Cheese Flavor Research Articles

Unlocking the potential of Kluyveromyces marxianus in the definition of aroma composition of cheeses.

The cheese microbiota is very complex and is made up of technologically-relevant, spoilage, opportunistic and pathogenic microorganisms. Among them lactic acid bacteria and yeasts are the main ones. One of the most interesting dairy yeasts is Kluyveromyces marxianus because of its technological properties including the ability to produce aroma compounds. This study investigated the contribution of Kluyveromyces marxianus to the gross composition and aroma profile of cow cheeses. Experimental cheeses were prepared by inoculating a co-culture of K. marxianus FM09 and a commercial strain of Lacticaseibacillus casei and compared with cheeses obtained with only L. casei. The gross composition was determined by a FoodScan™ 2 Dairy Analyser, and free amino acids were evaluated at 507 nm after reaction with Cd-ninhydrin. The volatile organic compounds were extracted by head-space solid phase micro-extraction and analyzed by gas chromatography-mass spectrometry coupled with odor activity values. qRT-PCR was applied to determine the expression of genes involved in esters synthesis and degradation. The inoculation of K. marxianus induced an increase of pH and a reduction of protein content of cheeses, in agreement with the stronger proteolysis detected in these cheeses. K. marxianus influenced the content of aroma compounds both quantitatively and qualitatively. In particular, an increase of higher alcohols, esters and organic acids was observed. Moreover, 12 compounds were detected only in cheeses obtained with the co-culture. These differences were in agreement with the odor activity values (OAV). In fact, only 11 compounds showed OAV > 1 in cheeses obtained with the commercial strain, and 24 in those obtained with the co-culture. The qPCR analysis revealed an over expression of ATF1, EAT1, and IAH1 genes. Kluyveromyces marxianus could act as an important auxiliary starter for cheese production through the development and diversification of compounds related to flavor in short-aged cow cheeses.

Optimisation of soft camel cheese production coagulated with green carob extract using response surface methodology: Yield, physicochemical, microbial, sensorial, and rheological properties

This study addresses the processing limitations of camel milk for production of textured camel milk cheese by utilising the green carob extract (GCE) as a novel coagulant. The response surface methodology was employed to assess the impact of GCE on the cheese quality parameters. Maximal soft camel cheese yield (24.1%) was achieved using 12% (v/v) of GCE, coagulation at 53.6°C, and incubation time of 9 h 52 min. Compositional analysis revealed the richness of soft camel cheese in dry matter (33.8 ± 81.61%), carbohydrates (3.66 ± 0.45%), and calcium (632.83 ± 68.43 mg/100 g). The addition of GCE enhanced the cheese's flavour and texture.

Characterization of cooked cheese flavor: Volatile components.

The aim of this work was to identify volatiles that contribute to the aroma of cooked cheese, including the role of fat content in their development during cooking. Volatiles and odorants in cooked mature Cheddar were identified using a combination of SPME (solid-phase microextraction)/GC-O (gas chromatography-olfactometry) and SPME/GC-MS (gas chromatography-mass spectrometry). A selection of the odorants was quantitated in six cheeses, uncooked and cooked, (mature Cheddar, high-, medium-, and low-fat mild Cheddar, mozzarella, and Parmesan). Many compounds showed significant differences between cooked and uncooked cheese; Strecker aldehydes, pyrazines, and furanones were all significantly higher in cooked cheeses than in uncooked cheese, while ethyl esters (key odorants in uncooked cheese) were not detected in any of the cooked cheese. Principal component analysis demonstrated that fat concentration in mild Cheddar was positively correlated with the formation of potential odorants (the Strecker aldehydes, methanethiol, 2-methylketones, and fatty acids) upon cooking. Potential lipid precursors for these compounds are discussed. PRACTICAL APPLICATION: This research can be used by the dairy industry to develop better cheeses, especially low- and reduced-fat cheeses, for use in cooked applications such as toppings for pizzas and ready meals. Alternatively, this research describes key volatile compounds in cooked cheese that can be used by the flavoring industry to develop authentic cooked cheese flavorings.

Tuning and modeling cheese flavor.

