Impact of Drying Conditions on the Physicochemical Properties of Wheat Bran Protein

Impact of Drying Conditions on the Physicochemical Properties of Wheat Bran Protein

Abstrakt

The growing global demand for sustainable and nutritious food sources has intensified the search for novel protein alternatives, with plant-based proteins receiving particular attention. Despite their potential, the efficient isolation of high-quality proteins from plant materials remains challenging, primarily due to the presence of dietary fiber and various antinutritional compounds. Each step in an improperly designed isolation process can lead to significant changes in protein characteristics, affecting not only their functional but also their nutritional properties. One of the most critical yet potentially harsh steps in protein isolation is drying. The impact of drying conditions on protein properties was investigated using wheat bran protein isolated via the pH-shift method. The protein fraction was extracted using 0.05 M NaOH (1:10 w/v) for 1 h. After centrifugation, the supernatant was collected and acidified to pH 4 using 1 M H₂SO₄ to induce protein precipitation. The resulting suspension was centrifuged again, and the obtained protein sediment was subsequently spray-dried under varying inlet (180–200 °C) and outlet temperature (70–90 °C) conditions. The characteristics (protein content, water and oil holding capacity, solubility, SDS-PAGE etc.) of the spray-dried wheat bran protein isolate (WBPI) samples were then compared to those of similarly prepared freeze-dried samples. Statistical analysis confirmed that the drying method significantly influenced the properties of WBPI. Freeze-drying was found to be a gentler technique, better preserving the native protein structure. However, with optimized process parameters, especially outlet temperature, the limitations of spray drying can be mitigated. With the correct spray drying temperature settings, the protein content in the isolated material can be increased by up to 5%. Furthermore, spray-drying may beneficially alter certain functional properties of proteins. For the spray-dried WBPI samples, a decrease in oil-binding capacity of more than 50% was observed compared to the lyophilized WBPI (2.931 ± 0.146 g g-1). The water-binding capacity of the spray-dried WBPI decreased by approximately 25% (2.180 ± 0.077 g g-1). However, the improvement of WBPI solubility was observed after spray-drying.

The growing global demand for sustainable and nutritious food sources has intensified the search for novel protein alternatives, with plant-based proteins receiving particular attention. Despite their potential, the efficient isolation of high-quality proteins from plant materials remains challenging, primarily due to the presence of dietary fiber and various antinutritional compounds. Each step in an improperly designed isolation process can lead to significant changes in protein characteristics, affecting not only their functional but also their nutritional properties. One of the most critical yet potentially harsh steps in protein isolation is drying. The impact of drying conditions on protein properties was investigated using wheat bran protein isolated via the pH-shift method. The protein fraction was extracted using 0.05 M NaOH (1:10 w/v) for 1 h. After centrifugation, the supernatant was collected and acidified to pH 4 using 1 M H₂SO₄ to induce protein precipitation. The resulting suspension was centrifuged again, and the obtained protein sediment was subsequently spray-dried under varying inlet (180–200 °C) and outlet temperature (70–90 °C) conditions. The characteristics (protein content, water and oil holding capacity, solubility, SDS-PAGE etc.) of the spray-dried wheat bran protein isolate (WBPI) samples were then compared to those of similarly prepared freeze-dried samples. Statistical analysis confirmed that the drying method significantly influenced the properties of WBPI. Freeze-drying was found to be a gentler technique, better preserving the native protein structure. However, with optimized process parameters, especially outlet temperature, the limitations of spray drying can be mitigated. With the correct spray drying temperature settings, the protein content in the isolated material can be increased by up to 5%. Furthermore, spray-drying may beneficially alter certain functional properties of proteins. For the spray-dried WBPI samples, a decrease in oil-binding capacity of more than 50% was observed compared to the lyophilized WBPI (2.931 ± 0.146 g g-1). The water-binding capacity of the spray-dried WBPI decreased by approximately 25% (2.180 ± 0.077 g g-1). However, the improvement of WBPI solubility was observed after spray-drying.

Wheat bran protein, Protein isolation, Spray drying, Freeze-drying

Wheat bran protein, Protein isolation, Spray drying, Freeze-drying

SLAVÍKOVÁ, Z.; GAJDUŠEK, M.; BIALAS, W.; POŘÍZKA, J.

11.12.2025

University of Zagreb Faculty of Food Technology and Biotechnology, Zagreb, Croatia Croatian Society of Food Technologists, Biotechnologists and Nutritionists, Zagreb, Croatia

Zagreb

ISSN 2975-710X

BOOK OF ABSTRACTS 11th International Congress of Food Technologists, Biotechnologists and Nutritionists

15

15

266