Spray-dried Egg Research Articles

Effect of lactic acid bacteria fermentation on spray-dried egg yolk powder: Powder characteristics, structural properties and gastrointestinal digestibility

Preparation of egg yolk powder with high solubility and high gastrointestinal digestibility is important for its effective utilization in the food industry. This study discovered that fermentation of egg yolks by lactic acid bacteria (LAB) resulted in a 54.3% increase in solubility, 110.6% increase in water dispersibility, and improved the stability of the dispersion to sedimentation. Fermentation resulted in smaller average particle size, enhanced hydrolysis of proteins and fats, and a more expansive protein structure in the egg yolk powder. Laser confocal microscopy showed increased hydrolysis of protein and fat in fermented egg yolk powder during simulated digestion, highlighting enhanced digestive properties due to LAB fermentation. This study validated the feasibility of LAB fermentation technology for modifying egg yolk powder, offering valuable insights for its processing and application in the food industry.

Extraction of Lipids and Functional Properties of Defatted Egg Yolk Powder Obtained Using a One-Step Organic Solvent Lipid Extraction Process.

A one-step organic solvent lipid extraction method was used to separate lipids from spray-dried egg yolk. Organic solvents tested were chloroform:methanol (CM, 2:1, v:v), methyl-tert-butyl ether (MTBE), or hexane:isopropanol (HI, 3:2, v:v). The resulting defatted egg yolk powder had between 21 and 30% more protein and between 22 and 25% less lipid than the initial spray-dried egg yolk powder (p < 0.05). The solubility of the powder decreased from 20% to 4% (p < 0.05) when CM was used as the organic solvent, likely due to protein denaturation by the chloroform. Gels made from MBTE and HI-extracted protein concentrates had similar hardness (p > 0.05) and were both harder than gels made using the initial egg yolk powder (p < 0.05). MTBE gels were springier, more cohesive, and gummier (p < 0.05) with similar resistance to the initial egg yolk powder (p > 0.05). The results of this study showed that the functionality of the protein in the defatted egg yolk powder was best retained when MTBE was used as the lipid extraction solvent.

Mechanism of enhancing rehydration capacity and foaming property of spray-dried egg white powder by lactic acid fermentation

Spray-dried egg white powder has limited applicability as a raw material in food production due to its deteriorative rehydration capacity. Lactic acid fermentation is a promising technique for protein denaturation and has been widely used in the food industry. In this work, we investigated the effects of 4, 8, and 12-h lactic acid fermentation on protein structure, powder characteristics, rehydration capacity, and foaming property of spray-dried egg white powder. Results show that the fermentation treatment significantly reduced the surface hydrophobicity of egg white powder samples, while 8 and 12 h of fermentation significantly increased their zeta potential. During the 12 h of fermentation, the particle size of the powder gradually decreased from 2.59 μm to 1.69, 1.23, and 0.76 μm, respectively. Scanning electron microscope result shows the same and also indicates a concave hole structure in fermented egg white powders. These changes in protein molecules result in the significantly improved wettability, dispersibility, and solubility of the powder, thus enhancing its rehydration capacity. The foaming ability and foam stability of egg white powder also significantly improved after fermentation. Furthermore, the fermentation process altered the secondary structure, moisture content, bulk densities, flowability, and color of the powder. This work demonstrates the usefulness of lactic acid fermentation in enhancing the quality of egg white powder. The findings have significant implications for the development of better-quality egg white powder products in the food industry.

Quantitative N-glycoproteomic analysis of egg yolk powder during thermal processing

