Cardoon-based rennets for cheese production

Optimization of caseinolytic and coagulating activities of Solanum tuberosum rennets for cheese making

BACKGROUND

In recent years, the rising global demand for cheese, the high cost and limited supply of calf rennet, and consumer choices have increased research into new alternatives to animal or recombinant chymosins for cheese making. Plant proteases with caseinolytic activity (CA) and milk-clotting activity (MCA) have been proposed as alternatives for milk clotting to obtain artisanal cheeses with new organoleptic properties. They have been named vegetable rennets (vrennets). The aim of this study was to evaluate the performance of two Solanum tuberosum aspartic proteases (StAP1 and StAP3) as vrennets for cheese making and to obtain a statistical model that could predict and optimize their enzymatic activity.

RESULTS

To optimize the CA and MCA activities, a response surface methodology was used. Maximum values of CA and MCA for both enzymes were found at pH 5.0 and 30-35 °C. Analysis of the degradation of casein subunits showed that it is possible to tune the specificity of both enzymes by changing the pH. At pH 6.5, the αS - and β- subunit degradation is reduced while conserving a significant MCA.

CONCLUSION

The statistical models obtained in this work showed that StAP1 and StAP3 exert CA and MCA under pH and temperature conditions compatible with those used for cheese making. The casein subunit degradation percentages obtained also allowed us to select the best conditions for the degradation of the κ-casein subunit by StAPs. These results suggest that StAP1 and StAP3 are good candidates as vrennets for artisan cheese making. © 2023 Society of Chemical Industry.

Future Perspective and Technological Innovation in Cheese Making Using Artichoke (Cynara scolymus) as Vegetable Rennet: A Review

Milk coagulation is a process used for the formulation of different dairy products such as cheese. In this process, milk undergoes changes in its chemical stability thanks to acidification or enzymatic reactions. Traditionally, milk coagulation has been carried out with rennet of animal origin, but recently, the research of new types of rennet such as microbial rennet and vegetable rennet has increased. This study aims to present an organized review of the most relevant information on lactic coagulation, its relationship with vegetable rennets, and the importance of the botanical genus Cynara in the extraction of vegetable rennets, focusing on the coagulant potential of artichoke (Cynara scolymus). We conducted this literature review and found that lactic coagulation and vegetable rennets are linked through the enzymatic activity of the latter. The results of the main studies demonstrated a strong relationship between vegetable rennets and protease enzymes as well as the presence of these enzymes in extracts of cardoon (Cynara scolymus) and artichoke (Cynara scolymus). In addition, studies highlight the presence of thistle extracts in artisanal cheese preparations in the Iberian Peninsula. Based on the results of the studies, a comparison between cheeses made with vegetable rennet and those made with traditional rennet was also carried out. Although the results show that the use of vegetable rennet in the manufacture of cheese can confer undesirable characteristics, the use of extracts from Cynara plants demonstrates that vegetable rennets have an industrial potential, especially the one obtained from artichoke (Cynara scolymus) due to its high availability. Nevertheless, specific studies are required for a better understanding and application of this rennet.

The wide spectrum of industrial applications for cultivated cardoon (Cynara cardunculus L. var. Altilis DC.): A review

Cynara cardunculus L. var. altilis DC. belongs to the Asteraceae family and is widely used. This species is integrated into the Mediterranean diet and has broad applicability due to its rich chemical composition. Its flowers, used as a vegetable coagulant for gourmet cheese production, are rich in aspartic proteases. Leaves are rich in sesquiterpene lactones, the most abundant being cynaropicrin, while stems present a higher abundance of hydroxycinnamic acids. Both classes of compounds exhibit a wide range of bioactive properties. Its chemical composition makes it applicable in other industrial sectors, such as energy (e.g., manufacturing of biodiesel and biofuel) or paper pulp production, among other biotechnological applications. In the last decade, cardoon has been identified as a competitive energy crop, constituting an opportunity for the economic recovery and development of the rural areas of the Mediterranean basin. This article reviews the chemical composition, bioactive properties, and multifaceted industrial applications of cardoon.

