Browsing by Autor "Sergio Carballo"

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Antioxidants in yacon products and effect of long term storage
(Sociedade Brasileira de Ciência e Tecnologia de Alimentos, 2012) Alejandra Castro; Maciel Caballero; Adelina Herbas; Sergio Carballo
Yacon (Smallanthus sonchifolius (Poepp. and Endl.) H. Robinson) is a storage root originally grown in the Andean highlands. The fresh roots are perishable and quickly turn brown during handling and processing. Aiming to prolong shelf-life and to preserve the antioxidant compounds in yacon roots, 3 mm thick yacon slices were dried in a drying cabinet at 40, 50, and 60 ºC to a moisture content of 10-14%, and yacon strips were sun dried to a moisture content of 15-20%. The total phenolic content was measured by the Folin-Ciocalteu method, and the quenching capacity was evaluated by measuring the amount of DPPH (1,1-diphenyl-2-pidrylhydrazyl) inhibited in samples after drying and after 7 months of storage. The results showed that it is possible to preserve the antioxidant capacity in yacon after cabinet or sun drying. Both yacon chips and strips presented total phenolic content values similar to those of fresh yacon roots. Both products also showed a high inhibition capacity of DPPH (1,1-diphenyl-2-pidrylhydrazyl). A significant decrease in the phenolic content was observed in the yacon chips after storage, which indicates that the sun dried strips are more suitable for storage.
Convective Drying and Water Adsorption Behavior of Unripe Banana: Mathematical Modeling
(Wiley, 2014) Rosa F. Zabalaga; Sergio Carballo
In this study, we modeled the convective drying of unripe banana slices and the water adsorption behavior of the banana flour. Drying experiments were conducted at temperatures from 30 to 60C with an air velocity of 1.5 m/s, and adsorption isotherms were measured at 15, 25 and 35C. A four-parameter empirical model that we proposed fitted quite satisfactorily with the experimental drying data. In addition, the drying behavior during the first hours was described by an effective diffusivity coefficient, which ranges from 1.2 × 10−10 m2/s to 6.6 × 10−10 m2/s. The observed sigmoid adsorption isotherms of unripe banana flour were modeled quite well by the GAB equation. Estimated monolayer moisture content has values between 0.08 and 0.09 g/g. Practical Applications Since unripe banana is easily transported and stored, it has become a potential food product for industrialization. Drying is one of the most important unit operations and classical methods for preserving foods, which extends their shelf-life, decreases their weight for transportation, and reduces their volume for storage. Studying the drying kinetics of fruits is necessary in order to provide information about the time required for attaining low and safe moisture content. On the other hand, adsorption isotherm predicts the shelf-life stability, which involves moisture changes that may occur during storage, and thus it is useful for selection of packaging materials. Sorption isotherms are important for modelling drying processes, as well for designing and optimizing drying equipment helping us to understand how a food material behaves during drying, but also how a dried product behaves after the drying process to maintain its quality and acceptability is essential.
Dietary fiber, fructooligosaccharides, and physicochemical properties of homogenized aqueous suspensions of yacon (Smallanthus sonchifolius)
(Elsevier BV, 2012) Alejandra Castro; Galya Céspedes; Sergio Carballo; Björn Bergenståhl; Eva Tornberg
Enzymatic hydrolysis of Canna indica, Manihot esculenta and Xanthosoma sagittifolium native starches below the gelatinization temperature
(Wiley, 2012) Daysi Perez‐Rea; Cinthia Carola Rojas; Sergio Carballo; Wilson Aguilar; Björn Bergenståhl; Lars Nilsson
Abstract The susceptibility to enzymatic hydrolysis of starch extracted from raw roots of Canna indica , Manihot esculenta and Xanthosoma sagittifolium , grown in Bolivia, were studied below the gelatinization temperature. The granule size and amylose content were as followed: C. indica > M. esculenta > X. sagittifolium . The hydrolysis showed a rapid rate at the initial stage, followed by a progressive decrease thereafter. At 30, 40 and 50°C, during the initial stage, the rate of hydrolysis was observed to be influenced by the size of the granules, being the highest for the small sized granules X. sagittifolium , followed by the medium sized granules M. esculenta and the lowest rate was for the large sized granules C. indica starch. During the slow phase, A‐type M. esculenta and B‐type C. indica showed higher hydrolysis rates than A‐type X. sagittifolium . At 60°C, a positive correlation was found between the amylose content and the rate of hydrolysis among the starches. Microscopic observations showed a pattern of attack by the enzyme towards C. indica starch granules, suggesting that high amylose content is concentrated around the hilum.
Physicochemical and structural properties of starch from five Andean crops grown in Bolivia
(Elsevier BV, 2018) Catalina Fuentes; Daysi Perez‐Rea; Björn Bergenståhl; Sergio Carballo; Malin Sjöö; Lars Nilsson
Production of poly(3-hydroxybutyrate) by Halomonas boliviensis in an air-lift reactor
(Springer Science+Business Media, 2015) Paola Rivera-Terceros; Estefanía Tito-Claros; Sonia Torrico; Sergio Carballo; Đoàn Văn Thược; Jorge Quillaguamán