RESUMO
Southern Chile native potatoes are an interesting raw material to produce novel snacks like colored potato chips. These novel products should be comprehensively evaluated for the presence of undesirable compounds such as acrylamide, 5-hydroxymethylfurfural and furan, the main neoformed contaminants in starchy rich fried foods. This study evaluated the neoformed contaminant levels and oil content on chips made from eleven Chilean potato accessions and compared them with commercial samples. The neoformed contaminant contents were related to Maillard reaction precursor levels (reducing sugars and asparagine) and secondary metabolites (phenolic compounds and carotenoids). Neoformed contaminants correlated well among them and were weakly correlated with reducing sugars and asparagine. Acrylamide level in native potato chips ranged from 738.2 to 1998.6 µg kg-1 while from 592.6 to 2390.5 µg kg-1 in commercial samples. Thus, there is need to implement neoformed contaminant mitigation strategies at different steps of the production chain of colored potato chips.
Assuntos
Acrilamida , Culinária , Contaminação de Alimentos , Reação de Maillard , Solanum tuberosum , Solanum tuberosum/química , Solanum tuberosum/metabolismo , Contaminação de Alimentos/análise , Acrilamida/análise , Acrilamida/metabolismo , Chile , Temperatura Alta , Metabolismo Secundário , Fenóis/metabolismo , Fenóis/análise , Fenóis/química , Tubérculos/química , Tubérculos/metabolismo , Carotenoides/análise , Carotenoides/metabolismo , Carotenoides/química , Furaldeído/análogos & derivadosRESUMO
Both the catalytic production of 5-hydroxymethylfurfural (5-HMF) from carbohydrates and the use of a catalyst obtained from residues stand out for adding value to by-products and wastes. These processes contribute to the circular economy. In this work it was evaluated optimized conditions for 5-HMF production from fructose with high yield and selectivity. The reaction was catalyzed by an acidic carbon obtained from glycerol, a byproduct of the biodiesel industry. Special attention has been given to the use of dimethyl sulfoxide (DMSO) as a solvent and its influence on system activity, both in the presence and absence of O2. Glycerol's carbon with acidic properties can be effectively used as catalyst in fructose dehydration, allowed achieving conversions close to 100% with 5-HMF selectivities higher than 90%. The catalyst can be reused in consecutive batch runs. The influence of DMSO in the presence of O2 should be considered in the catalytic activity, as the stabilization of a reaction intermediate by the [O2:DMSO] complex is favored and, both fructose conversion and 5-HMF yield increase.
RESUMO
Eight yeast isolates identified as Saccharomyces cerevisiae were recovered from molasses-using Cuban distilleries and discriminated by nucleotide sequence analysis of ITS locus. The isolates L/25-7-81 and L/25-7-86 showed the highest ethanol yield from sugarcane juice, while L/25-7-12 and L/25-7-79 showed high ethanol yield from sugarcane molasses. The isolate L/25-7-86 also displayed high fermentation capacity when molasses was diluted with vinasse. In addition, stress tolerance was evaluated on the basis of growth in the presence of inhibitors (acetic acid, lactic acid, 5-hydroxymethylfurfural and sulfuric acid) and the results indicated that L/25-7-77 and L/25-7-79 congregated the highest score for cross-tolerance and fermentation capacity. Hence, these isolates, especially L/25-7-77, could serve as potential biological platform for the arduous task of fermenting complex substrates that contain inhibitors. The use of these yeasts was discussed in the context of second-generation ethanol and the environmental and economic implications of the use of vinasse, saving the use of water for substrate dilution.
