High-efficiency removal of phytic acid in soy meal using two-stage temperature-induced Aspergillus oryzae solid-state fermentation

A novel thermophilic strain of Bacillus subtilis with antimicrobial activity and its potential application in solid-state fermentation of soybean meal

Soybean meal (SBM) is the most important source of plant protein in animal feeds, containing around 41%-48% crude protein. Nevertheless, 70%-80% of these proteins is allergenic antigens that can have adverse implications for the gastrointestinal well-being of animals, especially to young animals. Microbial fermentation is one of the most cost-effective strategies used to reduce allergenic antigens from plant sources. In this study, we report the isolation and characterization of a novel probiotic Bacillus subtilis "L5" strain from lake mud. L5 demonstrated remarkable temperature tolerance across a broad temperature spectrum, thriving at 25°C, 37°C, and 50°C. In addition, antimicrobial assay revealed that L5 exhibits strong antimicrobial activity against Escherichia coli, effectively reducing or eliminating the growth of Gram-negative bacteria in SBM when fermented with L5. When applied to SBM fermentation, L5 efficiently reduced SBM antinutritional factors such as glycinin, β-conglycinin, trypsin inhibitor, phytic acid, neutral detergent fiber, and acid detergent fiber, which in turn results in an increase in crude protein content and the free amino acid concentration. Our findings on the probiotic and fermentation capabilities of L5 suggest that this novel bacterium has dual functions that make it a strong candidate for improving the nutrient values of feed via its role in fermentation.IMPORTANCESoybean meal (SBM), containing 41%-48% crude protein, is the most important source of plant protein in animal feeds. Unfortunately, 70%-80% of the proteins in SBM is allergenic antigens including trypsin inhibition, β-conglycinin, and conglycinin, which negatively affect intestine health and function. Microbial solid-state fermentation methods have been applied to animal feeds for decades, to eliminate antinutritional factors. Here, a novel potential probiotic Bacillus subtilis "L5" strain with high enzymatic activity and antimicrobial activity will be a great help to improve the quality and reproducibility of SBM fermentation.

Physicochemical, structural, and functional characterization of guar meal protein isolate (Cyamopsis tetragonoloba)

Guar korma and churi protein isolates were assessed for their physicochemical, nutritional, functional, structural, and digestibility properties for their application in the food industry. The water extracted protein isolate of guar korma showed a protein content of 89.7 % and a yield of 48.7 %. Water extracted protein isolate of guar korma showed an excellent protein efficiency ratio, essential amino acid/total amino acids (34.35 %), amino acid score, and protein digestibility corrected amino acid score values, suggesting the existence of high-quality proteins. Water extracted protein isolate of guar korma contains all the essential amino acids except Methionine and Cysteine, according to World Health Organization recommendations for children and adults. The protein profiling of water extracted protein isolate of guar korma was analyzed using 12 % sodium dodecyl sulfate polyacrylamide gel electrophoresis and indicated the presence of eight major protein bands in the range of 17-100 kDa. In vitro digestibility of water extracted protein isolate of guar korma showed the complete digestion of the abundant protein bands within 15 min. Further, the foaming capacity, water/oil holding capacity, and emulsifying stability of water extracted protein isolate of guar korma were comparable with soy protein isolate. Fourier Transform Infrared and Circular Dichroism spectral analysis revealed the presence of several aromatic groups and β-sheets, random coils respectively in water extracted protein isolate of guar korma. The morphological nature of the guar protein isolate was characterized by Scanning Electron Microscopy. Overall, these findings support that water extracted protein isolate of guar korma has excellent functional and nutritional properties and could be a potential alternative plant protein in food industries.

Screening and Identification of a Strain with Protease and Phytase Activities and Its Application in Soybean Meal Fermentation

The aims of the study were to degrade the anti-nutritional factors (ANFs) such as phytic acid, glycinin, and β-conglycinin and improve the values of soybean meal (SBM). Firstly, in this study, a strain PY-4B which exhibited the best enzymatic activities of protease (403.3 ± 17.8 U/mL) and phytase (62.9 ± 2.9 U/mL) was isolated and screened among the isolates. Based on the analysis of physiological and biochemical characteristics and 16S rDNA sequence, the strain PY-4B was identified and named as Pseudomonas PY-4B. Next, Pseudomonas PY-4B was applied to fermentation of SBM. The results showed that the contents of glycinin and β-conglycinin were decreased by 57-63%, and the phytic acid was remarkably degraded by 62.5% due to the fermentation of SBM by Pseudomonas PY-4B. The degradation of glycinin and β-conglycinin resulted in increase of contents of water-soluble proteins and amino acids in fermented SBM. Moreover, Pseudomonas PY-4B exhibited no hemolytic activity and slight inhibitory effect on the growth of pathogen Staphylococcus aureus and the wide range of pH tolerance (3 to 9). In summary, our study indicates that isolated strain Pseudomonas PY-4B is a safe and applicable strain and has the ability to effectively degrade the ANFs (phytic acid, glycinin, and β-conglycinin) in SBM by fermentation.

