Physical, Chemical and Sensory Characterization of Deep-Fried Fresh-Cut Potatoes Coated with Hydrocolloid/Herbal Extracts

Research background. Recently, natural plant extracts have been used to increase the nutritional value of food and to potentially reduce the absorbed fat and formation of the acrylamide in fried foods. Literature data on use of edible polymers with nettle or olive leaf extracts is scarce. 
Experimental approach. The effect of novel coatings on colour, fat absorption, phenolic and sugar content, and acrylamide formation in deep fat fried fresh-cut potatoes was evaluated. Extracts of olive and nettle leaves were incorporated in carboxymethyl cellulose (CMC) and gum arabic (GA), used as coatings for potatoes and applied before frying. This aimed to improve the nutritional quality of deep fat fried fresh-cut potatoes.
Results and conclusions. Enrichment of the edible coatings with extracts resulted in a significant change in the visible colour of the potatoes before frying. Significant effect of the extract concentration on the sensory characteristics of potatoes was also observed. Most importantly, the perception of characteristic potato odour and taste was not significantly affected by the simple coating. Although higher concentration of extract resulted with higher phenolics content in fried potatoes, sensory scores decreased at higher extract concentration (1.5 %). After frying, fat content in the coated potatoes was reduced by about 15 % when compared to the uncoated samples. The type of extract affected the total sugar content in fried potatoes, such that lower total sugar content was measured in samples coated with coatings enriched with olive leaf compared to those with nettle leaf. Only GA coating showed a reducing effect on acrylamide content by 17 %. Based on all obtained results, as CMC and GA coatings did not influence sensory properties, they can be recommended as carriers of functional compounds or as a frying pre-treatment for potatoes with respect to favourable effect on fat and acrylamide content.
Novelty and scientific contribution. Knowledge obtained in this study can be exploited for preparation of coatings with functional compounds used as a pretreatment for fried food with respect to favourable effect on fat and acrylamide content.