Effects of low‐temperature microwave treatment of wheat germ

MERILES, SILVINA PATRICIA; STEFFOLANI, MARIA EUGENIA; PENCI, MARIA CECILIA; CURET, SEBASTIEN; BOILLEREAUX, LIONEL; RIBOTTA, PABLO DANIEL

JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE

JOHN WILEY & SONS LTD

Año: 2021

0022-5142

BACKGROUND: Wheat germ has a great potential byproduct in food formulation for its outstanding nutritional value. For a better valorization, it is required to inactivate endogenous enzymes like lipases to avoid lipid oxidation. In this study the effect of microwaves on enzyme activity, and on functional and physical properties of wheat germ were evaluated. Microwave treatments were performed at 50, 60 and 70 ºC for 5-20 min. RESULTS: Lipase activity was severely affected at 60 and 70 ºC contrary to lipoxygenase. Microwave treatment did not cause changes in germ moisture content or color parameters. No significant changes were observed in equilibrium moisture content when comparing adsorption and desorption processes of raw and microwave-treated wheat germ. The best model to describe sorption process was Guggenheim-Anderson-De Boer (GAB) equation. According to the dielectric properties of raw wheat germ, it could be considered as transparent to energy (ε' < 1.87 and ε" < 0.35). Thermal analysis of proteins showed a low denaturation degree (below 35% to raw material). In addition, some functional properties were enhanced like oil retention capacity. Conformational changes due to microwave treatment were associated with the slight decline observed on the monolayer moisture content. CONCLUSION: Microwave treatments of wheat germ at 60 and 70 ºC were effective in lipase inactivation. Physical properties did not change drastically after treatments. Microwave-treated wheat germ could be a good source of high-protein ingredient in food product development