SWEETENER and ingredients firm Tate & Lyle has cooked up an 85 per cent jump in pre-tax profits to £233 million for the year to March 31, thanks in part to a £40m boost from the weak pound. The group, which makes Splenda sweeteners, said even without the currency effect, profits rose by 20 per cent. Sales lifted 17 per cent to £2.78 billion over the year.