CONSUMER-BASED SENSORY CHARACTERIZATION AND PREFERENCE OF RAW AND PASTEURIZED MILK CHEESES

_________________ ABSTRACT Unpasteurized cheese commercialization remains a big discussion nowadays due to safety concerns, although consumers prefer them over industrialized ones. Extrinsic attributes of raw milk cheeses such as proximity to producers, being artisanal and traditional are important for purchasing, but the taste remains the most important intrinsic parameter and is crucial for commercialization. The main objective of this scientific article is to evaluate consumers' preference for pasteurized milk cheeses (PMC) or raw milk cheeses (RMC) and to evaluate the differences between sensory attributes using the consumer-based methodology CATA (check-all-that-apply). One hundred individuals participated, and results showed that the cheesy and milk aromas, the taste of salty, the texture soft and the texture of smooth and moist did not differ whether the milk was heat treated or not. RMC presented higher intensity of acid odor and taste, higher bitter taste, visually with higher yellow intensity and a colonial appearance, and with a texture more crumbly and drier. PMC were sweeter, buttery, and with more whitish color than those made of unpasteurized milk. Brazilian consumers preferred the PMC, and aroma, moist, and sweet taste are critical attributes for cheese preference.


INTRODUCTION
Colonial cheeses are traditional dairy products in Southern Brazil and stand out as one of the most produced and consumed cheeses in the region.They are made from the basic cow's milk cheese process and are presented as a medium-fat, mediummoisture variety.Normative Instruction No. 30, of August 7, 2013, from the Ministry of Agriculture, Livestock and Supply, recommends a 60-day maturation period for cheeses made with raw milk.According to this legislation, for shorter development times, raw milk cheeses (RMC) can be marketed only if there is scientific proof of quality and safety (BRASIL, 2013).
The food safety of (RMC) has been widely discussed worldwide, especially the artisanal ones since they are more susceptible to contamination by foodborne pathogen microorganisms (PRETTO; SANT 'ANNA, 2017).This feature (to be produced from raw milk) is an important criterion for willingness to buy cheeses (ALMLI et al., 2011), mainly because the traditional manufacturing process is valued by consumers (CRUZ; MENASCHE, 2014;ZIEMANN et al., 2022).
Colonial cheeses have been reported to be creamy, acid, bitter, salty, and present acid, milk, and butyric aroma, in addition to yellowish color and a bitter aftertaste (STEINBACH et al., 2021).Ambrosini et al. (2020) observed that consumers expect colonial cheese to present a gentile flavor, salty, and soft texture, which may be contradictory to ripped raw milk cheese.Some recent articles evaluated consumers' perception of colonial and artisanal cheeses (AMBROSINI et al., 2020;STEINBACH et al., 2021;ZIEMANN et al., 2022), but few studied their sensory profile of them.Steinbach et al. (2021) characterized colonial cheeses by a trained panel and observed that, in general, products did not present complex sensory properties, mainly due to the short ripening period in their study, which was 10 days.Also, the authors reinforced the data that artisanal dairy products present a lack of standardization, showing samples with different sensory characteristics, although they were produced in the same region and during the same period of the year.
The presence of lactic acid bacteria (LAB) in RMC is essential for the development of a wide and unique variety of flavors and textures, which happens during dairy ripening (FERNANDES, 2009).During the ripening process, cheeses present strong reductions in moisture and pH, and an increase in the concentration of sodium chloride, leading to the control of undesirable bacteria and contributing to the development of beneficial microorganisms _________________________________________________________________________________________________________________ _________________________________________________________________________________________________________________ Rev. Inst.Laticínios Cândido Tostes, Juiz de Fora, v. 78, n. 2, p. 46-53, abr/jun, 2023 responsible for the flavor and texture of cheeses (LECLERCQ-PERLAT et al., 2015;CALLON et al., 2016).However, there is no information in the current dairy literature on about the pasteurization procedure impacts cheese characteristics and if consumers' sensory perceive the changes.
Check-all-that-apply (CATA) is a consumerbased descriptive and discriminative methodology that uses ordinary consumers to sensorily characterize foods.CATA uses a predefined list of attributes and consumers are asked to check all terms they considered appropriate for describing each sample.It is a very popular methodology due to the easiness of the task for non-expert panelists and the fact that consumers have been shown to be able to use this type of methodology to generate product spaces that are like those from trained assessors in the sense that they, by and large, identify the same relative similarities and differences between samples (VARELA; ARES, 2018).However, there are little data in the current literature that evaluate whether these features are felt by consumers and mainly if they lead to higher acceptance.
In these contexts, the hypothesis that no heat treatment of the milk really brings unique sensorial characteristics to cheese and if they impact positively on consumers' acceptance stands out for the food science field and industries.Thus, this study aims to evaluate the sensory characteristics of "colonialtype" cheeses, made with pasteurized and raw milk, using the check-all-that-apply (CATA) method, a consumer-based sensory characterization technique, and consumer preference among them.

