title: Mineral elements, lipoxygenase activity, and antioxidant capacity of okara as a byproduct in hydrothermal processing of soy milk.
abstract: Minerals and antioxidative capacity of raw okara that was obtained as a byproduct from six soybean varieties during hydrothermal cooking (HTC) of soy milk were assessed. Lipoxygenase (Lox), an enzyme deteriorating the sensory characteristics of okara, was also investigated. All genotypes had very similar concentrations of Lox (4.32-5.62%). Compared to raw soybeans, the applied HTC significantly reduced Lox content in okara (0.54-0.19%) and lowered its activity to 0.004-0.007 μmol g(-1) min (-1). Correlation between the content of Lox in soybeans and that in okara (r = 0.21;p < 0.05) was not registered. This indicates that the content of this enzyme in okara depended much more on the technological process than on soybean genotype. Very strong correlation (r = 0.99; p < 0.05) between okara Lox content and its activity was found. The most abundant minerals in raw okara were potassium (1.04-1.21 g/100g), phosphorus (0.45-0.50 g/100 g), calcium (0.26-0.39 g/100 g), and iron (5.45-10.95 mg/100 g). A very high antioxidant capacity (19.06-29.36 mmol Trolox kg(-1)) contributes to the nutritional value of raw okara.
authors.affiliation: Department of Chemistry and Biochemistry, Faculty of Agriculture, Institute for Food Technology and Biochemistry, University of Belgrade , Belgrade, Serbia.
authors.forename: Sladjana P
authors.initials: SP
authors.lastname: Stanojevic
authors.forename: Miroljub B
authors.initials: MB
authors.lastname: Barac
authors.forename: Mirjana B
authors.initials: MB
authors.lastname: Pesic
authors.forename: Sladjana M
authors.initials: SM
authors.lastname: Zilic
authors.forename: Mirjana M
authors.initials: MM
authors.lastname: Kresovic
authors.forename: Biljana V
authors.initials: BV
authors.lastname: Vucelic-Radovic
mesh_terms: D000975:Antioxidants / Q000032:analysis*; D002118:Calcium / Q000032:analysis; D005511:Food Handling / Q000379:methods*; D005838:Genotype; D006358:Hot Temperature; D007501:Iron / Q000032:analysis; D008084:Lipoxygenase / Q000378:metabolism*; D008903:Minerals / Q000032:analysis*; D010758:Phosphorus / Q000032:analysis; D010940:Plant Proteins / Q000737:chemistry*; D011134:Polysaccharides / Q000737:chemistry*; D011188:Potassium / Q000032:analysis; D045730:Soy Foods; D041942:Soy Milk / Q000737:chemistry*; D013025:Glycine max / Q000235:genetics
chemical_list: D000975:Antioxidants; D008903:Minerals; D010940:Plant Proteins; D011134:Polysaccharides; C412882:okara, Glycine max; D010758:Phosphorus; D007501:Iron; D008084:Lipoxygenase; D011188:Potassium; D002118:Calcium
keywords: HTC processing; antioxidant capacity; lipoxygenase; mineral content; okara; soybean genotype