The production of egg yolk powder often involves critical processes such as pasteurization and spray drying, however, these thermal processes will inevitably affect the functional properties of egg yolk (especially gelation and emulsification). The aim of this study was to elucidate the mechanism of the effect of pasteurized egg yolk (P-EY) and spray-dried egg yolk (SD-EY) on the functional properties through quantitative N-glycoproteomic. The results showed, compared with fresh egg yolk (F-EY), emulsifying property of mild heat-treated P-EY was slightly reduced while the gelation property did not undergo significant changes, whereas emulsifying activity (EAI) and gelation strength of vigorously heat-treated SD-EY were significantly reduced by 48.72 % and 35.73 %, respectively. During thermal processing in SD-EY, larger aggregate particles (particle size ∼10 um) were formed, and the surface hydrophobicity was reduced (93.0 %) and the zeta potential was enhanced (62.8 %). The results of quantitative N-glycoproteomic showed that 13 N-glycosylated proteins (APOB, vitellogenin, etc.) were down-regulated while only 2 N-glycosylated proteins were up-regulated; 21 N-glycosylation sites were down-regulated and 2 N-glycosylation sites were up-regulated in SD-EY, suggesting that covalent cross-linking of protein N-glycoproteins may have occurred in the process of spray-drying, which altered molecular physicochemical characteristics of the yolk solution that further affecting the processing properties of egg yolk.

Application prospect of replacement of fish meal with spray-dried egg meal in diets for swimming crab (Portunus trituberculatus)

An 8-week feeding trial was conducted to evaluate the effects of replacing fish meal with spray-dried egg meal (SEM) on growth performance, anti-oxidative capacity, mTOR pathway, and cholesterol metabolism in juvenile Portunus trituberculatus. The results showed that the highest percent weight gain was observed in crabs fed diet with 10% replacement of fish meal with SEM. Essential amino acids in the muscle and hepatopancreas significantly decreased with the increase of dietary replacement levels of fish meal with SEM. The lowest content of MDA in hepatopancreas was occurred at those fed diet with 40% replacement of fish meal with SEM, the activities of T-AOC, GSH-PX and content of GSH in hepatopancreas significantly increased with dietary SEM replacement fish meal increasing from 10% to 50%. The expression of akt, eif4e1a, eif4e2, eif4e3, and 4ebp1 significantly up-regulated, however, the expression of tor was showed significantly linear down-regulated, and the highest expression of akt, eif4e2 and 4ebp1 were found in crabs fed diet with 20% replacement of fish meal with SEM, the highest expression of eif4e1a was observed in those fed diet with 10% replacement of fish meal with SEM, the highest expression of eif4e3 was occurred in crabs fed diet with 30% replacement of fish meal with SEM. In cholesterol metabolism, the expression of abcg1 and lrp2 significantly down-regulated and the expression of npc1 significantly up-regulated with increase of replacement level of fish meal with SEM. The content of T-CHO in hemolymph and hepatopancreas significantly linear increased. In conclusion, based on quadratic broken-line regression analysis of PWG against the dietary replacement of fish meal with SEM, the optimal replacement level of fish meal with SEM was estimated to be 15.94% for juvenile swimming crab.

Hyperimmune egg yolk antibodies developed against Clostridium perfringens antigens protect against necrotic enteritis

Necrotic enteritis (NE) is a widespread infectious disease caused by Clostridium perfringens that inflicts major economic losses on the global poultry industry. Due to regulations on antibiotic use in poultry production, there is an urgent need for alternative strategies to mitigate the negative effects of NE. This paper presents a passive immunization technology that utilizes hyperimmune egg yolk immunoglobulin Y (IgY) specific to the major immunodominant antigens of C. perfringens. Egg yolk IgYs were generated by immunizing hens with 4 different recombinant C. perfringens antigens, and their protective effects against NE were evaluated in commercial broilers. Six different spray-dried egg powders were produced using recombinant C. perfringens antigens: α-toxin, NE B-like toxin (NetB; EB), elongation factor-Tu (ET), pyruvate:ferredoxin oxidoreductase, a mixture of 4 antigens (EM-1), and a nonimmunized control (EC). The challenged groups were either provided with different egg powders at a 1% level or no egg powders (EN). The NE challenge model based on Eimeria maxima and C. perfringens dual infection was used. In Experiments 1 and 2, the EB and ET groups exhibited increased body weight gain (BWG; P < 0.01), decreased NE lesion scores (P < 0.001), and reduced serum NetB levels (P < 0.01) compared to the EN and EC groups. IgY against NetB significantly reduced Leghorn male hepatocellular cytotoxicity in an in vitro test (P < 0.01). In Experiment 3, the protective effect of the IgYs mixture (EM-2) against C. perfringens antigens (NetB and EFTu) and Eimeria antigens (elongation factor-1-alpha: EF1α and Eimeria profilin: 3-1E) was tested. The EM-2 group showed similar body weight, BWG, and feed intake from d 7 to 22 compared to the NC group (P < 0.05). On d 20, the EM-2 group showed comparable intestinal permeability, NE lesion scores, and jejunal NetB and collagen adhesion protein levels to the NC group (P < 0.05). In conclusion, dietary mixture containing antibodies to NetB and EFTu provides protection against experimental NE in chickens through passive immunization.

