Search Results (15)

This study investigated the potential of Yarrowia lipolytica, an oleaginous yeast, for producing lipid-rich biomass and its application in food technology. According to EFSA guidelines, lipid-rich biomass is recognized as a novel food with potential nutritional and technological value. However, cost-effective and scalable production of such biomass remains a challenge. The yeast was cultured in a nitrogen-limited medium using a cost-containment strategy based on the use of waste carbon sources, such as post-frying oil and untreated tap water. The composed batch culture approach studied in the experiments presented an example that reduces the cost of yeast biomass biosynthesis. This research aimed to characterize the biomass to assess its nutritional quality and suitability for food applications. Cultures were conducted in a laboratory bioreactor with a working volume of 4 litres. Key kinetic parameters were determined, including biomass yield (X), maximum lipid concentration (Lmax), lipid yield, protein yield relative to substrate and the specific rate of lipid synthesis or protein content and other cellular components. The biomass of Y. lipolytica demonstrated a high lipid content (39.43–50.53%), with significant levels of protein (24.16–27.03%) and unsaturated fatty acids, including oleic acid (62.73–66.44%) and linoleic acid (19.40–21.40%). Lipid-rich biomass produced in cultures with shorter times (20 h), which ended in the logarithmic growth phase, exhibited lower oxidative stability than longer cultures (65 h), which ended in the stationary growth phase. The results of this study highlighted that waste carbon sources and untreated tap water did not significantly impact the biomass yield or the nutritional profile, but did affect the stability of the produced oil. The biomass of Y. lipolytica, containing over 20% lipids, could serve as a promising raw material for food technology, providing a sustainable alternative to traditional vegetable oils. This work makes an important contribution to the development of alternative lipid sources by integrating waste processing in bioreactor-scale culture and kinetic modelling. Full article

The threadsail filefish, Stephanolepis cirrhifer, is an economically important marine species. However, wild catches have sharply decreased over the past 20 years, causing S. cirrhifer to be added to the IUCN Red List of Threatened Species. Accordingly, this study seeks to promote technological development for artificial breeding and early life-stage farming by defining the morphological characteristics of ontogenesis. The fertilized eggs, with a diameter of 0.62 ± 0.01 mm, were spherical and sticky and contained multiple oil globules of varying sizes. The embryonic development was observed and divided into eight phases, which were cleavage, blastocyst, gastrula, neurula, organogenesis, muscular contraction, heart pulsation, and hatching. At 3 days post-hatching (dph), the yolk sac was completely absorbed. The eye developed rapidly, and the mouth fissure and anus initially formed. Some larvae were fed on S-rotifers (Brachionus plicatilis). At 6–8 dph, the upper and lower jaws of larvae were gradually covered by leathery skin, and the head-to-body proportion increased. At 14–16 dph, the fin differentiation occurred in the dorsal, anal, and pectoral fins, with widespread distribution of yellow and melanin on the body surface. Swim bladder was clear. The swimming ability of larva was enhanced, resulting in an obvious clustering phenomenon. At 22–25 dph, the end of the notochord continued to tilt upwards, forming a tail fin. The trunk was evenly distributed with protruding circular punctate scales. The snout was covered with leathery epidermis, and the mouth began to round. At 40–45 dph, the juvenile completed metamorphosis, with horizontal dark stripes appearing on the trunk. Pigmented spots appeared on the tail fins. The counts of dorsal and anal fin spines were 34–36 and 32–34 dph, respectively. During the development of larvae and juveniles, the growth parameters, such as total length, standard length, body height, and body weight, were made as growth curves. The slopes of growth curves were calculated. We found two inflexion points occurring in the growth curves, which may be associated with metamorphosis and transitions in feeding habits. These results enrich the biological understanding of filefish species while providing guidance for artificial propagation and fry production in S. cirrhifer. Full article

