Grains marketing and processing firm GrainCorp is creating one of the largest edible oil enterprises in Australia with its $472 million buy-in of Gardner Smith and Goodman Fielder.

Gardner Smith, based in Sydney and the second-largest oilseed crusher and bulk liquid storage operator, will be bought for $302 million and Goodman, an integrated oil operations firm, for $170 million.

GrainCorp will issue 18 million new shares which are expected to raise $159 million to fund the purchase. Of the amount, $103 million will come from an institutional entitlement offer and $56 million from retail investors.

Alison Watkins, managing director of GrainCorp, said the acquisition will provide the firm with immediate scale in the edible oils sector in Australia and New Zealand and leading positions in the supply chain.

"While both are very good businesses in their own right, it is the combination of the two into a cohesive whole that allows us to unlock additional value for GrainCorp's shareholders, connects the grain growers who use our network more closely with edible oils customers and creates a seamless and compelling offer for those customers," The Australian quoted Ms Watkins.

With the integration, GrainCorp said it expected $4 million income for the first year of operations in synergies.

The firm, which was focused on wheat, barley and canola, provided a fresh guidance on Tuesday of its 2011-12 earnings before interest, tax, depreciation and amortization between $385 million and $415 million.

Analysts, however, are skeptical of the buy-in despite Integro and Goodman being considered good companies.

Macquarie Securities analyst Greg Dring pointed out that Integro's sale could dilute Goodman's earnings unless the firm makes a 21 per cent profit margin on home ingredients composed of fats, oils and finished products now that it has to purchase instead of sourcing these products internally.

Goodman Chief Executive Chris Delaney said Integro did not fit with the firm's new focus on core retail brands but admitted the divestment allows Goodman to concentrate on investment and internal resource on core categories and brand.

GrainCorp, which placed a trading halt while carrying the entitlement offer, expects the two deals to be wrapped up in October, Ms Watkins said.