MATERIALS AND METHODS Cheese and ripening
The cheeses were produced following the traditional colonial-type cheese production procedure (AMBROSINI et al., 2020) in a supervised and legalized family agroindustry in Teutônia (RS, Brazil) in January 2021.The same type of milk was used as the base material for the cheeses, with part of the milk being pasteurized and the other part kept unpasteurized.So, two types of cheeses were made: pasteurized milk cheese and raw milk cheese.Milk pasteurization was performed in a plate pasteurizer at 72°C for 15 seconds.Pasteurized milk had 4.19% (±0.15) of fat and 87.005% (±0.005) of moisture, while raw milk had 3.85% (±0.15) of fat and 87.21% (0.005) of moisture.Both kinds of milk were kept at 32ºC for the addition of commercial calf rennet (1mL/10L of milk).

Sensorial analysis
One hundred individuals (N=100), recruited by social media, were instructed about the sensorial tests, and signed informed consent before the experiment.The research was approved by the State University of Rio Grande do Sul's Research Ethics Committee (protocol 4.594.977)before the beginning of the study.Cheeses were analyzed for microbiological and physicochemical aspects before the sensorial trials.
Consumers initially were asked for their sociodemographic profile (gender, scholarly, monthly income, and the city they live in).Then, cheese samples with 60-day mature were offered and each taster carried out the analysis individually, in a bright environment free of sounds and odors that could influence the responses.Samples were presented in cubes and randomly coded in suitable containers.A list of 15 attributes (Aroma: cheesy, milk, acid, fruity, musty, odorless; taste: sweet, salty, buttery, bitter, acid; appearance: colonial, pleasant, yellow, whitish color, stained, holes; texture: fatty, soft, rubbery, crumbly, smooth, dry, moist) based on previous literature (STEINBACH et al., 2021) was presented and individuals were asked to analyze _________________________________________________________________________________________________________________ _________________________________________________________________________________________________________________ Rev. Inst.Laticínios Cândido Tostes, Juiz de Fora, v. 78, n. 2, p. 46-53, abr/jun, 2023 each sample and check all attributes they felt.Then, consumers indicated their preference for one of the samples.

Microbiological and physicochemical analysis
Microbiological analyzes of Listeria monocytogenes, Salmonella sp., Escherichia coli and positive coagulase Staphylococcus were performed based on official Brazilian methodology (BRASIL, 2003).Moisture, fat, and pH were measured by classical methods described in AOAC, (HORWITZ, LATIMER, 2005).

Statistical analysis
Frequencies of mention for each word were determined by counting the number of consumers that used that word to describe each cheese, and the Q Cochran test was carried out for each of the terms, considering sample and consumer as sources of variation to evaluate if the CATA question was able to detect differences in consumers' perception of the evaluated samples.
To get a bi-dimensional representation of the samples, correspondence analysis (CA) was used on the frequency table that contains the number of consumers who checked each term from the CATA question to describe each sample.
Microbiological and physicochemical analyzes were performed in three repetitions and means were compared by two-way analysis of variance (ANOVA) followed by Fischer's exact test, and statistical differences were considered when p<0.05.

