A novel pre-treatment for cheese production: Biochemistry, sensory perception and consumer acceptance.
Year: 2014
Type: dissertation
Abstract: Homogenisation is a physical process which results in the reduction in the size of fat-globules to reduce creaming. It is not generally used in cheesemaking as it allows access of the indigenous enzyme lipoprotein lipase (LPL) to the triacylglycerol core of the fat globule, resulting in uncontrollable lipolysis and rancidity both in the milk and cheese made therefrom. It was hypothesised that the inclusion of low-pressure homogenisation in a controlled fashion could be used to improve the sensory characteristics and consumer acceptability of cheese relative to un-treated cheeses. A pre-processing treatment was developed wherein raw milk was homogenised (at 0, 5 or 10 MPa pressure), incubated for 1 h at 37ºC and either batch pasteurised (63ºC for 30 min) or high-temperature short-time pasteurised (75ºC for 15 s). Control milks were treated similarly, but bypassed the homogenisation step. Cheddar and Emmental cheese were produced from the pre-treated milk and ripened according to respective ripening schemes. Reduced-fat Emmental cheese (20% fat) was also produced, using both homogenisation pressure of 10 MPa in the pre-treatment and with a control milk. Biochemical analyses showed higher moisture and NaCl levels in homogenised milk cheeses, while free fatty acids (FFA) were in some cases twice that of the control cheeses. The difference in amount of FFA can be attributed primarily to the lipolysis experienced in the pre-treatment. No differences were found in levels of bacteria in cheeses in any study. Confocal laser scanning microscopy (CLSM) showed a greater distribution of smaller homogenised fat globules throughout the cheese matrix. Sensory characteristics of the cheeses produced using the pre-treatment and Emmental cheesemaking were evaluated by descriptive sensory profiling using trained panels. Cheeses produced with homogenisation were rated higher for taste intensity and salty taste and were smoother, fattier and crumblier, lacked characteristic eyes and were less yellow and more colour consistent than those without homogenisation in the pre-treatment. Dynamic sensory characteristics were evaluated with the temporal dominance of sensations (TDS) method, where the evolution of the most dominant sensory attribute during mastication was followed. Homogenisation caused a drastic change in the texture during mastication. The control cheese was dominantly elastic at the start and then crumbly until swallowing while the homogenised milk cheese was experienced as crumbly-fatty-smooth. Evaluation of consumer responses and market positioning was carried out by projective mapping (PM), where respondents (n = 46) positioned the control and homogenised full-fat and reduced-fat test cheeses with six commercial cheeses. Similar cheeses were positioned closer together and different cheeses further apart. Participants were free to use their own criteria to position the cheeses. The reduced-fat homogenised cheese was rated as higher as more pleasant and positioned apart from similar commercial Emmental cheeses and the control cheeses. The full-fat homogenised milk cheese, ripened for 3 months, was rated higher for liking and positioned far from the other test cheeses, close to Gruyère-type (ripened for 7 months) and Gouda (ripened for 8 months) cheeses, described with words like full , tasty , melt-in-mouth and creamy . The positioning close to longer-ripened cheeses suggests a potential saving, through attainment of similar characteristics in a shorter ripening time. The effect of information on the expectations and perceptions of consumers was investigated. Participants (n = 229) completed a questionnaire with demographic and psychographic measures and were divided into four balanced groups based on age, sex, food neophobia and food technology neophobia. Each group received the same cheese sample and a different description, either, traditional , new-type , technology or cheese . Participants rated expected/actual pleasantness and purchase intent, as well as the suitability of descriptive words. Descriptions affected expected purchase intent, where the new-type group reported highest purchase intent, while no effect was found on expected pleasantness. Communication of novelty and technology raised the purchase intent of those with low food neophobia and low food technology neophobia, respectively. The pre-treatment is a viable and valuable addition prior to cheesemaking. Improvements in certain key sensory taste and texture attributes were seen, as well as improved positioning and consumer responses, indicating market potential and potential reduction in ripening costs. Although care should be taken in communication of both novelty and the technological nature of the process, the potential advantages of the pre-treatment are clear. Not only could the pre-treatment be applied prior to the manufacture of other types of cheeses, but potentially to other types of ripened-dairy products
Source: Työväentutkimus Vuosikirja
Author: Kevin C. Deegan
Language: English
Topic: Proteins in Food Systems
Subfield: Food Science
Domain: Life Sciences
SDG: Zero hunger
Open Access status: green
OpenAlex ID: W1876979446