title: Heating Reduces Proso Millet Protein Digestibility via Formation of Hydrophobic Aggregates.
abstract: Proso millet protein has reported structural similarities with sorghum. In order to explore the potential of this crop as an alternative protein source for people with gluten sensitivity, in vitro protein digestibility was analyzed. Dehulled proso millet flour was subjected to various processing techniques (dry heating and wet heating). Regardless of the processing technique there was a significant decline in digestibility of protein in proso millet flour when compared with unprocessed flour (from 79.7 ± 0.8% to 42.0 ± 1.2%). Reduced digestibility persisted even when cooking with reducing agents. Heating in the presence of urea (8 M) and guanidine-HCl (4.5 M) prevented the reduction in observed digestibility (urea cooked 77.4 ± 0.8%; guanidine HCl cooked 84.3 ± 0.9%), suggesting formation of hydrophobic aggregates during heating in water. This was supported by an increase in surface hydrophobicity upon cooking. Thus, the proso millet protein, termed panicin, forms hydrophobic aggregates that are resistant to digestion when subjected to heat.
authors.affiliation: Department of Food Science and Technology and ‡Department of Agronomy and Horticulture, University of Nebraska-Lincoln , Lincoln, Nebraska 68588, United States.
authors.forename: Paridhi
authors.initials: P
authors.lastname: Gulati
authors.affiliation: Department of Food Science and Technology and ‡Department of Agronomy and Horticulture, University of Nebraska-Lincoln , Lincoln, Nebraska 68588, United States.
authors.forename: Aixia
authors.identifier: http://orcid.org/0000-0002-1788-2957
authors.initials: A
authors.lastname: Li
authors.affiliation: Department of Food Science and Technology and ‡Department of Agronomy and Horticulture, University of Nebraska-Lincoln , Lincoln, Nebraska 68588, United States.
authors.forename: David
authors.initials: D
authors.lastname: Holding
authors.affiliation: Department of Food Science and Technology and ‡Department of Agronomy and Horticulture, University of Nebraska-Lincoln , Lincoln, Nebraska 68588, United States.
authors.forename: Dipak
authors.initials: D
authors.lastname: Santra
authors.affiliation: Department of Food Science and Technology and ‡Department of Agronomy and Horticulture, University of Nebraska-Lincoln , Lincoln, Nebraska 68588, United States.
authors.forename: Yue
authors.identifier: http://orcid.org/0000-0002-6140-3757
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Food Science and Technology and ‡Department of Agronomy and Horticulture, University of Nebraska-Lincoln , Lincoln, Nebraska 68588, United States.
authors.forename: Devin J
authors.identifier: http://orcid.org/0000-0002-1333-6318
authors.initials: DJ
authors.lastname: Rose
mesh_terms: D003296:Cooking; D004063:Digestion; D005433:Flour / Q000032:analysis; D057927:Hydrophobic and Hydrophilic Interactions; D000066928:Millets / Q000737:chemistry*; D010084:Oxidation-Reduction; D010940:Plant Proteins / Q000737:chemistry*; D045868:Sorghum / Q000737:chemistry
chemical_list: D010940:Plant Proteins
keywords: disulfide bonds; in vitro; prolamins; sorghum; urea