The Italian researchers, in a study published in Food Chemistry said that wheat, a major component of the human diet, is a source of lipophilic antioxidants, such as carotenoids and tocols, that inhibit lipid peroxidation of polyunsaturated fatty acids (PUFA) in cell membranes and thus play a vital role in delaying several degenerative diseases.
However as enzymatic activity and processing conditions exert a major influence on carotenoids preservation, the scientists argue that a better understanding of the critical steps in food processing, and of their effect on different wheat species, will help to limit carotenoid degradation during manufacturing.
This knowledge, they add, will lead to bakery products with improved nutritional properties.
The loss of carotenoids content during food processing was investigated during the production of bread, water biscuits and pasta from refined flours of einkorn and Blasco and also the production of pasta from durum wheat semolina.
The researchers said that four bread loaves, each from 100 grams of Monlis, ID331 or Blasco flour, were produced according to AACC method, but excluding ingredients such as shortening and ascorbic acid, in order to avoid any interference with the lipophilic oxidation mechanism, with baking performed at 215 °C for 25 minutes.
For analytical determinations, samples of flour, mix (just made dough), leavened dough (immediately before baking), as well as bread crumb and crust, were collected extruded and dried pasta and stored at -20°C until analysis, they added.
The authors said four water biscuits from Monlis, ID331 or Blasco flour, were manufactured according to AACC method but without shortening and non-fat dry milk, to again avoid interferences with the lipophilic oxidation mechanism and baking was carried out at 205°C for 25 minutes.
And they explained that for analytical determinations, samples of flour, mix (just made dough) and baked water biscuits were collected and stored at -20°C until analysis.
About 2 kg of durum wheat semolina, as well as Monlis and Blasco flours were processed into short-cut pasta extruded at 8000 kPa, 40°C, no vacuum, and about 15 kg of durum wheat semolina and Monlis were also processed into short-cut pasta, extruded at 10,000 kPa, 40°C and vacuum 100 kPa, continued the researchers.
For analytical determinations, samples of flour, mix (just made dough), extruded and dried pasta were collected and stored at -20°C until analysis, they said.
Carotenoids quantification, added the researchers, was performed by normal phase HPLC.
The findings of the study show that total carotenoids content decreased throughout the processing stages: “For bread and water biscuits, kneading led to limited degradation (on average, 15 per cent and 12 per cent respectively), bread leavening had almost negligible effects (3 per cent), while baking had a marked influence on carotenoids loss in bread crust and water biscuits (29 per cent and 19 per cent respectively) but not in bread crumb (3 per cent).”
The researchers found that, in pasta the longer kneading-extrusion phase led to major losses (48 per cent), but the drying step did not induce significant changes.
The results vary according to the flour type, said the researchers. Using Blasco, the total carotenoids degradation from flour to final product was 28 per cent in water biscuits, 24 per cent in bread crumb and 55 per cent in bread crust. For einkorn the loss was 32 per cent, 20 per cent and 43 percent respectively, they stated.
“During kneading, Triticum monococcum consistently showed lesser percentage degradation, probably because of the lower lipoxygenase activity of its flour,” explained the team.
And the researchers thus concluded that, notwithstanding the significant decrease, einkorn supplied considerably more carotenoids than durum and bread wheats in the end products, and was characterised by an attractive deep yellow colour.
Source: Food Chemistry
Published online ahead of print
Title: Carotenoids evolution during pasta, bread and water biscuit preparation from wheat flours
Authors: A Hidalgo, A Brandolini, C Pompei