Comparative assessment of antioxidant, nutritional and functional properties of soybean and its by-product okara

Abstract

Soybean is considered as functional food due to various bioactive components present in it. In the present study, antioxidants, nutrient composition and functional properties of okara (soybean milk residue) were compared to soybean. The study revealed that okara possessed good antioxidant activity, i.e., total phenolic content (122.57 mg gallic acid/100 g) and DPPH free radical scavenging activity (41.46 %). It also contained considerable concentrations of protein (24.79 g/100 g) and fat (10.52 g/100 g), although less than those of soybean. The total dietary fibre content of okara (58.21 g/100 g) was more than double the dietary fibre of soybean (24.75 g/100 g). Insoluble dietary fibre (46.64 g/100 g) was the major fraction in okara and remaining was the soluble dietary fibre. Okara had significantly lower phytic acid content (843.33 mg phytic acid per 100 g) and higher in vitro protein digestibility (68.26%) than soybean. Among minerals, total calcium (346.93 mg/100 g) and phosphorus (480.17 mg/100 g) were significantly higher in okara, while, potassium, iron and zinc contents were also in remarkable amounts. The availability of minerals was maximum in okara. In addition, okara had significantly higher water absorption (9.47 ml/g) and swelling (9.33 ml/g) capacity, whereas, lower oil absorption capacity (0.26 ml/g) and bulk density (0.21 g/ml) as compared to soybean. Thus, okara is a valuable by-product and can be considered as a potential source of value addition for food industry due to its promising antioxidants, nutritional and functional properties.

Quantitative determination of water soluble vitamins, minerals and proximate compositions of three varieties of beans in Bauchi State Nigeria

“…Glycine max was found to have the lowest carbohydrate content which was significantly different (p≤0.05) from the two cowpea species. The carbohydrate content of Glycine max was found to be about the same value as that reported by Ambawat and Khetarpaul (2018). The low carbohydrate content of these legumes is of paramount importance especially to diabetics and pre-diabetics as high carbohydrate diet has been implicated in certain chronic non communicable disease conditions (Jenkins et al, 2002).…”

Nutritional, textural, and sensory quality of oil fried donut enriched with extracted dietary fiber and okara flour

“…However, low nutrient quality of soybean products is mainly due to the presence of anti-nutritive factors (Ambawat & Khetarpaul, 2018). Okara contains significantly lower amount of phytic acid than soybean, hence, in vitro protein digestibility (IVPD) of okara increase the phytic acid content (56%).…”

Bioactive components, in vitro digestibility, microstructure and application of soybean residue (okara): a review

“…Protein digestibility of various okara‐based food formulations has been investigated earlier (Espinosa‐Martos & Rupérez, ; Ambawat & Khetarpaul, ; Kamble et al, ). Espinosa‐Martos and Rupérez () reported that okara was less digestible in vitro (84.3%) than soy seed (91.8%).…”