"Lard enriched with olive phenols has two advantages: improved oxidative stability and increased nutritional value," wrote lead author Antonella De Leonardis from the University of Molise, Italy.
Lard dominates the solid fat sector of the edible oils in the UK, according to market analysts Mintel. But a poor public image, mainly attached to the fact that it contains between 40 and 45 per cent saturated fats, has seen the value of this sector melt from £22m (€32.1m) to just £14m (€20.5m) since the start of the millennium, a decline of some 35 per cent.
The new research, published in the journal Food Chemistry (Vol. 100, pp. 998-1004), could potentially, suggest the researchers, lead to food manufacturers and consumers changing their image of this animal fat, with lard being considered "healthy".
The fat, with an annual production of 5.4m tons (FAO), is naturally poor in antioxidants, but in Europe and the USA, several antioxidants, such as gallates and tocopherols can be added to increase the oxidative stabilisation of lard, explained the authors.
The researchers behind the new research, used extracts from olive mill wastewater drawn from a mill situated in the Abruzzo region of Italy.
It is said that only one per cent of the total polyphenol compounds found in olives are actually still present when the olives are pressed to produce oil, leaving both the solid waste and wastewaters as potentially rich sources of extractable antioxidants.
The researchers used ethyl acetate to extract the polyphenols from the wastewaters, with an average yield of 50 mg of total phenol per 100 g of wastewaters.
The extract was then dissolved in distilled water and added to lard samples in different concentrations, ranging from 50 and 350 mg per kg of lard. The olive mill wastewater lard were compared to lard stabilized by propyl gallate.
"In all samples, propyl gallate was more effective than olive mill wastewaters. Nevertheless, the olive mill wastewater antioxidant effect was satisfactory, especially in the high-quality lard," reported the researchers.
However, compared to propyl gallate, polyphenols in olives, most notably tyrosol and ferulic acid, are considered to be nutraceutically active, thereby giving the olive mill wastewater lard an additional "nutritional" potential.
"It was found that phenols from olive-oil mill wastewater significantly increased the oxidative stability of lard," said De Leonardis.
And this, said the researchers, shows "a profitable use of olive phenol emerges as food a additive."
"The lard with olive phenol can be considered as a 'novel food' that satisfies the modern consumer's demand for natural, safe and healthy food," she concluded.
Whether such lard would be acceptable to consumers remains to be seen, but use of olive extracts may interest olive oil producers as an additional revenue stream.
Mintel's Edible Oils report said that the UK olive oil market has been on fire since 2000, growing by 39 per cent to date in order to break through the £100m mark.