Flavor is a major sensory attribute affecting consumers' preference for cheese products. Differences in cheesemaking change the cheese microenvironment, thereby affecting cheese flavor profiles. A framework for tuning cheese flavor is proposed in this study, which depicts the full picture of flavor development and modulation, from manufacturing and ripening factors through the main biochemical pathways to flavor compounds and flavor notes. Taking semi-hard and hard cheeses as examples, this review describes how cheese flavor profiles are affected by milk type and applied treatment, fat and salt content, microbiota composition and microbial interactions, ripening time, temperature, and environmental humidity, together with packaging method and material. Moreover, these factors are linked to flavor profiles through their effects on proteolysis, the further catabolism of amino acids, and lipolysis. Acids, alcohols, ketones, esters, aldehydes, lactones, and sulfur compounds are key volatiles, which elicit fruity, sweet, rancid, green, creamy, pungent, alcoholic, nutty, fatty, and sweaty flavor notes, contributing to the overall flavor profiles. Additionally, this review demonstrates how data-driven modeling techniques can link these influencing factors to resulting flavor profiles. This is done by providing a comprehensive review on the (i) identification of key factors and flavor compounds, (ii) discrimination of cheeses, and (iii) prediction of flavor notes. Overall, this review provides knowledge tools for cheese flavor modulation and sheds light on using data-driven modeling techniques to aid cheese flavor analysis and flavor prediction.

Temporal dominance of Sensations: Do different concepts of “dominance” affect the results?

The purpose of this study was to understand the role of “dominance” definitions in the results of TDS applied to consumers. This study compared two temporal dominance of sensations (TDS) approaches − TDS-I − that attracts the most attention and TDS-II − most intense/strongest sensation − in the context of evaluating artisanal Minas cheeses from the Serra da Canastra and chocolate with different cocoa concentrations samples. TDS curves were constructed and a trajectory-based principal component analysis (PCA) was performed dominance rates at ten equally spaced time points. Additionally, difference curves, multiple factor analysis (MFA) and regression vector coefficient (RV coefficient) were performed to compare the two approaches. The findings showed that the two approaches produced similar results, suggesting that consumers interpret the terms dominant and intense in a similar way during TDS evaluations, the results were even closer at the chocolate study than at the cheese study. However, in both approaches were observed low dominance rates and differences between the sensation perception time, mainly in the evaluation of cheese flavor. This variability may be attributed to the complexity of the cheese’s flavor and the varied interpretations of dominance among evaluators. Despite these differences, the approaches showed similar characterizations across the same samples, demonstrating high reproducibility and a strong ability to differentiate between samples. This study demonstrates that the choice between the terms dominant (which captures more attention) or intense (stronger) to guide consumers in performing the sensory test does not significantly influence the results. Consequently, it is possible to adopt greater freedom and flexibility in the terminology used to instruct participants in conducting the test.

Application of Ligilactobacillus salivarius SP36, a Strain Isolated from an Old Cheese Seal, as an Adjunct Culture in Cheesemaking.

Adjunct cultures originating from artisanal cheese environments may play an important role in recreating and developing traditional cheese flavours, thanks to their enzymatic activities, involved in different metabolic pathways that occur during cheese ripening. In this work, Ligilactobacillus salivarius SP36, a strain isolated from an old cheese seal, was added as an adjunct culture to the cheese's raw milk, and its effect on the microbiological, physical-chemical and sensory characteristics of the cheese was studied. The use of L. salivarius SP36 in cheese manufacturing had no significant (p > 0.05) effect on the cheese microbiota, gross composition (fat percentage, protein, total solids, moisture and NaCl concentration), colour or texture of the cheese. However, L. salivarius SP36 increased (p < 0.01) the formation of 25 volatile compounds, including 10 esters, 1 aldehyde, 8 alcohols and 6 carboxylic acids. In addition, cheeses made with L. salivarius SP36 received higher scores (p < 0.01) for aroma intensity and quality than control cheeses. L. salivarius SP36 proved to be a good candidate as an adjunct culture for cheesemaking, since it improved the cheese flavour by making it more intense and recovering typical sensorial notes of traditional cheeses.

