Extraction model of low methoxyl pectin from apple pomace effects of acid concentration and time on the process and the product

in brazil, one of the top apple producing countries in the world, apple processing is an increasing activity, with pomace as the main by-product. to extract pectin from pomace, factors affecting process and product should be studied for optimization. a model to produce lmp directly from dried apple pomace was established observing the effects of hno3 concentration and the time of reaction at 97oc, analyzed from a statistical and practical point of view. the model for gravimetric yield (r2 =0.9834) predicts the highest value of 20.07 g/100 g (126 mm; 14.07 min) of a pectin with a degree of esterification of 48.49%. the model for degree of esterification of extracted pectin (r2= 0.9797) predicts the lowest value of 43.73% (200 mm; 10.07 min) with a yield of 16.77g/100 g. the results using the central coordinates (100 mm; 10 min) for gravimetric yield were 19.01 g/100 g and for the degree of esterification, 50.79%.