Effect of extraction method on chemical composition and functional characteristics of high dietary fibre powders obtained from asparagus by-products

Abstract

Asparagus (Asparagus officinalis L.) by-products, which represent around 50% of the processed vegetable, are a potential source of dietary fibre. The way that these byproducts are treated affects the composition and functional properties of fibre-rich powders. Factors such as treatment intensity, solvent, and drying system were studied. Only the more soluble components (soluble sugars, uronic acids and proteins) showed significant differences. All the fibre-rich powders had a high concentration of TDF (62-77%). The IF/SF proportion decreased with the severity of treatment, and increasing in this way the physiological quality of the fibre. Functional properties-water holding capacity (WHC), oil holding capacity (OHC), solubility (SOL), and glucose dialysis retardation index (GDRI)-varied according to the obtaining procedure. WHC and GDRI were higher in intensely extracted fibres, due to the effect of thermal processing. WHC had similar values (11-20 mL water/g powder) than those described for other agricultural by-products, but OHC and GDRI were much higher (5-8 mL oil/g powder and 25-45%, respectively). These properties make fibre-rich powders from asparagus by-products a valuable source of dietary fibre to be included in the formulation of fibreenriched foods.

Physico-chemical properties of cell wall materials obtained from ten grape varieties and their byproducts: grape pomaces and stems

“…In the case of grape pomaces, FAC results were higher than those described by . Further, the FAC values of this study are in agreement with those determined for other DF concentrates derived from orange (Garau et al, 2007) and asparagus agricultural by-products (Fuentes-Alventosa et al, 2009).…”

Composition of by-products from cooked fruit processing and potential use in food products

“…This suggests that the cooking may have modified the structure and composition (in the contents in proteins and SDF notably) of the DF and consequently its properties. WHC can be related to SDF content due to the properties of fiber matrix (Fuentes-Alventosa et al, 2009), thus the rather high WHC values here should be correlated with the content in DF. However, pear by-products had the highest content in DF (Table 2), whereas they had the lowest WHC.…”

Effect of the extraction method on phytochemical composition and antioxidant activity of high dietary fibre powders obtained from asparagus by-products

“…Besides the chemical composition and functional characteristics (Fuentes-Alventosa et al, 2009), the bioactive profile of asparagus by-product fibres was affected by processing to obtain the powders. In general, intense treatments led to fibres with the highest content of bioactive compounds, especially those treated with ethanol, probably due to a concentration effect.…”

“…In comparison, other fibre sources such as cellulose, wheat bran, glucomannans, and others lack this intrinsic antioxidant activity and other bioactive compounds. These facts, together with the functional properties (water and oil holding capacities, and glucose retardation index); (Fuentes-Alventosa et al, 2009) and technical compatibility (Sanz, Salvador, Jiménez, & Fiszman, 2008) possessed by fibre from asparagus by-products, increases its attractiveness as an alternative source of dietary fibre. In vivo studies on the antioxidant status of asparagus fibre-fed rats and other physiological parameters are under way.…”

“…Assuming that the byproducts have a similar composition to the edible part of the spears, their fibre-rich products could contain significant amounts of all the phytochemicals mentioned above. In addition to changes in chemical composition and functional characteristics of the fibres (Fuentes-Alventosa et al, 2009), by-product processing conditions could modify the composition of bioactive compounds and, in doing so, the intrinsic antioxidant activity of these fibre-rich products. The aim of this work is to characterise phytochemicals from asparagus fibres and to study the effects that processing conditions have on their composition and antioxidant activity.…”