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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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| 2. |
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| 3. |
- Moorthy, SN, et al.
(författare)
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Determination of amylose content in different starches using modulated differential scanning calorimetry
- 2006
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Ingår i: Stärke. - : Wiley. - 0038-9056. ; 58:5, s. 209-214
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Tidskriftsartikel (refereegranskat)abstract
- A simple calorimetric method for determination of amylose content in starch is reported. Starches were heated in the presence of two common surfactants, viz., sodium dodecyl sulphate (SDS) and cetyltrimethylammonium bromide (CTAB), and the enthalpies of melting of the amylose-surfactant complexes were determined using Modulated Differential Scanning Calorimetry (MDSC). A large number of native starches including cereal, root and pea starches were examined. The results were compared with those obtained by iodimetry and gel permeation chromatography (GPC) for all the starches. There was a good correlation between the values from iodimetry and GPC with those obtained using the surfactants. Both surfactants seemed to work equally well, even for those starches with about 40% amylose content. However, in case of SIDS higher standard deviations were usually obtained than for CTAB in the determination of transition enthalpies.
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| 4. |
- Santacruz, S, et al.
(författare)
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Three under-utilised sources of starch from the Andena region in Ecuador. Part II. Rheological characterisation.
- 2003
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Ingår i: Carbohydrate Polymers. - 0144-8617. ; 51:1, s. 85-92
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Tidskriftsartikel (refereegranskat)abstract
- The dynamic rheological behaviour of Arracacha xanthorriza white carrot), Canna edulis (achira) and Oxalis tuberosa oca) starch gels were studied in strain-sweep mode. The starch was diluted with water to cover particle volume fractions of 1–3. The starch suspensions were heated at 89 8C for 30 min, and their swelling power and amylose leaching were measured. C. edulis showed the highest swelling power and particle rigidity (the elastic modulus, G0, of a starch gel at a particle volume fraction of 1 is defined as rigidity), forming stronger gels than O. tuberosa and A. xanthorriza. Storage of the three starch gels at 4 8C showed that A. xanthorriza formed gels which were stable in G0 and phase angle for three days of storage. C. edulis and O. tuberosa gels kept at the same refrigeration conditions showed a high increase in G0 during the first day of storage. A decrease in pH from 6.5 to 4.0 produced a loss of structure in the three starch gels, as was showed by the reduction of G0. Storage at freezing temperature (220 8C) produced higher changes in G0 than refrigeration conditions. There was a rapid formation of an elastic structure in C. edulis and O. tuberosa starch gels on the first day of storage in both refrigeration and freezing conditions.
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| 5. |
- Santacruz, Stalin, et al.
(författare)
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Three underutilised sources of starch from the Andean region in Ecuador Part 1. Physico-chemical characterisation
- 2002
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Ingår i: Carbohydrate Polymers. - 0144-8617. ; 49:1, s. 63-70
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Tidskriftsartikel (refereegranskat)abstract
- The physico-chemical aspects of three native Andean starches from Arracacha xanthorriza, Canna edulis and Oxalis tuberosa were investigated. Scanning electron microscopy-investigations showed that granules of A. xanthorriza were the smallest with irregular shape and sizes between 7 and 23 pm, whereas granules of O. tuberosa and C. edulis were both ovally shaped with granular sizes between 20 and 55 mum and 35-101 mum, respectively. All three starches revealed a B-type X-ray diffraction pattern. The gelatinisation behaviour was investigated using differential scanning calorimetry (DSC). The gelatinisation enthalpy was 14.6 J/g of starch for O. tuberosa, 15.7 J/g for C. edulis and 17.6 J/g for A. xanthorriza, and the peak temperature of the endothermic DSC-transition was 55.9, 61.2 and 60.1 degreesC, respectively. The amylose content determined by gel permeation chromatography after debranching with isoamylase was 4% for A. xanthorriza, 18.4% for O. tuberosa. and 23.8% for C. edulis. The amylopectin showed different structures among the three starches with a beta-amylolysis limit of 67.6% for C edulis, 64.5% for O. tuberosa and 56.6% for A. xanthorriza. The average chain length of the amylopectin was highest for A. xanthorriza (22.6), followed by O. tuberosa with 22.4, and lowest for C. edulis (21.9). The complexation ability of the three starches was investigated by adding sodium dodecyl sulphate (SDS), and the amylose content was positively correlated with the enthalpy of the amylose-SDS complex. (C) 2002 Elsevier Science Ltd. All rights reserved.
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