Evaluation of pumpkin seed products for bread fortification.

Pumpkin seed products (raw, roasted, autoclaved, germinated, fermented, pumpkin protein concentrate and pumpkin protein isolate) were incorporated into wheat flour to produce blends with protein levels of 15, 17, 19 and 21%. Dough properties were evaluated by a farinograph; loaves of breads were evaluated by a taste panel for crust color, crumb color, crumb texture, flavor, and overall quality. Results indicated that pumpkin seed products can be added to wheat flour up to a 17% protein level for raw, roasted and autoclaved pumpkin meal, 19% level for germinated, fermented and pumpkin protein concentrate and 21% level for pumpkin protein isolate without a detrimental effect on dough or loaf quality. On the other hand, the addition of pumpkin seed proteins resulted in increasing protein, lysine and mineral contents compared to the control. While lysine and tryptophan were the first and second limiting amino acids in the control bread, tryptophan and lysine were the first and second limiting amino acids for raw, roasted, autoclaved, germinated and fermented pumpkin meal; valine and lysine and valine and total sulfur amino acids were the first and second limiting amino acids for pumpkin protein concentrate and isolate, respectively. In vitro protein digestibility improved when the pumpkin seed proteins were added.