FOOD. Science. Technology. Quality

Food. SCIENCE. Technology. Quality

Food. Science. TECHNOLOGY. Quality

Food. Science. Technology. QUALITY




Effect of hydrocolloid coatings on quality parameters of french fries


Potatoes, cut into bars, were blanched and, then, coated by dipping in 1 % (w/w) solutions of the following polysaccharides: carboxymethylcellulose (CMC) of three viscosity types (30 CRT, CRT 1000, CRT 10000), pectins (PEC); or in 10 % (w/w) solutions of pea (PPI), soy (SPI), and whey (WPC) protein preparations. A reference sample was prepared using water instead of coating solutions. The frying process lasted 3 min at a temperature of 170 °C; the rapeseed oil was used as a heating medium. The quality of the obtained French fries was assessed by determining the contents of fat and moisture, weight loss, texture, colour, and sensory characteristics. The investigations performed showed that the presence of hydrocolloid layer on the surface of fried product could significantly reduce the amount of oil absorbed. The content of fat in French fries produced ranged from 15.92 to 25.21 g/100 g d.m. A statistically significant decrease (p < 0.05) in the content of oil in French fries was reported in five of seven of used hydrocolloids. The process of coating using CMC30 and CMC10000 had no impact on changes in the content of fat. The lowest amount of oil was found in the French fries coated with a WPC solution. In this case, the decrease in the content of fat was 36.9% compared to the control sample. The coating process did not increase the retention of water nor impacted the level of losses occurring during the heat treatment (p > 0.05). The measurements of French fries shearing force showed that, except for the  samples coated with a PPI solution, the coated chips had a significantly harder consistency (4.77 – 6.06 N) compared to the control sample (3.22 N). Additionally, the coating process contributed to the increase in the redness and/or yellowness of the total colour of French fries. The analysis of ΔE * value showed that when the fries were coated using a WPC solution, the resulting product had the most different colour compared to the colour of control sample. The French fries coated with a SPI solution exhibited the best sensory quality. The chips coated with a WPC solution appeared to be the least acceptable. The main reason thereof was their colour perceived by consumers as too intense; this statement was confirmed by the results of instrumental assessment. Provided the minimum overall rating should be at least 3 points (on a 5 point scale), it was proved that the application of a coating process made it possible to manufacture French fries with a reduced content of fat and, at the same time, of satisfactory sensory properties.


French fries, edible coatings, hydrocolloids