ingår i: Journal of Food Science. - : Wiley. - 0022-1147 .- 1750-3841. ; 80:6, s. E1235-E1242
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Tidskriftsartikel (refereegranskat)abstract
- The objectives of this work were to evaluate infrared (IR) dry blanching in comparison with conventional water blanching prior to hot air drying of mango to inactivate polyphenol oxidase (PPO) and ascorbic acid oxidase (AAO) enzymes, and to study its effect on color change and retention of vitamin C and β‐carotene. Mango cylinders were blanched under similar temperature–time conditions either by IR heating or by immersion in a water bath during 2 min at 90 °C (high‐temperature‐short‐time—HTST) or for 10 min at 65 °C (low‐temperature‐long‐time—LTLT). After blanching mango was hot air dried at 70 °C. PPO was completely inactivated during the blanching treatments, but AAO had a moderate remaining activity after LTLT treatment (∼30%) and a low remaining activity after HTST treatment (9% to 15%). A higher retention of vitamin C was observed in mango subjected to IR dry blanching, 88.3 ± 1.0% (HTST) and 69.2 ± 2.9% (LTLT), compared with water blanching, 61.4 ± 5.3% (HTST) and 50.7 ± 9.6% (LTLT). All‐trans‐β‐carotene retention was significantly higher in water blanched dried mango, 93.2 ± 5.2% (LTLT) and 91.4 ± 5.1% (HTST), compared with IR dry blanched, 73.6 ± 3.6% (LTLT) and 76.9 ± 2.9% (HTST). Increased levels of 13‐cis‐β‐carotene isomer were detected only in IR dry blanched mango, and the corresponding dried mango also had a slightly darker color. IR blanching of mango prior to drying can improve the retention of vitamin C, but not the retention of carotenoids, which showed to be more dependent on the temperature than the blanching process. A reduction of drying time was observed in LTLT IR‐blanching mango.
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| 3. |
- Guiamba, Isabel, 1963, et al.
(författare)
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Effects of blanching, acidification, or addition of EDTA on vitamin C and β-carotene stability during mango purée preparation
- 2016
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Ingår i: Food Science and Nutrition. - : Wiley. - 2048-7177. ; 4:5, s. 706-715
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Tidskriftsartikel (refereegranskat)abstract
- The impact of acidification with citric acid, addition of EDTA or water blanching at high temperature, and short time (HTST) conducted at 90°C for 4 min, on the retention of vitamin C (L-AA and DHAA) and β-carotene was studied in mango purée 30 min after crushing. HTST blanching prior to matrix disruption into purée resulted in complete inactivation of polyphenol oxidase (PPO) and minor residual activity (8%) of ascorbic acid oxidase (AAO). The retention of total vitamin C was 100% in blanched purées and in purée with EDTA and about 90% in purées at pH 3.9 and 5.0. Acidification, blanching, and addition of EDTA preserved vitamin C mainly as L-AA, while complete conversion into DHAA was observed in purée at pH 5.0. The retention of all-trans-?-carotene was between 65 and 72%, with the highest value in purée with EDTA and the lowest value in purée of blanched mango. The ratio of 13-cis-β-carotene in fresh mango was 8.2 ± 0.5% that increased significantly after blanching and in purée at pH 5.0.
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| 4. |
- Guiamba, Isabel, 1963, et al.
(författare)
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Enhancing the retention of β-carotene and vitamin C in dried mango using alternative blanching processes.
- 2018
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Ingår i: African Journal of Food Science. - 1996-0794. ; 12:7, s. 165-174
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Tidskriftsartikel (refereegranskat)abstract
- The effects of microwave (MW) dry blanching of mango in comparison with conventional water blanching and blanching in closed plastic bags prior to hot air drying (70°C) were evaluated on the retention of vitamin C and β-carotene and on the activity of polyphenol oxidase (PPO) and ascorbic acid oxidase (AAO) enzymes. Blanching conditions for MW and water blanching were 2 min at 90°C high temperature and short time (HTST) or for 10 min at 70°C low temperature and low time (LTLT). PPO was completely inactivated by the blanching treatments, while low AAO activity remained. High retentions (~100%) of vitamin C were found in dried mango after blanching treatments HTST with MW and blanching in closed plastic bags, while lower retention was observed after LTLT with MW (81.8 ± 4.5%), and conventional water blanching 86.7 ± 2.6% (HTST) and 78.6 ± 2.5% (LTLT). Blanching resulted in partial oxidation of L-AA into dehydroascorbic acid (DHAA). Lower retention of all-trans-β-carotene was obtained in MW and HTST water blanched dried mango (82 to 90%) compared with LTLT water blanched dried mango (~100%). In all dried blanched mango samples the levels of 13-cis-β-carotene isomer increased. A slight darkening of colour was observed only in conventional blanched mango samples.
