Popping of amaranth grain (Amaranthus caudatus) and its effect on the functional, nutritional and sensory properties

The popping of amarunth grain (Amaranthus caudatus var INIAP-Alegria) by hot air processing was studied. A household corn popper adapted to control heating and airflow was used. The effects of temperature, load, airflow and moisture on the popping capacity and on the functional properties, nutritional quality, crude protein content, lysine content and sensory texture of the poppei grain were investigate. The yield, expansion volume and density of popped grain showed that the optimal conditions for the popping process were 240degreesC, 22g load, 0.013m(3) s(-1) airflow and 12% grain moisture. The proportion of popped grain with butterfly shape was highest (P < 0.05) at 220degreesC, 22 g load, 0.014m(3) s(-1) airflow and 14% grain moisture. The functional and physic-chemical properties of popped grain obtained by various treatments showed completely gelatinised starch. The total, available and resistant starch contents were similar among the different treatments. The enzymatic degradation of starch was 65% within 5-15min of incubation with a-amylase. The crude protein content was almost 15% for all the treatments, while the total lysine content was 45.2-48.0 mg g(-1) protein. The in vitro availability of protein of popped grain obtained at 0.013 m(3) s(-1) airflow and 14% grain moisture was above 84%. The highest available lysine value was found for popped grain obtained at 0.014 m(3) s(-1) airflow, 18-22 g load and 12-14% grain moisture. However, six of the eight treatments had available lysine contents that varied between 41.2 and 47.4mg g(-1) protein. Sensory analyses showed that the treatments with the highest popping capacity produced grains with high crunch and expansion capacities. (C) 2002 Society of Chemical Industry.