ABSTRACT

Prosopis alba Griseb is a leguminous tree that grows naturally in the 
Argentinean Chaco. Its fruits (pods) are sweet and have significant protein 
content. They have been used for human and animal feeding, especially 
dried and milled, and also as an aqueous extract. The objective of the 
present work was to develop a coffee substitute from the pods of Prosopis 
alba Griseb. The pods were roasted at six different temperatures (100, 115, 
130, 145, 160 y 175ºC) and at three different times (30, 45 y 60 min). 
Samples of roasted material retained by 0,25 mm sieve, were analyzed in 
order to determine: degree of roasting (colour), particle size distribution, 
isotherm adsorption curves, soluble solids, chemical-nutritional properties 
(moisture, protein, lipids, minerals, crude and dietary fibre, total 
carbohydrates, energy value, tannins, polyphenols, caffeine, lysine, and 
sugars). Moreover, sensorial properties of infusions prepared from the 
roasted material were evaluated. The study of the influence of roasting on the 
product properties revealed that apparent activation energy (Ea), values were 
similar to the colour functions: luminosity (L*) and metric chroma (C*ab). This 
fact shows that both parameters are good indicators for the evolution of 
browning during the roasting process. On the samples roasted at 160 and 
175ºC, the resulting values for hue, chroma and luminosity are comparable 
with those found for roasted coffee. Roasting changed the water adsorption 
behaviour of pod: roasted pod showed a lower hygroscopicity. Sucrose 
content decreased when time and temperature of roasting were increased. 
Taste of assayed infusions was described as roast, honey, herbal and 
chocolate tones. The sample roasted at 160ºC during 60 min developed the 
best aroma (closely related to coffee) and it had the highest acceptability by 
the surveyed consumers. In conclusion, this work let to develop a new food 
product that could be produced with a simple technology. This technology 
offers defined parameters for the roasting process control such as colour, 
temperature and time. The product is natural, caffeine-free and has good 
taste and flavour.