This study investigated the capabilities of Yarrowia lipolytica strains to grow in media with different hydrophobic wastes from the meat industry. The yeast growth, cellular lipid accumulation, production of lipases, and degree of utilization of liquid and solid lipid wastes were studied in shaken cultures in media with organic and inorganic nitrogen sources. The effects of the type of waste, initial concentration of carbon source, Yarrowia strain, and inoculum size were investigated in two experimental sets using the Latin Square 5 × 5 design method. Post-frying rapeseed oil from chicken frying was selected as the carbon source to promote biomass growth. In contrast, the solid lipid fraction from meat broths promoted efficient lipid accumulation and yeast lipolytic activity. An initial concentration of the carbon source at 8% m/v stimulated efficient lipid biosynthesis and lipase production, while 2.5% v/v inoculum provided optimal conditions for the growth and utilization of hydrophobic substrates. No significant differences were observed in the particle dispersion of the liquid and solid wastes in the culture media (span = 2.51–3.23). The maximum emulsification index (62%) was observed in the culture of the Y. lipolytica KKP 323 strain in the medium with post-frying rapeseed oil from chicken frying, which was correlated with biosurfactant synthesis. It was concluded that the type of waste, its structure, and its composition affected various physiological yeast responses. Full article

The imperative of utilising alternative fuels for the operation of internal combustion engines stems from the requirements to reduce the emissions of greenhouse gases and other contaminants, the substantial demand for fuels, and the diminishing reserves of natural resources. The global inclination towards sustainable development necessitates the employment of biofuels as a substitute for fossil fuels. Nonetheless, the expenditures on raw materials for the manufacture of biodiesel remain substantial, thus underlining the importance of exploring solutions for reducing them. An instance of this could be the utilisation of plant and animal by-products, such as used frying oils and slaughterhouse waste, as feedstock for biodiesel production. Not only will this facilitate the creation of less costly biofuel, but it will also provide an effective solution for the management of post-production waste. The objective of the research delineated in this paper was to ascertain select physicochemical attributes of second-generation biodiesel, derived from spent frying oil, as well as mixtures of this biodiesel with diesel and biodiesel concentrations of 10, 20, and 30% (v/v). The biodiesel produced is the waste frying oil methyl esters WFOME. The proprietary GW-201 reactor was employed in the production of biodiesel. For WFOME biodiesel, DF diesel, and their blends—B10, B20, and B30—properties that influence the formation process of the combustible mixture, autoignition, and combustion of fuel–air mixtures in self-ignition engines were determined. The conducted research has established that “B” type fuels prepared from WFOME and DF present a viable alternative to fossil fuels. Pure biodiesel exhibited a marginally reduced lower heating value, however, in the case of fuel mixtures comprising up to 30% (v/v) biodiesel and diesel, the lower heating values approximated that of diesel. An elevated cetane number alongside an increased flash point of pure B100 biodiesel have been noted. The values of cetane number for WFOME and DF mixtures were found to be either comparable or marginally higher than those of pure DF diesel fuel. Full article

Diesel exhaust particles (DEPs) contribute to air pollution exposure-related adverse health impacts. Here, we examined in vitro, and in vivo toxicities of DEPs from a Caterpillar C11 heavy-duty diesel engine emissions using ultra-low-sulfur diesel (ULSD) and biodiesel blends (20% v/v) of canola (B20C), soy (B20S), or tallow–waste fry oil (B20T) in ULSD. The in vitro effects of DEPs (DEP_ULSD, DEP_B20C, DEP_B20S, and DEP_B20T) in exposed mouse monocyte/macrophage cells (J774A.1) were examined by analyzing the cellular cytotoxicity endpoints (CTB, LDH, and ATP) and secreted proteins. The in vivo effects were assessed in BALB/c mice (n = 6/group) exposed to DEPs (250 µg), carbon black (CB), or saline via intratracheal instillation 24 h post-exposure. Bronchoalveolar lavage fluid (BALF) cell counts, cytokines, lung/heart mRNA, and plasma markers were examined. In vitro cytotoxic potencies (e.g., ATP) and secreted TNF-α were positively correlated (p < 0.05) with in vivo inflammatory potency (BALF cytokines, lung/heart mRNA, and plasma markers). Overall, DEP_ULSD and DEP_B20C appeared to be more potent compared to DEP_B20S and DEP_B20T. These findings suggested that biodiesel blend-derived DEP potencies can be influenced by biodiesel sources, and inflammatory process- was one of the potential underlying toxicity mechanisms. These observations were consistent across in vitro and in vivo exposures, and this work adds value to the health risk analysis of cleaner fuel alternatives. Full article

