Influence of the addition of Geotrichum candidum on the microbial, chemical, textural, and sensory features of soft soy cheese

Recent updates on plant protein-based dairy cheese alternatives: outlook and challenges

In response to population growth, ethical considerations, and the environmental impacts of animal proteins, researchers are intensifying efforts to find alternative protein sources that replicate the functionality and nutritional profile of animal proteins. In this regard, plant-based cheese alternatives are becoming increasingly common in the marketplace, as one of the emerging dairy-free products. However, the dairy industry faces challenges in developing dairy-free products alternatives that meet the demands of customers with specific lifestyles or diets, ensure sustainability, and retain traditional customers. These challenges include food neophobia, the need to mimic the physicochemical, sensory, functional, and nutritional properties of dairy products, the inefficient conversion factor of plant-based proteins into animal proteins, and high production expenses. Given the distinct nature of plant-based milks, understanding their differences from cow's milk is crucial for formulating alternatives with comparable properties. Designing dairy-free cheese analogs requires overcoming electrostatic repulsion energy barriers among plant proteins to induce gelation and curd formation. Innovative approaches have substantially enhanced the physicochemical and sensory properties of these alternatives. Researchers are exploring the application of microalgae as a plant protein source and investigating new microbial fermentation methods to increase protein content in dairy-free products.

Selection of adjunct cultures for the ripening of plant cheese analogues

Fermentation contributes to the taste and odor of plant cheeses. The selection of functional cultures for the fermentation of plant cheeses, however, is in its infancy. This study aimed to select lactic acid bacteria for ripening of soy and lupin cheese analogues. Bacillus velezensis and B. amyloliquefaciens were used for germination of seeds to produce proteolytic enzymes; Lactococcus lactis and Lactiplantibacillus plantarum served as primary acidifying cultures. Levilactobacillus hammesii, Furfurilactobacillus milii, or Lentilactobacillus buchneri were assessed as adjunct cultures for the ripening of plant cheese. Growth of bacilli was inhibited at low pH. Both Lc. lactis and Lp. plantarum were inactived during plant cheese ripening. Cell counts of Lv. hammesii remained stable over 45 d of ripening while Ff. milii and Lt. buchneri grew slowly. Sequencing of full length 16S rRNA genes confirmed that the inocula the plant cheeses accounted for more than 98% of the bacterial communities. HPLC analysis revealed that Lt. buchneri metabolized lactate to acetate and 1,2-propanediol during ripening. Bacilli enhanced proteolysis as measured by quantification of free amino nitrogen, and the release of glutamate. LC-MS/MS analysis quantified kokumi-active dipeptides. The concentrations of γ-Glu-Leu, γ-Glu-Ile, and γ-Glu-Ala, γ-Glu-Cys in unripened cheeses were increased by seed germination but γ-Glu-Phe was degraded. Lt. buchneri but not Lv. hammesii or Ff. milii accumulated γ-Glu-Val, γ-Glu-Ile or γ-Glu-Leu during ripening, indicating strain-specific differences. In conclusion, a consortium of bacilli, acidification cultures and adjunct cultures accumulates taste- and kokumi-active compounds during ripening of plant cheeses.

The role of fermentation with lactic acid bacteria in quality and health effects of plant-based dairy analogues

The modern food industry is undergoing a rapid change with the trend of production of plant-based food products that are more sustainable and have less impact on nature. Plant-based dairy analogues have been increasingly popular due to their suitability for individuals with milk protein allergy or lactose intolerance and those preferring a plant-based diet. Nevertheless, plant-based products still have insufficient nutritional quality, undesirable structure, and earthy, green, and bean-like flavor compared to dairy products. In addition, most plant-based foods contain lesser amounts of essential nutrients, antinutrients limiting the bioavailability of some nutrients, and allergenic proteins. Novel processing technologies can be applied to have a homogeneous and stable structure. On the other hand, fermentation of plant-based matrix with lactic acid bacteria can provide a solution to most of these problems. Additional nutrients can be produced and antinutrients can be degraded by bacterial metabolism, thereby increasing nutritional value. Allergenic proteins can be hydrolyzed reducing their immunoreactivity. In addition, fermentation has been found to reduce undesired flavors and to enhance various bioactivities of plant foods. However, the main challenge in the production of fermented plant-based dairy analogues is to mimic familiar dairy-like flavors by producing the major flavor compounds other than organic acids, yielding a flavor profile similar to those of fermented dairy products. Further studies are required for the improvement of the flavor of fermented plant-based dairy analogues through the selection of special microbial cultures and formulations.

