Microstructural and crystallinity changes in starch-gluten model dough with varying palm oil solid fat content.

Area of Science:

• Food Science and Technology
• Material Science
• Biochemistry

Background:

• Understanding starch-protein-oil interactions is crucial for optimizing dough properties and baked product quality.
• Palm oil's varying melting points significantly influence its solid fat content (SFC) and behavior during processing.

Purpose of the Study:

• To investigate the impact of palm oils with different melting points (PO38, PO32, PO24) on dough characteristics and microstructure during mixing and thermal treatment.
• To elucidate the relationship between palm oil SFC, dough component interactions, and final product quality.

Main Methods:

• Utilized palm oils with distinct melting points (38 °C, 32 °C, 24 °C) and measured their solid fat content (SFC) at 25 °C.
• Analyzed dough properties (hardness, elasticity, shear strength) and microstructure (gluten network, oil distribution) using techniques like microstructural characterization.
• Assessed the crystallinity and hydrophobic interactions of thermally treated doughs, correlating them with protein secondary structure changes (β-sheet).

Main Results:

• Increased SFC of palm oil led to decreased dough hardness and increased elasticity in fresh dough.
• Thermal treatment of PO38 dough resulted in higher shear strength and shorter gluten network lengths compared to PO32 and PO24.
• PO38 oil localized at the starch-protein interface, while PO24 formed smaller droplets, creating a more continuous gluten network in fresh dough. Thermally treated PO38 dough exhibited greater crystallinity.
• Changes in hydrophobic interactions in thermally treated doughs correlated with alterations in protein β-sheet structures.

Conclusions:

• Palm oil's solid fat content (SFC) critically influences dough rheology and microstructure during processing.
• The melting point and SFC of palm oil dictate its distribution and interaction with starch and protein components, affecting dough structure and thermal behavior.
• Findings provide valuable insights for selecting and utilizing specific palm oils to control dough properties and enhance baked product quality.