Breaded chicken coated in whey protein isolate (WPI) has been shown to reduce oil absorption during batch frying. What is not known is how this is affected by repeated fryings and whether antioxidant-rich oil will enhance this effect. The objective of this research was to determine how successive daily frying of WPI-coated breaded chicken in antioxidant-rich oil affects oil quality and oil inhibition, moisture retention, color, and texture of the breaded chicken. Chicken fritters with and without a 10% WPI post-breading dip were fried successively for 6 h per day over five days in oil without antioxidant or with either 1000 ppm rosemary extract or propyl gallate. The control oil became spent at 12 h of frying (>24% TPM, <50% DEGLEV). During this time, the oils treated with antioxidants were significantly less spent, and the WPI-treated fritters fried in these oils exhibited 22–49% less lipid; retained 10–18% more moisture; and became darker, less red, and less yellow (lower L*, a*, and b* values) compared to the un-dipped fritters fried in the control oil. These results suggest that the presence of antioxidants in the frying oil mitigated some of the degradative changes in the oil during frying but likely did not play a major role in moisture retention or inhibition of oil absorption. Full article

Extraction is one of the most commonly used methods for obtaining and purifying chemical compounds for commercial usage. The aim of this study was to evaluate the effect of unconventional permeabilization and cell disruption methods on the yield of lipid extraction from cells of the oleaginous yeast Yarrowia lipolytica. Batch cultures in a medium with molasses and waste post-frying oil were carried out. The biomass was subjected to pulsed electric field (PEF), high-pressure processing (HPP), ultrasounds (US), and several conventional processing techniques with chemical and mechanical agents (glass beads, acetone, Triton and Tween surfactants). The effectiveness of the applied methods, either on cell permeabilization or cell disruption, was investigated by analyzing the oil and total protein extraction yield and oil leaching efficiency, as well as by using microscope images. The PEF and US treatments proved to be effective permeabilization methods as a step of sample pretreatment for extraction. These unconventional physical methods could efficiently increase intracellular lipid extraction yield in solvent applications. Full article

There is growing consumer and food industry interest in plant protein-based foods. However, quality evolution of plant protein-based meat analog (MA) is still a rarely studied subject. In this study, wheat and rice flour-based batter systems were used to coat plant protein-based MA, and were partially fried (at 180 °C, 1 min) in canola oil, subsequently frozen (at −18 °C) and stored for 7 days. Microwave heating (MH), infrared heating (IH), air frying (AF) and deep-fat frying (DFF) processes were employed on parfried frozen MA products, and their quality evolution was investigated. Results revealed that the fat content of MH-, IH- and AF-treated products was significantly (p < 0.05) lower than DFF-treated counterparts. Batter coatings reduced fat uptake in DFF of MA-based products. Both the batter formulations and cooking methods impacted the process parameters and quality attributes (cooking loss, moisture, texture, color) of MA-based coated food products. Moreover, the post-cooking stability of moisture and textural attributes of batter-coated MA-based products was impacted by both the batter formulations and cooking methods. Glass transition temperature (Tg) of MA-based products’ crust ranged from −20.0 °C to −23.1 °C, as determined with differential scanning calorimetry. ATR-FTIR spectroscopy and scanning electron microscopy analysis revealed that surface structural–chemical evolution of MA-based products was impacted by both the coating formulations and cooking methods. Overall, AF has been found as a suitable substitute for DFF in terms of studied quality attributes of meat analog-based coated products. Full article

