Pectin characterisation in vegetable waste streams: A starting point for waste valorisation in the food industry

Abstract

a b s t r a c tVegetable waste streams, which are a major disposal issue in food industry, present a promising source of compounds which may be valorised because of their favourable functional features. In this context, the potential of five vegetable waste streams (rejected carrots, carrot steam peels, green beans cutting waste, leek cutting waste and celeriac steam peels) as a source for the extraction of pectin with interesting structural, and hence functional, properties was evaluated. Specifically, cell-wall components were extracted from the waste streams as alcohol-insoluble residue and subsequently fractionated into different (pectin) fractions based on their solubility. The pectic polysaccharides were characterised in terms of GalA content, neutral sugar content, linearity/branching, degree of methyl-esterification (DM), molar-mass distribution and the presence of bound protein. Pectin characterisation revealed considerable differences between the pectic polymers present in the investigated waste streams. For example, pectin in carrot steam peels showed a low DM, whereas the cutting waste of leek contained pectin with a very high DM. Furthermore, the level of protein bound to pectin was generally highest in carrot-derived waste streams. Depending on the intended pectin functionality, a deliberate choice for one of these vegetable waste streams as a source for pectin extraction can be made.

In vitro β‐Carotene Bioaccessibility and Lipid Digestion in Emulsions: Influence of Pectin Type and Degree of Methyl‐Esterification

“…The linearity/branching of pectin can be studied by determining and interpreting different ratios between the monosaccharides present (Christiaens and others ). The ratio of the molar amount of GalA over the molar amount of fucose (Fuc), rhamnose (Rha), arabinose (Ara), galactose (Gal), and xylose (Xyl) indicates the linearity of pectin.…”

“…To measure the GalA content, pectin was 1st hydrolyzed with sulphuric acid according to the method of Ahmed and Labavich (), after which the concentration of GalA was determined spectrophotometrically as described by Blumenkrantz and Asboe‐Hansen (). The quantification of neutral sugars glucose (Glu), fucose (Fuc), rhamnose (Rha), arabinose (Ara), galactose (Gal), xylose (Xyl), and mannose (Man) was performed by high‐performance anion exchange chromatography after hydrolyzing the pectin with trifluoroacetic acid (Christiaens and others ). All analyses were carried out in duplicate.…”

“…The MM was determined using high‐performance size exclusion chromatography (HPSEC) in combination with a refractive index (RI) detector and multi‐angle laser light scattering (MALLS) detector as described by Christiaens and others (). The RI detector was used to measure the pectin concentration, whereas the MALLS detector allowed for an absolute determination of the pectin MM.…”

Effect of Processing Methods on the Quality of Tomato Products

“…In addition, when using HTS to process tomatoes, the resultant physical, chemical, and/or product behavior all change in both the serum and pulp, compared to those obtained by high temperature only, or high pressure at 25˚C, or other processing methods [31] [32]. Furthermore, HTS method provided high temperature and mechanical shear resulting in molecular transformation and chemical reaction [33].…”

Influence of Pectin Structural Properties on Interactions with Divalent Cations and Its Associated Functionalities

“…Pectin is abundantly present in waste streams of the citrus, apple, and sugar beet processing industries. Therefore valorizing these waste streams (for example, citrus peel, or sugar beet pulp), to obtain pectin for use as a biosorbent is an interesting area to explore (Christiaens et al, 2015a;Naqash, Masoodi, Rather, Wani, & Gani, 2017). Citrus peel was found to be the most effective in binding Cd 2+ (Schiewer & Patil, 2008), but also pectin modified with adipic acid (Li, Yang, Zhao, & Xu, 2007) or sugar beet pulp (Castro, Blázquez, González, Muñoz, & Ballester, 2017) were shown to effectively adsorb metal ions.…”