The Extraction of Pectins from Apple Marc Preparations

Abstract

SUMMARY Methods of preparing alcohol‐insoluble solids from apple tissue and different extractives were compared. Marked differences were found in extractability of peetins present in marts prepared in various ways from the same lot of apples. Enzymatic browning during preparation markedly decreased the solubility of pectins but did not alter the composition of pectins extracted. The solubility of pectins present in fresh or dried commercial apple pomace was markedly lower than that from carefully prepared non‐oxidized apple tissue. Pretreatment of browned mart preparations with chlorous acid bleached the mares, yielded colorless pectins, and increased yields with some preparations. A variety of solvents were used, and the yield of pectins obtained differed markedly. The pectins extracted were precipitated by alcohol and characterized by determination of anhydrogalacturonide content and esterification degree. Some measurements of intrinsic viscosity were made, but without extensive studies of the molecular weight and degree of polymerization.

Dual-Chamber Micro Cross-Section Detector for Permanent Gas Analysis.

“…Although it has been stated that the response of a cross-section detector is linear to 100rc gas or vapor concentration (S), we have not found this to be Gray peaks are components eluted from the molecular sieve column: (I) unresolved components, (2) Hi, (3) Oi, (4) CiHe, (5! N,, (6) C02, (7) CH,, (8) C2H4, (9) CO, (10) C2HS, (11) C3H8 injection was required.…”

“…Although not shown in Figure 3, carbon monoxide and methane also show nonlinearity of response but do not exhibit peak reversal. The cause of peak reversal of H2 in helium in the cross-section detector is not clear; however, Otvos and Stevenson (4) reported that the value obtained for the apparent ionization cross-section of H2 in helium was different from that obtained when only H2 was present and speculated that this might be due to interaction of helium in its metastable state.…”

Changes in Water‐Soluble Calcium and Magnesium Content of Pear Fruit Tissue During Maturation and Ripening in Relation to Changes in Pectic Substances

“…Joslyn and Deuel (1962) recently observed that the extractability of pectins from green firm apples varies markedly with the method used to prepare mart.…”

Pectina: da matéria-prima ao produto final

“…A descoberta da pectina, enquanto composto químico, foi feita por Vauquelin em 1790 e Braconnot, no ano de 1824, foi o primeiro a caracterizá-la como composto das frutas responsável pela formação do gel e sugerir o nome pectina, proveniente do grego πηχτοζ, que significa espesso [8] . A ocorrência de substâncias pécticas diferindo em solubilidade e facilidade de extração é conhecida desde 1848, quando Fremy reportou a existência de um precursor péctico insolúvel em água, denominado posteriormente de protopectina, por Tschirch [9] . Durante a investigação da turbidez de suco, Kelhofer, em 1908, concluiu que o sedimento observado em fermentado de pera compreendia um complexo de proteínas, pectinas e compostos fenólicos oxidados [10] .…”