Microwave Heat Treatment Induced Changes in Forage Hay Digestibility and Cell Microstructure

Md Safiqur Rahaman Shishir,Graham Brodie,Long Cheng,Brendan Cullen,Ravneet Kaur,Ellie Cho

doi:10.3390/app10228017

Md Safiqur Rahaman Shishir, Graham Brodie + Show 4 more

Open Access

https://doi.org/10.3390/app10228017

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Abstract

To investigate the effects of microwave (MW) treatment on hays nutritive value, five types of hay (50 g) were treated with MW for 0 (control), 20, 40, 60, and 80 s (0, 440, 880, 1320, and 1760 kJ kg−1 of MW energy, respectively) and analyzed for nutritive value prior to scanning by an electron microscope to observe microstructure changes. The dry matter (DM) % of hays were increased with increasing treatment time (p < 0.001). The improved DM and digestible organic matter in the DM were recorded from MW treated lucerne (60 s), wheat (40 s), and canola (20 s) (p < 0.001), which might have been due to the MW ruptured cell wall. The MW energy required for maximal DM digestibility improvement was linearly related to control hay crude protein content (r2 = 0.79; p < 0.001). Overall, the study showed MW treatment can increase some hays’ digestibility. In addition, the crude protein content from control hay may be a proxy to indicate DM digestibility improvement.

Highlights

Forage hay is a major conserved forage used worldwide for ruminant production
Different hays showed no difference in Organic matter (OM), neutral detergent fiber (NDF), and acid detergent fiber (ADF) change due to MW treatment and forage type interaction (Table 1)
In consideration of forage type and MW treatment interaction, it was observed that crude protein (CP) content of canola and oat hay after 20 s and 40 s MW treatment increased by 25% and 15% compared with the control, respectively

Summary

Introduction

A range of physical, chemical, and biological treatments have been previously explored to investigate the effect on hay digestibility [4]. Microwave (MW) treatment is a non-ionizing electromagnetic physical heating method which proved to be effective for the improvement of the nutritional value of food [5,6] due to its safe, quick, and energy-efficient properties [7]. The rapid increase of inner temperature in the MW treated material due to heating, generally known as “thermal run-way,” is usually linked to the dielectric properties of the material that may cause plant cell wall destruction [9] and might increase the utilization of previously unavailable cell nutrients [10]

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