Effects of different protectants on the IgY content and physico-chemical properties of spray-dried egg yolk powder.

Egg yolk powder (EYP) with high immunoglobulin of yolk (IgY) content and good solubility is in great demand in the market of functional foods. In this article, the properties of spray-dried EYP with the addition of five protectants (maltodextrin, trehalose, mannitol, maltitol and sucrose) were investigated. All the protectants increased IgY activity and solubility of EYP. Among them, EYP with maltodextrin displayed the highest activity of IgY (27.11 mg/g), the highest solubility (66.39%) and the lowest surface hydrophobicity. Moreover, the average particle size of EYP with maltodextrin was the smallest (9.78 μm). The egg yolk particles obtained by adding the protectants are more uniformly distributed and have smaller particle size. Fourier-transform infrared spectroscopy confirmed the structural integrity of the proteins, indicating that the protectants addition enhanced the hydrogen bonding forces between the EYP protein molecules. The addition of protectants can significantly improve the IgY content, solubility and structural stability of EYP. © 2023 Society of Chemical Industry.

Development of an IgY-Based Treatment to Control Bovine Coronavirus Diarrhea in Dairy Calves

Bovine Coronavirus (BCoV) is a major pathogen associated with neonatal calf diarrhea. Standard practice dictates that to prevent BCoV diarrhea, dams should be immunized in the last stage of pregnancy to increase BCoV-specific antibody (Ab) titers in serum and colostrum. For the prevention to be effective, calves need to suck maternal colostrum within the first six to twelve hours of life before gut closure to ensure a good level of passive immunity. The high rate of maternal Ab transfer failure resulting from this process posed the need to develop alternative local passive immunity strategies to strengthen the prevention and treatment of BCoV diarrhea. Immunoglobulin Y technology represents a promising tool to address this gap. In this study, 200 laying hens were immunized with BCoV to obtain spray-dried egg powder enriched in specific IgY Abs to BCoV on a large production scale. To ensure batch-to-batch product consistency, a potency assay was statistically validated. With a sample size of 241, the BCoV-specific IgY ELISA showed a sensitivity and specificity of 97.7% and 98.2%, respectively. ELISA IgY Abs to BCoV correlated with virus-neutralizing Ab titers (Pearson correlation, R2 = 0.92, p < 0.001). Most importantly, a pilot efficacy study in newborn calves showed a significant delay and shorter duration of BCoV-associated diarrhea and shedding in IgY-treated colostrum-deprived calves. Calves were treated with milk supplemented with egg powder (final IgY Ab titer to BCoV ELISA = 512; VN = 32) for 14 days as a passive treatment before a challenge with BCoV and were compared to calves fed milk with no supplementation. This is the first study with proof of efficacy of a product based on egg powder manufactured at a scale that successfully prevents BCoV-associated neonatal calf diarrhea.