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| 5. |
- Guiamba, Isabel, 1963, et al.
(författare)
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Retention of beta-carotene and vitamin C in dried mango osmotically pretreated with osmotic solutions containing calcium or ascorbic acid
- 2016
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Ingår i: Food and Bioproducts Processing: Transactions of the Institution of of Chemical Engineers, Part C. - : Elsevier BV. - 1744-3571 .- 0960-3085. ; 98, s. 320-326
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Tidskriftsartikel (refereegranskat)abstract
- The retention of vitamin C and carotenoids was studied in the cv. 'Tommy Atkins' mango as affected by osmotic dehydration prior to hot air drying. Osmotic dehydration (OD) was carried out over 15 h at 25°C using sucrose solutions of 45°BRIX with and without 1% (w/w) calcium chloride or 1% ascorbic acid with a fruit to solution ratio of 1:10 (w/w), and the OD-treated mango samples were then dried in an air convection oven at 50°C or 70°C. An osmotic pretreatment before drying significantly reduced the drying time and prevented colour change in dried mango. Addition of calcium in the OD solution significantly improved vitamin C retention, on average from 44% to 57%. However, the addition of ascorbic acid to the osmotic solution highly increased the retention of vitamin C content in the dried mango. The retention of all-trans-β-carotene was significantly lower in all OD treated mango samples dried at 50°C but remained unchanged in OD-treated mango samples with calcium or vitamin C dried at 70°C. Moreover, osmotic dehydration with and without additives reduced the ratio of 13-cis-β-carotene to all-trans-β-carotene. The results showed that the addition of calcium or vitamin C to the osmotic solution can improve the nutritional value of dried mango.
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| 6. |
- Hellström, Andreas, 1980, et al.
(författare)
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Secretion of non-cell-bound phytase by the yeast Pichia kudriavzevii TY13
- 2015
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Ingår i: Journal of Applied Microbiology. - : Oxford University Press (OUP). - 1365-2672 .- 1364-5072. ; 118:5, s. 1126-1136
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Tidskriftsartikel (refereegranskat)abstract
- AimsMineral deficiencies cause several health problems in the world, especially for populations consuming cereal-based diets rich in the anti-nutrient phytate. Our aim was to characterize the phytate-degrading capacity of the yeast Pichia kudriavzevii TY13 and its secretion of phytase. Methods and ResultsThe phytase activity in cell-free supernatants from cultures with 100% intact cells was 35-190mUml(-1) depending on the media. The K-m was 028mmoll(-1) and the specific phytase activity 032Umg(-1) total protein. The phytase activity and secretion of extracellular non-cell-bound phytase was affected by the medium phosphate concentrations. Further, addition of yeast extract had a clearly inducing effect, resulting in over 60% of the cultures total phytase activity as non-cell-bound. ConclusionsOur study reveals that it is possible to achieve high extracellular phytase activity from the yeast P.kudriavzevii TY13 by proper composition of the growth medium. Significance and Impact of the StudyTY13 could be a promising future starter culture for fermented foods with improved mineral bioavailability. Using strains that secrete phytase to the food matrix may significantly improve the phytate degradation by facilitating the enzyme-to-substrate interaction. The secreted non-cell-bound phytase activities by TY13 could further be advantageous in industrial production of phytase.
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| 7. |
- Khan, M.A.M., et al.
(författare)
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Contribution of native fruits to alleviation of poverty and malnutrition in rural areas in Mozambique
- 2016
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Ingår i: Acta Horticulturae. - 0567-7572. - 9789462611412 ; 1128, s. 73-78
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Konferensbidrag (refereegranskat)abstract
- In Mozambique, 80% of the population depend on agriculture for their livelihoods, and 64% are food insecure. Malnutrition is the major health problem in some rural areas, and this is related to micro- and macronutrient deficiency. Irregular food availability throughout the year caused by seasonality and critical events contributes to this situation. The main cause of malnutrition, particularly in women and children, is insufficient intake of foods rich in micronutrients. During the dry season, native fruits play an important and crucial role in ensuring food security and, in many cases, are becoming the only way of survival for rural families. This study examined the potential use of native fruits as an alternative source of nutrients for alleviating malnutrition in Mozambique. Two key native fruits, Strychnos spinosa and Strychnos madagascariensis, were identified, and their chemical and nutritional Ipotential determined. The results showed that both products are rich in sugar and fiber, as well as in vitamins A and C. The fat content of S. spinosa pulp (0.15%) was much lower than that of S. madagascariensis (64%). Protein content was relatively low in both products. Mineral content analysis showed that both of these fruits are highly nutritional, being rich in K, Na, Mg, and Ca, and also in the essential microelements Cu, Zn, and Fe. For these reasons, they may contribute in a significant way to alleviation of poverty and malnutrition in Mozambique.
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