Study finds milk chocolate has a dark side by adding peanut skin extract

The study notes that many consumers prefer the taste of milk chocolate over dark, due to latter tending to impart a bitter flavor.

The research aimed to to replicate the antioxidant polyphenol content dark chocolate possesses without altering the sweeter, smoother taste of milk chocolate.

 “These peanut skins contain the same types of compounds that can be found in tea, cocoa, cranberries,”​ lead author and research food technologist for the USDA, Lisa L. Dean, PhD, told ConfectioneryNews.

“So we thought, what if could use the power of this extract to make milk chocolate just as bioactive as dark chocolate without the bitterness that dark chocolate has?”​ Dean said.

Fitting into consumer demand for tastes and nutrition​

Consumer testing showed all 80 respondents liked the taste of the milk chocolate fortified with peanut skin extract just as much as the control sample of milk chocolate.  

The researchers also found that the threshold for detecting the presence of peanut skin extract was higher than the amount needed to achieve the same levels of antioxidants found in dark chocolate.

Functional foods such as those with added antioxidants are projected to be worth $67bn by 2016, presenting an opportunity for milk chocolate fortified with peanut skin extract.

“As consumer demand for antioxidant polyphenol products develops into a multibillion dollar industry, the peanut industry can capture value from their waste streams,”​ Dean wrote.

“Peanut skin phenolic extracts have significant potential in a growing market.”​

Dean and her team worked on extracting these key compounds from the skins and it was during this process that researchers noticed the delicate consistency after extraction needed encapsulation with maltodextrin to reduce the bitterness.

“The acceptance of chocolate by consumers has been related to the degree of bitterness,”​ Dean wrote citing a study titled “Tolerance for high flavanol cocoa powder in semisweet chocolate,” ​conducted by department of food science at Pennsylvania State University.

The result was a product that contained a similar antioxidant content to dark chocolate while maintaining the milder, sweeter flavor of milk chocolate.

Waste management solution​

According to Dean, 50% of the US peanut supply goes to making peanut butter, leaving behind a stockpile of peanut skins.

“For the most part they just go into a land fill,”​ Dean said, besides the small amounts that can be used in animal feed, but only in limited amounts because of adverse nutritional impact if consumed in larger amounts by livestock.

Peanut skin waste is a lost economic opportunity to the industry especially as their reported high levels of polyphenols make them useful as natural antioxidant food ingredients or as a source of health-promoting compound, the study stated.

“Although peanut skin material is currently a waste product to the peanut processing industry that often incurs financial liability for its disposal, this study demonstrated that the high-value phenolic material can be recovered from this waste stream and used as an effective additive for producing confections with equivalent health benefits,”​ the study concluded.

Source: Journal of Food Science
Published online ahead of print -  doi: 10.1111/1750-3841.13533​
'Minimizing the Negative Flavor Attributes and Evaluating Consumer Acceptance of Chocolate Fortified with Peanut Skin Extracts'
Authors: L.L. Dean, C.M. Klevorn, and B.J. Hess