Protective effects of egg yolk immunoglobulins (IgY) against CyHV-2 infection in gibel carp (Carassius gibelio)

Herpesviral hematopoietic necrosis caused by cyprinid herpesvirus-2 (CyHV-2) is highly prevalent in gibel carp (Carassius gibelio Bloch) and is associated with high mortality and great economic loss. Currently, no efficient methods of prevention and control of CyHV-2 infection are available. Increasing evidence suggests that antigen-specific egg yolk immunoglobulins (IgY) are highly effective against various pathogens in farmed fish. Therefore, the aim of this study was to develop a specific IgY against CyHV-2 infection in gibel carp. We first produced a recombinant D4ORFs protein that encodes four open reading frames of CyHV-2 and then generated specific IgY by immunizing laying hens with this protein. The eggs laid by immunized hens were processed into spray-dried egg powder containing D4ORFs IgY. The D4ORFs IgY showed high neutralizing activity in vitro against CyHV-2, as evidenced by a significant reduction in cytopathic effect in gibel carp brain cells cultured in the presence of the IgY antibodies. Whole-egg powder containing IgY specific to D4ORFs protein was incorporated into the basal diet at levels of 0, 0.1, 0.3, and 0.6% to prepare experimental diets for use in intervention studies in gibel carp. Another group received non-specific IgY. For preventive intervention, all fish were fed these experimental diets for 25 days before being immersion challenged with CyHV-2, after which the fish were switched to the basal diet for 21 days. For therapeutic intervention, fish were first challenged with CyHV-2 and then fed the diet with 0.6% D4ORFs IgY. Fish that received D4ORFs IgY prior to CyHV-2 challenge had significantly higher survival rates and significantly lower viral load in the trunk kidney compared to those that received non-specific IgY. Improved survival and reduced viral load were also observed in CyHV-2-challenged fish that received dietary supplementation of D4ORFs IgY. Hematological and serum biochemical analysis also showed improved health and enhanced antiviral defense in fish that received D4ORFs IgY. Overall, these findings demonstrated both preventive and therapeutic effects of anti-D4ORFs IgY against CyHV-2 infection.

Feeding thermally processed spray-dried egg whites, singly or in combination with 15-acetyldeoxynivalenol or peroxidized soybean oil on growth performance, digestibility, intestinal morphology, and oxidative status in nursery pigs.

Two experiments (EXP) determined the susceptibility of spray-dried egg white (SDEW) to oxidation (heating at 100 °C for 72 h; thermally processed, TP) and whether feeding TP-SDEW, 15-acetyldeoxynivalenol (15-ADON), or peroxidized soybean oil (PSO), singularly or in combination, would affect pig performance, intestinal morphology, digestibility, and markers of oxidative stress in nursery pigs. In EXP 1, 32 pigs (7.14 kg body weight, BW) were placed individually into pens and fed diets containing either 12% SDEW, 6% TP-SDEW plus 6% SDEW, or 12% TP-SDEW. Performance was measured at the end of the 24-d feeding period with biological samples harvested following euthanasia. In EXP 2, 64 pigs (10.6 kg BW) were placed individually into pens and fed diets containing 7.5% soybean oil or PSO, 10% SDEW or TP-SDEW, and diets without or with 3 mg 15-ADON/kg diet in a 2 × 2 × 2 factorial arrangement. Performance was measured at the end of the 28-d feeding period with biological samples harvested following euthanasia. In EXP 1, dietary treatment did not affect pig performance, apparent ileal digestibility of amino acids (AAs), apparent total tract digestibility (ATTD) of gross energy (GE) or nitrogen (N), ileal crypt depth, or villi height:crypt depth ratio (P > 0.05). The effects of feeding TP-SDEW on protein damage in the plasma and liver (P < 0.05) were variable. In EXP 2, there were no three-way interactions and only one two-way interactions among dietary treatments on parameters evaluated. There was no effect of feeding TP-SDEW on ATTD of GE or N, intestinal morphology, or on oxidative markers in the plasma, liver, or ileum (P > 0.05). There was no effect of feeding diets containing added 15-ADON on ATTD of GE, ileal AA digestibility, intestinal morphology, oxidative markers in the plasma, liver, or ileum, or pig performance (P > 0.05). Feeding pigs diets containing PSO resulted in reduced ATTD of GE and N, plasma vitamin E concentration, and pig performance (P < 0.01) but did not affect intestinal morphology or oxidative markers in the liver or ileum (P > 0.05). In conclusion, it was difficult to induce protein oxidation in SDEW and when achieved there were limited effects on performance, digestibility, intestinal morphology, and oxidative status. Furthermore, singly adding 15-A-DON to a diet had no effect on the animal. At last, adding PSO reduces animal performance, but has limited effect on digestibility, intestinal morphology, and oxidative status in nursery pigs.