Quinoa dough fermentation by Saccharomyces cerevisiae and lactic acid bacteria: Changes in saponin, phytic acid content, and antioxidant capacity

The effects of two fermentation processes (common fermentation with Saccharomyces cerevisiae and fermentation by Lacticaseibacillus casei subsp. casei PTCC 1608 and Lactiplantibacillus plantarum subsp. plantarum PTCC 1745) on pH, titratable acidity, total phenolic and flavonoid contents, antioxidant capacity, saponin content, as well as phytic acid content of quinoa dough were investigated during the 24-h fermentation (4-h interval). According to the results, the highest titratable acidity was observed in the samples fermented by L. casei subsp. casei. Moreover, the highest antioxidant capacity was observed after 12 h of fermentation by L. plantarum subsp. plantarum (31.22% for DPPH, 104.67% for FRAP) due to a higher concentration of phenolic compounds produced (170.5% for total phenolic content). Also, all samples have been able to reduce saponin by 67% on average. Furthermore, the samples fermented by L. plantarum subsp. plantarum showed the most significant decrease in phytic acid content (64.64%) during 24-h fermentation. By considering the reduction of the antinutritional compounds and improvement in the antioxidant properties of quinoa flour, the Lactiplantibacillus plantarum strain was recommended.

Double-Fermented Soybean Meal Totally Replaces Soybean Meal in Broiler Rations with Favorable Impact on Performance, Digestibility, Amino Acids Transporters and Meat Nutritional Value

Inclusion of microbial fermented soybean meal in broiler feed has induced advantageous outcomes for their performance and gastrointestinal health via exhibiting probiotic effects. In this study, soybean meal (SBM) was subjected to double-stage microbial fermentation utilizing functional metabolites of fungi and bacteria. In broiler diet, DFSBM replaced SBM by 0, 25, 50 and 100%. DFSBM was reported to have higher protein content and total essential, nonessential and free amino acids (increased by 3.67%, 12.81%, 10.10% and 5.88-fold, respectively, compared to SBM). Notably, phytase activity and lactic acid bacteria increased, while fiber, lipid and trypsin inhibitor contents were decreased by 14.05%, 38.24% and 72.80%, respectively, in a diet containing 100% DFSBM, compared to SBM. Improved growth performance and apparent nutrient digestibility, including phosphorus and calcium, and pancreatic digestive enzyme activities were observed in groups fed higher DFSBM levels. In addition, higher inclusion levels of DFSBM increased blood immune response (IgG, IgM, nitric oxide and lysozyme levels) and liver antioxidant status. Jejunal amino acids- and peptide transporter-encoding genes (LAT1, CAT-1, CAT-2, PepT-1 and PepT-2) were upregulated with increasing levels of DFSBM in the ration. Breast muscle crude protein, calcium and phosphorus retention were increased, especially at higher inclusion levels of DFSBM. Coliform bacteria load was significantly reduced, while lactic acid bacteria count in broiler intestines was increased with higher dietary levels of DFSBM. In conclusion, replacement of SBM with DFSBM positively impacted broiler chicken feed utilization and boosted chickens’ amino acid transportation, in addition to improving the nutritional value of their breast meat.

Isolation and characterization of a novel hydrolase-producing probiotic Bacillus licheniformis and its application in the fermentation of soybean meal

Soybean meal (SBM) is one of the most important sources of plant-based protein in the livestock and poultry industry. However, SBM contains anti-nutritional factors (ANFs) such as glycinin, β-conglycinin, trypsin inhibitor and phytic acid that can damage the intestinal health of animals, inevitably reducing growth performance. Fermentation using microorganisms with probiotic potential is a viable strategy to reduce ANFs and enhance the nutritional value of SBM. In this study, a novel potential probiotic Bacillus licheniformis (B4) with phytase, protease, cellulase and xylanase activity was isolated from camel feces. The ability of B4 to tolerate different pH, bile salts concentrations and temperatures were tested using metabolic activity assay. It was found that B4 can survive at pH 3.0, or 1.0% bile salts for 5 h, and displayed high proliferative activity when cultured at 50°C. Furthermore, B4 was capable of degrading glycinin, β-conglycinin and trypsin inhibitor which in turn resulted in significant increases of the degree of protein hydrolysis from 15.9% to 25.5% (p < 0.01) and crude protein from 44.8% to 54.3% (p < 0.001). After fermentation with B4 for 24 h, phytic acid in SBM was reduced by 73.3% (p < 0.001), the neutral detergent fiber (NDF) and the acid detergent fiber of the fermented SBM were significantly decreased by 38.40% (p < 0.001) and 30.20% (p < 0.05), compared to the unfermented SBM sample. Our results suggested that the effect of solid-state fermented SBM using this novel B. licheniformis (B4) strain, could significantly reduce phytic acid concentrations whilst improving the nutritional value of SBM, presenting itself as a promising alternative to phytase additives.

