Drying Behavior of Bulgur and Its Effect on Phytochemical Content

Area of Science:

• Food Science and Technology
• Agricultural Engineering
• Nutritional Biochemistry

Background:

• Bulgur production involves drying processes that can impact its nutritional quality.
• Yellow berry percentage in wheat is a quality parameter that may influence processing outcomes.
• Understanding the effects of different drying methods and wheat characteristics is crucial for optimizing bulgur production.

Purpose of the Study:

• To investigate the influence of hot air oven and vacuum dryer on bulgur drying.
• To determine the effect of varying yellow berry percentages on the drying kinetics and phytochemical content of bulgur.
• To evaluate the suitability of the Midilli model for describing moisture diffusion in bulgur.

Main Methods:

• Bulgur samples with different yellow berry percentages (1.75%, 36.25%, 43.25%) were dried using a hot air oven and a vacuum dryer at 60 °C.
• Drying curves were analyzed using the Midilli model to determine moisture diffusion characteristics.
• Effective diffusion coefficient (D_eff) was calculated for each drying condition.
• Phytochemical content, including total polyphenol (TPC), total flavonoid (TFC), and yellow pigment content (YPC), was quantified.

Main Results:

• The Midilli model accurately described moisture diffusion in bulgur under tested conditions.
• Increased yellow berry percentage led to higher initial moisture content in bulgur.
• Vacuum drying demonstrated significantly faster and more effective moisture removal compared to hot air oven drying.
• Effective diffusion coefficient (D_eff) was significantly influenced by dryer type and yellow berry percentage.
• Total polyphenol, total flavonoid, and yellow pigment contents were positively correlated with higher yellow berry percentages.

Conclusions:

• Vacuum drying is superior to hot air oven drying for bulgur processing, offering enhanced efficiency and speed.
• The yellow berry percentage significantly impacts bulgur's drying behavior and phytochemical profile.
• Higher yellow berry content in wheat results in bulgur with increased levels of beneficial phytochemicals, making it a desirable trait for nutritional quality.