Effect of stretching pre-rigor muscle on the backscattering of polarized near-infrared

Strips of neck muscle were taken before the onset of rigor from pork and beef carcasses in an abattoir. The strips were clamped at their natural rest length, then stretched to 164% rest length. The common trunk of a bifurcated, fiber-optic light guide touched the muscle strips, illuminating through one branch of the light guide and collecting backscattered near-infrared (NIR) (700 to 800 nm) with the other branch. With non-polarized NIR, stretching produced no detectable effect. But when crossed polarizers were placed on the illuminating and receiving windows of the common trunk of the light guide, stretching increased (P less than or equal to 0.001) the detectable levels of backscattered NIR. Whether or not this phenomenon can be exploited to detect tenderness related to sarcomere length in bulk meat remains to be seen. Copyright (C) 1996 Canadian Institute of Food Science and Technology.