Monitoring of fungal biomass changed by Rhizopus oryzae in relation to amino acid and essential fatty acids profile in soybean meal, wheat and rice

Protein hydrolysates derived from superworm (Zophobas morio): Composition, bioactivity, and techno-functional properties

This study aimed to produce protein hydrolysates from superworm (Zophobas morio) flour using the enzymes alcalase (HA), protamex (HP), or flavourzyme (HF), and to characterize their nutritional composition, techno-functional properties, bioactive capacity, and bioaccessibility index. The enzymatic process increased the total amino acid and crude protein contents of the hydrolysates by approximately 36 % and 46 %, respectively, generating better foaming capacity, oil retention, and emulsification capacity, when compared to raw flour. Although 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical capture was similar between the hydrolysates, HA (1479,66 μM FeSO4/g) and HP (1514,66 μM FeSO4/g) showed greater antimicrobial and iron reducing power (FRAP) activity, while HF has a higher scavenging efficiency for the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical (27.53 %). The best antimicrobial activity was observed for HA against Vibrio corallilyticus (400 mg/mL), and HP showed a better antioxidant response scavenging for DPPH radical. The antioxidant capacity against ABTS radical after in vitro simulation of gastrointestinal digestion (GID) was as follows: HA (79.07 ± 1.53 %), HP (74.65 ± 5.85 %), and HF (57.95 ± 8.31 %). Therefore, insect flour is a promising ingredient for the production of protein hydrolysates and their application in animal and human feeds.

Household fermentation of leftover bread to nutritious food

Resource dependency of food production is aggravated when food is wasted. In Sweden, it is estimated that 37% of the total bread waste is generated at the household level. This work aimed to assess whether fermentation using edible filamentous fungi at households can provide a solution to valorize leftover bread in the production of fungi-based food for consumption. Bread was fermented in household and laboratory conditions with Neurospora intermedia and Rhizopus oligosporus. The results show that bread can be successfully and easily fermented at households, without signs of microbial contamination even though the conditions were not sterile. Fermentation at the household resulted in higher protein, fat and fiber content as well as greater starch reduction compared to the samples fermented under laboratory conditions. Household engagement in bread fermentation will likely depend on values that motivate reusing leftover bread. Perceived values that are expected to motivate engagement vary across individuals, but may include improved nutritional benefits, food waste prevention, convenience, responsibilities, and being part of sustainable societies and actions.

Nutritional value of commercial broiler feed supplemented with olive mill waste fermented with probiotic Rhizopus oryzae strains

AIMS

The changes in chemical composition and metabolizable energy of both olive mill waste (OMW) upon fermentation by three potential probiotic Rhizopus oryzae strains and commercial feed (CF) upon its supplementation by fermented olive mill waste (FOMW) were investigated. The objective was to test if there will be an enhancement in the nutritional value of olive mill waste after fermentation and/or commercial broiler feed upon supplementation by potentially probiotic filamentous fungi.

METHODS AND RESULTS

A three Rhizopus oryzae strains (92/1, 236/2, and 284) isolated from agricultural soil that were proven to have good probiotic properties (non-toxic, antimicrobial activity, antioxidant capacity, and gastrointestinal tolerance) were used to ferment OMW, then the chemical composition was analyzed after 7 and 14 days of fermentation. The FOMW with the R. oryzae 284 strain, which gave the best results, was added to a commercial broiler feed at 20%, 30%, and 40% supplementation ratios. Then proximal analyses were done to compare non-supplemented with supplemented CF. Chemical analyses included dry weight, crude protein, crude fats, crude fibers, crude ash, sugars, and starch, then metabolizable energy was calculated from the given values.

CONCLUSIONS

Compared to non-fermented OMW, the best results were obtained by the R. oryzae 284 strain allowing an increase in crude protein content by 23.4% after 7 days of fermentation, a decrease in crude fiber content by 9.8% after 14 days of fermentation, and an increase in metabolizable energy by 3.6% after 7 days of fermentation. Compared to non-supplemented CF, the metabolizable energy changes of 20, 30, and 40% supplementation increased by 8.38, 2.83%, and decreased by 4.27% respectively.

