China's exports of high fructose corn syrup to the Philippines, where sugar producers are protesting at the trade, could be the "start of something major" in the sweeteners market, if use spreads in Asia.
China has been, up to now, the only substantial user of high fructose corn syrup (HFCS) in Asia, with use equivalent to some 4m-5m tonnes a year, said Robin Shaw, analyst at London broker Marex Spectron.
However, imports by the Philippines of 235,000 tonnes of HFCS last year, according to customs data, equivalent to some 352,000 tonnes of sugar, and trade which prompted the country two weeks ago to impose curbs on corn syrup.
"HFCS is significantly cheaper than locally-produced sugar," according to a US report which said that the imports had "driven down sugar prices" in the country by some 17% since September.
Indeed, Mr Shaw said that the imports could be a sign of a structural shift in sweeteners users towards corn syrup - a move which would be "anti-bullish" for sugar prices.
"It looks like HFCS is invading the world sugar market more," Mr Shaw told Agrimoney.com.
Asia's top sugar importers 2016-17
1: China, 4.635m tonnes
2: Indonesia, 4.15om tonnes
3: Bangladesh, 2.064m tonnes
4: Malaysia, 1.767m tonnes
5: South Korea, 1.600m tonnes
Data for net imports, ie total imports less exports, sugar only, on a tel quel basis
Source: International Sugar Organization
Indeed, it could prove "another nail in the coffin" of the bullish sugar story, as "the world adapts to high sugar prices", with New York raw sugar futures standing above 21 cents a pound as recently as last month.
May futures on Monday stood at 17.59 cents a pound, down 0.7% on the day.
The apparent paradox of China, the world's biggest sugar importer, becoming an exporter of HFCS comes despite a large incentive from prices for the country to consume the grain-based sweetener domestically.
"In China, the price of sugar is almost double that of HFCS, so you would expect a big swing [in consumption] from sugar to HFCS," Mr Shaw said.
A sugar premium of some 30-40% is typically enough to fuel a switch to HFCS, according to research group CCM.
However, Mr Shaw added that a switch from sugar has "already occurred in sectors which can take HFCS," which is favoured more for use in liquids, such as fizzy drinks, than solids.
Meanwhile, HFCS production is being fuelled by the country's attempts to run down its huge corn inventories, a drive also seeing a boost in ethanol output.
China's industrial use of corn will rise by 3.0m tonnes this season to 58.0m tonnes, according to the International Grains Council.
One factor mitigating against the popularity of HFCS is the health concern, with allegations that it is a bigger hazard than sugar, whose own reputation has suffered a downturn in recent years.
Furthermore, Mr Shaw said that sweetener consumers changing to HFCS in their products from sugar "are at the mercy of HFCS suppliers" - a limited pool, contrasting with the plethora of sugar providers.
North America is also a major user of HFCS, with the US exporting the sweetener to Mexico, with consumption also widespread in the European Union, under the name isoglucose.
By Mike Verdin