Effect of CSN3 Gene Polymorphism on the Formation of Milk Gels Induced by Physical, Chemical, and Biotechnological Factors

During the last decade, research into genetic markers in the casein gene cluster has been actively introduced in cattle breeding programs. A special interest has been paid to the polymorphism of the CSN3 gene, responsible for the expression of the k-casein, playing a key role in protein coagulation, interaction with whey proteins, stabilization, and aggregation of casein micelles. This paper aimed to determine the effect of CSN3 genetic polymorphism on acid; rennet; acid-rennet; heat- and acid-induced as well as heat- and calcium-induced coagulation in skimmed milk; and protein-standardized milk systems (UF, NF, RO, VE). The influence of polymorphic variants of the CSN3 gene on the coagulation ability of milk proteins was assessed by the particle size of casein micelles, protein retention factor in the clot, and coagulation ability (duration of induction period, mass coagulation period, dynamic viscosity in gel point). The correlation between CSN3 gene polymorphism and protein coagulation was revealed. Milk systems obtained from CSN3 BB milk were found to have the shortest duration of coagulation, formation of better gel strength values, and increased yield compared to CSN3 AA. This study will improve the efficiency of milk processing and optimize the technology of dairy product production.

Safety evaluation of the food enzyme phytepsin from Cynara cardunculus L

The food enzyme phytepsin (EC 3.4.23.40) is extracted from the pistils of the cardoon (Cynara cardunculus L.) by different manufacturers represented by the Dirección General de Salud Pública, Gobierno de Canarias, España. It is intended to be used in milk processing for cheese production. As no concerns arose from the source of the food enzyme, from its manufacture, and based on a history of safe use and consumption, the Panel considered that toxicological data and the estimation of dietary exposure were not required. A search for the similarity of the amino acid sequences of the food enzyme to known allergens was made and no matches were found. The Panel considered that allergic reactions to this phytepsin cannot be excluded in individuals allergic to cardoon. However, the likelihood of allergic reactions to the phytepsin from C. cardunculus L. is expected not to exceed the likelihood of allergic reactions to cardoon. As the prevalence of allergic reactions to cardoon is low, also the likelihood of such reactions to occur to the food enzyme is low. Based on the data provided, the Panel concluded that this food enzyme does not give rise to safety concerns under the intended conditions of use.

Waste from Artichoke Processing Industry: Reuse in Bread-Making and Evaluation of the Physico-Chemical Characteristics of the Final Product

A relevant amount of waste is produced in the canning industry of globe artichoke. This study proposes to use flours of artichoke waste (stems and bracts) in durum wheat bread-making, replacing the re-milled durum wheat semolina at increasing levels (5, 7.5 and 10 g/100 g). No study had evaluated this type of enrichment in durum wheat bread, widespread in the same area where artichoke waste is mostly produced. The replacement had a visible effect on the flour color, increasing a* and reducing b* and L*, and this was reflected in the color of bread crumb. The water absorption determined by farinography, dough development time and dough stability increased as the level of replacement increased (up to 71.2 g/100 g, 7.3 min and 18.4 min, respectively). The mixograph peak height and mixing time increased compared to control. The alveograph W decreased, while the P/L ratio increased. The artichoke waste-enriched breads had a lower volume (as low as 1.37 cm³/g) and were harder than control, but they did not show relevant moisture losses during five days of storage. The obtained data show therefore an interesting potential of artichoke waste flours in bread-making, but further investigations are needed for achieving improved quality features.

Comparative Chemical Profiling and Biological Potential of Essential Oils of Petal, Choke, and Heart Parts of Cynara scolymus L. Head

The essential oil and macroelemental composition of different parts of flower bud (petal, choke, and heart) of Cynara scolymus L. were explored and compared using gas chromatography mass spectrometry (GC-MS) and inductively coupled plasma mass spectrometry (ICP-MS). Overall, 62 organic components were detected in the flower bud based on mass spectra characteristics and retention indices. The essential oil extracted from the petals, choke, and bud showed the presence of thirty-one, twenty-one, and twenty-one compounds, respectively, with linoleic acid and palmitic acid as the major components. 21 components were identified in the oil of the petals, comprising 94.45% of the total oil, in which linoleic acid methyl ester, palmitic acid methyl ester, octadecanoic acid methyl ester, O-α-d-glucopyranoside, and heptyl oct-3-yl ester were the major constituents. Twenty-one compounds, representing 89.13% of the total oil, were detected in the choke oil. Linoleic acid methyl ester, palmitic acid methyl ester, and 2-methyl-1-hexadecanol were the main components. However, the edible heart oil contains twenty compounds, comprising 86.84% of the total oil. Cyclopropane butanoic acid, linoleic acid, methyl ester, and palmitic acid were the major constituents. The analysis executed by ICP-MS revealed the presence of significant amounts of various inorganic elements in all the three samples. The extracted essential oils were tested for antibacterial, antioxidant, and anticancer activities. The results showed that the oil extracted from the petals of C. scolymus flower bud displayed the highest antibacterial, antioxidant, anti-inflammatory, and anticancer effects, as compared to choke and heart oils.

