Pineapple showed the highest (p < 0.05) IDF content, followed
(p < 0.05) by guava, passion fruit and mango. This large amount
of IDF present in exotic fruit co-products is an indicator of the considerable
amounts of celluloses and hemicelluloses present. A high
proportion of IDF in the exotic fruit co-products could be considered
an advantage because IDF can be used by the food industry
as an ingredient to increase the content of indigestible insoluble
compounds (Navarro-González, García-Valverde, García-Alonso, &
Periago, 2011). In addition, a high IDF content could have beneficial
health effects related to increases in satiety and in the volume and
weight of faecal mass, thus promoting improved functioning of the
digestive system (Ku & Mun, 2008).
For certain food applications, it may be advantageous for TDF
concentrates to have balanced contents of soluble (SDF) and insoluble
(IDF) fractions. In the case of the exotic fruit analysed here,
only mango and passion fruit showed similar levels (p < 0.05) with
IDF/SDF ratios of 1.5:1 and 1.3:1, respectively, as recommended by
Spiller (1986), who indicated that the ratio should be in the range
of 1.0–2.3 in order to obtain the physiological effects associated
with both soluble and insoluble fractions. Pineapple showed the
greatest difference between IDF and SDF content with an IDF/SDF
ratio of 120:1.
3.2. Technological