Chemical characterization of prickly pear pulp, Opuntia ficus-indica, and the manufacturing of prickly pear jam

ABSTRACT

Attempts were made to use prickly pear fruits, Opuntia ficus-indica, which are locally abundant and relatively inexpensive in the manufacturing of jam.

Physical characterization of the strained pulp showed a value of 14.2° Brix for total soluble solids (TSS), 14.5% total solids and a pH of 5.75. The acidity of the pulp as citric acid was 0.18%. Proximate analysis revealed low amounts of protein (0.21%) as Nx6.25, crude fat (0.12%), crude fibre (0.02%), ash (0.44%) and pectin (0.19%). All the sugars were present as reducing sugars (12.8%) and consisting mainly of glucose and fructose (60:40). Vitamin analysis showed only trace amount of vitamin A @-carotene) and 22.1 mg% of vitamin C. The pulp was rich in potassium, fair in calcium, magnesium and phosphorus and poor in sodium and iron.

Pilot plant studies on the manufacturing of the jam in conjunction with sensory evaluation of the final products showed that blanching in comparison to non-blanching resulted in no significant difference in the sensory quality of the jam. Citric acid and a combination of citric and tartaric acids (1 :l) wcrc preferred over several other natural acids used as acidifying agents. The addition of cloves, grapefruit, orange and almond flavours ranked best among several other flavours added in addition to the pulp containing 20% date paste.