Phenolic Composition and Antioxidant, Anti-Inflammatory, Cytotoxic, and Antimicrobial Activities of Cardoon Blades at Different Growth Stages

Simple Summary

The rapid increase of the world population has promoted a more sustainable and efficient use of natural resources. To achieve complete and proper upcycling of plant crops, it is important to know their potential for industrial exploitation. Cardoon (Cynara cardunculus L.) is a species native to the Mediterranean basin widely used in different sectors, including food and pharmaceuticals. Despite their multiple industrial applications, not all plant tissues have been incorporated into the value chain. Therefore, this work aimed to characterize the phenolic composition and bioactive properties of cardoon blades throughout the phenological growth cycle. In addition to the structural variety of phytochemicals detected in the blade extracts, their antioxidant, anti-inflammatory, anti-proliferative, and antimicrobial properties were also highlighted. While immature material showed higher levels of phenolic compounds and greater potential to inhibit lipid peroxidation, samples at higher development stages had greater anti-proliferative, anti-inflammatory, and antimicrobial potential. These results demonstrate that the growth cycle influences the bioactive potential of cardoon blades and will be useful to establish suitable industrial applications, such as the development of ingredients for functional foods and nutraceuticals, among other products.

Abstract

Cardoon (Cynara cardunculus var. altilis) blades were collected at sixteen sampling dates (B1–B16) to study the influence of the phenological growth stage on the phenolic composition and biological properties. Twenty phenolic compounds were identified, among which trans 3,4-O-dicaffeoylquinic acid, 5-O-caffeoylquinic acid, and luteolin-O-hexoside (39.6, 42.6, and 101.0 mg/g extract, respectively) were the main compounds. Immature blades (B3) had a higher content of phenolic compounds (178 mg/g extract) and a greater ability to inhibit the formation of thiobarbituric acid reactive substances (IC₅₀ of 1.61 µg/mL). Samples at more advanced growth stages revealed a greater capacity to inhibit oxidative hemolysis (B8, IC₅₀ of 25 and 47.4 µg/mL for Δt of 60 and 120 min, respectively) and higher cytotoxic (B8–B13, GI₅₀ between 7.1 and 17 µg/mL), anti-inflammatory (B13, IC₅₀ of 10 µg/mL), and antibacterial activities. In turn, the antifungal activity varied depending on the tested fungi. All these results suggest that maturity influences the phenolic composition and bioactive properties of cardoon blades, which reveal great potential for the development of bioactive ingredients for food and pharmaceutical applications, among others.

Plant Milk-Clotting Enzymes for Cheesemaking

The reduced availability and the increasing prices of calf rennet, coupled to the growing global demand of cheese has led, worldwide, to explore alternative clotting enzymes, capable to replace traditional rennet, during the cheesemaking. In addition, religious factors and others related to the vegetarianism of some consumers, have led to alternative rennet substitutes. Nowadays, several plant-derived milk-clotting enzymes are available for cheesemaking technology. Many efforts have also been made to compare their effects on rheological and sensory properties of cheese to those arising from animal rennet. However, vegetable clotting enzymes are still partially suitable for cheesemaking, due to excessive proteolytic activity, which contribute to bitter flavor development. This review provides a literature overview of the most used vegetable clotting enzymes in cheese technology, classified according to their protease class. Finally, clotting and proteolytic activities are discussed in relation to their application on the different cheesemaking products.

