"Mapuey" tubers in Venezuela are staple food for indigenous peoples from the Caribbean coast and Amazon regions. Noticeable differences between genotypes of yam starches were observed. Granules were large, triangular, or shell-shaped with monomodal particle size distribution between 24.5 and 35.5 μm. Differential scanning calorimetry (DSC) analyses revealed onset gelatinization temperatures from 69.1 to 73.4 °C with high gelatinization enthalpy changes from 22.4 to 25.3 J g(-1). All X-ray diffractograms of starches exhibit B-type crystallinity. Crystallinity degrees varied from 24% to 40%. The highest crystallinity was found for the genotype having the highest amylose content. Iodo-colorimetric, amperometric, and DSC amylose determinations varied from 1.4 to 8.7%, 2.2 to 5.9%, and 1.4 to 3.5% for Amazonian genotypes, in comparison with commercial Mapuey starches: 12.0, 9.5, and 8.7%, respectively. Solubility and swelling power at 90 °C varied from 2.1 to 4.4% and 20.5 to 37.0%, respectively. Gel clarity fluctuated from 22.4 to 79.2%, and high rapid visco analyzer (RVA) viscosity was developed at 5% starch suspension (between 1430 and 2250 cP). Amylopectin weight average molar mass M(w), radius of gyration R(G), hydrodynamic coefficient ν(G), and apparent molecular density d(Gapp) were determined using high-performance size exclusion chromatography (HPSEC) and asymmetrical flow field flow fractionation (A4F) techniques coupled with multiangle laser light scattering (MALLS) on the Dioscorea trifida genotypes exhibiting the lowest and highest amylose contents. Amylopectins showed very similar molecular conformations. M(w) values were 1.15 × 10(8) and 9.06 × 10(7) g mol(-1) using HPSEC and A4F, respectively, thus, 3-5 times lower than those reported with the same techniques for other yam species, and very close to those of potato and cassava amylopectins. This discovery of a new natural amylose-free starch in the neglected yam "Mapuey" could present some potential for the food industry.

The morphological, physical, and chemical characteristics of 23 unripe cultivated varieties of Colombian Musaceae were assessed. Fresh pulp dry matter helped to discriminate the following consumption subgroups: FHIA dessert hybrids (hydes: 24.6%) < dessert bananas (des: 29.4%) < nonplantain cooking bananas (cook: 32.0%) < FHIA cooking hybrids (hycook: 34.2%) < plantains (pl: 41.1%). Banana flour starch content on dry basis (db) varied from 74.2 to 88.2% among the varieties, with: pl: 86.5% > cook and hycook: 84% > des: 81.9% > hydes: 79.7% (p

The starch and flour thermal and functional characteristics of 23 cultivated varieties of bananas in Colombia were assessed. Onset temperature for gelatinization of starches measured by differential scanning calorimetry (DSC) varied from 59.7 to 67.8 degrees C, thereby significantly differentiating dessert bananas (63.2 degrees C) from nonplantain cooking bananas (65.7 degrees C) from FHIA hybrids (66.6 degrees C) and plantains (67.1 degrees C). FHIA hybrids are significantly discriminated from dessert banana landraces but not from the cooking group. The starch amylose contents varied from 15.4 to 24.9%; most dessert banana starch amylose contents were below 19%, whereas in cooking banana starches the contents were over 21%. Flour functional properties were assessed by Rapid ViscoAnalyser (RVA) using silver nitrate as alpha-amylase inhibitor. The flour pasting temperature was relevant to differentiate dessert bananas (69.5 degrees C) from FHIA dessert hybrids and nonplantain cooking bananas (72.8 degrees C) from cooking hybrids and plantains (75.8 degrees C). Among other criteria, the cooking ability also helped to differentiate dessert bananas and FHIA hybrids from cooking bananas. A close relation between cultivar genotypes and uses with the thermal and pasting properties were revealed.

No abstract

No abstract