The study, published in Food Chemistry, compared spaghetti prepared from durum semolina substituted with various amounts of either durum bran or germ (pollard) fibre, and dried at high temperature.
The researchers reported that if spaghetti is dried at high temperature, it can be prepared with 10 per cent substitution of semolina with minimal impact on sensory and technological properties – while providing higher antioxidant activity, total dietary fibre, and no affect on starch hydrolysis.
“In milling of durum wheat the bran and germ (commonly referred to as pollard) are largely removed with little remaining in the semolina. However, most of the vitamins, minerals, fibre and antioxidants of wheat are found in the bran while the germ is rich in phytosterols, tocopherols, B group vitamins and oil,” said the researchers, led by Dr Mike Sissons from the department of Industry and Investment at Tamworth Agricultural Institute, Australia.
Sissons and his colleagues explained that insoluble fibres “are important in human health and disease prevention and can be incorporated into food.”
However, they noted that high fibre pasta, prepared with bran, is typically inferior quality compared to durum pasta:
“It has frequently been reported that the colour, cooking and sensory properties of whole-wheat or bran enriched pasta are inferior to pasta made from only semolina,” said Sissons and his colleagues.
“However, these studies used pasta dried at low temperature, and high temperature drying is known to improve cooking properties,” they added.
The researchers evaluated pasta for its cooking properties, texture, sensory, fibre content, antioxidant status, and in vitro starch digestibility to determine the dose producing acceptable quality.
They reported that at ten per cent, pollard substitution had minimal impact on quality ratings, and provided higher antioxidant activity and total fibre than the control pasta.
Higher levels of pollard produced pasta with undesirable colour and sensory properties and starch was digested to a greater extent, suggesting a potential higher glycaemic index.
“By comparison, bran inclusion at all the levels tested had negative impacts on many sensory and some technological properties, which was exacerbated with higher levels of bran inclusion,” said the researchers.
Sissons and his co-workers said that by offering much higher fibre and antioxidant activity with no impact on starch digestibility, such products may have a place in the consumer market.
“Interestingly, a significant amount of antioxidant activity was retained in the cooked pasta,” they added.
Source: Food Chemistry
Published online ahead of print, doi: 10.1016/j.foodchem.2011.07.042
“Effect of insoluble dietary fibre addition on technological, sensory, and structural properties of durum wheat spaghetti”
Authors: N. Aravind, M. Sissons, N. Egan, C. Fellows