Nopalito and Cactus Pear (Opuntia spp.) Polysaccharides: Mucilage and Pectin

摘要

Cactus pear cladodes and to a lesser extent its fruits, are natural sources of structural polysaccharides. Regarding this, there are a number of studies on Opuntia ficus-indica, mostly using a single variety. The objective of this research was to evaluate the variability of mucilage and pectin (crude, residual and total) content of 13 nopalito (Opuntia spp.) varieties of commercial importance, as well as the fruits of three varieties. Additionally, the pectin content of nopalitos cooked in boiling water was quantified. The polysaccharides were quantified by gravimetric method. Polysaccharides fluctuated widely between varieties without a well-defined pattern; the total pectin content ranged from 5.32 to 14.19%, while mucilage fluctuated between 3.78and 8.5%. The relative pectin content increased up to twice as much in most of the varieties after cooking. This relative increase was due to the release of some soluble components, like mucilage, to the cooking media. The fruits were considerably low in mucilage and pectin, since both polysaccharides together reached less than 2% of the dry weight. The nopalito contrasted with the fruits in richness of polysaccharides.