RESUMO
In the present study, the synthesis of an organic group-modified alumina by the sol-gel method is proposed. This material has shown to have an enhanced catalytic performance with grafted organic groups and showed an improved stability. The prepared material has shown to have several O - H groups and an enhanced surface acidity. The alumina acidity was improved by incorporating thiol groups by grafting method, which promotes the tautomerization of fructose to its furanose form. Furthermore, the grafting of sulfonic groups catalyzes its dehydration. The modified alumina was thermally treated up to 200 °C to improve the functional groups stability. After, this modified material was packed into a continuous reactor system, designed and built by this group, to obtain 5-hydroxymethylfurfural (5-HMF) from fructose dissolved in a single-phase solution of tetrahydrofuran (THF) and H2O (4:1 w/w). The catalytic activity of this material was evaluated by the reaction of fructose dehydration at different reaction temperatures (60, 70, 80 and 90 °C). Fructose conversion and selectivity toward 5-HMF were determined by high performance liquid chromatography (HPLC), obtaining 95% and 73% respectively for the highest temperature. The catalyst showed an efficient stability after 24 hours in continuous flow at 70 °C. The loss of sulfur content was 15%, but the fructose conversion yield and the selectivity to 5-HMF after 24 hours of continuous reaction did not undergo significant changes (less than 5%). The nuclear magnetic resonance (NMR) tests confirmed the presence of the thiol and sulfonic groups before and after 24 hours of reaction, as well as the conservation of the same structure, demonstrating the efficient catalytic performance of the material. The catalysts were characterized by nitrogen adsorption/desorption, X-ray diffraction and infrared (IR) spectroscopy. Also, before and after use by utilizing elemental analysis and 1 H - 13 C cross-polarization magic-angle spinning (CPMAS) and dynamic-nuclear polarization (DNP)-enhanced 1 H - 13 C and 1 H - 29 Si CPMAS as well as directly excited 29 Si magic-angle spinning (MAS) NMR methods in solid-state.
RESUMO
Heat induced color change kinetics in a tuna-vegetable mixture was evaluated by measuring color parameter "L" (Hunter-Lab) and 5-hydroxi-methyl-furfural (5-HMF) accumulation. For this purpose small reusable stainless steel TDT cans were used and the kinetic studies performed in a temperature range characteristic of thermal processing of low acid canned foods (110-125°C). The color parameter L was better described by a pseudo zero order while a pseudo first order reaction was found for 5-HMF accumulation, indicating the progression of the Maillard reaction during heating. In both cases, temperature dependence of the rate constants followed the Arrhenius relationship, with Ea= 92.0 and 38.9kJ·mol-1 for lightness L and for 5-HMF accumulation, respectively. The color parameter L was more sensitive to temperature changes than 5-HMF accumulation, and therefore is suggested for evaluation of heat induced color changes in this product.
Se evaluó la cinética del cambio de color inducido por el calor en una mezcla de atún con vegetales mediante la medición del parámetro de color "L" (Hunter-Lab) y la acumulación de 5-hidroxi-metil-furfural (5-HMF). Los estudios cinéticos se llevaron a cabo en un rango de temperatura característico del procesamiento térmico de alimentos de baja acidez (110-125°C), empleando envases TDT reutilizables. El parámetro de color L tuvo un mejor ajuste a una cinética de pseudo orden cero, mientras que la acumulación de 5-HMF se ajustó a una cinética de pseudo orden uno, indicando el desarrollo de la reacción de Maillard durante el calentamiento. En ambos casos, la dependencia de la constante de la velocidad de reacción con la temperatura se ajustó a la ecuación de Arrhenius con Ea= 92,0 y 38,9kJ·mol-1 para la luminosidad L y para la acumulación de 5-HMF, respectivamente. El parámetro de color L fue más sensible a los cambios de temperatura que la acumulación de 5-HMF y por consiguiente se sugiere para la evaluación de los cambios de color inducidos por el calor en este producto.
Foi avaliada a cinética da mudança de cor induzido pelo calor em uma mistura de atum com vegetais mediante a medição do parâmetro de cor "L" (Hunter-Lab) e a acumulação de 5-hidroxi-metil-furfural (5-HMF). Os estudos cinéticos foram levados a efeito em uma faixa de temperatura característica do processamento térmico de alimentos de baixa acidez (110-125°C), empregando envases TDT reutilizáveis. O parâmetro de cor L teve um melhor ajuste a uma cinética de pseudo ordem zero, enquanto que a acumulação de 5-HMF foi ajustada a uma cinética de pseudo ordem um, indicando o desenvolvimento da reação de Maillard durante o aquecimento. Em ambos os casos, a dependência da constante de velocidade de reação com a temperatura foi ajustada à equação de Arrhenius com Ea= 92,0 y 38,9kJ·mol-1 para a luminosidade L e para a acumulação de 5-HMF, respectivamente. O parâmetro de cor L foi mais sensível às mudanças de temperatura que a acumulação de 5-HMF e, por tanto, é sugerido para a avaliação das mudanças de cor induzidas pelo calor em este produto.