Filamentous fungi for future functional food and feed

In this review, we offer our opinion of current and expected trends regarding the use of mushrooms and mycelia in food and feed. Mushrooms have provided food for millennia and production methods and species diversity have recently expanded. Beyond mushrooms, cultured fungal mycelia are now harvested as a primary product for food. Mushrooms and mycelia provide dietary protein, lipids and fatty acids, vitamins, fibre, and flavour, and can improve the organoleptic properties of processed foods (including meat analogues). Further, they are often key ingredients in nutritional or therapeutic supplements because of diverse specialised metabolites. Mycelia can also improve feed conversion efficiency, gut health, and wellbeing in livestock. New molecular tools, coupled with quality genetic data, are improving production technologies, enabling the synthesis of specialised metabolites, and creating new processing and valorisation opportunities. Production systems for submerged culture are capital intensive, but investment is required considering the scale of the protein market.

Physicochemical, Microbiological and Functional Properties of Camelina Meal Fermented in Solid-State Using Food Grade Aspergillus Fungi

Camelina meal (CAM) was fermented in solid-state using food grade Aspergillus fungi (A. sojae, A. ficuum and their co-cultures), and the physicochemical composition, microbiological and functional properties were investigated. SSF increased the starch contents but reduced (p < 0.05) the contents of soluble carbohydrate. The microbiological counts of the fermented meals were higher (p < 0.05) than that of the unfermented CAM. Phytic acid content reduced (p < 0.05) in the fermented meals. SSF reduced the protein molecular weight and colour attributes of CAM. The fermented camelina meals had increased (p < 0.05) bulk density and swelling capacity but reduced (p < 0.05) water absorption capacity. Thus, the study indicated that SSF with A. sojae, A. ficuum and their co-cultures influenced the physicochemical, microbiological and functional properties of CAM. There is potential for the development of value-added novel food and feed products from solid-state fermented camelina meal.

Reduction of Phytic Acid in Soymilk by Immobilized Phytase System

In this study, three carriers (glass microsphere, cellulose beads and AlgNa/PVA beads) were evaluated as phytase solid carriers for reduction of phytic acid within soymilk. Phytase was covalently immobilized onto or entrapped within carriers for repeated use. Glass microsphere was chosen due to its high catalytic efficiency. Optimal operating condition (pH 6.0, 60 °C) was determined using 4-Nitrophenyl phosphate disodium salt hexahydrate as an indicator. Operational reusability was confirmed for more than seven batch reactions and the storage stability was capable of sustaining 70% of its catalytic activity for 40 days. The kinetic parameters including rate constant (K), time (τ₅₀ ) in which 50% of phytic acid hydrolysis was reached, and time (τ_complete ) required to achieve complete phytic acid hydrolysis, were 0.023 min^-1 , 35.7 min, 110 min. The current procedure provides a cheap as well as an easy way to carry out the reduction of phytic acid in soymilk, which has great potential in practical application.

Interactions between plant proteins/enzymes and other food components, and their effects on food quality

Plant proteins are the main sources of dietary protein for humans, especially for vegetarians. There are a variety of components with different properties coexisting in foodstuffs, so the interactions between these components are inevitable to occur, thereby affecting food quality. Among these interactions, the interplay between plant proteins/enzymes from fruits and vegetables, cereals, and legumes and other molecules plays an important role in food quality, which recently has gained a particular scientific interest. Such interactions not only affect the appearances of fruits and vegetables and the functionality of cereal products but also the nutritive properties of plant foods. Non-covalent forces, such as hydrogen bond, hydrophobic interaction, electrostatic interaction, and van der Waals forces, are mainly responsible for these interactions. Future outlook is highlighted with aim to suggest a research line to be followed in further studies.

Valorisation of untreated cane molasses for enhanced phytase production by Bacillus subtilis K46b and its potential role in dephytinisation

BACKGROUND

The high cost of phytase production is the most limiting factor in its application in animal feeds. The present study aimed to develop a low-cost medium for production of a novel phytase in submerged fermentation using inexpensive agro-industrial by-products. The applicability of phytase in dephytinisation of commonly used food/feed ingredients, i.e. soybean meal and wheat bran, was also investigated.

