Pectin oligosaccharides from sugar beet pulp: molecular characterization and potential prebiotic activity

Abstract

Pectin oligosaccharides (POS) have been indicated as a new class of potential prebiotic compounds, which can be produced from pectin-rich food byproducts. In the present study, different technological means of POS production were explored to produce tailor-made POS mixtures starting from sugar beet pulp. The overall POS production process consisted of two steps: the extraction of pectin and the hydrolysis of pectin to tailored POS by combined hydrolysis/fractionation approaches. Different extraction as well as hydrolysis and fractionation methodologies were applied. The obtained POS were characterized for their total galacturonic acid content and, at a deeper level, using a HILIC-ESI/MS methodology, for the POS structure and composition. The composition of POS fractions was studied as a function of the technology used to obtain them. Finally, the potential prebiotic properties of the POS mixtures obtained were thoroughly explored by several in vitro experiments aimed at detecting lactic acid bacteria (LAB) stimulation by POS fractions. Several fractions were very efficient in stimulation, in a species-dependent manner. The overall best fractions were in general those rich in arabinans having a low degree of polymerization, obtained from the enzymatic extraction of biomass and subsequent fractionation with low-medium molecular weight cut-off. Quite interestingly, no POS fraction was able to stimulate pathogenic E. coli strains. The data reported here clearly indicate the possibility to obtain diverse fractions with different prebiotic properties starting from the same biomass, and outline clear potential for POS obtained from sugar beet pulp with the appropriate technology to act as prebiotic compounds.

Physicochemical, microbial, and rheological properties of yogurt substituted with pectic polysaccharide extracted from Ulmus davidiana

“…The study demonstrated that rhamnogalacturonan pectic oligosaccharide could be used as a prebiotic, giving a possible added health benefit. Prandi et al () also observed that high amounts of arabinose in rhamnogalacturonan pectic oligosaccharides could promote the growth of lactic acid bacteria. The present study suggested that lactic acid bacteria counts were directly affected by pectin structure, in which high amounts of rhamnoglacturonan in UDP effectively promoted the growth of lactic acid bacteria.…”

Pectin Hydrolysates from Different Cultivars of Pink/Red and White Grapefruits (Citrus Paradisi [macf.]) as Culture and Encapsulating Media for Lactobacillus Plantarum

“…(). As galacturonic acid was reported to be responsible for the inhibition of certain species of lactic acid bacteria (Prandi et al., ), a 2‐hr partial hydrolysis was the condition selected to obtain pectin‐hydrolysates.…”

“…, it can be concluded that hydrolysates with higher concentrations of glucose were those in which microorganisms adapted faster (shorter lag times), because of the high availability of a fermentable sugar (glucose). On the contrary, nonfermentable sugars, particularly galacturonic acid and xylose, have a negative effect on the growth of certain lactobacilli strains (Prandi et al., ). This can explain the larger lag times in hydrolysates having lower R values, that is, with a higher contribution of non‐fermentable sugars.…”

Prebiotic compounds from agro‐industrial by‐products

“…Hereof, agro‐industrial by‐products have been studied as a rich source of POS. For instance, sugar beet pulp has been reported to contain galacturonic acid (16.5%), arabinose (16.0%), galactose (5.6%), and rhamnose (1.1%) (Babbar, Dejonghe, Sforza, & Elst, ; Prandi et al, ). Also, POS from citrus peel contain 1‐rhamnose, ᴅ‐galacturonic acid, ᴅ‐glucose, and ᴅ‐galactose (Zhang et al, ).…”

“…Hence, the study of the composition of pectin as an agro‐industrial by‐product is pivotal (Hotchkiss et al, ; Manderson et al, ). The structural elucidation of POS is often troublesome since their distribution is dependent on the agricultural source and the method of extraction; for this reason, the evaluation of the prebiotic activity of POS from different sources is often accompanied by structural studies (Prandi et al, ). In this sense, Zhang et al () assessed various POS fractions obtained from citrus peel pectin by chemical degradation with trifluoroacetic acid (TFA) using hydrogen peroxide.…”