Fermentation of mung bean milk by Lactococcus lactis: Focus on the physicochemical properties, antioxidant capacities and sensory evaluation

Molecular investigation of soybean protein for improving the stability of quinoa (Chenopodium quinoa willd.) milk substitute

Soybean could greatly improve stability of quinoa milk substitute. However, the key compound and underlying mechanisms remained unclear. Here we showed that soybean protein was the key component for improving quinoa milk substitute stability but not oil or okara. Supplementary level of soybean protein at 0%, 2%, 4%, and 8% of quinoa (w/w) was optimized. Median level at 4% could effectively enhance physical stability, reduce particle size, narrow down particle size distribution, and decrease apparent viscosity of quinoa milk substitute. Microscopic observation further confirmed that soybean protein could prevent phase separation. Besides, soybean protein showed increased surface hydrophobicity. Molecular docking simulated that soybean protein but not quinoa protein, could provide over 10 anchoring points for the most abundant quinoa vanillic acid, through hydrogen bond and Van-der-Waals. These results contribute to improve stability of quinoa based milk substitute, and provide theoretical basis for the interaction of quinoa phenolics and soybean protein.

Reduction of Beany Flavor and Improvement of Nutritional Quality in Fermented Pea Milk: Based on Novel Bifidobacterium animalis subsp. lactis 80

Peas (Pisum sativum L.) serve as a significant source of plant-based protein, garnering consumer attention due to their high nutritional value and non-GMO modified nature; however, the beany flavor limits its applicability. In this study, the effects of Bifidobacterium animalis subsp. Lactis 80 (Bla80) fermentation on the physicochemical characteristics, particle size distribution, rheological properties, and volatile flavor compounds of pea milk was investigated. After fermentation by Bla80, the pH of pea milk decreased from 6.64 ± 0.01 to 5.14 ± 0.01, and the (D4,3) distribution decreased from 142.4 ± 0.47 μm to 122.7 ± 0.55 μm. In addition, Lactic acid bacteria (LAB) fermentation significantly reduced the particle size distribution of pea milk, which was conducive to improving the taste of pea milk and also indicated that Bla80 had the probiotic potential of utilizing pea milk as a fermentation substrate. According to GC-MS analysis, 64 volatile compounds were identified in fermented pea milk and included aldehydes, alcohols, esters, ketones, acids, and furans. Specifically, aldehydes in treated samples decreased by 27.36% compared to untreated samples, while esters, ketones, and alcohols increased by 11.07%, 10.96%, and 5.19%, respectively. These results demonstrated that Bla80 fermentation can significantly decrease the unpleasant beany flavor, such as aldehydes and furans, and increase fruity or floral aromas in treated pea milk. Therefore, Bla80 fermentation provides a new method to improve physicochemical properties and consumer acceptance of fermented pea milk, eliminating undesirable aromas for the application of pea lactic acid bacteria beverage.

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.

Investigating lactic acid bacteria genus Lactococcus lactis properties: Antioxidant activity, antibiotic resistance, and antibacterial activity against multidrug-resistant bacteria Staphylococcus aureus

Background

Lactic acid bacteria (LAB) are utilized as a starter culture in the manufacturing of fermented dairy items, as a preservative for various food products, and as a probiotic. In our country, some research has been carried out, even if LAB plays a principal role in food preservation and improves the texture and taste of fermented foods, that is why we tried to evaluate their probiotic effect. The objective of this research was to determine the antibacterial activity of Lactococcus lactis (L. lactis) against Staphylococcus aureus (S. aureus) ATCC 29213, investigate their antioxidant activity, and characterize their sensitivity against 18 antibiotics.

Methods

A total of 23 LAB (L. lactis subsp. cremoris, L. lactis subsp. Lactis diacetylactis, L. lactis subsp. lactis) were isolated from cow's raw milk. The antibacterial activity was performed using two techniques, competition for nutrients and a technique utilizing components nature, using the disk diffusion method. The sensitivity of the studied LAB to different antibiotics was tested on Man rogosa sharp (MRS) agar using commercial antibiotic disks. All strains of LAB were examined for their antioxidant activity. The antioxidant activity of L. lactis was tested by 2,2-diphenyl-1 picrylhydrazyl (DPPH).

Results

The results showed that the MRS medium was more adapted than Muller Hinton Agar (MHA) to investigate the antibacterial activity of L. lactis against S. aureus ATCC 29213. Also, L. lactis exhibited a notable degree of antibacterial activity against S. aureus ATCC 29213. L. Lactis subsp. Lactis displayed higher antibacterial activities, followed by L. lactis ssp. lactis biovar. diacetylactis, and lastly, L. lactis ssp. cremoris against S. aureus ATCC 29213. Lc 26 among all strains of L. lactis showed a high potential antibacterial activity reaching 40 ± 3 mm against S. aureus ATCC 29213. All strains of L. lactis showed a slightly moderate antioxidant activity (10.56 ± 1.28%-26.29 ± 0.05 %). The results of the antibiotic resistance test indicate that all strains of L. lactis were resistant to cefotaxime, sulfamethoxazole-trimethoprim, and streptomycin and were sensitive to Ampicillin, Amoxicillin, Penicillin G, Teicoplanin, Vancomycin, Gentamicin 500, Tetracycline, and Chloramphenicol. These test results indicate that this strain falls within the criteria of not posing any harmful effects on human health. The important antibacterial properties recorded for all L. Lactis strains were derived from the production of antibacterial active metabolites, such as protein, diacetyl, hydrogen peroxide, and lactic acid, together with the fight for nutrients.