Effects of microbial coagulants from Rhyzomucor miehei on composition, sensory and textural characteristics of long-ripened hard cheeses

The increasing use of rennet substitutes entails evaluating their performances on different types of cheese. The production of hard cheese using either microbial coagulants from Rhyzomucor miehei (MC) or calf rennet (CR) from different manufacturers was investigated in parallel cheese makings at three industrial dairies. Cheeses were analysed after 9, 12, 16 and 18 months of ripening. Minor differences in cheese composition were found between treatments, principally related to fat content. Cheeses produced with one out of the three MC showed slower primary proteolysis on both αs1- and αs0-casein, compared to the corresponding CR cheeses, indicating a different activity of this coagulant. The same cheeses also had significantly different sensory profiles at 9 months of ripening. Treatments did not differ in free amino acid composition nor in rheological parameters, regardless of ripening period. The long ripening of hard cheeses thus smooths possible differences attributable to MC.

Chemical composition and biological activity of cardoon (Cynara cardunculus L. var. altilis) seeds harvested at different maturity stages

Cardoon seeds collected in Greece at four different maturity stages (samples S1 to S4) were analysed in terms of chemical composition and in vitro bioactivities. The content of phenolic compounds (six compounds in total) increased with increasing maturity, and 3,5-O-dicaffeyolquinic (14.8-33.8 mg/g extract) acid was the compound detected in higher abundance. Mature seeds (sample S4) also revealed the highest content in lipids (23 g/100 g extract) and tocopherols (29.62 mg/100 g dw) and demonstrated the highest cytotoxic (GI₅₀ of 97-216 µg/mL) and anti-inflammatory (IC₅₀ = 148 µg/mL) activities, and capacity to inhibit the formation of thiobarbituric acid reactive substances (TBARS) (IC₅₀ = 5 µg/mL). Cardoon seed hydroethanolic extracts also revealed high antibacterial and antifungal potential, particularly samples S3 and S1, respectively. This study proved the multifaceted potential associated with valorisation of cardoon seeds, while their biological and chemical composition can be influenced by the maturity stage.

Towards a Cardoon (Cynara cardunculus var. altilis)-Based Biorefinery: A Case Study of Improved Cell Cultures via Genetic Modulation of the Phenylpropanoid Pathway

Cultivated cardoon (Cynara cardunculus var. altilis L.) is a promising candidate species for the development of plant cell cultures suitable for large-scale biomass production and recovery of nutraceuticals. We set up a protocol for Agrobacterium tumefaciens-mediated transformation, which can be used for the improvement of cardoon cell cultures in a frame of biorefinery. As high lignin content determines lower saccharification yields for the biomass, we opted for a biotechnological approach, with the purpose of reducing lignin content; we generated transgenic lines overexpressing the Arabidopsis thaliana MYB4 transcription factor, a known repressor of lignin/flavonoid biosynthesis. Here, we report a comprehensive characterization, including metabolic and transcriptomic analyses of AtMYB4 overexpression cardoon lines, in comparison to wild type, underlining favorable traits for their use in biorefinery. Among these, the improved accessibility of the lignocellulosic biomass to degrading enzymes due to depletion of lignin content, the unexpected increased growth rates, and the valuable nutraceutical profiles, in particular for hydroxycinnamic/caffeoylquinic and fatty acids profiles.

Introduction of a Glycine Linker Connecting the Heavy and Light Chains in Synthetic Cardosin B-Derived Rennet Changes the Specificity of Subpocket S3'

The development of plant-based synthetic rennets is of high commercial interest, due to the current great consumer demand for animal product alternatives. A previously developed recombinant form of the aspartic protease cardosin B with a three-glycine linker showed great potential due to its good performance in milk coagulation. This enzyme was found to be more specific and less proteolytically active than the native form for milk clotting, but the underlying structural causes for these activity changes were not completely clear. Here, we have performed molecular dynamics simulations with the recombinant enzyme with and without the linker. Our results showed that the introduction of the linker changes the subpocket S3', which is located more than 4 nm away. These results showcase how small modifications in proteins can have significant effects in distant regions in the protein structure that affect their biotechnological applications.

Artichoke cv. Francés flower extract as a rennet substitute: effect on textural, microstructural, microbiological, antioxidant properties, and sensory acceptance of miniature cheeses

BACKGROUND

The most common milk-clotting enzymes in the cheese industry are recombinant chymosins. Food naturalness is a factor underpinning consumers' food choice. For consumers who avoid food with ingredients from genetically modified organisms (GMOs), the use of vegetable-based rennet substitute in the cheese formulation may be a suitable solution. Artichokes that deviate from optimal products, when allowed to bloom due to flower protease composition, are excellent as raw material for vegetable rennet preparation. As enzymatic milk clotting exerts a significant impact on the characteristics of the final product, this product should be studied carefully.