Adjunct cultures of autochthonous Lactobacillus strains to diversify and improve cheese maturation

This study evaluated the influence of 11 autochthonous mesophilic lactobacilli strains on maturation profile of a miniature semihard cheese. Five strains of Lactiplantibacillus plantarum, three Lacticaseibacillus rhamnosus, two Lacticaseibacillus casei and one Lacticaseibacillus paracasei, were evaluated individually as adjunct cultures. Three groups of strains were distinguished regarding their influence: One group was characterised by consumption of citrate and production of several volatile compounds, another group by its acidification and peptidolytic activity, while two strains had no influence. The combined use of strains with different properties as adjunct cultures probably allows further improvement and diversification of cheese flavour.

Metagenomic and flavoromic profiling reveals the correlation between the microorganisms and volatile flavor compounds in Monascus-fermented cheese

The Monascus-fermented cheese (MC) is a unique cheese product that undergoes multi-strain fermentation, imparting it with distinct flavor qualities. To clarify the role of microorganisms in the formation of flavor in MC, this study employed SPME (arrow)-GC–MS, GC-O integrated with PLS-DA to investigate variations in cheese flavors represented by volatile flavor compounds across 90-day ripening periods. Metagenomic datasets were utilized to identify taxonomic and functional changes in the microorganisms. The results showed a total of 26 characteristic flavor compounds in MC at different ripening periods (VIP＞1, p < 0.05), including butanoic acid, hexanoic acid, butanoic acid ethyl ester, hexanoic acid butyl ester, 2-heptanone and 2-octanone. According to NR database annotation, the genera Monascus, Lactococcus, Aspergillus, Lactiplantibacillus, Staphylococcus, Flavobacterium, Bacillus, Clostridium, Meyerozyma, and Enterobacter were closely associated with flavor formation in MC. Ester compounds were linked to Monascus, Meyerozyma, Staphylococcus, Lactiplantibacillus, and Bacillus. Acid compounds were linked to Lactococcus, Lactobacillus, Staphylococcus, and Bacillus. The production of methyl ketones was closely related to the genera Monascus, Staphylococcus, Lactiplantibacillus, Lactococcus, Bacillus, and Flavobacterium. This study offers insights into the microorganisms of MC and its contribution to flavor development, thereby enriching our understanding of this fascinating dairy product.

Brazilian indigenous nonstarter lactic acid bacteria enhance the diversification of volatile compounds in short-aged cheese.

There is growing interest in using autochthonous lactic acid bacteria (LAB) that provide unique sensory characteristics to dairy products without affecting their safety and quality. This work studied the capacity of three Brazilian indigenous nonstarter LABs (NSLAB) to produce biogenic amines (BAs) and evaluated their effect on the volatile organic compounds (VOCs), microbial LAB communities, and physicochemical profile of short-aged cheese. Initially, the strain's potential for biosynthesis of BAs was assessed by PCR and in vitro assays. Then, a pilot-scale cheese was produced, including the NSLAB, and the microbial and VOC profiles were analyzed after 25 and 45 days of ripening. As a results, the strains did not present genes related to relevant BAs and did not produce them in vitro. During cheese ripening, the Lactococci counts were reduced, probably in the production of alcohols and acid compounds by the NSLAB. Each strain produces a unique VOC profile that changes over the ripening time without the main VOCs related to rancid or old cheese. Particularly, the use of the strain Lacticaseibacillus. paracasei ItalPN16 resulted in production of ester compounds with fruity notes. Thus, indigenous NSLAB could be a valuable tool for the enhancement and diversification of flavor in short-aged cheese.

