A Japanese food products company is re-establishing its presence in New York City after 18 years. Ajinomoto rented a 5,000-square-foot, 10th-floor penthouse at 532 Broadway in Soho. Sinvin Realty Corp. represented the company, and Schack Realty Co. represented owner Schack and Schack Real Estate Co. Asking rents average $26 a square foot. Ajinomoto moved its U.S. headquarters to New Jersey in 1986.