Lycopene retention higher in rice and corn based snacks, study

And the researchers, whose findings were published in the journal Food Chemistry, ​claim that although the amount of lycopene retained after extrusion was very low, variation in the chemical composition of the base ingredients of snacks especially increases in the starch content, improved the retention values.

The use of physically resistant material such as tomato skin as a source of lycopene demonstrated that that higher levels of the nutritional compound can be retained in the final product, added the authors.

They noted that lycopene, a pigment from the carotenoid family, has been associated with various health benefit claims including immune system modulation, as a free radical scavenger and as having anticarcinogen properties.

While improving nutritional properties of snacks appeals to the growing demand for healthier foods, consumer acceptability of such products still mainly depends on their flavour, texture and overall appearance.

And the researchers said that such parameters relate to the proportion and type of the starch used which affects the number and size of air cells developed during extrusion.

They added that the “incorporation of tomato derivatives into extruded snacks changes the chemical composition of the melt by reducing the starch content and adding fibre, sugar and probably other polysaccharides.”​

Thus, the goal of their research, said the authors, was to determine the fate of lycopene and the physico-chemical properties of extruded snacks manufactured from three different base ingredients namely, rice, corn and wheat, as the source of starch and freeze dried tomato paste or skin powder, as the lycopene source.

The explained how crisp, low density extruded snacks were manufactured from those starches, both with and without dried tomato skin or paste powder and extruded at temperatures of 140°C, 160°C or 180°C.

Lycopene content, expansion, product density, hardness, percentage of moisture loss and colour parameters of the snacks were all measured subsequently, said the researchers.

They found that lycopene retention was higher in products containing tomato skin powder and significantly lower when wheat flour was used to make the snacks, and that increases in the processing temperature improved the physico-chemical characteristics of the snacks but had no significant effect on lycopene retention.

“The degradation of lycopene was greatest for extruded products containing wheat… Wheat had a lower starch and higher protein content compared to rice and corn, therefore the starch content may have provided some protection for lycopene,”​ concluded the authors.

Source: Food Chemistry ​
Published online ahead of print
Title: The physico-chemical characteristics of extruded snacks enriched with tomato lycopene​
Authors: Z. Dehghan-Shoar, A K Hardacre, C S. Brennan