Diet supplementation with commercial enzymatically-hydrolyzed egg white peptides ameliorates the severity of allergy in a mouse model of egg white allergy.

Commercial spray-dried egg white (S-EW) is often used for oral immunotherapy (OIT). Peptifine® (PF), a commercial preparation of enzymatically-hydrolyzed egg white (EW) peptides, is considered safe OIT food. Here, we examined the therapeutic effect of PF or S-EW in a mouse model of EW allergy. Sensitized female BALB/c mice underwent 4-week OIT by supplementation of 19% casein diet with 1% PF (PF group) or S-EW (S-EW group), and non-supplementation of 20% casein diet (non-OIT group). Non-sensitized mice acted as the non-allergy group. Oral and intraperitoneal EW challenges were performed and allergic biomarkers were determined. Changes in rectal temperature after oral challenge were comparable in the allergy groups. However, after intraperitoneal challenge, rectal temperature decrease in the PF and S-EW groups was lower than in the non-OIT group. After 4 weeks, plasma levels of ovalbumin- and ovomucoid-specific antibodies were assessed; IgE levels in the PF and S-EW groups were lower than those in the non-OIT group. Interleukin-4 secretion after EW challenge was significantly lower in splenocyte cultures derived from PF and S-EW groups than in the non-OIT group. Furthermore, the percentage of CD4+ Foxp3+ splenocytes in the PF group was significantly higher than that in the non-OIT and S-EW groups. Oral gavage of 40 mg PF did not induce an allergic response in sensitized mice with EW. Diet supplementation with 1% PF mildly ameliorated the severity of allergy in mouse with EW allergy, indicating that PF is a safe OIT food.

Evaluation of spray-dried eggs as a micronutrient-rich nutritional supplement

Regular consumption of hen eggs can help to prevent deficiencies of essential nutrients, such as essential amino acids, vitamin A and E or trace elements zinc and selenium, for vulnerable populations. This study focused on assessing the nutritional value of spray-dried eggs, favored by their manufacturability, storability and ease of addition to (complementary) foods. Using a wide range of analytical techniques, we recorded and compared the nutrient profiles of commercially produced pasteurized whole eggs and their respective powder samples spray-dried at 160°C. Important nutrients that were not significantly affected by spray-drying include total fat content, several amino acids, α- and δ-tocopherol, lutein, zeaxanthin, essential trace elements and cobalamin. The most notable mean losses were found for unsaturated fatty acids, e.g., linoleic (by −38.7%, from 4.11 ± 0.45 to 2.52 ± 0.75 g/100 g DM) and linolenic acid (by −60.8%, from 0.76 ± 0.05 to 0.30 ± 0.04 g/100 g DM). Despite recording significant retinol losses in two out of three batches, the overall low reduction of −14% recommend spray-dried eggs as a valuable source of vitamin A. A daily intake of spray-dried egg powder corresponding to one medium sized egg meets dietary reference values for children, e.g., by 100% for vitamin E, by 24% for retinol, by 61% for selenium and by 22% for zinc. In conclusion, even though a dry weight comparison favors supplementation with pasteurized whole eggs, our results demonstrate a high potential for spray-dried eggs as nutritional supplement. However, the spray-drying process should be optimized toward higher retentions of unsaturated fatty acids and retinol.

Protein-Sourced Feedstuffs for Aquatic Animals in Nutrition Research and Aquaculture.

