Characterization of fractions enriched in dietary fiber obtained from waste (leaves, stems, rhizomes and peels) of Beta vulgaris industrialization.

ERHARDT E.; SANTO DOMINGO C.; ROJAS AM; FISSORE EN; GERSCHENSON LN

Dietary Fiber: Production, Challenges, Food Sources and Health Benefits

Nova Science Publishers, Inc.

Lugar: New York. Estados Unidos.; Año: 2015; p. 113 - 134

According to many scientific studies, people who have a diet rich in fiber have a low incidence of gastrointestinal disorders, diabetes mellitus, obesity and cardiovascular disease. An alternative to compensate the deficiency of dietary fiber in foods is to incorporate it as a supplement. Pectin is a fermentable dietary fiber as it resists digestion and absorption in the human small intestine and experiences a total or partial fermentation in the large intestine. Besides possessing multiple health benefits, pectin has applications in the food industry as a gelling agent, thickener, fat replacement, emulsion stabilizer, among others. The annual consumption of pectin is estimated at 45x106 kg and its production is estimated at about 20 - 25,000 tones each year. In industry, pectin is usually extracted by treating the raw material (i.e., apple, citrus) with dilute mineral acid to pH near 2, generating large amounts of effluents in need of treatment. Enzymatic methods of pectin isolation are an environmentally friendly alternative to acidic methods usually used and allow labeling products with ecological connotations tending to promote the consumption of products with these features. On the other hand, the increased consumption of fresh cut and peeled products generates a huge amount of wastes that is usually discarded; its use to obtain pectin can help to reduce pollution and restore biomass and nutrients. The isolation techniques and characteristics of different fractions of dietary fiber isolated from industrialization wastes (leaves, stems, rhizomes and peels) of Beta vulgaris var. conditiva were studied in this research. The cell wall material was obtained through drying and grinding of Beta vulgaris wastes and its treatment with boiling ethanol rendered the alcohol insoluble residue. To isolate pectin enriched fractions, two different pre-treatments were assayed: one with sodium carbonate and another one with sodium hydroxide. The last one was selected because of the high yields and the product obtained was subjected to enzymatic digestion with cellulase and hemicellulase to obtain previously cited fractions. The highest antioxidant activity was detected in the cell wall material. The highest yield of the pectin enriched fractions was observed for the sodium hydroxide treatment followed by hydrolysis with cellulase. Rheological characterization showed pseudoplastic behavior with yield stress in flow assays. Dynamic assays showed weak gel behavior for all pectin enriched fractions in the presence of CaCl2. Carbohydrate characteristics and polyphenol content influenced the antioxidant activity and rheological behavior. Isolated fractions exhibited different technological characteristics and may be applied as food additives or ingredients.