The short answer is that the white stuff extruding from the body of the new hose is adhesive, and of no concern. The longer answer is that all SCUBA hoses are constructed of several layers of different materials, and then covered in an outer jacket of either rubber or braided polyester that is adhered together with adhesive. With a very freshly manufactured hose exposed to heat during shipping or direct sunlight, a small amount of the adhesive might extrude out of tiny pin holes in a rubber jacket or between the braids of the polyester strands on a flex jacket. It is not a defect or failure in the hose, and does not mean the hose is leaking now or going to leak in the future. The adhesive will wear off naturally or can be washed off if you wish, and is of no consequence or concern. Regardless, the best practice for dive equipment care is to avoid prolonged exposure to direct sunlight, as the heat and UV from strong sunlight can shorten equipment service life.