By Joan E. Solsman and Doug Cameron Of DOW JONES NEWSWIRES Ralcorp Holdings Inc. (RAH) said Friday that it had rejected a third unsolicited takeover offer from ConAgra Foods Inc. (CAG) that valued the private-label food company at around $5.2 billion. ConAgra sweetened its all-cash offer to $94 a share in its first response to Ralcorp's defense of announcing plans to spin off its Post cereals unit and bulk up by paying $545 million for the refrigerated dough business of Sara Lee Corp. Ralcorp said its board unanimously rejected the nonbinding offer contained in a letter sent by ConAgra on Thursday. It had previously turned down a $82 per share offer in April and a $86 approach in May. In a statement Sunday, ConAgra Chief Executive Gary Rodkin expressed disappointment at Ralcorp's rejection and its "repeated refusals to explore this opportunity for shareholders." ConAgra also said its proposal provides more certainty and upfront value for Ralcorp shareholders than the company's spinoff plan, especially given volatile raw materials costs, which partly led Ralcorp to lower its fiscal third-quarter outlook and lower its full-year guidance last month. Ralcorp said in July it would spin off its Post business to shareholders in a tax-free transaction. Omaha-based ConAgra, best known for its Hebrew National hot dogs and Hunt's canned vegetables, wants to acquire Ralcorp to tap the faster growth rates in private label groceries as budget-conscious shoppers pare spending on branded goods. But the company also feels that the Post brand will field competition better within the ConAgra stable of brands, rather than as an independent cereal company. The new offer pushed Ralcorp shares up by almost 9% in after-hours trade Friday. ConAgra shares closed up 0.8% at $23.19 on Friday, valuing the company at $9.5 billion, compared with around $4.4 billion for Ralcorp. Any deal would also see it assume more than $2.5 billion in debt, and analysts have speculated it may opt to make an approach direct to Ralcorp shareholders or opt to wait until after the Post spinoff before launching a further bid. In the Aug. 11 letter addressed to Ralcorp Chairman William Stiritz, ConAgra's Rodkin said he was forced to make the revised, $94-a-share offer by letter because Ralcorp was unwilling to engage in a conversation. "Without your constructive engagement, be assured that this is our last private letter to you," Rodkin wrote, indicating that ConAgra could take its offer directly to shareholders. ConAgra has been canvassing Ralcorp investors in recent days and is confident of their support, people familiar with the matter said. Ralcorp said ConAgra's latest bid wasn't in the best interests of the company and its shareholders. In a letter to ConAgra released Friday, Stiritz said the company is firmly committed to its plan to separate cereal brand PostFoods from Ralcorp. He said the board unanimously determined that it and ConAgra "have nothing further to discuss." -By Joan E. Solsman and Doug Cameron, Dow Jones Newswires; 212-416-2291; firstname.lastname@example.org --Anupreeta Das contibuted to this article.