Replacing flour in muffins with 24 per cent of a dried apple skin powder could boost the fibre content of the product without detrimentally affecting the sensory profile of the product, according to findings published in the Journal of Food Quality.
The study, led by H.P. Vasantha Rupasinghe from Nova Scotia Agricultural College, follows an earlier study from the same group, which was said to be the first report on the use of the apple skin powder as a fibre-enhancer (Food Chemistry, Vol. 107, pp. 1217-1224).
The new study provides sensory data on the incorporation of the apple skin powder, a by-product of apple pie and sauce manufacturing, following tasting by a panel of 66 people.
“The compatibility of apple skin powder for replacement of wheat flour coupled with the consumer acceptability of sensory characteristics provide new insight for use of apple skin as a value-added food ingredient for muffins, other bakery products or selected functional foods and nutraceuticals,” wrote the researchers.
The need for more fibre
Insoluble fibre contains cellulose, hemicellulose and lignin and cannot be dissolved in water, unlike soluble fibre. It is found in wheat or cereal bran and in most vegetables and fruits.
Consumption of insoluble fibre has previously been associated with a reduced risk of obesity and diabetes.
The researchers obtained a blanched, dehydrated, and ground apple skin powder (ASP), with a reported content of 41 per cent for dietary fibre. Moreover, the powder was found to contain high levels of antioxidant activity, with an oxygen radical absorption capacity (ORAC) of 52 mg Trolox equivalents per gram of dry weight.
Rupasinghe and his co-workers prepared muffins with varying levels of apple skin powder as replacements for wheat flour. Six levels of incorporation were used: 0, 4, 8, 16, 24 or 32 per cent.
According to the results, only the highest level of replacement was found to detrimentally affect the baking characteristics. When tasted by the panellists, the best acceptability was observed for the muffins formulated with 8, 16 or 24 per cent apple skin powder.
“The results of the present study indicate that blanched and dehydrated apple skin powder could be considered as an alternative dietary fibre source or specialty food ingredient for muffins,” wrote the researchers.
“Therefore, the potential for the industrial exploitation of apple skin powder as a health food ingredient for the bakery industry and selected functional foods is promising,” they concluded.
Source: Journal of Food Quality
Published online ahead of print, doi: 10.1111/j.1745-4557.2009.00275.x
"Baking and sensory characteristics of muffins incorporated with apple skin powder"
Authors: H.P.V. Rupasinghe , L. Wang, N.L. Pitts, T. Astatkie