TRADITIONAL CHEESE PRODUCED IN FOGO ISLAND - CAPE VERDE: PHYSICO-CHEMICAL, SENSORY, HYGIENIC AND SAFETY CHARACTERISTICS

Cheese is a nutritionally rich product, distinguished by its unique sensorial qualities. Processing technology for cheeses in different countries is still handmade, thus, the microbial community structure is complex and the cheese flavour fluctuates wildly. Therefore, this study aimed to investigate the sensory acceptance, microbiological and physical-chemical properties of traditional cheese produced in Fogo Island – Cape Verde. Coalho cheese is the most produced and consumed cheese in Cape Verde and is frequently made according to traditional or artisanal procedures. Regarding to physical-chemical analyses, parameters such as fat, moisture, pH, titratable acidity, protein, and ash were studied. Microbiological parameters such as Escherichia coli, Listeria monocytogenes, salmonella and coliforms were studied. A Sensory acceptance test was carried out by 23 panellists, where all evaluated attributes obtained an acceptability index greater than 70%. According to the Cape Verdean standard for cheese, the cheeses were classified as fresh and low-fat cheese. Regarding moisture content, the obtained results allow to classify cheese A as semi-soft cheese and B and C as soft cheese. Concerning pH and titratable acidity, the values ranged from 5.68 to 6.19 and 6.4 to 11.1 mLNaOH1N/100g, respectively. Salmonella and L. monocytogenes were not detected, E. Coli was lower than the maximum accepted value established by Commission Regulation (EC) No 2073/2005 and Commission Regulation (EC) No 1441/2007. In contrast, faecal coliforms in cheeses B and C were higher than those established by the Commission Regulation (EC). Overall, the results from this study may contribute to improving the production process and quality control of coalho cheese.

Genomic Characterization of Wild Lactobacillus delbrueckii Strains Reveals Low Diversity but Strong Typicity.

Investigating the diversity of a given species could give clues for the development of autochthonous starter cultures. However, few studies have focused on the intraspecies diversity of Lactobacillus delbrueckii strains, a technologically important lactic acid bacterium for the dairy industry. For this reason, Lactobacillus delbrueckii strains from the Saint-Nectaire Protected Designation of Origin (PDO) area were isolated and characterized. Genetic diversity was determined based on core genome phylogenetic reconstruction and pangenome analysis, while phenotypic assessments encompassed proteolysis and volatile compound production potential. A total of 15 L. delbrueckii ssp. lactis unique new strains were obtained. The genetic analysis and further proteolytic activities measurement revealed low variability among these Saint-Nectaire strains, while substantial genetic variability was observed within the L. delbrueckii ssp. lactis subspecies as a whole. The volatile compound profiles slightly differed among strains, and some strains produced volatile compounds that could be of particular interest for cheese flavor development. While the genetic diversity among Saint-Nectaire strains was relatively modest compared to overall subspecies diversity, their distinct characteristics and pronounced differentiation from publicly available genomes position them as promising candidates for developing autochthonous starter cultures for cheese production.

Comparative analysis of microbial succession and proteolysis focusing on amino acid pathways in Asiago-PDO cheese from two dairies

In this study, a comprehensive and comparative analysis was conducted on Italian Asiago-PDO cheese obtained from two different dairies named Dairy I and Dairy II using industrial and natural fermented milk, respectively. The analysis encompassed the evaluation of chemical composition, the succession of the microbiota during manufacture and ripening, and proteolysis mainly focusing on free individual amino acid (FAA) profiles. A metagenomic approach was used to investigate the cheese microbiome functionality. Differences in gross chemical composition were more evident during ripening, with Dairy II showing higher variability within batches. The microbiota varied significantly between the two dairies and ripening stages. The choice of starter culture shaped the microbiota during production and affected the microbial diversity of non-starter lactic acid bacteria (NSLAB) originated from the raw milk during ripening. Peptide chromatographic profiles and FAA concentrations increased as ripening progressed, with Dairy I showing higher production of FAA. Functional analysis of the metagenomes linked species to specific amino acid metabolism/catabolism pathways. The amino acid metabolism pathways, particularly those related to aromatic amino acids, lysine, and branched-chain amino acids, were affected by the presence of specific NSLAB species, which differed between the two dairies. The results obtained in this study reveal the impact of starter culture on peculiar cheese microbiota assemblies, which selectively targets amino acid pathways, providing insights into the potential flavor and aroma characteristics of Asiago-PDO cheese.

