Nutritional and antinutritional evaluation of raw and processed Australian wattle (Acacia saligna) seeds

Raw and processed (soaked, soaked/boiled, roasted) wattle, Acacia saligna subspecies (subsp.) saligna, pruinescens, stolonifera and lindleyi, seeds were analysed for nutritional and antinutritional qualities. Whole wattle seeds mainly comprised proteins (27.6-32.6%) and carbohydrates (30.2-36.4%), which had approximately 12.0-14.0% fat and 13.0-15.0% crude fibre. Palmitic (9.6%), stearic (2.0%), oleic (20.0%) and linoleic (64.3%) acids were identified by gas chromatography (GC) analysis. Phenolic (∼0.2%), oxalate (2.2-3.4%) and saponin (2.6-3.0%) contents were fairly high; phytate content was low. All untreated samples contained a high level of trypsin inhibitor (2474.3-3271.4 trypsin inhibitor units per gramme (TIU/g) of flour) and low level of α-chymotrypsin inhibitor (120.4-150.6 CIU/g). Soaking overnight following with 2-min boiling led to a significant reduction of protease inhibitor activity. Roasting at 2 min or longer was sufficient to reduce both trypsin and α-chymotrypsin inhibitors to negligible values, also to reduce phytate, oxalate and saponin contents, simultaneously enhanced the nutritional values of wattle seeds.