Digestion kinetics of carbohydrate fractions of citrus by-products

Abstract

The present experiment was carried out to determine the digestion kinetics of carbohydrate fractions of citrus by-products. Grapefruit pulp (GP), lemon pulp (LE), lime pulp (LI) and orange pulp (OP) were the test feed. Digestion kinetic of whole citrus by-products and neutral detergent fiber (NDF) fraction and acid detergent fiber (ADF) fractions of citrus by-products were measured using the <em>in vitro</em> gas production technique. Fermentation kinetics of the neutral detergent soluble carbohydrates (NDSC) fraction and hemicelluloses were calculated using a curve subtraction. The fermentation rate of whole was the highest for the LE (<em>p</em> < 0.05). For all citrus by-products lag time was longer for hemicellulose than other carbohydrate fractions. There was no significant difference among potential gas production (<em>A</em>) volumes of whole test feeds (<em>p </em>< 0.16). Dry matter (DM) digestibility contents of LE and LI were the highest (<em>p</em> < 0.02). The NDF digestibility was the highest (<em>p</em> < 0.05) in LI and GP, while the lowest (<em>p</em> < 0.03) values of ADF digestibility were observed in LI and LE. According to the results of the present study, carbohydrate fractions of citrus by-products have high potential for degradability. It could also be concluded that carbohydrate fractions of citrus by-products have remarkable difference in digestion kinetics and digestive behavior.