Effect of different debittering processes on mineral and phytic acid content of lupin (Lupinus albus L.) seeds.

Abstract

Lupin is a valuable ancient legume which contains high amount of protein, dietary fiber, oil, minerals and different functional components. Bitter lupin seeds cannot be consumed directly since its high toxic alkaloid content. Cooking and soaking are effective processes for removing these toxic substances and antinutrients as phytic acid, trypsin inhibitors and oligosaccharides. In this study, debittering process containing cooking and soaking up to 144h was applied to lupin seeds. Raw lupin seeds had 3.3% ash and 41.3% protein content. Ash and protein content of debittered seeds changed between 2.1 and 2.5%, 39.5 and 40.9% respectively. After debittering process, significant (p < 0.05) decreases (between % 5.7 and 75.7) were observed in calcium, phosphorus, zinc, iron, magnesium and manganese contents of the lupin seeds. Phytic acid was removed from raw lupin seeds up to 71.4% ratio by debittering processes, and soaking in distilled water at 55°C and long soaking time (144h) was found the most effective methods on phytic acid loss. While more lighter (L*) seeds were obtained with soaking in distilled water at 25°C, soaking in 0.5% NaHCO3 solution gave more yellowish (b*) seed properties compared to other soaking methods. Soaking in 0.5% NaHCO3 solution at 144h gave the most liked products in terms of sensorial evaluation.