Thermal Stabilization of Wheat Germ: Nutritional and Biochemical Characterization of a Valuable Agri-Food By-Product

Abstract

Wheat germ (WG), a byproduct of wheat grinding, is the most nutrient-dense part of the grain; however, its high oil content and enzymatic activity lead to a limited shelf life. This study aimed to identify the optimal stabilisation temperature for prolonging WG’s shelf life and to examine the impact of temperature on its biochemical composition. We used five temperatures: 50 °C, 60 °C, 80 °C, and 100 °C to inhibit the lipase enzyme that degrades WG. Its activity is monitored by measuring fatty acidity over a one-month storage period. Results revealed that steaming at 80 °C for 20 min was the most effective method for stabilisation. FTIR revealed heat effects while key functional groups remained intact. This finding is supported by SDS-PAGE, which shows that protein profiles do not change much. This suggests that the treatment keeps the nutritional and functional integrity of the proteins in wheat germ, even though the concentrations of some amino acids are slightly lower, as shown by UFLC. The GC analysis of lipids identified seven fatty acids characterised by a high proportion of polyunsaturated fatty acids, which remained stable after heat treatment. HPLC detected twelve polyphenols, preserving the majority, except for certain polyphenols lost post-treatment. This study provides valuable insights for the food and nutrition industries by introducing a simple, cost-effective, and gentle stabilisation method that extends the shelf life of wheat germ while preserving its essential nutritional properties, thereby increasing its potential as a rich and affordable supplement.