Heinz is to enter the soy sauce business in China through the acquisition of local firm Foodstar from private-equity fund Transpac Industrial Holdings.The US food giant is to pay US$165m for the business, with the potential for a further payment in 2014 based on the performance of the Chinese firm.Heinz, which markets Amoy soy sauces in markets around the world, including the UK, said China's retail soy-sauce market was worth $2bn and growing at 7-8% a year.