Cookies Fortified with Polyphenols Extracts: Impact on Phenolic Content, Antioxidant Activity, Inhibition of α-Amylase and α-Glucosidase Enzyme, Colour and Sensory Attractiveness.

ABSTRACT

The goal of the research was to determine the impact of fortification with polyphenolic compounds on (i) sensory attractiveness (global satisfaction, appearance, colour, odour, flavour, sweetness, bitterness), (ii) content of polyphenols and colour (L*, a*, b*) after the baking process and (iii) their bioactive potential (antioxidants activity and inhibiting of α-amylase and α-glucosidase enzyme). Fortification was made with extracts of polyphenolic compounds of selected plant raw materials rich in polyphenols from quince (fruits), tilia (flowers), pomegranate (skin), passion fruit (endocarp), sour cherries (leaves), haskap and chokeberry (berries), silver skin (coffee beans), rosehip (seeds). Depending on the nature of the polyphenol extract, flavan-3-ols (monomeric and polymeric), phenolic acid, flavonols and anthocyanins were identified in the product in amounts ranging from 53.7 to 212.6 mg/100 g DM. Cookies' colour (L*, a*, b*) depended on the type of polyphenol extract used for fortification. Cookies with haskap, chokeberry and sour cherry presented the highest antioxidant potential. Cookies with chokeberry, haskap and rosehip presented high activity in inhibiting α-amylase (65.5, 60.6 and 62.2% of inhibition, respectively), but cookies with haskap, silver skin and quince in inhibiting α-glucosidase activity (23.0, 20.4 and 21.4% of inhibition, respectively). In the sensory evaluation, the most attractive were cookies with rosehip and pomegranate (6.3 and 5.8 score, respectively), but the lowest ratings were given to cookies with passion fruit and silver skin but especially quince cookies, which obtained the lowest desirability (3.7 score). The acceptability of fortified cookies was determined to the least extent by monomeric flavan-3-ols and phenolic acids (in minus in odour/flavour, bitterness, sweetness and global satisfaction), but anthocyanins, polymeric procyanidins and flavonols had the most significant positive impact on consumer acceptance of the assessed features, i.e., global satisfaction, odour/flavour, sweetness and bitterness (positive consumer drivers).