Aquatic animals have particularly high requirements for dietary amino acids (AAs) for health, survival, growth, development, and reproduction. These nutrients are usually provided from ingested proteins and may also be derived from supplemental crystalline AA. AAs are the building blocks of protein (a major component of tissue growth) and, therefore, are the determinants of the growth performance and feed efficiency of farmed fish. Because protein is generally the most expensive ingredient in aqua feeds, much attention has been directed to ensure that dietary protein feedstuff is of high quality and cost-effective for feeding fish, crustaceans, and other aquatic animals worldwide. Due to the rapid development of aquaculture worldwide and a limited source of fishmeal (the traditionally sole or primary source of AAs for aquatic animals), alternative protein sources must be identified to feed aquatic animals. Plant-sourced feedstuffs for aquatic animals include soybean meal, extruded soybean meal, fermented soybean meal, soybean protein concentrates, soybean protein isolates, leaf meal, hydrolyzed plant protein, wheat, wheat hydrolyzed protein, canola meal, cottonseed meal, peanut meal, sunflower meal, peas, rice, dried brewers grains, and dried distillers grains. Animal-sourced feedstuffs include fishmeal, fish paste, bone meal, meat and bone meal, poultry by-product meal, chicken by-product meal, chicken visceral digest, spray-dried poultry plasma, spray-dried egg product, hydrolyzed feather meal, intestine-mucosa product, peptones,blood meal (bovine or poultry), whey powder with high protein content, cheese powder, and insect meal. Microbial sources of protein feedstuffs include yeast protein and single-cell microbial protein (e.g., algae); they have more balanced AA profiles than most plant proteins for animal feeding. Animal-sourced ingredients can be used as a single source of dietary protein or in complementary combinations with plant and microbial sources of proteins. All protein feedstuffs must adequately provide functional AAs for aquatic animals.

246 Effects of Feeding Thermally Processed Spray-dried Egg Whites on Growth Performance, Apparent Digestibility, and Oxidative Stress in Nursery Pigs

Abstract The objectives of this study were to determine if feeding thermally processed (TP, heated at 100°C for 120 h) spray-dried egg whites (SDEW) to nursery pigs would impact growth performance, apparent total tract digestibility (ATTD) of GE, N, and S, and oxidative stress. Thirty-two barrows, (initial BW 7.1 kg) were randomly assigned to dietary treatments with 1 pig per pen. In a preliminary study, thermally processing SDEW at 100°C for 120 h increased protein carbonyls (PC) from 6 µmol/g to 19.4 µmol/g (P ≤ 0.01). Diets included either 12% SDEW, 6% TP-SDEW plus 6% SDEW, or 12% TP-SDEW. The experiment lasted 24 d for collection of growth performance data, while plasma was collected on d 21 and liver tissue harvested on d 24 to analyze for markers of oxidative stress. Feces were collected on d 22 for measures of ATTD. Daily gain, daily feed intake, feed efficiency, and ATTD of GE were not found to be different among dietary treatments (P ≥ 0.57). In contrast, ATTD of N (P = 0.11) and S (P = 0.03) were found to increase with increasing protein oxidation in the diet. There was no change in the plasma or liver F2-isoprostanes and 8-hydroxy-2’-deoxyguanosine among dietary treatments (P ≥ 0.28). An increase in plasma PC (P = 0.02) was observed in pigs fed 12% TP-SDEW compared to pigs fed 12% SDEW and pigs fed 6% TP-SDEW. In contrast, a decrease in liver tissue PC (P = 0.04) was observed in pigs fed 6% TP-SDEW compared to pigs fed 12% SDEW and 12% TP-SDEW. These results indicate that feeding TP-SDEW does not affect growth performance, ATTD of GE, and oxidative stress as indicated by F2-isoprostanes or 8-hydroxy-2’-deoxyguanosine; but appeared to have variable effects on oxidative stress as measured by PC.

Effect of Different Egg Products on Lipid Oxidation of Biscuits.

Egg products are one of the main ingredients used in bakery industries, and they contain cholesterol. Cholesterol suffers several chemical changes during the food processes, allowing some potentially toxic compounds called cholesterol oxidized products (COPs). Thus, the aim of this work was to study the evolution of lipid oxidation from eggs to egg products, and to evaluate the influence of egg products on COPs formation in biscuits formulated with them. The results confirmed that spray-drying technology improves the cholesterol oxidation 2.6 times compared to pasteurized eggs. Biscuit samples showed a COPs content that is strictly related to the egg products used. Samples formulated with spray-dried eggs noticed lower amounts of COPs compared to those formulated with pasteurized eggs. It is important to stress that COPs composition was different between the two samples, underlining that the kinetic of COPs formation is dependent on the type of egg products.

