Dietary Fibre - Some Properties of Alcohol-insoluble Solids Residues from Apples

Alcohol-insoluble solids (AIS) material prepared from apples contains about 80% dietary fibre and has therapeutic properties. The AIS content of seven apple cultivars was tested, three from a soil management experiment and four from a cultivar trial. Values for AIS content were different (P < 0.001) for cultivars in both trials, ranging from 2.89 to 4.41%. The grass soil management treatment gave higher (P < 0.05) AIS levels in the fruit than the overall herbicide treatment. In-vitro water holding capacities (WHC) of the AIS materials were not significantly different even though values ranged from 20.8 to 25.5 g water bound g−1 AIS. However, calcium binding capacities (CBC) were different for cultivars, with ranges of 3.69-4.38 mg Ca g−1 AIS material (P < 0.001) and 3.25-4.08 mg (P < 0.05) in the two trials. Pectin content of the AIS material was different (P < 0.05) for cultivars in the soil management trial, ranging from 20.7 to 22.5%. Method of soil management had no effect on WHC, CBC or pectin content of the AIS material. Values for WHC, CBC and pectin based on 100 g fresh apple samples, as eaten, were significantly different in both trials, with grand means of 80.9 g, 14.2 mg and 0.76 g, respectively. The grass treatment gave higher CBC and pectin content in fruit than the overall herbicide treatment. These data indicate that AIS material from different apple cultivars varies in both amount and properties. The method of soil management had a lesser effect.