RESULTS

Using a one-factor-at-a-time approach, soybean meal and cane molasses were identified as significant agro-industrial by-products and these factors were subsequently optimised using response surface methodology (RSM). A central composite design was employed to further enhance phytase yield. Under optimum conditions of soybean meal 22.3 g L-1 , cane molasses 100 g L-1 and 39 h fermentation, phytase production increased to 56.562 U mL-1 , indicating more than 28-fold enhancement. The enzyme efficiently dephytinised wheat bran and soybean meal after 24 h incubation at 56.5 °C and increased inorganic phosphate content by 240% and 155%, respectively.

CONCLUSION

Soybean meal and cane molasses were successfully used for enhancement of phytase production as economical carbon, nitrogen and phytic acid sources using RSM. The phytase showed a good capability to dephytinise wheat bran and soybean meal, demonstrating that the enzyme can be considered as a potential candidate for industrial food and feed applications. © 2016 Society of Chemical Industry.

Phytase production by solid-state fermentation of groundnut oil cake by Aspergillus niger: A bioprocess optimization study for animal feedstock applications

This investigation deals with the use of agro-industrial waste, namely groundnut oil cake (GOC), for phytase production by the fungi Aspergillus niger NCIM 563. Plackett-Burman design (PBD) was used to evaluate the effect of 11 process variables and studies here showed that phytase production was significantly influenced by glucose, dextrin, distilled water, and MgSO4 · 7H2O. The use of response surface methodology (RSM) by Box-Behnken design (BBD) of experiments further enhanced the production by a remarkable 36.67-fold from the original finding of 15 IU/gds (grams of dry substrate) to 550 IU/gds. This is the highest solid-state fermentation (SSF) phytase production reported when compared to other microorganisms and in fact betters the best known by a factor of 2. Experiments carried out using dried fermented koji for phosphorus and mineral release and also thermal stability have shown the phytase to be as efficient as the liquid enzyme extract. Also, the enzyme, while exhibiting optimal activity under acidic conditions, was found to have significant activity in a broad range of pH values (1.5-6.5). The studies suggest the suitability of the koji supplemented with phytase produced in an SSF process by the "generally regarded as safe" (GRAS) microorganism A. niger as a cost-effective value-added livestock feed when compared to that obtained by submerged fermentation (SmF).

The Investigation of Virginiamycin-Added Fungal Fermentation on the Size and Immunoreactivity of Heat-Sensitive Soy Protein

The usage of soy protein for young monogastric animals is restricted due to potential allergens and high molecular weight. The investigation of fungi fermentation effect on soy protein has been interrupted by substrate sterilization. Virginiamycin at 0.05% was added together withAspergillus oryzaefor solid state fermentation (SSF) in unsterilized soy meal (SM). When compared toA. oryzaeSSF alone, virginiamycin did not cause the interference of fungal fermentation but elucidated the protein degradation. SDS-PAGE results showed that bothαandα′ subunits ofβ-conglycinin were degraded significantly. In addition, western blot results showed that the immunoreactive signals of soy protein were considerably reduced in virginiamycin-added fermentation with unsterilized SM. Furthermore, fungal fermentation increased total protein and essential amino acid contents, suggesting the value enhancement of SM products. Taken together, this study demonstrated for the first time that virginiamycin could help investigate fermentation effect on heat-sensitive soy protein. Fermented SM has several potential applications in feed industry.

Soy 11S Globulin Acid Subunits as the Novel Food Polymer Carrier

Aflatoxins were conjugated with soy 11S globulins acid subunits and the hapten-specific monoclonal antibodies (McAbs) cross-reactive with four major aflatoxins were achieved using indirect competitive ELISA screening procedure. The two antibodies (clones 1B2 and 2D3) had similar reaction efficiency with aflatoxins B1, B2, and G1 but showed a weak cross-reaction to G2. The clone 4C5 exhibited the highest sensitivity for all four aflatoxins. The concentrations of aflatoxins B1, B2, G1, and G2 at 50% inhibition for 4C5 were 1.1, 1.2, 2.1, and 17.6 pg mL−1. The results indicated that soy 11S globulin acid subunits were suitable novel carriers for aflatoxin antigen in immunization experiments and clone 4C5 could be used for simultaneous analysis of total aflatoxins.

Current research and future perspectives of phytase bioprocessing

A focused platform for phytase bio-processing and application oriented research will help in developing an integrated technological solution to phytase production.