Reducing emissions for artisanal cheeses

Liz Whitley reports

Volume 78:3 closed on 27 September and comprised three reviews, 26 original research papers and two editorials, with authors from 13 countries. “Visual and textual prompts as a nudge to promote the selection of healthy dairy products among adolescent and young adult students” by Filho and colleagues from Brazil, was selected as the Editor’s Choice article and the second editorial  was entitled “Guidance for submitting research on previously unreported cheeses” in order to give guidance to authors.

Reviews

A study of greenhouse gas emissions and related abatement technologies found that anaerobic digestion was the most promising mitigation technology, capable of reducing methane emissions by 50-70% while producing renewable biogas and organic fertiliser. Co-digestion was found to increase biogas yields by 10-30% through enhanced carbon-to-nitrogen balance. 3-Nitrooxypropanol feed additives demonstrated up to 40% methane reduction in controlled settings, but widespread adoption has significant hurdles. The report concluded that despite the availability of multiple mitigation strategies, implementation in developing countries remains constrained by capital costs, technical expertise and infrastructure gaps.

An invited review, entitled, “A systematic review of the internet of things and artificial intelligence applications in milk quality monitoring and analysis,” concluded that spectroscopy was a leading method for compositional and adulteration analysis, while gas sensors were preferred for microbial spoilage detection. Edge computing was the leading data processing strategy, enabling real-time analysis, though hybrid edge-cloud platforms demonstrated good scalability potential. Machine Learning models achieved high predictive accuracy, while Deep Learning excelled in classification tasks, particularly for adulteration detection.

The final review was also an invited review covering the milk metabolome and its potential use for enhanced dairy processing. Milk metabolomics has emerged as a valuable tool in dairy science, offering detailed insight into the molecular composition of milk. The milk metabolome is affected by multiple intrinsic and extrinsic factors, including species, breed, diet, stage of lactation and health status, each of which influences nutritional value and processability of milk. As such, several milk metabolites, including choline, acetate and myo-inositol, have been correlated with gelation, a key techno-functional indicator.

Original research: Microbiology

The first of two studies under the microbiology heading investigated how seasonal variations influence the microbial dynamics, biochemical profile and nutritional quality for 21 days ripening of Artisanal Colonial Cheese, a Brazilian speciality cheese. It was found that cheese produced during the summer exhibited a dominance of Lactococcus, which correlated with elevated levels of unsaturated fatty acids, favourable hypocholesterolaemic/ hypercholesterolaemic (H/H) ratios and ester-rich volatile profiles.

On the other hand, winter samples showed dynamic microbial succession resulting in more short chain fatty acids. Additionally, the fungal communities showed differentiation according to season. Finally, nutritional indices suggested that summer cheese promoted improved anti-atherogenic properties.

The second microbiology based study aimed to develop efficient, user-friendly, biosafe and broadly applicable genome editing methods for Streptococcus thermophilus a widely used organism in dairy research and production. The methods employed were successful and the study group felt that they were successful across most strains.

New product development

The use of hyperimmune bovine colostrum (HC) in neutralising the virulence of enterohaemorrhagic Escherichia coli(EHEC) O157:H7 was investigated and was found to be effective, leading to potential for the utilisation of HC for controlling EHEC colonisation in calves and to prevent the development of haemolytic uraemic syndrome in humans.

Milk production

The first of three studies on milk production aimed to identify single nucleotide polymorphisms (SNPs) within the bovine ACSS2 gene identified three novel SNP. Investigations into their associations with milk production traits in dairy cattle showed associations with protein and fat concentration. The results suggest that ACSS2 intronic polymorphisms may serve as molecular markers for improving milk yield and composition in dairy cattle through marker-assisted selection.

A comparative study using two groups of Friesian Holstein cows (one group first and second calvers and the second mature cows) showed that different lactation stages affect milk yield and milk components, while parity only affects milk quality; both affect enteric methane production.

In smart livestock farming, machine learning has shown promising potential for enhancing precision, efficiency and productivity. The third study in the milk production category focussed on the use of a smart production prediction model that can improve the management efficiency of dairy buffalo. Results for calf gender, lactation length, total and daily yield were produced and it was concluded that the model was efficient for managing buffalo production.

Dairy chemistry

A comparative analysis of donkey, cow and camel resources found that donkey milk protein hydrolysates exhibited superior antimicrobial, anticancer and antioxidant activities, while camel milk hydrolysates showed strong α-amylase inhibition. These findings highlight the potential of milk-derived bioactive peptides for developing functional foods and therapeutic agents, offering natural alternatives for disease prevention and management.

Foam is an undesirable occurrence during the manufacture of nutritional oil-in-water emulsion food products, such as infant formula, and also during the preparation of nutritional formulas by consumers. The impact of commonly used oil sources on the foaming properties of model infant formula emulsions was investigated using soybean oil, 1, 3-dioleoyl-2-palmitoylglycerol (OPO)-rich palm oil, coconut oil, anhydrous milk fat (AMF), sunflower oil and an oil mix (blend of oils typically used in infant formulas).

