AF1_2021

FREDERIQUE RESPONDEK*, NELIDA PASCALE *Corresponding author CP Kelco ApS, Lille Skensved, Denmark PRE- PROBIOTICS PECTIN, A TRADITIONAL DIETARY FIBRE AND PREBIOTIC INGREDIENT KEYWORDS: Prebiotic, gut microbiota, gut health, pectin, oligosaccharides, diversity, Peer Reviewed. Pectin is extracted from various botanical origins and is well-known as a dietary fibre. Functional health claims have been made in different regions (e.g., EU and US), including the reduction of cholesterol and post-prandial blood glucose. As a dietary fibre, pectin is fermented by bacteria inhabiting the digestive tract. Recent research shows the selective effects on the gut microbiota composition and activity that make pectin and pectin-derived oligosaccharides serious prebiotic candidates. This review will highlight the recent findings on how the structure of pectin-derived ingredients influences its effects on gut health via modulation of the gut microbiota or direct, local immune modulation. ABSTRACT INTRODUCTION High fibre diets are recognised for several health benefits, including those related to gut health due to their impact on gut function, microbiota and local immune system. Besides the well-known effects on gut laxation, high fibre and prebiotic diets have been shown to increase the gut microbiota diversity that is considered key to maintain higher resilience and homeostasis (1). While it is generally recommended to consume around 30g of dietary fibres per day to maintain normal gut function, most populations in Western countries do not reach the recommended intake and only consume about half (2). This can result in a lower gut microbiota diversity and resilience. It also limits the potential benefits of prebiotic dietary supplementation (3). Therefore, there is still an interest to diversify the type of dietary fibres and prebiotics that we consume to enlarge their associated benefits. Pectin is a polysaccharide commercially produced by extraction from plants; mainly from citrus peels, apple pomace and sugar beet pulp. The backbone of the pectin structure is composed of linear chains of alpha-(1,4)-galacturonic acid units with varying degree of methylation and side chains including galacturonic acid (4; see Figure 1). The general description of pectin centers on an alternation of ‘smooth’ and ‘hairy’ regions along the entire length of the molecule. Smooth regions are represented by homogalacturonans (HG) which form the linear backbone, and rhamnogalacturonans (RGI and RGII) represent the hairy regions, among which RG-I designates the main ramified structure in the pectin molecule (5). The botanical origin as well as the extraction process influence the structure of pectin and, particularly, its degree of esterification, its molecular weight, and its linear-to-branched structure ratio (homogalacturonan to rhamnogalacturonan). Due to its well-known gelling properties, pectin is mostly used as a food additive. However, pectin is also a well-known dietary fibre acknowledged by various health authorities (EFSA, FDA) for its benefits on blood glucose and cholesterol metabolism (6, 7). In Europe, foods containing pectin can bear claims related to reduction of post-prandial blood glucose if one serving of such foods provides 10g of pectin, and to the reduction of blood cholesterol when pectin is consumed at a minimum of 6g per day(*). There is also scientific evidence showing that pectin can enhance a sensation of satiety (8, 9), however this has not yet been acknowledged by scientific bodies. Furthermore, two pectin-derived ingredients have been submitted for novel food approval in the EU: pectic acidic oligosaccharides and RGI. The former refers to pectic acidic oligosaccharides obtained by enzymatic hydrolysis of citrus pectin, which was submitted for approval in 2009 (and withdrawn in 2013) for utilisation in infants and follow-on formula. Even though this ingredient is not yet on the market, its safety has been noticed respectively by JECFA (2016) and EFSA (2018) (10,11) in the context of the re-evaluation of pectin as a food additive. Figure 1. Structure of pectin polysaccharides. Copyright Beukema et al. Experimental Molecular Medicine. 2020 (4). Agro FOOD Industry Hi-Tech - vol. 32(1) 2021 18