I had some problems taking photos in front of a white object, here's my tips.
First, white balance is key if you're shooting JPG. I highly recommend shooting in RAW, which you can change later but JPG is cool, just get the white balance set up first. Take a photo a near white item, usually I like to use in a pinch a sheet of 8x11 paper. It's easier if the white paper is larger, then take a photo, from your camera set it as a custom white balance.
I'm not sure in your camera how to set it but it's very simple. Just select the custom white balance function and then select the image you just took, then in the camera select custom white balance for your photos. Take a test photo and your shots should be the same color as your subject, no strange tints appearing. As for the gray of off color back ground, this could be an exposure tuning. I like to take a few test shots as I'm taking photos and keep the camera in manual mode.
I personally prefer manual mode when shooting a still life subject because as long as I'm taking the same photo, the image will not change. Sometimes in auto mode the camera gets mixed up and will change settings, giving you a strange vary between shots. Also I like to start with my strobes at their lowest setting and work up, there's a more technical method but honestly I don't know it and prefer to get the shot right by viewing the LCD results. (I'm a cheater) 
Here's a result using the method explained above taking a photo of some skateboard wheels. Done with two cheapy strobes and 48" umbrellas.
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