The oil mix and OPO-rich palm oil were found to inhibit foaming significantly, or destabilised the foam and were followed by AMF, whereas the other oils had no effect. It was felt that the  inhibitory effect of oils may be multifactorial, and further research can be conducted to deduce the mechanisms.

A novel method of assessing the quality of goat milk used phosphofructokinase gene mutation and the interaction between phosphofructokinase and small nutrients through molecular simulation with success. The authors felt that this may be a useful tool for monitoring the quality of goat milk.

Yak ghee is a traditional dairy product in the Chinese plateau area, and is rich in lipids. The lipid composition of dairy products is affected by various factors, and the geographical origin of food has attracted consumer attention. In order to establish a basis for determining the origins of yak ghee, samples from five major Chinese yak pastoral areas were collected. Lipids were extracted and analysed and significant differences in lipid composition, carbon chain length, unsaturation and side-chain fatty acyl composition were found across different pastoral areas. It was felt that the results of this study provide a basis for establishing a ghee origin traceability system.

Advances in dairy process technology

An investigation into the influence of hydrocolloids at varying concentrations on the physicochemical, functional, textural and rheological properties of processed cheese products formulated with milk protein concentrate 80 concluded that xanthan gum had a better performance than k-carrageenan and guar gum. The study proposed that incorporating xanthan gum at a level of 0.3% during the production of PCP using MPC80 and butter could yield a processed cheese-like product with improved textural matrix, functional and rheological attributes.

The evaluation of the different effects of three polysaccharides on whey protein composite gels, which could be used as natural thickeners is reported. Whey protein-polysaccharide composite gels were prepared from whey protein with three polysaccharides. Results of the study showed that a composite gel with added hydroxypropyl methyl cellulose exhibited high viscoelasticity improving the gel strength and the viscosity. 

Milk beer is a fermented beverage made from milk that is popular in China, but it faces limitations due to the high preservation and transportation costs associated with fresh milk. An exploration of the potential of using reconstituted milk as a fresh milk substitute for its production found that the overall quality remained comparable, although sensory evaluation scores were slightly lower on the product using reconstituted milk, but were still acceptable.

Of interest to cheese makers a study aiming to evaluate the possibility of eliminating the cutting, mixing and cooking stages of milk gel during cheese production is reported. This study employed a hydrodynamic (wave) method to induce forced oscillations in milk during coagulation. It was found that hydrodynamic oscillations produced cheese grain and curd in milk and at low oscillation frequencies, the fat content of whey was very low, at 0.08%. At higher frequencies, fat loss into the whey increased. The protein content in the whey remained frequency-independent and did not exceed 0.8%. Cheese samples produced using the hydrodynamic method exhibited similar characteristics to those produced via conventional techniques. The findings suggest that the hydrodynamic method holds promise for industrial cheese curd production, as it reduces processing time (by 0.5-1.5 hours) and minimises milk fat losses.

A study on the combined effect of direct steam injection and pH change on the functionality of Milk Protein Concentrate  using two different powders is reported under the topic of dairy process technology and engineering. Two temperatures (85°C and 105°C) and three pH values (7, 8 and 9) were studied. The samples were evaluated for chemical composition, total and soluble protein profile, zeta potential, hydrodynamic diameter, functionality (solubility, foaming capacity and stability, apparent viscosity, heat stability and rennet gelation time) and microstructure. It was found that functionalities improved for the MPC70 samples treated with increased pH treatment at both evaluated temperatures.

The next study focussed on water-flushing fermented milk (WFFM) as the primary raw material for the production of analogue cheese (AC), aiming to investigate the effects of varying water content (10%-25%) on the quality characteristics of AC prepared from WFFM curds. Results showed that as the water content increased from 10% to 20%, the sensory characteristics, microstructure, elasticity and adhesiveness of WFFM AC gradually improved, whereas its hardness, chewiness and water-holding capacity deteriorated with increasing water content. When the water content reached 20%, the AC exhibited optimal elasticity, adhesiveness and sensory evaluation characteristics, along with a close and stable three-dimensional protein network structure. When the water content exceeded 20%, excessive separation of proteins and fats occurred within the matrix, leading to fragmentation of the protein network, weakening the characteristics of the AC.

Dairy technology

A study involving the concentration of goat milk oligosaccharides(GMOS) and their effects on the metabolism of intestinal flora in a simulator of the human intestinal microbial ecosystem found that enriched GMOS stimulated the growth of probiotic bacteria. This then enhanced the production of short-chain fatty acids, thereby contributing to the alleviation of Escherichia coli-induced gut microbiota dysbiosis.

