Description of recovery method used for curdlan produced by Agrobacterium sp. IFO 13140 and its relation to the morphology and physicochemical and technological properties of the polysaccharide

Abstract

Curdlan is a linear polysaccharide considered a dietary fiber and with gelation properties. This study evaluated the structure, morphology and the physicochemical and technological properties of curdlan produced by Agrobacterium sp. IFO 13140 recovered by pre-gelation and precipitation methods. Commercial curdlan submitted or otherwise to the pre-gelation process was also evaluated. The data obtained from structural analysis revealed a similarity between the curdlan produced by Agrobacterium sp. IFO 13140 (recovered by both methods) and the commercial curdlans. The results showed that the curdlans evaluated differed significantly in terms of dispersibility and gelation, and only the pre-gelled ones had significant potential for food application, because this method influence on the size of the particles and in the presence of NaCl. In terms of technological properties, the curdlan produced by Agrobacterium sp. IFO 13140 (pre-gelation method) had a greater water and oil holding capacity (64% and 98% greater, respectively) and a greater thickening capacity than the pre-gelled commercial curdlan. The pre-gelled commercial curdlan displayed a greater gelling capacity at 95°C than the others. When applied to food, only the pre-gelled curdlans improved the texture parameters of yogurts and reduced syneresis. The curdlan gels, which are rigid and stable in structure, demonstrated potential for improving the texture of food products, with potential industrial use.

Hydrocolloid composites – their contribution to physical and oral perception of dairy products

“…However, the addition of higher levels of curdlan increased syneresis up to 40%. Although previous studies found that the addition of curdlan decreased the syneresis of yoghurt (Mangolim, et al, 2017;, however the concentration they used (1.5%) was higher than that used in this study and the yoghurt formulation in this study did not include fat. Further previous studies (Chapter 5) found that the selected pure curdlan started to form gel at concentration > 1.0%.…”

“…This suggests that addition of curdlan endows the yoghurt to have a better ability to maintain the structure, hindering rearrangements among the casein network during storage and reducing the expulsion of whey. Yoghurts contains curdlan were produced by Ortiz Martinez et al (2016) and Mangolim et al (2017), and compared with the yoghurt without curdlan they also found the curdlan-contained yoghurts got an obvious reduction in syneresis. The authors attributed this improvement to the interactions among curdlan molecules, either between curdlan itself or with the dairy proteins.…”

“…Due to the heat-gelling property of curdlan, heat treatment before fermentation promoted the intermolecular hydrophobic interactions in the milk system to structure the system (Mangolim, et al, 2017), making the set-yoghurt more consistent, which may longer the processing time in mouth because of its denser texture, this provides consumers with a full taste. Besides, it also can be noted that the yoghurt with curdlan had higher viscosity values due to the gelling of the curdlan (Table 5.1).…”

“…suggested adding curdlan to products would not only impact their gelation property but also the flow and lubrication behaviour of the dairy product. Some studies have investigated the gelling and rheological property of curdlan and its application in food industry Mangolim, et al, 2017;. However, information related to the application of curdlan into dairy products is limited, and its lubrication property, which is one of the non-rheological…”

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“…Xanthan, gellan, and curdlan are the three exopolysaccharides, which has been approved as food additives by the food and drug administration 2 . Curdlan clumps as a strong gel totally in the thermal suspension and never return to aqueous state again 3 .…”