RESULTS

Mature flowers from unharvested artichokes (Cynara scolymus cv. Francés) that did not meet aesthetic standards for commercialization were collected and used to prepare a flower extract. This extract, as a coagulant preparation, enabled the manufacture of cheeses with distinctive characteristics compared with cheeses prepared with chymosin. Rennet substitution did not affect the actual yield but led to significant changes in dry matter yield, humidity, water activity, protein content, and color, and conferred antioxidant activity to the cheeses. The rennet substitution promoted significant modifications in springiness, and in the microstructure of the cheese, with a more porous protein matrix and an increment in the size of the fat globules. Both formulations showed a similar microbiota evolution pattern with excellent microbiological quality and good sensory acceptance.

CONCLUSIONS

The rennet substitute studied here produced a cheese adapted to specific market segments that demand more natural and healthier products made with a commitment to the environment but well accepted by a general cheese consumer. © 2020 Society of Chemical Industry.

Exploring the Milk-Clotting and Proteolytic Activities in Different Tissues of Vallesia glabra: a New Source of Plant Proteolytic Enzymes

Proteolytic enzymes are widely distributed in nature, playing essential roles in important biological functions. Recently, the use of plant proteases at the industrial level has mainly increased in the food industry (e.g., cheesemaking, meat tenderizing, and protein hydrolysate production). Current technological and scientific advances in the detection and characterization of proteolytic enzymes have encouraged the search for new natural sources. Thus, this work aimed to explore the milk-clotting and proteolytic properties of different tissues of Vallesia glabra. Aqueous extracts from the leaves, fruits, and seeds of V. glabra presented different protein profiles, proteolytic activity, and milk-clotting activity. The milk-clotting activity increased with temperature (30-65 °C), but this activity was higher in leaf (0.20 MCU/mL) compared with that in fruit and seed extracts (0.12 and 0.11 MCU/mL, respectively) at 50 °C. Proteolytic activity in the extracts assayed at different pH (2.5-12.0) suggested the presence of different types of active proteases, with maximum activity at acidic conditions (4.0-4.5). Inhibitory studies indicated that major activity in V. glabra extracts is related to cysteine proteases; however, the presence of serine, aspartic, and metalloproteases was also evident. The hydrolytic profile of caseins indicated that V. glabra leaves could be used as a rennet substitute in cheesemaking, representing a new and promising source of proteolytic enzymes.

Seasonal variation in bioactive properties and phenolic composition of cardoon (Cynara cardunculus var. altilis) bracts

Cardoon (Cynara cardunculus L.) bracts were collected at different maturation stages to investigate seasonal changes in the phenolic compounds profile and in vitro bioactivities. Among the 12 phenolic compounds tentatively identified, 3,5-O-dicaffeoylquinic acid (21.83 mg/g extract) and apigenin-7-O-glucuronide (10.6 mg/g extract) were the most abundant. Immature bracts (C1: principal growth stage (PGS) 5) had the highest phenolic compounds content, and anti-inflammatory (IC₅₀ = 72 µg/mL) and cytotoxic (GI₅₀ of 30-79 µg/mL) activities. Moreover, extract C1 inhibited efficiently the formation of thiobarbituric acid reactive substances (TBARS; IC₅₀ = 26.8 µg/mL), while extract C8 (PGS 8/9) was more effective against oxidative haemolysis (IC₅₀ 38 and 75 µg/mL). The highest antibacterial and antifungal activities were attributed to samples C1 and C6 (PGS 7/8) and samples C2 (PGS 5/6) and C4 (PGS 6/7), respectively. Overall, the obtained results suggest the seasonal changes of polyphenolic composition and bioactivity of cardoon bracts of variable maturity.