Traditional production of the Algerian cheese, Bouhezza, uses goatskin bags, known as Djeld. The next study examined the microstructural and microbial changes in these bags following interactions with fermented milk (Lben). It was found that the increased biofilm richness and skin porosity contributed to the unique characteristics of this cheese.

The reduction of freezing induced damage in cream cheese assessed the ice recrystallisation inhibition effect of dairy protein–polysaccharide complexes by incorporating them into a commercial cream cheese spread. The complexes made from the unhydrolysed biopolymers showed a reduction in ice crystal size relative to a negative control for both gum types in the study. The cream cheese spread, with added complex, after repeated freeze-thaw treatment cycles, showed rheological and textural properties more similar to the fresh control spread compared to the other treatments.

Whey protein concentrate (WPC) powders are widely used as ingredients in the food industry due to their high-protein content and desirable functional properties. Sub-optimal spray drying conditions can lead to poor powder flowability and/or increased cohesiveness, influencing the risk of handling challenges. The next study investigated the impact of varying spray drying temperatures and powder storage temperatures on particle size distribution, particle shape, cohesiveness and flowability of WPC80 powders. Results showed that moderate and higher spray drying temperatures yielded smaller, more irregularly shaped particles with reduced flowability, compared to WPC spray-dried at lower temperatures. This was related to particle breakage, lower bulk density and increased compressibility. Lower spray drying temperatures yielded larger, more uniformly shaped particles with better flowability but higher levels of residual moisture and water activity, and more cohesive compressed powder.

A study from Iran aimed to encapsulate propolis by breaking down the structure of sodium caseinate, and embedding the propolis. It was found that encapsulation not only protected the propolis extract from light and oxidation but also masked its herbal fragrance and unpleasant taste. It was felt that these results supported the efficient design of delivery systems for hydrophobic nutraceuticals, enabling their incorporation into dairy products such as yogurt, as well as a broad range of functional food and beverage applications.

The impact on the profile of bioactive peptides, fatty acid composition and rheological properties after the addition of the spore-forming probiotic Weizmannia coagulans GBI-30 to Minas Frescal cheese, an artisanal cheese from Brazil, was the subject of another study. A range of concentrations of the added species was evaluated and it was found that addition of W. coagulans promoted the release of different bioactive peptides with potential antihypertensive, antimicrobial, antidiabetic and immunomodulatory activities. Furthermore, the lipid profile of the probiotic cheeses showed a significant increase in unsaturated fatty acids (mono- and polyunsaturated), recognised for their health-promoting effects, including benefits for cardiovascular and metabolic health. Cheeses supplemented with W. coagulans exhibited improved rheological and textural properties, including greater firmness and cohesiveness.

Calcium-induced milk gels are excellent matrices for formulating calcium-fortified semisolid foods. The next study reported examined the gelation process and physicochemical properties of calcium-induced skim milk gels with caseinglycomacropeptide. Results were encouraging, showing rapid gel formation with similar behaviour across samples. Gels exhibited a homogeneous structure, no phase separation and pseudoplastic behaviour. The addition of caseinglycomacropeptide slightly increased elasticity and after storage enhanced gel firmness was noted. Water holding capacity and protein hydration remained unchanged. However, calcium retention increased with higher caseinglycomacropeptide levels, suggesting it binds calcium within the matrix.

Consumer acceptance

Combining visual and textual prompts in a simulated cafeteria increased the selection of healthier dairy options, such as yogurt and white cheese, among adolescents and young adults. This low-cost educational nudge may support healthier eating habits during a critical stage of dietary habit formation. This article was chosen as the Editor’s Choice for this issue.

Quality control

An investigation into the chemical components and molecular arrangement of dairy food emulsions by the use Raman confocal microscopy is reported and the study further aimed to enable an understanding of how these arrangements change with component types and temperatures. The process successfully resolved and distinguished the chemical components of the model emulsions. The results showed that Raman confocal microscopy is a useful approach to the study of oil-in-water emulsions. It was felt that it is possible to establish a strong scientific basis for the targeted choice of emulsifiers and ingredients to resolve emulsion-related issues in the development of dairy food systems, including hybrid dairy/non-dairy food emulsions.

Sustainability

Aimed at improving prediction of salt diffusion and pH in cheese  a study compared the predictive performance of multiple machine learning (ML) techniques (including artificial neural networks (ANNs), support vector machines (SVMs), Gaussian process regression (GPR) and bootstrap forest) with response surface methodology (RSM) for modelling salt diffusion coefficients and final pH in rennet-induced micellar casein concentrate (MCC) gels. Gaussian process regression yielded the highest predictive accuracy for both salt diffusion and pH followed by SVM. Artificial neural network performance was moderate showing sensitivity to dataset size. The RSM model achieved an R² of 0.94 for pH prediction. This study is among the first to systematically benchmark these methods using a single, experimentally consistent dataset.