Anti-nutritional factors and “in vitro” digestibility of leaves of Pereskia aculeata Miller

Abstract

Humans need amino acids, especially the essential ones, which are obtained from the proteins ingested in the diet. With the rampant growth of the world population, it is necessary to increase the protein supplies, especially those of plant origin, which now play a major role as a food source. Leaves of ora-pro-nobis (Pereskia aculeata Miller) are a high quality protein source and have been used in the traditional cuisine of Minas Gerais for decades. However, it is important to analyze the anti-nutritional and/or toxic factors to consider the use of the plant leaves as an alternative source of nutrients. This work aimed to study the presence of proteic anti-nutritional factors, such as protease inhibitors and lectins, and to evaluate the “in vitro” digestibility throughout Tricine SDS-PAGE of these factors extracted from ora-pro-nobis (Pereskia aculeata Miller) leaves. The extraction of protease inhibitors and lectins from ora-pro-nobis leaves was performed in phosphate buffer. The partial purification of the fractions presenting activity of trypsin inhibitor and lectins was performed by ammonium sulfate precipitation and gel-filtration chromatography. The “in vitro” activity of the fractions with protease inhibitor and lectins, with or without heat treatment in the presence of digestive enzymes, showed that the cooking time of 1 minute was  sufficient  for protease  inhibitors  degradation.  However,  this  time was not

satisfactory for lectins, which remained resistant even after heating. This work shows that with proper cooking, ora-pro-nobis leaves can be used in the diet as a source of aminoacids.