## 1 Introduction  
Nowadays, the majority of countries in the world follow a Western diet, which is rich in refined carbohydrates and saturated fats [1], leading to civilisation diseases such as obesity or type 2 diabetes [2, 3]. Moreover, although childhood obesity rates have historically been lower compared to adults, in many countries, the escalation of childhood obesity has exceeded the rate of increase observed in adults [4]. Dietary fibre intake is inversely associated with obesity, while higher consumption is often linked to reduced weight gain, improved satiety and lipid metabolism, and prebiotic effects [5, 6, 7, 8]. However, despite the benefits of dietary fibre intake, such as obesity prevention or stimulation of the growth of beneficial intestinal microbiota, its intake is still below the recommended intake levels [9]. Moreover, children do not consume the appropriate amount of products containing large amounts of dietary fibre, such as vegetables or legumes [10]. For this reason, it is necessary to look for new products rich in dietary fibre, especially for children [11, 12]. One of the possible solutions may be functional foods, i.e., those enriched with an additional amount of dietary fibre. Functional foods can be defined as foods that offer additional health benefits beyond basic nutrition [13]. The term \"functional\" refers to the specific health-promoting or disease-preventing properties these foods may possess [14, 15].  
Dextrinization represents one of the methods to derive dietary fibre products by thermal/enzymatic modification of starch, yielding soluble, indigestible dextrins/ maltodext [16]. Many health benefits of enzyme-resistant dextrins have been demonstrated so far, including a beneficial effect on the intestinal microbiota, ensuring health of the host [17; 18; 19]. In previous studies, resistant dextrins have been obtained by heating potato starch acidified with catalytic amounts of food-grade hydrochloric and citric acids. Soluble dextrin fibre (SDexF) was obtained on a laboratory scale [20; 21; 22]. However, due to the launch of the project with the acronym PreSTFibre4 Kids, it became necessary to develop and implement a semi-industrial scale in order to obtain the required amount of resistant dextrin. The project assumed examining vegetable and fruit mousses enriched with SDexF from potato starch with prebiotic properties [23], in terms of the prevention of overweight and obesity in children and the reduction of metabolic disorders secondary to obesity. The project was carried out by a consortium consisting of Jan Dlugosz University (Czestochowa, Poland) as leader, Tymbark LLC (Olsztynek, Poland), The Children's Memorial Health Institute (Warsaw, Poland), Lodz University of Technology (Lodz, Poland) and Maria Sklodowska-Curie National Research Institute of Oncology. During the implementation of the project, it was necessary to optimise the production process in the prototype machine and to characterise the obtained product.  
The aim of the study was to optimize the production of SDexF on a semi-industrial scale. Moreover, the conducted research will provide information on whether SDexF obtained on a semi-industrial scale can be used to enrich vegetable and fruit products as a dietary fibre source.