Isolated starches from yams (Dioscorea sp) grown at the Venezuelan Amazons: structure and functional properties.

This work aimed to characterize the molecular structure and functional properties of starches isolated from wild Dioscorea yams grown at the Amazons, using conventional and up-to-date methodologies. Among the high purity starches isolated (≥99%), the chain lengths were similar, whereas variations in gelatinization profile were observed. Starches have shown varied-shaped granules with monomodal distribution, and B-type crystallinity. Variations in amylose contents found by three analyses were hypothesized being related to intermediate material. Linear chain lengths were similar, and their amylopectins showed a dense, spherical conformation and similar molecular characteristics. The average molar mass and the radius of gyration of the chromatograms of the yam amylopectin, M¯W and R¯G were ranging between 174×10(6) g mol(-1) and 237×10(6) g mol(-1), and 201 nm and 233 nm, respectively. The white yams starches were more sensible to enzymes than the other two. All starches have shown a wide range of functional and nutritional properties.

Effect of physiological harvest stages on the composition of bioactive compounds in Cavendish bananas.

The combined influence of maturation, ripening, and climate on the profile of bioactive compounds was studied in banana (Musa acuminata, AAA, Cavendish, cv. Grande Naine). Their bioactive compounds were determined by the Folin-Ciocalteu assay and high-performance thin layer chromatographic (HPTLC) method. The polyphenol content of bananas harvested after 400 degree days remained unchanged during ripening, while bananas harvested after 600 and 900 degree days exhibited a significant polyphenol increase. Although dopamine was the polyphenol with the highest concentration in banana peels during the green developmental stage and ripening, its kinetics differed from the total polyphenol profile. Our results showed that this matrix of choice (maturation, ripening, and climate) may allow selection of the banana (M. acuminata, AAA, Cavendish, cv. Grande Naine) status that will produce optimal concentrations of identified compounds with human health relevance.

Physicochemical, functional, and macromolecular properties of waxy yam starches discovered from "Mapuey" (Dioscorea trifida) genotypes in the Venezuelan Amazon.

"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.

Differentiation between cooking bananas and dessert bananas. 1. Morphological and compositional characterization of cultivated Colombian Musaceae (Musa sp.) in relation to consumer preferences.

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

Differentiation between cooking bananas and dessert bananas. 2. Thermal and functional characterization of cultivated Colombian Musaceae (Musa sp.).

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.

Evaluation of lactoperoxidase system treatment to reduce anthracnose, stem-end rot, and bacterial black spot development during storage of mangoes.

The lactoperoxidase system (LPS) was evaluated for the prevention of postharvest diseases caused by Xanthomonas campestris, Botryodiplodia theobromae, and Colletotrichum gloeosporioides in 'Keitt' and 'Kent' mangoes. The LPS treatment significantly reduced the disease development on both cultivars after storage at 12 degrees C for 2 weeks, which was followed by a ripening at 25 degrees C. The LPS treatment did not alter the sensory quality of mango fruits (color, firmness, titrable acidity, and total soluble solids) when compared to untreated fruits. The LPS thus presents good potential alternative to the chemical fungicides traditionally used to improve the shelf life of mangoes.

Physicochemical characterization of a new pineapple hybrid (FLHORAN41 Cv.).

The physicochemical characteristics (pH, total and soluble solids, and titratable acidity), sugars, organic acids, carotenoids, anthocyanins, volatile compounds, and cell wall polysaccharides of a new pineapple hybrid (FLHORAN41 cultivar) were measured throughout maturation and compared with the Smooth Cayenne cv. At full maturity, the FLHORAN41 cv. has a higher titratable acidity and soluble solids content than the Smooth Cayenne cv. The golden yellow flesh and red-orange to scarlet shell of ripe FLHORAN41 cv. fruits are due to carotenoid and anthocyanin levels that are, respectively, 2.5 and 1.5 times higher than those of the flesh and shell of the ripe Smooth Cayenne cv., respectively. During maturation of the FLHORAN41 cv., there was an increase in all classes of aroma compounds (mainly terpene hydrocarbons and esters), although their relative proportions were similar in both cultivars at full maturity. Cell wall polysaccharides undergo little change during maturation.

Distribution of volatile compounds in the pulp, cloud, and serum of freshly squeezed orange juice.

The quantitative distribution of volatile compounds in the pulp, cloud, and serum of a freshly squeezed orange juice (cv. Naveline) was measured. Juice monoterpene and sesquiterpene hydrocarbons were primarily recovered from the pulp (74.0 and 87.2%, respectively) and cloud (7.3 and 14.9%, respectively). Esters and monoterpene alcohols were mainly found in the serum (90.4 and 84.1%, respectively). Long chain aliphatic aldehydes tend to concentrate in the pulp. The relative proportions of individual volatile compounds were similar in the pulp and cloud. Pulp and cloud alcohol insoluble residues exhibited similar compositions; half of them are made of nonwall proteins, and the rest are made of cell wall materials. Pulp and cloud total and neutral lipids had similar fatty acids distributions, although the cloud was much richer in total lipids than the pulp. No relationship was found between the retention of aroma compounds in the pulp or cloud and their AIR and lipid content or composition.