SIGNIFICANCE AND IMPACT OF STUDY

FOMW can be incorporated into broiler feed rations until 30% without causing any decrease in metabolizable energy. It can be a cheaper alternative with promising productivity and chicken health improvements.

Effects of "nine steaming nine sun-drying" on proximate composition, protein structure and volatile compounds of black soybeans

Nine steaming nine sun-drying is a traditional processing technology for food or medicinal materials. The dynamic changes of the proximate composition, protein structure and volatile compounds during nine-time steaming and sun-drying of black soybeans (BS) were studied. The proximate composition results showed that the content of protein, carbohydrate and fat of BS decreased after processing, whereas the relative content of amino acids remained basically unchanged. Protein structure was evaluated using Fourier transform infrared spectroscopy (FT-IR), Ultraviolet absorption spectroscopy (UV) and Fluorescence spectroscopy. FT-IR result revealed that the relative contents of β-sheet and β-turn of the secondary structure of black soybean protein isolate (BSPI) decreased but the relative contents of α-helix and random coil increased after steaming and sun-drying. The results of UV and fluorescence spectroscopy confirmed changes in the protein conformation. In addition, SPME-GCMS analysis demonstrated that hydrocarbons, alcohols and aldehydes were the main volatile compounds. The relative contents of 1-octen-3-ol and hexanal, which are the main sources of beany flavor decreased significantly compared with raw BS. Principal component analysis (PCA) results showed that the volatile compounds of nine steamed and nine sun-dried BS could be well distinguished during the process. These findings may therefore provide a scientific basis for the application of nine-time steamed and sun-dried BS in food industry and contribute to the understanding of process-induced chemical transformations in this ancient processing technique.

Functional properties of Rhizopus oryzae strains isolated from agricultural soils as a potential probiotic for broiler feed fermentation

The most crucial and expensive fragment in the broiler chicken production industry is the feed. Because of the rising demand, finding a cheap and effective feed is an urgent necessity. Fermentation of broiler feed by probiotic fungal starters can enhance the nutrient's availability and digestibility while preventing pathogenic growth. In this study different Rhizopus spp. have been isolated from agricultural soils around Izmir, Turkey, and tested for their probiotic potential and fermentative capacity. The isolated Rhizopus strains first underwent microscopical fluorescent investigation to exclude endofungal bacterial presence, then, those without endofungal bacteria (totally 82) were tested for antimicrobial activity counter bacterial and fungal pathogens. The ones with wide-spectrum antimicrobial activity (totally 10) were tested for gastrointestinal tolerance and antioxidant ability. Upon phenotypic and genotypic identification, the 10 isolates were found to belong to Rhizopus oryzae species. While all 10 strains showed variable gastrointestinal tolerance and antioxidant activities, three of them (92/1, 236/2, and 284) had relatively high antioxidant activity. Upon fermentative capacity assay, compared to unfermented commercial feed, there was a general decrease in crude fiber content by 56% after fermentation by 92/1 isolate for 4 days and 236/2 isolate for 2 days. The highest increase in crude protein content (by 14.5%) occurred after a 4-day fermentation period by 236/2 isolate. The highest increase in metabolizable energy was 8.64%, by the 284 isolate after 2 days of fermentation. In conclusion, the three strains showed good probiotic properties and fermentative capacities hence can be beneficial for the poultry industry.

Effects of Soaking Tempe in Vinegar on Metabolome and Sensory Profiles

Tempe is a fermented soybean food that is globally renowned for its high protein content. Methods of preparing tempe vary worldwide, and include soaking in vinegar before fermentation. This study aimed to determine the effects of soaking in vinegar by metabolome analysis, gas chromatography/mass spectrometry, and sensory attribute evaluation. Vinegar affected metabolism during tempe fermentation, which led to altered metabolite profiles in the final product. We validated the metabolite profiles of two types of tempe using triangle tests and rate-all-that-apply (RATA) tests, which revealed that the sensory attributes of a golden-brown color, ammonia smell, pleasant smell, salty flavor, and acceptance significantly differed (p < 0.05) between the two types of tempe. A high concentration of specific amino acids in the control tempe explained a strong ammonia smell, saltiness, and darker golden-brown sensory attributes. Tempe soaked in vinegar contained high concentrations of metabolites associated with a roasted aroma and cooked meat. In conclusion, most RATA panelists who were being introduced to tempe preferred that soaked in vinegar to the control that was not.