Linoleic acid enrichment of cheese by okara flour and Geotrichum candidum overexpressing Δ12 fatty acid desaturase

BACKGROUND

Mold-ripened cheeses have low levels of unsaturated fatty acids (UFAs). Geotrichum candidum is an adjunct culture for the development of Geotrichum-ripened cheese but has a low ability to produce high levels of UFAs. Δ12 fatty acid desaturase (FADS12) is a pivotal enzyme that converts oleic acid (OA) to linoleic acid (LA) and plays a vital role in UFA biosynthesis. By investigating FADS12 catalytic activity from various species with OA substrates, we found that FADS12 from Mucor circinelloides (McFADS12) had the highest catalytic activity for OA.

RESULTS

In the current study, a plasmid harboring McFADS12 was constructed and overexpressed in G. candidum. Our results showed that LA production increased to 31.1 ± 1.4% in engineered G. candidum - three times higher than that in wild-type G. candidum. To enhance LA production, an exogenous substrate (OA) was supplemented, and the yield of LA was increased to 154 ± 6 mg L^-1 in engineered G. candidum. Engineered G. candidum was used as an adjunct culture for Geotrichum-ripened cheese production. The LA level reached 74.3 ± 5.4 g kg^-1 cheese, whereas the level of saturated fatty acids (SFAs) decreased by 9.9 ± 0.5%. In addition, the soybean byproduct (okara) was introduced into the engineered G. candidum growth and the level of LA increased to 126 ± 4 g kg^-1 cheese and the percentage of UFAs:SFAs increased from 0.8:1 to 1.3:1.

CONCLUSION

This study offers a suitable technology for converting SFAs to UFAs in Geotrichum-ripened cheeses and provides a novel trend for converting soybean waste into a value-added product. © 2022 Society of Chemical Industry.

Uncovering the Biotechnological Importance of Geotrichum candidum

Fungi make a fundamental contribution to several biotechnological processes, including brewing, winemaking, and the production of enzymes, organic acids, alcohols, antibiotics, and pharmaceuticals. The present review explores the biotechnological importance of the filamentous yeast-like fungus Geotrichum candidum, a ubiquitous species known for its use as a starter in the dairy industry. To uncover G. candidum's biotechnological role, we performed a search for related work through the scientific indexing internet services, Web of Science and Google Scholar. The following query was used: Geotrichum candidum, producing about 6500 scientific papers from 2017 to 2022. From these, approximately 150 that were associated with industrial applications of G. candidum were selected. Our analysis revealed that apart from its role as a starter in the dairy and brewing industries, this species has been administered as a probiotic nutritional supplement in fish, indicating improvements in developmental and immunological parameters. Strains of this species produce a plethora of biotechnologically important enzymes, including cellulases, β-glucanases, xylanases, lipases, proteases, and α-amylases. Moreover, strains that produce antimicrobial compounds and that are capable of bioremediation were identified. The findings of the present review demonstrate the importance of G. candidum for agrifood- and bio-industries and provide further insights into its potential future biotechnological roles.

Fermentation for Designing Innovative Plant-Based Meat and Dairy Alternatives

Fermentation was traditionally used all over the world, having the preservation of plant and animal foods as a primary role. Owing to the rise of dairy and meat alternatives, fermentation is booming as an effective technology to improve the sensory, nutritional, and functional profiles of the new generation of plant-based products. This article intends to review the market landscape of fermented plant-based products with a focus on dairy and meat alternatives. Fermentation contributes to improving the organoleptic properties and nutritional profile of dairy and meat alternatives. Precision fermentation provides more opportunities for plant-based meat and dairy manufacturers to deliver a meat/dairy-like experience. Seizing the opportunities that the progress of digitalization is offering would boost the production of high-value ingredients such as enzymes, fats, proteins, and vitamins. Innovative technologies such as 3D printing could be an effective post-processing solution following fermentation in order to mimic the structure and texture of conventional products.