RESULTS AND DISCUSSION
The profile of the consumers who participated in the work showed that they are between 18 and 60 years old, 45% were female and 39% finished high school (Table 1).Among the individuals, 85% self-reported consuming colonial cheese frequently.Raw and pasteurized milk cheeses were within the legal standard parameters for microbiological and physicochemical analyzes (Table 2).L. monocytogenes and Salmonella sp. were absent in 25g of samples and E. coli and positive coagulase Staphylococcus were below the quantification limit.Moisture did not differ among RMC and pasteurized ones (p>0.05), and cheeses may be classified as low moisture (also known as hard mass cheese).
Both samples were classified as semi-fat cheeses since their concentration of fat was between 25.0 and 44.9% (BRASIL, 1996).The fat content was higher when the milk was pasteurized than in the traditional procedure (p<0.05),probably due to a methodological limitation of the fat analysis.In relation to pH values, they did not differ between samples (p>0.05).Steinbach et al. (2021) also observed little pH differences between samples made with unpasteurized milk and pasteurized ones.It is not uncommon that artisanal cheeses to be not able to human consumption due to foodborne pathogens.Carvalho et al. (2019) recently observed that just 33.3% of colonial cheeses presented a lower thermotolerant coliform population and 58.3% of positive coagulase Staphylococcus than Brazilian legislation established.Steinbach et al. (2021) were not able to perform sensory analysis of nine out of the fifteen colonial cheese samples due to microbiological aspects.After checking that samples were safe for consumption, sensory analyzes were performed.Results of the discriminative analysis of both samples by CATA are presented in Table 3. Fruity (n=4, 2%), musty (n=16, 8%), odorless (n=14, 7%), stained (n=1, 1%), holes (n=1, 1%), fatty (n=10, 5%) and rubbery (n=15, 8%) were attribute cited less than 10% of all possibilities, and thus they are not suitable for the description of the samples.Within this list, it is important to highlight the appearance attribute "holes": it was not cited by most of the consumers because cheeses did not present the typical holes in the center of the cheeses.Since all samples presented high microbiological quality, this feature was not presented.Brazilian cheeses' holes are mainly due to the presence of thermotolerant coliforms (SOUZA et al., 2003).However, the presence of holes in the center of cheeses is an important attribute of artisanal cheeses in Brazil from the consumers' point of view (AMBROSINI et al., 2020;ZIEMANN et al., 2022).
Thus, for further analysis, these attributes were removed.The aroma of cheesy and milk, the taste of salty, the texture soft, and the texture of smooth and moist did not differ (p>0.05)whether _________________________________________________________________________________________________________________ _________________________________________________________________________________________________________________ Rev. Inst.Laticínios Cândido Tostes, Juiz de Fora, v. 78, n. 2, p. 46-53, abr/jun, 2023 the milk was heat treated or not.RMC presented higher (p<0.05)intensity of acid odor and taste, higher bitter taste, visually with higher yellow intensity and a colonial appearance, and with a texture more crumbly and drier.PMC was sweeter, more buttery (possibly due to PMC presenting a higher concentration of fat (p<0.05)(Table 2), and with more whitish color than RMC (p<0.05).Since RMCs keep their intrinsic microbiota, which mostly is composed of LAB, they may imply important changes in the sensory profile.2021) also observed using a trained panel that RMC was characterized by acid taste and aroma and bitter taste.The bitter taste related to these products is due to the hydrolysis of casein which initially results in large peptides, later in small peptides, and finally in free amino acids.The large peptides formed are usually tasteless or bitter and do not directly contribute to the typical flavor of the cheese (FARKYE, 2004).The higher acid odor and taste in RMC are related to organic acids, mainly lactic acid, produced by LAB and are felt by consumers, although they did not differ (p>0.05) on pH measurement (Table 2).Brazilian consumers characterized colonial cheese, one of the traditional raw milk cheeses in southern Brazil, as round and with a light yellowish color (AMBROSINI et al., 2020) and the main reasons for consumption would be characteristic flavor, aroma, and textures (STEINBACH et al., 2021).
The results of the present work indicate that cheeses present a different appearance when milk is not pasteurized, which may be related to the higher yellow color in these samples (p<0.05).
Preference analysis showed that pasteurized milk cheese was preferred (p<0.05)over those raw milk cheese (Table 3) and Figure 1 shows the preference perception map based on the CATA, which statistical analysis shows that the main cheeses' feature related to consumers' preference were cheesy aroma, moist, and sweet taste.For Steinbach et al. (2021), consumer perception was negatively affected by the acidity and springiness of colonial cheese samples, whose characteristics were found in the RMC sample.The preference for either PMC or RMC may be a cultural issue.Almli et al. (2011) observed that French consumers are more willing to buy raw milk cheese, while Norwegians prefer pasteurized.
In Brazil, Steinbach et al. (2021) found that the number of consumers who consider it important for colonial cheese to be made with raw milk was not significantly greater than the number of consumers who consider production with pasteurized milk to be important.However, this study shows that consumers in southern Brazil prefer the taste of pasteurized milk cheeses.

CONCLUSION
In conclusion, the pasteurization of milk led to cheeses with different characteristics and PMC was preferred in the present study.The results show that the attributes of cheese aroma, moist and sweet taste are the most desired by consumers in southern Brazil when tasting colonial cheese.Consumers' purchasing and liking of food is complex and it is important to consider other non-sensorial attributes thus further studies are necessary to deeply explore these important food safety and security issues.

Figure 1 .
Figure 1.Preference perception map by correspondence analysis of CATA results and consumer preference.

Table 2 .
Microbiological and physicochemical results of raw and pasteurized milk cheeses and Brazilian legal standards Different superscript letters indicate statistical difference between raw and pasteurized milk at 5% of significance by Analysis of Variance (ANOVA) and Fischer's test.