Dietary fibre is associated with health-promoting properties, in particular physiological actions on the gastrointestinal tract. Components of dietary fibre can bind several substances such as cholesterol and gastric juice. It also plays an important role in the prevention and treatment of diabetes, obesity, atherosclerosis, heart disease, colon cancer and colorectal cancer.

Soluble dietary fibre fractions undergo bacterial fermentation in the gastrointestinal tract and influence of metabolism of carbohydrates and fats. Insoluble dietary fibre fractions shorten the gastrointestinal transit time and thus prevent constipation. They also stimulate the growth of intestinal microflora and prevent the growth of putrefactive bacteria, thus exerting an inhibiting effect on the development of many rectal cancer forms.

The definition of dietary fibre generally refers to vegetable polysaccharides and lignins that retain their resistance to digestive enzymes in the gastrointestinal tract. Components include cellulose, hemicellulose, lignins, pectins, resins and waxes. As the chemical structure of dietary fibre differs between fractions, this can alter its nutritional implications and potential for food enrichment. Waste from industrial fruit and vegetable processing could be a convenient and cost-effective source of dietary fibre for food enrichment.

A study by Nawirska and Uklanska¹, investigated the neural dietary fibre (NDF) and acid dietary fibre (ADF) contents of pomace from the processing of apples (cv. Idared and Champion), strawberries (cv. Ducat and Kent), blackcurrant, red cabbage, chokeberry and carrots (cv. Black carrot and Dolanka). Fractions of cellulose, hemicelluose and lignins were also determined. Highest levels of both dietary fibres were found in chokeberry pomace, while the lowest levels were found in carrot pomace. Results indicated that pomace from chokeberry, strawberry and blackcurrant were best suited for the production of both ADF and NDF food components.
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¹ Nawirska, A; Uklanska, C (2008). Waste products from fruit and vegetable processing as potential sources for food enrichment in dietary fibre. Acta Science Poland, Technologia Alimentaria 7 (2) 35-42.

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