Conclusion

This study suggests that the strains of L. lactis could be added as an antibacterial agent against S. aureus ATCC 29213 and can provide an important nutritional property for their antioxidant potential.

Legume protein fermented by lactic acid bacteria: Specific enzymatic hydrolysis, protein composition, structure, and functional properties

In recent years, with increasing emphasis on healthy, green, and sustainable consumption concepts, plant-based foods have gained popularity among consumers. As widely sourced plant-based raw materials, legume proteins are considered sustainable and renewable alternatives to animal proteins. However, legume proteins have limited functional properties, which hinder their application in food products. LAB fermentation is a relatively natural processing method that is safer than chemical/physical modification methods and can enrich the functional properties of legume proteins through biodegradation and modification. Therefore, changes in legume protein composition, structure, and functional properties and their related mechanisms during LAB fermentation are described. In addition, the specific enzymatic hydrolysis mechanisms of different LAB proteolytic systems on legume proteins are also focused in this review. The unique proteolytic systems of different LAB induce specific enzymatic hydrolysis of legume proteins, resulting in the production of hydrolysates with diverse functional properties, including solubility, emulsibility, gelability, and foamability, which are determined by the composition (peptide/amino acid) and structure (secondary/tertiary) of legume proteins after LAB fermentation. The correlation between LAB-specific enzymatic hydrolysis, protein composition and structure, and protein functional properties will assist in selecting legume protein raw materials and LAB strains for legume plant-based food products and expand the application of legume proteins in the food industry.

Flavour by design: food-grade lactic acid bacteria improve the volatile aroma spectrum of oat milk, sunflower seed milk, pea milk, and faba milk towards improved flavour and sensory perception

BACKGROUND

The global market of plant-based milk alternatives is continually growing. Flavour and taste have a key impact on consumers' selection of plant-based beverages. Unfortunately, natural plant milks have only limited acceptance. Their typically bean-like and grassy notes are perceived as "off-flavours" by consumers, while preferred fruity, buttery, and cheesy notes are missing. In this regard, fermentation of plant milk by lactic acid bacteria (LAB) appears to be an appealing option to improve aroma and taste.

RESULTS

In this work, we systematically studied LAB fermentation of plant milk. For this purpose, we evaluated 15 food-approved LAB strains to ferment 4 different plant milks: oat milk (representing cereal-based milk), sunflower seed milk (representing seed-based milk), and pea and faba milk (representing legume-based milk). Using GC‒MS analysis, flavour changes during anaerobic fermentations were studied in detail. These revealed species-related and plant milk-related differences and highlighted several well-performing strains delivered a range of beneficial flavour changes. A developed data model estimated the impact of individual flavour compounds using sensory scores and predicted the overall flavour note of fermented and nonfermented samples. Selected sensory perception tests validated the model and allowed us to bridge compositional changes in the flavour profile with consumer response.

CONCLUSION

Specific strain-milk combinations provided quite different flavour notes. This opens further developments towards plant-based products with improved flavour, including cheesy and buttery notes, as well as other innovative products in the future. S. thermophilus emerged as a well-performing strain that delivered preferred buttery notes in all tested plant milks. The GC‒MS-based data model was found to be helpful in predicting sensory perception, and its further refinement and application promise enhanced potential to upgrade fermentation approaches to flavour-by-design strategies.

A comprehensive review of mung bean proteins: Extraction, characterization, biological potential, techno-functional properties, modifications, and applications

The popularity of plant-based proteins has increased, and mung bean protein (MBP) has gained immense attention due to its high yield, nutritional value, and health benefits. MBP is rich in lysine and has a highly digestible indispensable amino acid score. Dry and wet extractions are used to extract MBP flours and concentrates/isolates, respectively. To enhance the quality of commercial MBP flours, further research is needed to refine the purity of MBPs using dry extraction methods. Furthermore, MBP possesses various biological potential and techno-functional properties, but its use in food systems is limited by some poor functionalities, such as solubility. Physical, biological, and chemical technologies have been used to improve the techno-functional properties of MBP, which has expanded its applications in traditional foods and novel fields, such as microencapsulation, three-dimensional printing, meat analogs, and protein-based films. However, study on each modification technique remains inadequate. Future research should prioritize exploring the impact of these modifications on the biological potential of MBP and its internal mechanisms of action. This review aims to provide ideas and references for future research and the development of MBP processing technology.