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243 results on '"Martinez, Mario M"'

45. High amylose starch thermally processed by ohmic heating:Electrical, thermal, and microstructural characterization

Author

Castro-Campos, Fernanda G., Morales-Sánchez, Eduardo, Cabrera-Ramírez, Ángel H., Martinez, Mario M., Rodríguez-García, Mario E., and Gaytán-Martínez, Marcela

Subjects
Granular swelling, Ohmic heating, Starch gelatinization, Amylotype maize starch
Abstract

High amylose starch (HAS) exhibits restricted granular swelling, limiting its use in many food applications. In this work, we investigated for the first time the potential of ohmic heating (OH) to enhance the swelling of HAS granules in a very efficient manner in terms of processing times. Specifically, the impact of OH at two voltages (130 and 150 V), two moisture conditions (1:3 and 1:5 w/v), and two final temperatures (160 and 180 °C) on the structural, thermal, pasting, and digestion of HAS (70% amylose, AM) was investigated. The electrical conductivity of native HAS showed a transition at 168 ± 1 °C consistent with the thermal transition at 139–192 °C (DSC) with an enthalpy of 11.39 J/g. Furthermore, OH caused a reduction of resistant starch (RS) from 52.0 to 34.5%, and a significant increase in granular swelling (as represented by the increased initial, maximum, and final viscosities). The above was further corroborated by SEM micrographs, which showed the disruption of the granular structure that aligned with a decrease in the relative crystallinity and shift to a B-type polymorphism. Results showed that the high temperatures reached during ohmic heating result in partial HAS gelatinization and enhanced granular swelling.

Published
2023

46. Modulating temperature and pH during subcritical water extraction tunes the molecular properties of apple pomace pectin as food gels and emulsifiers

Author

Yilmaz Turan, Secil, Gál, Teodóra, Lopez-Sanchez, Patricia, Martinez, Mario M., Menzel, Carolin, Vilaplana, Francisco, Yilmaz Turan, Secil, Gál, Teodóra, Lopez-Sanchez, Patricia, Martinez, Mario M., Menzel, Carolin, and Vilaplana, Francisco

Abstract

This study explores the cascade extraction of polyphenols and pectins from apple pomace and their potential application as food emulsifiers. The extraction of polyphenols was achieved by a simple method using ethanol and resulted in remarkable antioxidant activity. Pectic polysaccharides were sequentially extracted (5, 10 and 15 min) using subcritical water at two different temperatures (120 °C and 140 °C) and three different pH conditions (pH 3.0, 5.0 and 7.0). Acidic pH resulted in higher pectin yields when combined with higher temperature, whereas neutral conditions were less selective towards pectin. Pectin with different branching patterns could be isolated by tuning the process conditions. Linear homogalacturonan (HG) was preferentially isolated at milder conditions, whereas more branched rhamnogalacturonan (RG-I) populations required longer extraction times. Subcritical water enabled the extraction of pectins with different degrees of methoxylation (DM) depending on the extraction pH, which enabled the production of pectin acid gels with varying rheological properties. Low DM pectin was directly recovered from apple pomace at lower pH, eliminating the need for its conventional derivatization from high DM pectin. The emulsifying properties of two apple pomace pectin fractions with high and low methoxyl content were compared; the pectin with higher methoxyl content showed higher emulsifying capacity and stability. This study demonstrates that the relative abundance of the different pectic domains and the methoxylation of pectin can be controlled by subcritical water extraction, which has important implications for the valorization of pectic-rich agricultural wastes into valuable food ingredients., QC 20230905

Published
2023
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49. Fucose modifies short chain fatty acid and H2S formation through alterations of microbial cross-feeding activities.

Author

Høgsgaard, Karina, Vidal, Natalia P, Marietou, Angeliki, Fiehn, Oliver Gam, Li, Qing, Bechtner, Julia, Catalano, Jacopo, Martinez, Mario M, and Schwab, Clarissa

Subjects
SHORT-chain fatty acids, BUTYRATES, FUCOSE, SYNTROPHISM, FUCUS vesiculosus, GUT microbiome
Abstract

Algae are a rich but unexplored source of fibers with the potential to contribute to the next generation of prebiotics. The sulfated brown algae polysaccharide, fucoidan, is mainly composed of the deoxy-hexose L-fucose, which can be metabolized to 1,2-propanediol (1,2-PD) or lactate by gut microbes as precursors of propionate and butyrate. It was the aim of this study to investigate the impact of fucoidan on the fermentation capacity of the fecal microbiota and to compare to fucose. In batch fermentations of fecal microbiota collected from 17 donor samples, fucose promoted the production of propionate while no consistent effect was observed for commercial fucoidan and Fucus vesiculosus extract prepared in this study containing laminarin and fucoidan. H2S production was detected under all tested conditions, and levels were significantly lower in the presence of fucose in a dose-dependent manner. The addition of high fucose levels led to higher relative abundance of microbial 1,2-PD and lactate cross-feeders. Our results highlight that fucose and not fucoidan addition impacted fermentation capacity and increased the proportions of propionate and butyrate, which allows for precise modulation of intestinal microbiota activity. [ABSTRACT FROM AUTHOR]

Published
2023
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