Filamentous Fungus Aspergillus oryzae for Food: From Submerged Cultivation to Fungal Burgers and Their Sensory Evaluation-A Pilot Study

New food sources are explored to provide food security in sustainable ways. The submerged fermentation of edible filamentous fungi is a promising strategy to provide nutritious and affordable food that is expected to have a low environmental impact. The aim of the current study was to assess the novel use of Aspergillus oryzae cultivated in submerged fermentation on oat flour as a source for food products that do not undergo secondary fermentation or significant downstream processing. The fungus was cultivated in a pilot-scale airlift bioreactor, and the biomass concentration and protein content of the biomass were assessed. A tasting with an untrained panel assessed consumer preferences regarding the taste and texture of minimally processed vegetarian and vegan burger patties made from the biomass, and how the patties fared against established meat-alternative-based patties. The cultivation of Aspergillus oryzae resulted in a yield of 6 g/L dry biomass with a protein content of 37% on a dry weight basis. The taste and texture of the minimally processed fungal burger patties were to the liking of some participants. This was also reflected in diverse feedback provided by the participants. The cultivation of the fungus on oat flour and its utilization in developing burger patties shows its promising potential for the production of nutritious food. The applications of the fungus can be further developed by exploring other favorable ways to texture and season this relatively new functional food source to the preferences of consumers.

A Short Review: Bioactivity of Fermented Rice Bran

Rice bran is a by-product of the rice milling process, which refers to the processing of brown rice into polished rice. It contains a considerable amount of functional bioactive compounds. However, the utilization of these compounds is limited and calls for an effort to ferment rice bran. One of the methods that can significantly increase the added value of rice bran as well as its bioactivity is the solid-state fermentation. It can also be one of the strategies that help in the production of rice bran as a functional ingredient with higher bioactivity for health promotion.

From stale bread and brewers spent grain to a new food source using edible filamentous fungi

By-products from the food sector with a high load of organic matter present both a waste-handling problem related to expenses and to the environment, yet also an opportunity. This study aims to increase the value of stale bread and brewers spent grain (BSG) by re-introducing these residues to the food production chain by converting them to new protein-enriched products using the edible filamentous fungi Neurospora intermedia and Rhizopusoryzae. After 6 days of solid state fermentation (at 35°C, with a95% relative humidity and moisture content of 40% in the substrate) on stale bread, a nutrient-rich fungal-fermented product was produced. The total protein content, as analyzed by total amino acids, increased from 16.5% in stale sourdough bread to 21.1% (on dry weight basis) in the final product with an improved relative ratio of essential amino acids. An increase in dietary fiber, minerals (Cu, Fe, Zn) and vitamin E, as well as an addition of vitamin D2 (0.89 µg/g dry weight sample) was obtained compared with untreated stale bread. Furthermore, addition of BSG to the sourdough bread with the aim to improve textural changes after fermentation showed promising outcomes. Cultivation of N. intermedia or R. oryzae on stale sourdough bread mixed with 6.5% or 11.8% BSG, respectively, resulted in fungal-fermented products with similar textural properties to a commercial soybean burger. Bioconversion of stale bread and BSG by fungal solid state fermentation to produce a nutrient-enriched food product was confirmed to be a successful way to minimize food waste and protein shortage.

Estimation of glucosamine in biomass of Trichoderma reesei cultivated on lignocellulosic substrates

Effects of the compositions of lignocellulosic substrate including hemicellulose, cellulose, lignin, and protein on the glucosamine content in biomass of Trichoderma reesei TISTR3080 were studied. A synthetic solid surface media containing different ratios of xylan (hemicellulose), carboxymethyl cellulose (cellulose), lignin, and various concentrations of yeast extract (source of protein) were used to cultivated T. reesei. Regression analysis identified significant individual and interaction factors that affected glucosamine quantity in T. reesei biomass. A regression model was developed to estimate the glucosamine content in biomass of T. reesei from the compositions of the lignocellulosic substrate. An acceptable error (not more than 10%) of the regression model was obtained from validation with the experimental results of glucosamine content in biomass of T. reesei cultivated on lignocellulosic solid surface media made from copra waste and banana peel.