Quantitative N-glycoproteomic analyses provide insights into the effects of thermal processes on egg white functional properties

This study tries to elucidate the different mechanisms of functional properties among pasteurized egg white (P-EW), spray-dried egg white (SD-EW) and fresh egg white (F-EW) via quantitative N-glycoproteomic analyses. The results showed that spray-drying increased the surface hydrophobicity (181.4%) and zeta potential (25.6%) of egg white, which contributed to the enhancement of emulsifying activity index (20.1%) and foaming capacity (35.2%). Pasteurization caused the disintegration of natural protein aggregates in F-EW and resulted in a “block-like” P-EW gel and higher water holding capacity (6.2%). Spray-drying caused formation of thermal aggregates and led to a “mesh-like” SD-EW gel and better cohesiveness (3.6%). Quantitative N-glycoproteomic analysis showed that the abundance of 32 N-glycosites from 18 N-glycoproteins (such as Mucin 5B) of SD-EW was significantly reduced comparing to F-EW, indicated that the N-glycans of egg white protein are likely to be covalently cross-linked during spray-drying and are involved in thermal aggregation.

Pasteurized Chicken Egg Powder Stimulates Proliferation and Migration of AGS, RIE1, and Caco-2 Cells and Reduces NSAID-Induced Injury in Mice and Colitis in Rats

Chicken eggs and bovine colostrum contain proteins possessing antimicrobial, immunoregulatory, and growth factor activity. The ability of eggs to influence gut defense and repair is largely unexplored. We examined the effect of pasteurized spray-dried egg on gastrointestinal injury using cell culture and animal models and sought to determine whether adding colostrum provided extra benefit. Egg alone, colostrum alone, and a 40:60 egg: colostrum combination were tested for proliferative (Alamar blue) and migratory (wounded monolayer) activity at 1 mg.mL-1 using human colon adenocarcinoma (Caco-2), human gastric cancer (AGS), and rat intestinal epithelioid-1 (RIE1) cells. Four groups of adult male C57BL/6 mice received 20 mg.kg-1.d-1 test products in drinking water for 7 d and indomethacin (85 mg.kg-1, administered subcutaneously) on day 7. Villus height and morphology were assessed. Three groups of adult male Sprague Dawley rats received 20 mg.kg-1.d-1 test product by gavage for 9 d and dextran sodium sulfate (DSS, 4% in drinking water) for the final 7 d. Histology, microscopic damage scoring, and myeloperoxidase were assessed. Egg or colostrum alone caused 3-fold increases in cell proliferation and migration (P<0.05 compared with baseline). Heating the egg removed its bioactivity. Addition of neutralizing antibodies or tyrphostin showed that ovomucoid, ovalbumin, and the epidermal growth factor receptor mediated the effects of egg (all P<0.05 compared with egg). Egg reduced shortening of villi caused by indomethacin in mice by 34% and reduced DSS-induced colonic damage in rats by 44-61% (P<0.05 compared with DSS). Similar results were seen using colostrum alone. In each assay, the 40:60 combination gave improved results compared with the same dose of egg or colostrum alone (P<0.05). Studies using AGS, RIE1, and Caco-2 cells, C57BL/6 mice, and Sprague Dawley rats showed protective effects of egg against gut injury. Enhanced results were seen if colostrum and egg were coadministered. Egg powder with or without colostrum may have therapeutic value for prevention and treatment of gut injuries.