A New Insight on Cardoon: Exploring New Uses besides Cheese Making with a View to Zero Waste

Cardoon, Cynara cardunculus L., is a perennial plant whose flowers are used as vegetal rennet in cheese making. Cardoon is native from the Mediterranean area and is commonly used in the preparation of salads and soup dishes. Nowadays, cardoon is also being exploited for the production of energy, generating large amount of wastes, mainly leaves. These wastes are rich in bioactive compounds with important health benefits. The aim of this review is to highlight the main properties of cardoon leaves according to the current research and to explore its potential uses in different sectors, namely the food industry. Cardoon leaves are recognized to have potential health benefits. In fact, some studies indicated that cardoon leaves could have diuretic, hepato-protective, choleretic, hypocholesterolemic, anti-carcinogenic, and antibacterial properties. Most of these properties are due to excellent polyphenol profiles, with interesting antioxidant and antimicrobial activities. These findings indicate that cardoon leaves can have new potential uses in different sectors, such as cosmetics and the food industry; in particular, they can be used for the preparation of extracts to incorporate into active food packaging. In the future, these new uses of cardoon leaves will allow for zero waste of this crop.

Influence of Cardoon Flower (Cynara cardunculus L.) and Flock Lactation Stage in PDO Serra da Estrela Cheese

Serra da Estrela (SE) cheese is one of the most appreciated Portuguese cheeses, being produced only from raw ewe's milk, cardoon flower and salt. Cardoon takes part in two important processes in cheese production-coagulation and proteolysis-contributing to its unique features. Furthermore, milk chemical characteristics change during the milking season, being another factor that account for the high variability of cheese attributes. Therefore, the purpose of this work is to study the influence of cardoon flower (commercial, 6 M and 3 M) and flock lactation stage (November 2018, February and April 2019) in the final characteristics of SE cheese. The parameters analysed were moisture, protein, fat and salt contents, texture and colour. Results showed that flock lactation stage has the highest influence in all the studied characteristics, corresponding the early stages of lactation to the most protein-rich and low-fat cheeses. Cardoon flower affects mainly fat and rind colour. This study allows us to conclude that seasonal changes in ewe's milk have a considerable impact in cheese attributes, and that although cardoon type had a more restrained effect, when used with expertise it may help adjust cheese sensory characteristics in order to obtain a final product that matches consumer acceptability requirements.

Toward alternative sources of milk coagulants for cheese manufacturing: establishment of hairy roots culture and protease characterization from Cynara cardunculus L

Extracts from hairy root cultures of Cynara cardunculus L. contain proteases and show milk-clotting activity. Cynara cardunculus L. or cardoon is often used as rennet in traditional cheese manufacturing, due to the presence of specific proteases in the flower. However, the flower extracts are variable depending on the provenance and quality of the flowers as well as high genetic variability among cardoon populations, and this affects the quality of the final product. In search for alternative sources of milk-clotting enzymes, hairy root cultures from cardoon were obtained and characterized regarding their protease content and proteolytic activity toward milk proteins. Aspartic, serine and cysteine proteases were identified in hairy roots by mass spectrometry analysis and an azocasein assay combined with specific inhibitors. RT-PCR analysis revealed the expression of cardosin A and D, and immunoblotting analysis suggested the presence of cardosin A or cardosin A-like enzyme in its mature form, supporting this system as an alternative source of cardosins. Hairy root protein extracts showed activity over caseins, supporting its use as milk coagulant, which was further tested by milk-clotting assays. This is also the first report on the establishment of hairy root cultures from cardoon, which paves the way for future work on controlled platforms for production of valuable metabolites which are known to be present in this species.

An Evaluation of the Clotting Properties of Three Plant Rennets in the Milks of Different Animal Species

Cynara cardunculus, Carica papaya and Ficus carica extracts are proposed as milk coagulants herein. Their coagulation efficiency was measured in bovine, buffalo, goat and sheep milk incubated at different temperatures. The milk-clotting and proteolytic activities as well as the lactodynamographic parameters were determined considering animal rennet as a reference coagulant. The vegetable coagulant, extracted from C. cardunculus pistils, proved to be the most suitable milk-clotting enzyme for cheesemaking, since it possesses similar milk clotting properties to conventional calf rennet. F. carica latex, but seemed to be a promising alternative coagulant at higher temperatures. The strong proteolytic activity of papain caused poor milk coagulation in all milk samples. To conclude, this result also supports the original hypothesis of this study that the excessive proteolytic nature of plant coagulants can negatively affect the cheesemaking process. The optimization of using a plant rennet in a dairy application can be done by selecting the appropriate plant rennet with a consistent clotting efficiency. These innovative manufacturing processes may also lead to the optimization and production of new cheese varieties.