Maria Helene Giovanetti Canteri

Physicochemical properties of modified citrus pectins extracted from orange pomace

Modified pectin is a polysaccharide rich in galacturonic acid altered by pH adjustment and thermal treatment used especially as an anti-cancer agent. The aim of this work was to study the physical and chemical properties of modified pectins extracted from orange pomace with citric and nitric acids. The galacturonic acid content, degree of esterification, Fourier Transform Infrared Spectroscopy profile, molecular weight, intrinsic viscosity, rheological properties and antioxidant activity of the pectins were evaluated. The modification process caused the de-esterification of pectins and a decrease of molecular weight due to removal of neutral sugars, maintaining the linear chain of galacturonic acid. Such changes also caused a significant increase in the in vitro antioxidant activity (p ≤ 0.05) and influenced the rheological properties of pectin, reducing its viscosity. This work showed that the modification of pectin from orange pomace with citric and nitric acids altered its structural and physical characteristics as well as its biological activity toward a free-radical.

Pectina: da matéria-prima ao produto final

Pectin, probably the most complex macromolecule in nature is a hetero-polysaccharide containing predominantly residues of galacturonic acid (GalA). This polymer, which belongs to a group of dietary fibers, is widely used as a gelling agent and stabilizer in the food industry. The main industrial processing to obtain pectin is based on the solubilization of protopectin from apple pomace and citrus peels, which is done under low acidity and heated conditions. Recent studies have reported the extraction of pectin from new raw materials and using different extraction conditions, which influence the yield and quality of the final product, and may improve the rheological properties. This review describes the structure, sources, applications and industrial extraction processes, as well as the analysis methods of physicochemical characterization of pectin.

Characterization of Apple Pectin – A Chromatographic Approach

The center of the origin of the Malus cultivars is understood to be in Asia Minor, in the Caucasus, located between the Caspian and the Black Seas, the Indian Himalayas, Pakistan and Western China[2], all areas that had access to the Silk Road where marketable products were transported from the east to Europe since antiquity. This is a series of trade routes that crossed Eurasia by land and by stretches of sea or river for over 2,000 years until 1,500 BC, and which enabled the movement of important materials that promoted the exchange of ideas and innovations between different cultural groups. Over the centuries, gunpowder, the compass, the printing press, silk, mathematics and ceramics all migrated along this road, as well as stringed instruments. Resources, information and news were all spread in this fashion among many cultures for such a long period that is often difficult to identify the source of many traditions.

IMPORTÂNCIA DO TRATAMENTO TÉRMICO NA CASCA DE MARACUJÁ PARA EXTRAÇÃO DE PECTINA

Brazil has an increasing industrialization of passion fruit to juice production and it generates waste. The pericarp of Passiflora edulis was found to give satisfactory results for source of pectic substances. Pectin, a polysaccharide, is able to gel formation under controlled conditions and can be used for thickening and stabilizing foods. Commercial manufacturing consists in a chemical extraction by acid hydrolysis. Two comparative production processes were acid extraction (20 min, 80 oC and 50 mM nitric acid) of bleaching raw material and aqueous extraction of fresh raw material. The specific analysis of pectin content carried out were yield, viscosity, degree of esterification, neutral sugar, GalA and HPSEC elution profiles. The purpose of this paper was to investigate the chemical composition and physical properties of extracted pectin by cold aqueous process compared with the pectin obtained by hot acid process. The results of analyses showed that the bleaching played an important positive role on the composition and physical properties of pectin extracted. Key-words: bleaching, passion fruit rind flour, pectin.

Extração, Caracterização e Purificação Parcial da Pectina Liase do Albedo de Passiflora edulis f. flavicarpa O. Deg.

A Passiflora edulis f. flavicarpa O. Deg (maracuja amarelo) e um fruto amplamente cultivado, consumido e industrializado no Brasil, principalmente na producao de sucos. A casca do maracuja e constituida essencialmente pelo mesocarpo (albedo), rico em pectina e por isso poderia ser utilizada em processos industriais, mas devido a presenca da acao de enzimas pectinoliticas, como a pectina liase (PL), a casca fica sem valor nutricional. Neste contexto o presente trabalho visa a extracao, caracterizacao enzimatica e purificacao parcial da PL a partir do albedo de Passiflora edulis f. flavicarpa O. Deg. Os ensaios abrangeram as etapas de: preparo da amostra por meio do isolamento do albedo, protocolo de extracao enzimatica, caracterizacao da faixa de pH mais adequada, concentracao do extrato (20 g L -1 ; 35 g L -1 e 70 g L -1 ), precipitacao com etanol (30% e 60%), cromatografia de troca ionica, analise eletroforetica e teste de atividade final com a PL parcialmente purificada. Apos preparo da amostra e extracao enzimatica, a PL promoveu maior queda de viscosidade cinematica na pectina de alto grau de metoxilacao (AGM), selecionada para as demais etapas. Quando concentrada, sua atividade intensificou-se, promovendo 53,7% de queda de viscosidade cinematica em concentracao de 70 g L -1 apos 72 h. O pH 5.5 e a temperatura de 45 oC foram estimados como otimos de atividade para PL. Por meio do teste espectrofotometrico, foram obtidos valores de atividade de 547.3 U g -1 e 9121.2 nkat g -1 . Apos a precipitacao, foi obtida atividade na concentracao de alcool 30%, com atividade de 680.0 U g -1 e 11333.3 em nkat g -1 . Em cromatografia anionica foi observado um maximo de absorbância correspondente a 0.8 mg mL -1 de concentracao proteica. Analises comparativas da proteina parcialmente purificada com proteina de massa molar padrao apontaram a presenca de proteina com aproximadamente 35 kDa, condizente com a massa molar esperada para a PL, na fracao parcialmente purificada por cromatografia. A atividade enzimatica, pos cromatografia, foi ainda maior com valores de 925.5 U g -1 e de 15424.2 nkat g -1 . Esses resultados confirmaram a presenca da enzima pectina liase no albedo de maracuja e permitiram estabelecer um protocolo para sua purificacao parcial.