Encapsulation of caffeine in spray-dried micro-eggs for controlled release: The effect of spray-drying (cooking) temperature

This work has found that the spray-drying temperature affects the microencapsulation and release behaviour of caffeine from spray-dried egg albumen in the form of a powder (“micro-eggs”, filled in a gelatine capsule), not in the form of compressed tablets. The spray-dried micro-eggs are more spherical when spray-dried at 60–120 °C but are more crumpled when spray-dried at 140–200 °C, which is related to the critical denaturation temperature of 56 °C for egg albumen. At low inlet temperatures, the particle size of spray-dried micro-eggs and the yield are small while the free moisture content is high. A free moisture content of less than 4.2% is required for high yields. FTIR-ATR (for surface analysis) and Raman (for bulk analysis) spectra indicate greater surface enrichment of protein for higher inlet temperatures. DSC spectra show greater denaturation of protein for the spray-dried micro-eggs produced at higher inlet temperatures, and the spectra also suggest that caffeine is amorphous in the spray-dried micro-eggs. Moreover, the release rate of caffeine has been controlled by changing the inlet temperature. The releases last for 2.5–14 h with inlet temperatures of 60–200 °C. The release profiles have been found to fit the first-order, Higuchi, Hixson-Crowell, and Korsmeyer-Peppas release models, well. The release mechanisms of caffeine are suggested to be non-Fickian (more release occurs when the protein matrices are eroded) for the spray-dried micro-eggs produced at low inlet temperatures, whereas Fick's law (corresponding to the molecular diffusion of caffeine) is followed more closely for the spray-dried micro-eggs denatured/cooked at high inlet temperatures, due to the characteristics of the protein shell.

Composition of amino acids and related nitrogenous nutrients in feedstuffs for animal diets

We analyzed the composition of amino acids (AAs) in oligopeptides, proteins, and the free pool, as well as creatine, agmatine, polyamines, carnosine, anserine, and glutathione, in animal- and plant-derived feedstuffs. Ingredients of animal origins were black soldier fly larvae meal (BSFM), chicken by-product meal, chicken visceral digest, feather meal, Menhaden fishmeal, Peruvian anchovy fishmeal, Southeast Asian fishmeal, spray-dried peptone from enzymes-treated porcine mucosal tissues, poultry by-product meal (pet-food grade), spray-dried poultry plasma, and spray-dried egg product. Ingredients of plant origins were algae spirulina meal, soybean meal, and soy protein concentrate. All animal-derived feedstuffs contained large amounts of all proteinogenic AAs (particularly glycine, proline, glutamate, leucine, lysine, and arginine) and key nonproteinogenic AAs (taurine and 4-hydroxyproline), as well as significant amounts of agmatine, polyamines, creatine, creatinine, creatine phosphate, and glutathione. These nitrogenous substances are essential to either DNA and protein syntheses in cells or energy metabolism in tissues (particularly the brain and skeletal muscle). Of note, chicken by-product meal, poultry by-product meal, and spray-dried poultry plasma contained large amounts of carnosine and anserine (potent antioxidants). Compared with most of the animal-derived feedstuffs, plant-derived feedstuffs contained much lower contents of glycine and proline, little 4-hydroxyproline, and no creatine, creatinine, creatine phosphate, carnosine or anserine. These results indicate the unique importance of animal-source feedstuffs in improving the feed efficiency, growth and health of animals (including fish and companion animals). Because soy protein concentrate is consumed by infants, children and adults, as are BSFM and algae for children and adults, our findings also have important implications for human nutrition.

Subcritical fluid extraction treatment on egg yolk: Product characterization

In this study, the method of subcritical fluid-propane extraction (SPE) used to coproduce egg yolk oil (EYO) and low-fat egg yolk powder from spray-dried egg yolk powder (EYP) was investigated. Results showed that the optimum parameters were: extraction temperature of 313.15 K, extraction time of 120 min, and solid-liquid ratio of 1:9 (g/mL). Under this condition, the residual oil rate of EYP was 21.04%, which was much lower than that of ethanol extraction (39.24%). Scanning electron microscopy reveled that serious disruptions of egg yolk sphere extracted by SPE were observed, facilitating the EYO extraction. In addition, oil extracted by SPE had lower acid value and peroxide value than that of ethanol extraction. Moreover, the emulsifying properties and solubility of low-fat EYP obtained by SPE were similar to the original egg yolk powder. This study provides a new technique for coproducing high-quality oil and protein.