Fungi Burger from Stale Bread? A Case Study on Perceptions of a Novel Protein-Rich Food Product Made from an Edible Fungus

The current study aims to assess how a novel fungi product made from the filamentous fungus Neurospora intermedia, cultivated on bread residuals, is perceived using questionnaires. Participants were asked to rate characteristic attributes of a fungi burger patty and state their preference when comparing it to Quorn and hamburger patties. The data were analyzed to assess whether gender or age was statistically associated with preference profiles. Neither age nor gender was associated with the preference profiles regarding the comparison of burger patties. Except for age and bitterness, age and gender were also not associated with the preference profiles regarding the sensory characteristics of the fungi burger patty. Most of the participants liked the characteristics of the fungi burger patty. The results indicate that fungi products from waste can become accepted products when information dissemination targets environmental benefits. Moreover, to be commercially accepted, the chewiness and bitterness of the product should be improved. Other improvements should target the overall taste in order to cater to people who prefer meat-based protein sources.

Biotechnological Strategies for Chitosan Production by Mucoralean Strains and Dimorphism Using Renewable Substrates

We investigated the influence of corn steep liquor (CSL) and cassava waste water (CWW) as carbon and nitrogen sources on the morphology and production of biomass and chitosan by Mucor subtilissimus UCP 1262 and Lichtheimia hyalospora UCP 1266. The highest biomass yields of 4.832 g/L (M. subtilissimus UCP 1262) and 6.345 g/L (L. hyalospora UCP 1266) were produced in assay 2 (6% CSL and 4% CWW), factorial design 2², and also favored higher chitosan production (32.471 mg/g) for M. subtilissimus. The highest chitosan production (44.91 mg/g) by L. hyalospora (UCP 1266) was obtained at the central point (4% of CWW and 6% of CSL). The statistical analysis, the higher concentration of CSL, and lower concentration of CWW significantly contributed to the growth of the strains. The FTIR bands confirmed the deacetylation degree of 80.29% and 83.61% of the chitosan produced by M. subtilissimus (UCP 1262) and L. hyalospora (UCP 1266), respectively. M. subtilissimus (UCP 1262) showed dimorphism in assay 4–6% CSL and 8% CWW and central point. L. hyalospora (UCP 1266) was optimized using a central composite rotational design, and the highest yield of chitosan (63.18 mg/g) was obtained in medium containing 8.82% CSL and 7% CWW. The experimental data suggest that the use of CSL and CWW is a promising association to chitosan production.

Evaluation of biochemical and antioxidant dynamics during the co-fermentation of dehusked barley with Rhizopus oryzae and Lactobacillus plantarum

Barley is an ancient and important functional crop. In this study, the biochemical and antioxidant dynamics of dehusked barley during co-fermentation with Lactobacillus plantarum and Rhizopus oryzae were investigated. Results showed that amino acid nitrogen, soluble protein, <10 kDa peptide, and free phenolic contents increased with fermentation time; whereas the lactic acid bacteria count, reducing sugar, and free flavonoid contents showed a tendency to increase first and then decrease. SDS-PAGE analysis indicated that bands at >25 and <18.4 kDa were shown with improved intensity with time, whereas bands at 18.4-25 kDa were disappeared. Additionally, fermentation time led to an increase in DPPH, hydroxyl, ABTS⁺ radical scavenging activity, and ferric reducing antioxidant power. Thus, this study demonstrated that co-fermentation with L. plantarum and R. oryzae could improve nutrition and potential bioactivity of barley, and use barley as a good solid-state food carrier for probiotics. PRACTICAL APPLICATIONS: Barley is rich in nutrition and has a huge production. However, due to its high-fiber and special protein composition, there is a certain palatability problem whether it is used to produce flour or other products. Therefore, most of the barley is destined to animal feed and malt, and only a small part is used directly for human consumption. Aiming at this problem, on the basis of the optimization of the fermentation process at early stage, our results further demonstrated co-fermentation with L. plantarum and R. oryzae could enhance the nutritional value and potential bioactivity of barley, thus providing a novel approach to develop functional barley food and improve the direct utilization rate of barley in food processing.