Corn Protein Research Articles

Effective intercalation of zein into Na-montmorillonite: role of the protein components and use of the developed biointerfaces.

Biohybrid materials based on the intercalation of zein, the major storage protein in corn, into sodium-exchanged montmorillonite were prepared following two synthesis strategies. The first one made use of zein dissolved in 80% (v/v) ethanol/water solution, the usual solvent for this protein, while the second method is new and uses a sequential process that implies the previous separation of zein components in absolute ethanol. This treatment of zein with ethanol renders a soluble yellow phase and an agglomerate of insoluble components, which are able to intercalate the layered silicate when an aqueous dispersion of montmorillonite is added to the ethanol medium containing both phases. The diverse steps in this second route were investigated individually in order to understand the underlying mechanism that drives to the intercalation of this complex hydrophobic biomacromolecule into the hydrophilic interlayer space of sodium-exchanged montmorillonite. In addition to physicochemical characterization of the resulting materials, these biohybrid interfaces were also evaluated as biofillers in the preparation of diverse ecofriendly nanocomposites.

Analysis of Water Soluble and Insoluble Polysaccharides in Kernels of Different Corns (<i>Zea mays</i> L.)

Phytoglycogen and starch components were assayed in twelve lines of fresh kernels belonging to different types of corns such as normal corn (field corn), sweet corn and quality protein maize (QPM). The technique, using single kernel and a series of digestions and dilutions, measured glucano lactone contents of soluble and insoluble components in the three groups of corn with distinct and diverse uses. Extensive variability was found among sweet corn, field corn and QPM for the water soluble and insoluble carbohydrate components and kernel weight, especially for genotypes belonging to different types of corn. Further, such differences are broadly related and comprehendible to distinct types which give an insight into the unique characteristics and their end use.

Water adsorption characteristics of extruded blends of corn gluten meal and distillers dried grains with solubles

Corn-based ethanol has experienced exponential growth during the last decade. As a consequence, the production of byproduct corn protein meals, in the form of DDGS (distillers dried grains with solubles) and CGM (corn gluten meal) has grown as well. These materials are used as livestock feed. Extrusion processing is one method of converting these materials into other value-added materials, bioplastics, or other industrial precursors. The objectives of this study were to extrude blends of these materials, then examine dynamic and equilibrium relationships of extruded products with water. Blends consisted of DDGS:CGM ratios of 0, 33, 50, 66, and 100%. After processing, extrudates were placed in sealed chambers with headspace relative humidities ranging from 10% to 90%. Moisture contents were monitored over time. All samples achieved moisture equilibrium in less than three weeks. As with all biological materials, the extruded corn protein blends exhibited sorption behavior, the magnitude of which varied according to blend ratio. EMC values ranged from approximately 0% to nearly 50%, depending upon the humidity level and fiber:protein ratio. Nonlinear regression was successfully used to model the effects of relative humidity and blend ratio on the equilibrium moisture contents, with a coefficient of determination of ∼99%. Future work should aim to characterize the mechanical properties of these blends to assess their suitability as either bioplastic feedstocks or pelletized animal feeds.

Nutritive value of distillers dried grains with solubles from barley, corn and wheat for growing rabbits

