Influência da concentração de ácidos no processo de extração e na qualidade de pectina de bagaço de maçã

Abstract

ResumoNo processamento do suco concentrado de maçã, o bagaço residual da primeira extração é reidratado e prensado novamente a fim de aumentar o rendimento, tornando-se então a matéria-prima para a obtenção industrial de pectina. Neste trabalho os objetivos compreenderam estabelecer os protocolos de beneficiamento do bagaço e de uso de ácidos minerais e orgânicos no rendimento gravimétrico, usando o grau de esterificação, medido por técnicas espectrofotométricas e titulométricas como referencial de qualidade. A farinha de bagaço de maçã, com umidade de 12% apresentava 33,4% de açúcares redutores, e 40% de fibra alimentar e 10-15% de pectina, em base seca, com coloração própria. Os parâmetros do processo de extração das substâncias pécticas, 97ºC/10 minutos e proporção soluto: solvente 1:40 permitiram estabelecer a eficiência de cada ácido na concentração de 1 a 750 mMol/L na solubilização da protopectina. Foram diferenciados dois tipos de comportamentos dos agentes ácidos: [1] liberação de pectina em baixas concentrações e destruição em elevados teores e [2] rendimento gravimétrico crescente, atingindo valores superiores aos possíveis, indicando uma agregação de grupamentos orgânicos na estrutura. O HNO 3 foi considerado o mais indicado para a extração de pectina, em concentração máxima de 100 mMol/L. Palavras-chave: Resíduos agroindustriais, substâncias pécticas, extração, rendimento, qualidade AbstractIn concentrated apple juice processing units the pomace is washed with tap water in order to increase the yield so that the industrial by-product contains no more soluble pectin but only insoluble protopectin. In this article the main objectives were to establish a procedure to prepare the apple pomace as raw material and to extract pectin with several kinds and concentration of mineral and organic acids considering its degree of esterification, determined by titrimetric and spectroscopic techniques, as quality references. Dried apple pomace, with 12% moisture, showed 33.4% reducing sugars and 40% dietary fiber in dry

Extraction and characterization of pectic substances in Myrciaria cauliflora (Jaboticaba sabará) fruit

“…Among all the analysed sugars, the arabinose from the skin presented the highest content (60%) while the galactose of the juice only appeared as traces. The rhamnose was homogeneous in the three fractions, with low values of about 1.5%, while arabinose values were consistent with the standard HM (19.6%) and galactose was lower than the standard HM (49.7%), both in the pulp and in the juice (FERTONANI, 2006). Fucose, a sugar considered to be rare in pectin, presented levels similar to rhamnose, while xylose was found in low levels in all three fractions.…”

“…Mannose showed intermediate values that were greater than the standards, with higher concentrations in the juice and pulp than in skin, as well as glucose, which had values that were twice as high. The comparison of the sugars from the experimental samples with those of the commercial samples contributed to the perception of great diversity related to several different factors (FERTONANI, 2006). Table 4 presents the combined results of the titration method (which gives the proportions of the acidic fraction) with the chromatographic method (which makes it possible to establish the proportions of each of the neutral sugars).…”

“…The extraction and isolation of the pectin followed the methodology of previous studies, with minor modifications (FERTONANI et al, 2006). Approximately five grams of each powder were suspended in about 100 mL of water and stirred for 10 minutes at 80 °C.…”

“…Samples at a concentration of 3mg mL-1 were solubilised in water and filtered under pressure through filters with pore size of 0.2 µm. The samples were then injected into a steric exclusion chromatograph, model 150C ALC/GPC (Waters, Milford, Massachusetts, USA), with differential refractive index detector, model 2410 (Waters, Milford, Massachusetts, USA), and a for multi-angle laser scattering (MALLS) detector (Wyatt Technology, Santa Barbara, California, USA) (FERTONANI, 2006).…”

Bioactive compounds and acceptance of cookies made with Guava peel flour

“…Souza et al (2008) found moisture content of 6.09 g.100 g -1 in passion fruit peel flour; which is lower compared to that of the present study but is in agreement with the maximum value set by ANVISA for flours. In terms of moisture, the GPF value gives exhibited physicochemical stability and long shelflife since it was properly stored (Fertonani et al, 2006).…”