Microbial interactions shape cheese flavour formation

Cheese fermentation and flavour formation are the result of complex biochemical reactions driven by the activity of multiple microorganisms. Here, we studied the roles of microbial interactions in flavour formation in a year-long Cheddar cheese making process, using a commercial starter culture containing Streptococcus thermophilus and Lactococcus strains. By using an experimental strategy whereby certain strains were left out from the starter culture, we show that S. thermophilus has a crucial role in boosting Lactococcus growth and shaping flavour compound profile. Controlled milk fermentations with systematic exclusion of single Lactococcus strains, combined with genomics, genome-scale metabolic modelling, and metatranscriptomics, indicated that S. thermophilus proteolytic activity relieves nitrogen limitation for Lactococcus and boosts de novo nucleotide biosynthesis. While S. thermophilus had large contribution to the flavour profile, Lactococcus cremoris also played a role by limiting diacetyl and acetoin formation, which otherwise results in an off-flavour when in excess. This off-flavour control could be attributed to the metabolic re-routing of citrate by L. cremoris from diacetyl and acetoin towards α-ketoglutarate. Further, closely related Lactococcus lactis strains exhibited different interaction patterns with S. thermophilus, highlighting the significance of strain specificity in cheese making. Our results highlight the crucial roles of competitive and cooperative microbial interactions in shaping cheese flavour profile.

Ecological diversity and associated volatilome of typical mountain Caciotta cheese from Italy

Traditional products are particularly appreciated by consumers and among these products, cheese is a major contributor to the Italian mountainous area economics. In this study, shotgun metagenomics and volatilomics were used to understand the biotic and abiotic factors contributing to mountain Caciotta cheese typicity and diversity. Results showed that the origin of cheese played a significant role; however, curd cooking temperature, pH, salt concentration and water activity also had an impact. Viral communities exhibited higher biodiversity and discriminated cheese origins in terms of production farms. Among the most dominant bacteria, Streptococcus thermophilus showed higher intraspecific diversity and closer relationship to production farm when compared to Lactobacillus delbrueckii. However, despite a few cases in which the starter culture was phylogenetically separated from the most dominant strains sequenced in the cheese, starter cultures and dominant cheese strains clustered together suggesting substantial starter colonization in mountain Caciotta cheese. The Caciotta cheese volatilome contained prominent levels of alcohols and ketones, accompanied by lower proportions of terpenes. Volatile profile not only demonstrated a noticeable association with production farm but also significant differences in the relative abundances of enzymes connected to flavor development. Moreover, correlations of different non-homologous isofunctional enzymes highlighted specific contributions to the typical flavor of mountain Caciotta cheese. Overall, this study provides a deeper understanding of the factors shaping typical mountain Caciotta cheese, and the potential of metagenomics for characterizing and potentially authenticating food products.

Роль липолитических ферментов в улучшении органолептических показателей низкожирных сыров

Lipolytic enzymes can improve the sensory profile of low-fat cheeses. In this study, bovine lipase improved the flavor of semi-hard cheese with a 30.0% fat mass fraction.

Regulation of the pleiotropic transcriptional regulator CodY on the conversion of branched-chain amino acids into branched-chain aldehydes in Lactococcus lactis.

Branched-chain aldehydes are the primary compounds that contribute to the nutty flavor in cheddar cheese. Lactococcus lactis, which is often applied as primary starter culture, is a significant contributor to the nutty flavor of cheddar cheese due to its ability of conversion of BCAAs into branched-chain aldehydes. In the present study, we found that the regulatory role of CodY is crucial for the conversion. CodY acts as a pleiotropic transcriptional regulator via binding to various regulatory regions of key genes. The results presented valuable knowledge into the role of CodY on the regulation and biosynthetic pathway of branched-chain amino acids and the related aldehydes. Furthermore, it provided new insight for increasing the nutty flavor produced during the manufacture and ripening of cheese.

Effect of Lactiplantibacillus plantarum on the Conversion of Linoleic Acid of Vegetable Oil to Conjugated Linoleic Acid, Lipolysis, and Sensory Properties of Cheddar Cheese.

