Hydrothermal Techniques for a Hard-To-Cook Nigerian Legume


Hydrothermal Techniques for a Hard-To-Cook Nigerian Legume

Legumes are considered as important sources of dietary protein in many nations of the world and especially in the developing countries. Legumes are used as a source of protein for animal and human1. Recently, consumption of legumes has been on the increase. This is because legume seeds have been reported to be good sources of nutrients. They are recommended as health promoting foods by health organizations and dieticians. Legumes have been reported to reduce the incidences of cardiovascular diseases, cancers and type II diabetes2.

In spite of the advantages of legumes as good sources of beneficial nutrients, legumes often contain anti nutritional components which interfere with the digestive processes and prevent efficient utilization of nutrients. But still these anti nutritional components can be removed or reduced via different processes. However, the problem of prolonged cooking constitutes a major hindrance to the utilization of many underutilized legumes.

Mallotus is one of the underutilized legumes in Nigeria. This specie of legume is not available in much commercial quantity but is found with peasant farmers. Apart from the presence of anti nutritional factors, Mallotus is a hard-to-cook legume. In the view of this context in a new study, efforts were made in order to investigate the effects of hydrothermal processing methods on the nutrients and anti nutritional components of Mallotus with the endeavor of enhancing its utilization3.

For study purpose, the seeds were soaked at varying hydration levels and then subjected to thermal processing to determine the effect of four hydrothermal techniques, on mineral elements present in the Mallotus seeds. The four hydrothermal techniques used were atmospheric boiling, atmospheric steaming, pressure boiling and pressure steaming on the cooking time and chemical components of the seed after soaking to varying hydration levels.

It was observed from the study results that there were significant differences in the cooking time when the raw sample of Mallotus were cooked using the different processing methods. The hydrothermal processing did not induce remarkable change in the oil content of the legumes. Generally, the oil content of the legume seed samples before and after thermal processing was low and hence they do not qualify as oil seeds. The specific effects of processing on mineral element contents of legumes depend on the methods of processing. Hydrothermal processing methods significantly affected the concentration of the mineral element in the legume studied.

It was thus concluded that hydrothermal processing methods have significant effects on the chemical compositions of the legume studied. Although hydrothermal processing methods resulted in varying degrees of losses of nutrients through leaching, the quantity of nutrients remaining after processing are of nutritional importance to meet physiological/nutritional needs. Generally, the extent of reduction of nutrients in the legume was dependent on the hydration levels, hydrothermal processing methods employed and duration of application of the processing methods. In general, samples cooked at higher hydration levels appeared to have better retention of nutrients.


Mallotus subullatus, underutilized legume, nutrients, anti-nutritional components, hydrothermal techniques, higher hydration levels, nutrients retention, mineral element concentration, pressure steaming, nutritive status, legumes plants.


  1. Graham, P.H. and C.P. Vance, 2003. Legumes: Importance and constraints to greater use. Plant Physiol., 131: 872-877.
  2. Gepts, P., W.D. Beavis, E.C. Brummer, R.C. Shoemaker, H.T. Stalker, N.F. Weeden and N.D. Young, 2005. Legumes as a model plant family. Genomics for food and feed report of the cross-legume advances through genomics conference. Plant Physiol., 137: 1228-1235.
  3. Moses A.O., Beatrice I .A. and Patrick O.N., 2017. Impact of Hydrothermal Techniques on the Chemical Components of Mallotus subulatus. J. Nutr., 16: 813-825.