Yield and Quality of Pectins Extractable from the Peels of Thai Mango Cultivars Depending on Fruit Ripeness

Abstract

Pectins, recovered from the peels of four mango ( Mangifera indica L.) cultivars by mimicking industrial techniques, were evaluated in terms of yield, composition, macromolecular properties, and technofunctional quality. Freeze-dried peels of mature-green fruits, after major mesocarp softening, and at full ripeness were extracted using hot acid. The pectins were precipitated in propan-2-ol and their crude yields quantified as alcohol-insoluble substance. Like apple pomace, the dried peels provided hardly acetylated (DAc < 6.3%) rapid-set to ultrarapid-set high-methoxyl pectins at starch-adjusted yields of 11-21 g/100 g. However, despite similar high molecular weight fractions and galacturonic acid/rhamnose ratios, their average molecular weight was markedly reduced by a characteristic, almost monodisperse fraction of 16000-19000. Expanded galactans, indicated by galactose/rhamnose ratios of 15-24 mol/mol, probably represented arabinogalactan side-chain fragments withstanding hot-acid extraction at pH 1.5 and 2.0, as implied by arabinose/galactose ratios of 8-15 and 33-56 mol/100 mol, respectively. Limited galacturonic acid contents made the mango peel pectins less valuable than commercial apple pectins with regard to gelling capacity and thickening properties. Whereas starch and matrix glycan fragments almost completely degraded during ripening, depolymerization of pectins and galactans was insignificant. Technofunctional properties, modulated by extraction at different pH values, were ascribed to structural differences influencing macromolecular entanglements.

Mango Peel as Source of Antioxidants and Pectin: Microwave Assisted Extraction

“…Some researchers report similar yields of pectin extraction that the obtained in our experiment, but they worked with acid extraction, (170-245 mg g -1 dry matter) specifically using HCl or H2SO4 at pH 1.5 onto Ceni or Tommy Atkins mango peels [2]. Other authors [35] reports higher yield of pectin extractable of mango peel (25-42 g/100 g), however they worked with Tai mango and extracted pectin with H 2 SO 4 2N and lasts 1 h in the extraction, we obtain 13 g/ 100 g in 20 min so in 60 min we achieve practically the same quantity that them (39 g/100 g). This result demonstrates that microwave assisted extraction using only water and focused heat is equal efficient that use acids but presents the advantage that is an ecofriendly technology.…”

“…For antioxidants extraction, the values obtained in the present investigation are higher that the obtained in previous reports [2] who achieve only 4.066 mg g -1 in dry basis with drying at 90°C/1 h 30 min. This difference may be due to the heat sensitivity of phenolic [35] solution; may be due to the time of extraction that can affect the integrity of phenolic compounds. In the case of ABTS radical inhibition our results were higher that the obtained for unripe mango peel and flesh obtained by ethanolic extract and riped flesh and peel mango equivalent of 200 lg of catequin equivalents per mL of solution [36], revealing that microwave assisted extraction is a viable technology to obtain phenolic compounds with high antioxidant activity.…”

Mango pectin quality as influenced by cultivar, ripeness, peel particle size, blanching, drying, and irradiation

“…While the fat of the stones can be recovered and utilized as cocoa butter equivalent up to a maximum of 5% in certain EU member states (Directive 2000/36/EC), a valorization process for the peels is still urgently needed. The recovery of valuable phytochemicals, such as flavonol glycosides, monoterpenes, alkylresorcinols, and, most importantly, mango pectin, has been proposed previously (Neidhart, Sirisakulwat, Nagel, Sruamsiri, & Carle, 2009;Schieber, Stintzing, & Carle, 2001;Sirisakulwat, Nagel, Sruamsiri, Carle, & Neidhart, 2008). The high content in such valuable bioactives and techno-functional compounds as well as their excellent digestibility has been shown in numerous studies (Engels et al, 2009;Geerkens et al, 2013;Larrauri, Rup erez, Borroto, & Saura-Calixto, 1996;Schieber et al, 2001), thus making mango peels a promising target for commercial valorization Panouill e, Ralet, Bonnin, & Thibault, 2009).…”

“…Although Sirisakulwat, Sruamsiri, Carle, and Neidhart (2010) reported only insignificant degradation of the mango peel pectin within 5 h after peeling, middle-and long-term storage of the peels is impeded due to enzymatic decay and microbial spoilage. Hence, post-processing treatments preserving the peels and retaining their valuable constituents were previously recommended (Sirisakulwat et al, 2008). In the EU, the galacturonic acid content of food grade pectins shall be not less than 65% according to EU regulation No 231/2012.…”

Pectina: da matéria-prima ao produto final

“…Novas fontes potenciais permanecem não usuais em função de certas propriedades estruturais indesejáveis [3,39] . Dentre as matérias-primas alternativas estudadas para extração de substâncias pécticas podem ser citadas: os frutos de Chaemomeles japonica ou marmelo do Japão [39] , as folhas do Krueo Ma Noy, uma planta trepadeira nativa da Tailândia [40,41] , o pericarpo de ambarela (fruta nativa da Polinésia) [42] , a casca de manga [43,[44][45] , o repolho [46] , as cascas de banana [47] , o resíduo de cacau [48] e a casca de maracujá [49][50][51][52][53][54] . Na Tabela 1, podem ser encontrados os teores aproximados de pectina em diferentes fontes vegetais [55,56] .…”