Conjugated linoleic acid (CLA) is perceived to protect the body from metabolic diseases. This study was conducted to determine the effect of Lactiplantibacillus plantarum (Lp. plantarum) on CLA production and sensory characteristics of cheddar cheese. Lp. plantarum can convert linoleic acid (LA) to CLA. To increase CLA in cheddar cheese and monitor the conversion of LA to CLA by Lp. plantarum, the LA content of cheese milk (3.4% fat) was increased by partially replacing fat with safflower oil (85% LA of oil) at 0, 3, 6, and 9% concentrations (T1, T2, T3, and T4). Furthermore, Lp. plantarum 108 colony-forming units (CFU)/mL (8 log CFU mL-1) was added in all treatments along with traditional cheddar cheese culture (Lactococcus lactis ssp. lactis and L. lactis ssp. cremoris). After 30 days of ripening, Lp. plantarum in T1, T2, T3, and T4 was 6.75, 6.72, 6.65, and 6.55 log CFU g-1. After 60 days of ripening, Lp. plantarum in T1, T2, T3, and T4 was 6.35, 6.27, 6.19, and 6.32 log CFU g-1. After 60 days of ripening, Lp. plantarum in T1, T2, T3, and T4 was 6.41, 6.25, 6.69, and 6.65 log CFU g-1. GC-MS analysis showed that concentrations of CLA in the 90 days' control, T1, T2, T3, and T4 were 1.18, 2.73, 4.44, 6.24, and 9.57 mg/100 g, respectively. HPLC analysis revealed that treatments containing Lp. plantarum and LA presented higher concentrations of organic acids than the control sample. The addition of safflower oil at all concentrations did not affect cheese composition, free fatty acids (FFA), and the peroxide value (POV) of cheddar cheese. Color flavor and texture scores of experimental cheeses were not different from the control cheese. It was concluded that Lp. plantarum and safflower oil can be used to increase CLA production in cheddar cheese.

Consumer Preferences in Traditional Snacks, Bipang (Case Study of Pak Tani’s Bipang Company in Pasuruan)

There is a shift in people's attitudes and interest in traditional snacks due to the influence of globalization and the perception that traditional snacks are out of date, causing the abandonment of these traditional snacks. The Covid-19 pandemic has added to the decline in income in many business sectors. This impact was also experienced by the Pak Tani’s bipang company, which has existed since 1976. For this reason, it is necessary to do a way to attract public interest in bipang products by innovating the flavor, product size, packaging design and accessibility. This study aimed to determine consumer preferences for traditional bipang snacks. The research conducted in October – November 2022 with a total sample were 400 respondents from Surabaya residents, which was carried out using a purposive sampling technique by distributing questionnaires. Respondents were asked to determine the combination of attributes from the most preferred to least preferred. This study uses descriptive quantitative methods using conjoint analysis techniques. The results showed that respondents liked bipang products with cheese flavor, bite size, standing pouch packaging design with zipper and offline accessibility. Based on the importance value factor, the order of the most important variables for respondents is flavor.&#x0D; Keywords: conjoint analysis, consumer preferences

Characterisation of Cooked Cheese Flavour: Non-Volatile Components.

This work examined the role of selected non-volatile compounds in cooked cheese flavour, both as tastants and as precursors of aroma generation in the Maillard reaction. The effect of cooking on the concentration of selected non-volatile compounds (organic acids, sugars, amino acids, γ-glutamyl dipeptides, and diketopiperazines) in six cheeses (mature Cheddar, mozzarella, Parmesan, and mild Cheddar (low, medium, and high fat)) was determined. Sugars, amino acids, and γ-glutamyl dipeptides were extracted and analysed by LC, whereas diketopiperazines were extracted by solid-phase extraction and analysed by GC-MS. Sugars, amino acids, and γ-glutamyl dipeptides decreased in concentration during cooking, whereas diketopiperazines and some organic acids increased in concentration. Diketopiperazines were above the taste threshold in some cooked cheeses and below the threshold in uncooked cheeses. The role of fat content in cooked cheese flavour is discussed. Furthermore, γ-glutamyl dipeptide concentration increased during 24 months of ageing in low, medium, and high-fat Cheddars, with similar levels of γ-glutamyl dipeptide detected in aged low and high-fat Cheddars. This work will give valuable insight for the dairy industry to inform the development of cheeses, especially low-fat variants, for use in cooked foods.

Free fatty acid hydrolyzed with lipases and their effects on enzyme-modified cheese flavor

Free fatty acid hydrolyzed with lipases and their effects on enzyme-modified cheese flavor