Potatoes are essential for chip production, requiring high quality for processors and high yields for farmers. This two-year study was carried out for the purpose of investigating the influence of irrigation, fertilization, and cultivar on potato yield and tuber and chip quality. Field experiments were conducted in Sombor, Serbia, using a split-split plot design with three replications. Whole-plot treatments involved two irrigation schemes: sprinkler irrigation (SI) used as standard (control) and drip irrigation (DI). Subplot treatments included nitrogen (N) and potassium (K) fertilization in four different combinations: 64 kg N/ha and 64 kg K/ha (N₆₄K₆₄) as control; 77 kg N/ha and 110 kg K/ha (N₇₇K₁₁₀); 90 kg N/ha and 156 kg K/ha (N₉₀K₁₅₆); and 103 kg N/ha and 202 kg K/ha (N₁₀₃K₂₀₂). Sub-subplots comprised three cultivars: VR-808; Pirol; and Brooke. The VR-808 cultivar consistently yielded the highest amount (25.6 and 24.9 t/ha) under both irrigation methods. DI raised tuber flesh temperature compared to SI. The N₉₀K₁₅₆ × Pirol interaction exhibited the highest number of tubers with defects, while N₉₀K₁₅₆ × VR-808 had the fewest. Under DI, the VR-808 cultivar produced chips with the highest total defects, whereas Brooke had the lowest. The postfrying palm oil temperature was the highest for N₆₄N₆₄ × Brooke and the lowest for N₁₁₀K₂₂₀ × Pirol. This study underscores the role of irrigation, fertilization, and cultivar in achieving high yields and high chip quality, providing valuable insights into the whole process, from field to chip bag. Full article

Food byproduct streams can potentially be transformed into value-added products such as microbial lipids in bioprocesses based on the non-conventional Yarrowia yeast. The effect of culture conditions of Y. lipolytica KKP 379 wild strain in waste media on the efficiency of lipid accumulation, fatty acid composition, presence of selected sterols, yield and elemental composition of biomass has been studied. Batch and fed-batch bioreactor cultures were carried out in media with molasses hydrolysate (MH) and post-frying rapeseed oil. It was determined that biomass grown in MH contained more minerals than in medium with rapeseed post-frying oil. Considering the PDSC study, the T_max of oxidation induction ranged from 10.04–26.36 min for the analyzed samples. The biomass from fed-batch cultures with MH had the highest total sterol content (68.40 mg/g_oil), dominated by ergosterol at 60.16 mg/g. Feeding with post-frying rapeseed oil with new doses of mineral medium promoted maintaining the cellular lipid content at a high level (30.75–31.73%) for 50 h, with maximum yield at 37.50%. The results of the experiment showed that the cellular lipid accumulation efficiency of Y. lipolytica yeast and the content of sterols in the cell membrane can be manipulated by selecting waste substrates and culture mode. Full article

Waste management solutions including the valorization of waste materials in biotechnological processes is an important issue needing to be explored. A significant amount of waste is being generated by the food industry. In this study, an attempt was made to utilize two fish industry wastes simultaneously—waste brine and post-frying oil from frying fish fillets in Yarrowia lipolytica culture with high single cell oil synthesis yield. Oxygenation in the culture medium had a positive effect on the biosynthesis efficiency of microbial oil, resulting in the highest content of lipids in yeast cells at the level of 0.431 g/g d.m (dry mass). Y. lipolytica yeast preferentially accumulated oleic acid and linoleic acid, and the high content of linolenic acid, valuable from a nutritional point of view, was also found in microbial oil. This study proved that the use of post-frying rapeseed oil gives a chance to obtain valuable storage lipids in Y. lipolytica yeast cells via ex novo biosynthesis pathway. Furthermore, the wastewater stream could be limited using a waste brine as a solvent in medium preparation, but the brine share should not exceed 30% so as not to inhibit yeast cell growth. Full article

Microbial lipids called a sustainable alternative to traditional vegetable oils invariably capture the attention of researchers. In this study, the effect of limiting inorganic phosphorus (KH₂PO₄) and nitrogen ((NH₄)₂SO₄) sources in lipid-rich culture medium on the efficiency of cellular lipid biosynthesis by Y. lipolytica yeast has been investigated. In batch cultures, the carbon source was rapeseed waste post-frying oil (50 g/dm³). A significant relationship between the concentration of KH₂PO₄ and the amount of lipids accumulated has been revealed. In the shake-flask cultures, storage lipid yield was correlated with lower doses of phosphorus source in the medium. In bioreactor culture in mineral medium with (g/dm³) 3.0 KH₂PO₄ and 3.0 (NH₄)₂SO₄, the cellular lipid yield was 47.5% (w/w). Simultaneous limitation of both phosphorus and nitrogen sources promoted lipid accumulation in cells, but at the same time created unfavorable conditions for biomass growth (0.78 g_d.m./dm³). Increased phosphorus availability with limited cellular access to nitrogen resulted in higher biomass yields (7.45 g_d.m./dm³) than phosphorus limitation in a nitrogen-rich medium (4.56 g_d.m./dm³), with comparable lipid yields (30% and 32%). Regardless of the medium composition, the yeast preferentially accumulated oleic and linoleic acids as well as linolenic acid up to 8.89%. Further, it is crucial to determine the correlation between N/P molar ratios, biomass growth and efficient lipid accumulation. In particular, considering the contribution of phosphorus as a component of coenzymes in many metabolic pathways, including lipid biosynthesis and respiration processes, its importance as a factor in the cultivation of the oleaginous microorganisms was highlighted. Full article

