Because Mexico is the number one producer of avocados in the world, this fruit has potential as a source for oil extraction. It is appropriate to further investigate the detailed changes that the oil undergoes when different extraction methods are applied. This research paper presents the study of the physical and chemical changes, the fatty acids profile, the trans fatty acid content, and the identification of volatile compounds of the oils from avocado pulp (Persea americana Mill.), obtained by four different extraction methods. The method with the greatest extraction yield was the combined microwave-hexane method. The amount of trans fatty acids produced in the microwave-squeezing treatment was <0.5 g/100 g. On the other hand, the amounts of trans fatty acids produced with the hexane and acetone treatments were 0.52 and 0.87 g/100 g, respectively. The method that caused the slightest modification to the oil quality was a novel combined extraction method of microwave-squeezing proposed by the authors.

A protein isolate from the guava seed meal (Psidium guajava) was obtained by use of isoelectric precipitation, with 78% extraction yield (extracted protein to that in raw material) and 96.7% protein content of the product. Protein solubilization was done at pH 11.5 and 40C for 30 min, followed by precipitation at its isoelectric point (pH 5). Solubility of the isolate was minimal at pH 4 to 6, and increased below pH 4 and above pH 6. Emulsifying capacity and stability of the emulsion was maximum at pH 8. However, the water and oil absorption capacity, as well as the foaming capacity and foam stability, were relatively low. The essential amino acid profile of the guava seed protein isolate, except for lysine content, is above that proposed in the FAO/WHO pattern for adults. The isolate is also an important source of tryptophan. Its in‐vitro protein digestibility was higher than for soybean isolate.

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