Fermentation of plant-based dairy alternatives by lactic acid bacteria

Ethical, environmental and health concerns around dairy products are driving a fast‐growing industry for plant‐based dairy alternatives, but undesirable flavours and textures in available products are limiting their uptake into the mainstream. The molecular processes initiated during fermentation by lactic acid bacteria in dairy products is well understood, such as proteolysis of caseins into peptides and amino acids, and the utilisation of carbohydrates to form lactic acid and exopolysaccharides. These processes are fundamental to developing the flavour and texture of fermented dairy products like cheese and yoghurt, yet how these processes work in plant‐based alternatives is poorly understood. With this knowledge, bespoke fermentative processes could be engineered for specific food qualities in plant‐based foods. This review will provide an overview of recent research that reveals how fermentation occurs in plant‐based milk, with a focus on how differences in plant proteins and carbohydrate structure affect how they undergo the fermentation process. The practical aspects of how this knowledge has been used to develop plant‐based cheeses and yoghurts is also discussed.

Ingredients, Processing, and Fermentation: Addressing the Organoleptic Boundaries of Plant-Based Dairy Analogues

Consumer interest and research in plant-based dairy analogues has been growing in recent years because of increasingly negative implications of animal-derived products on human health, animal wellbeing, and the environment. However, plant-based dairy analogues face many challenges in mimicking the organoleptic properties of dairy products due to their undesirable off-flavours and textures. This article thus reviews fermentation as a viable pathway to developing clean-label plant-based dairy analogues with satisfactory consumer acceptability. Discussions on complementary strategies such as raw material selection and extraction technologies are also included. An overview of plant raw materials with the potential to be applied in dairy analogues is first discussed, followed by a review of the processing steps and innovative techniques required to transform these plant raw materials into functional ingredients such as plant-based aqueous extracts or flours for subsequent fermentation. Finally, the various fermentation (bacterial, yeast, and fungal) methodologies applied for the improvement of texture and other sensory qualities of plant-based dairy analogues are covered. Concerted research efforts would be required in the future to tailor and optimise the presented wide diversity of options to produce plant-based fermented dairy analogues that are both delicious and nutritionally adequate.

Plant-Based Cheeses: A Systematic Review of Sensory Evaluation Studies and Strategies to Increase Consumer Acceptance

Animal protein provides unique sensory and textural properties to foods that are not easily replicated when replaced with plant-based alternatives. Food scientists and researchers are currently developing innovative approaches to improve their physical and sensory characteristics in plant-based analogs. In terms of plant-based cheese substitutes (PBCS), soy is the most commonly used plant-based protein but is associated with undesirable sensory attributes (i.e., beany and gritty). In order to determine if the approaches result in a significant improvement in sensory quality and liking, sensory evaluation is employed. The aim of this review is to summarize the original literature (n = 12) relating to 100% PBCS which utilizes sensory evaluation methods. Overall, a major theme identified in this review is the innovative strategies used to increase acceptance of PBCS, whether products are aimed at improving existing non-dairy-based cheese formulations or to more closely mimic a conventional dairy-based cheese product. Studies demonstrate processing and fermentation of soybeans and blending of non-dairy milks are potential ways to improve consumer liking of PBCS. A secondary focus is to discuss the current sensory methodology carried out in the reviewed literature. Future studies should consider using more specific measures of flavor and mouthfeel, integrate evaluation of consumer liking with instrumental textural methods, and use a larger more diverse group of consumers. The outcome of this review is to highlight the importance of integrating sensory science in order to help facilitate the improvement of the sensory and quality attributes of PBCS and streamline product development.