Microbial oils, also called single-cell oils, are lipids synthesized by microorganisms exceeding 20% of the dry weight of the cell. The aim of this work was to investigate the possibility of applying a rapeseed post-frying oil from fish fillets as a carbon source in growth medium for Yarrowia lipolytica oleaginous yeast species in order to synthesize a microbial oil. The key contribution of this work is that the solution provides a sustainable method for valorization of post-frying waste oil. Shaken batch cultures were provided and the influence of triacylglyceride hydrolysis on yeast growth was evaluated. In conclusion, post-frying rapeseed oil seems to be an easily utilizable carbon source by yeast. Regardless of the method of lipid substrate pretreatment, the yeast strain preferentially accumulated oleic acid (C18: 1) from 52.07% to 66.62% and linoleic acid (C18: 2) from 12.98% to 24.10%. To the best of our knowledge, this is the first report of using the oxygen nanobubbles as an unconventional method of aerating the culture medium containing lipid carbon sources. The use of water oxygenated with nano-sized bubbles to prepare culture media resulted in obtaining a higher yield of biomass compared to the biomass yield in distilled water-based medium. Full article

Tempura is a dish of battered and deep-fried foods, and wheat flour is typically used; however, barley, buckwheat, and Job’s tears have an antioxidant capacity. This study investigated whether replacing wheat flour with flours from these three crops in tempura affects the antioxidant capacity and deterioration of frying oil. Radical scavenging activity and polyphenol content of tempura were measured by chemiluminescence-based assay and the Folin–Denis method, respectively. The peroxide value, p-anisidin value, acid value, and polar compound of the oil used in frying were measured as indexes of oil deterioration post-frying due to oxidation. Although the frying oil of barley showed higher p-anisidin value than that of wheat, the oil samples’ deterioration level measured in this study was low. The antioxidant capacity and polyphenol content in the three flours samples were higher than those in wheat sample, with buckwheat producing the greatest values, followed by Job’s tears, and then barley. Thus, deep-fried products prepared using the three flours demonstrated superior antioxidant capacity owing to the abundance of antioxidant components. Therefore, tempura can be enjoyed in a healthier manner by using batter prepared using those flours, and substituting wheat flour with the three flours can increase the antioxidant capacity of deep-fried products. Full article

This study aimed to evaluate the production of a surfactant by Cunninghamella echinulata, using agro-industrial residues, corn steep liquor (CSL), and soybean oil waste (SOW). The study had a factorial design, using as a variable response to the reduction of surface tension. C. echinulata was able to produce biosurfactant in assay, CSL (8.82%) and SOW (2%). The results showed that the biosurfactant was successfully produced by C. echinulata and had attractive properties, such as a low surface tension (31.7 mN/m), a yield of 5.18 g/L at 120 h of cultivation, and an anionic profile. It also achieved a reduction in surface tension stability in a wide range of pH values, temperatures, and salinity values. The biosurfactant produced by C. echinulata showed an absence of toxicity to Artemia salina. The influence of the biosurfactant on the viscosity of engine oil, burnt engine oil, diesel, soybean oil post-frying, canola oil, and water was investigated. The results reveal a mechanism for the decrease of the viscosity using hydrophobic substrates and the new biosurfactant solution at 1.5% of the (CMC). This enables the formulation of a low-cost culture medium alternative, based on corn steep liquor and the reuse of soybean oil after frying to produce a biosurfactant. Additionally, performance of the biosurfactant isolated from C. echinulata showed an excellent ability to remove spilled oil, such as diesel (98.7%) and kerosene (92.3%) from marine sand. Full article