Comparative analysis of the nutritional composition of pulp and peel of prickly pear

Abstract

Objective: Nowadays, there are two major concerns of society, namely: (i) concern for health and demand for foods that may have health benefits; and (ii) increase of food waste produced by the food industry. The study of food and its by-products features can be one of the solutions for these two major concerns. In this study a comparative analysis was performed between the pulp and the by-product of prickly pear determining moisture, ash, total protein, total fat and dietary fibre contents.

Material and Methods: In 2017, the prickly pears were obtained at Herdade de Peliteiros Silveiras, Montemor-o-Novo, Évora). For determination of moisture content, a gravimetric method was used applying a dry air oven, and the ash content was determined using the process of incineration at 525 °C. For total protein content, Kjeldahl method was applied, and for total fat, acid hydrolysis followed by extraction with petroleum ether using a Soxhlet apparatus. Finally, the dietary fibre content was determined by an enzymatic-gravimetric method.

Results: With the results obtained, it was possible to verify that water is the main constituent of the pulp and peel of prickly pear, 83% and 84%, respectively. It was also found that the pulp had a higher content of total protein, total fat and dietary fibre than the by-product of prickly pear. However, the peel also shows considerable amounts of dietary fibre (2,8 g/100 g).

Conclusions: In summary, both parts of prickly pear can be considered a good source of dietary fibre. This study may also contribute to promote the use of prickly pear by- product in the formulation of new food products and therefore to reduce food waste.

Acknowledgements

This work was financed by INSA under the project BioCOMP (2012DAN730). Tânia Gonçalves Albuquerque acknowledges the PhD fellowship (SFRH/BD/99718/2014) funded by the FCT, FSE and MEC.