Discipline: cheese; Key words: pectin, fat replacers, reduced-fat cheese, cheese texture, sensory profile.
Due to perceived health reasons, consumers have shown an increasing interest in the consumption of cheese with a lower fat content. One of the main properties of reduced-fat cheeses is a higher protein to fat ratio that results in a more compact structure leading to a firmer and rubbery texture, a lack of flavour, bitterness (unacceptable sensory properties), development of off-flavours, poorer melting properties and a translucent appearance. To compensate for the increased proportion of protein in the matrix, it is possible to increase the moisture content of the cheese by various techniques, such as the modification of processing steps or the addition of ingredients that may increase the water-holding capacity. Hydrocolloids have been used to modify the composition, and hence the texture and functionality of reduced or low-fat cheeses. Pectin is a polysaccharide obtained from plant cells and is commonly used as a stabilizer for acidified dairy beverages. The work of Dr R. A. Ibáñez and colleagues aimed to evaluate the effect of three types of commercial pectins on the characteristics of reduced-fat Cheddar cheese during a ripening period of 180 days. Their study was published in Dairy Science. & Technology, Volume 96 of 2016, Page 297 to 316, the title being: Effect of pectin on the composition, microbiology, texture, and functionality of reduced-fat Cheddar cheese.
The authors made five Cheddar cheeses: full-fat control (FF), reduced-fat control (RF), and reduced-fat cheeses with amidated (RA), high-methoxy (RH), or low-methoxy (RL) pectin added to milk prior processing at concentrations of 0.175%, 0.100% and 0.075%, respectively. The levels were chosen to avoid phase separation of the casein micelles due to depletion flocculation.
The addition of amidated pectin increased the moisture content of the experimental cheese by about 49%, compared to 45% for RF (P<0.05). A significant reduction (P<0.05) in the proportion of insoluble calcium observed in RA and RL at 180 days (40% versus 56% in RF) was probably caused by calcium-induced gelation mechanisms of amidated and low-methoxy pectins. Texture profile analysis showed a softening of cheeses with added pectin (hardness less than 100 N versus more than 100 N in RF at 180 days; P<0.05). The melting properties of cheeses were significantly improved during ripening, although RF exhibited the lowest values (diameter increase more than 85 versus less than 70% at 180 days; P<0.05). These results suggest that pectin addition can be used to modify the moisture content, texture, and melting properties of reduced-fat Cheddar cheese.
To develop low-fat food, e.g. cheese, without altering their sensory properties is often challenging because fat contributes to the overall quality of the products and, thus, influences their acceptability. A classical strategy for increasing acceptability of low-fat foods is to rebalance the sensory characteristics impacted by fat reduction to keep the global sensory profile of the reduced-fat foods unchanged. The identification of the sensory characteristics impacted by the reduction of fat is a first step to choose the most appropriate strategy to offset the adverse effects of a fat reduction, and therefore Dr C. Martin and colleagues examined the impact of fat content and tasting temperature on the sensory characteristics of cottage cheese. They published their results in Dairy Science & Technology, Volume 96 of 2016, page 735 to 746. The title of their paper is: Sensory properties linked to fat content and tasting temperature in cottage cheese.
A conventional sensory profile was conducted to characterize seven cottage cheeses at two tasting temperatures (7 and 15 °C). Five of the products differed in fat content (0, 1, 3, 8 and 11%), while the last two contained 1% fat and were flavoured by the addition of 0.07 and 0.13% cream flavour.
Differences among the cottage cheeses varying in fat content were based on a range of differences related to aroma (mainly a cream aroma), taste (mainly bitterness), trigeminal sensation (astringency) and texture (greasy film). The tasting temperature did not impact taste, aroma, or astringency. However, thickness was strongly modified by tasting temperature, regardless of the fat content of the different cottage cheeses. Moreover, this study suggests that fattiness is difficult to define and that this descriptor could be advantageously replaced by greasy film which was shown to be highly reliable in discriminating between various fat contents in cottage cheese. In conclusion, it is evident that the problem of sensory acceptability of low fat cheeses requires more research.