Due to their fibrous nature, distillers dried grains with solubles (DDGS) from the bioethanol industry could be considered an interesting feedstuff for rabbit nutrition. To characterize the DDGS available in the Iberian Peninsula the chemical, amino acid and fatty acid composition of eight DDGS batches (2, 2 and 4 from barley, corn and wheat grains, respectively) was performed. Five diets were formulated to determine the nutritive value of DDGS in growing rabbits by the substitution method: a control diet and four experimental diets containing 200g of the DDGS being evaluated kg−1 dry mater (DM) [DDGS from national barley, national corn, Brazilian corn and national wheat grains]. The digestibility trial was performed using 60 three-way crossbred fattening rabbits (12 per diet), aged 42days with average live weight of 1.49kg (S.E.: 0.033kg). DDGS can be characterized as a raw material really rich in fibre (neutral detergent fibre and neutral detergent soluble fibre) and crude protein (CP, on av. 352, 208 and 318gkg−1 DM, respectively). Barley DDGS had higher fibre and lower protein contents than wheat DDGS (+25g of acid detergent fibre and −91g of CPkg−1DM, respectively; P<0.05), as well as the highest ash content (on av. +16gkg−1DM; P<0.05). Corn DDGS had intermediate fibre and protein values between barley and wheat DDGS, but were the richest in ether extract (on av. +70gkg−1 DM). DDGS’ protein was richer in proline, phenylalanine, valine and arginine for barley DDGS (107, 55, 54 and 51gkg−1 CP, respectively), in leucine, alanine and histidine for corn DDGS (114, 75 and 27gkg−1 CP, respectively), and in glutamic acid for wheat DDGS (290gkg−1CP). Barley DDGS was richer in saturated (236gkg−1 total fatty acids), corn DDGS in monounsaturated (278gkg−1 total fatty acids) and wheat DDGS in polyunsaturated fatty acids (615gkg−1 total fatty acids). Barley DDGS was characterized by the lowest nutritive value traits of DDGS evaluated (11.9MJ digestible energy (DE) and 168g digestible protein (DP)kg−1DM). In spite of higher protein and lower fibre content of the Brazilian corn (+1.7gCP and −31g neutral detergent fibrekg−1DM), no significant differences for the nutritive value of both corn DDGS were observed (on av. 15.3MJ DE and 208gDPkg−1DM). Wheat DDGS might be considered as the DDGS with the highest nutritive value of those evaluated (15.7MJ DE and 263gDPkg−1DM).

Nanocarriers from GRAS Zein Proteins to Encapsulate Hydrophobic Actives.

One factor limiting the expansion of nanomedicines has been the high cost of the materials and processes required for their production. We present a continuous, scalable, low cost nanoencapsulation process, Flash Nanoprecipitation (FNP) that enables the production of nanocarriers (NCs) with a narrow size distribution using zein corn proteins. Zein is a low cost, GRAS protein (having the FDA status of "Generally Regarded as Safe") currently used in food applications, which acts as an effective encapsulant for hydrophobic compounds using FNP. The four-stream FNP configuration allows the encapsulation of very hydrophobic compounds in a way that is not possible with previous precipitation processes. We present the encapsulation of several model active compounds with as high as 45 wt % drug loading with respect to zein concentration into ∼100 nm nanocarriers. Three examples are presented: (1) the pro-drug antioxidant, vitamin E-acetate, (2) an anticholera quorum-sensing modulator CAI-1 ((S)-3-hydroxytridecan-4-one; CAI-1 that reduces Vibrio cholerae virulence by modulating cellular communication), and (3) hydrophobic fluorescent dyes with a range of hydrophobicities. The specific interaction between zein and the milk protein, sodium caseinate, provides stabilization of the NCs in PBS, LB medium, and in pH 2 solutions. The stability and size changes in the three media provide information on the mechanism of assembly of the zein/active/casein NC.

Enhancing reducing ability of α-zein by fibrillation for synthesis of Au nanocrystals with continuous flow catalysis

Green low-cost synthesis and efficient recyclability are two major hindrances for Au nanocrystals as catalysts applying in diverse industrial reaction processes. By the use of low-cost α-zein (i.e. a major storage protein of corn) as the reductant, capping agent and stabilizer, Au nanocrystals with tunable catalytic activity were synthesized in a wet-chemical approach. Fibrillation of α-zein further enhanced its reducing ability due to larger specific surface area and more hydrophilic groups exposed on the surfaces. The obtained Au nanocrystals had biocompatibility, high stability in various solvents, unique solubility in aqueous alcohol and high catalytic ability, being able to detect ethanol composition in aqueous ethanol as well as H2O2 for diagnosis of diabetes mellitus. These advantages also enable efficient recyclability of Au nanocrystals with continuous flow catalysis in different solvents and environments. Thus, the use of α-zein offered Au nanocrystals not only with green low-cost synthesis, but also with tunable catalytic activities, ethanol-responsiveness and efficient recyclability, which may be applicable in diverse fields.

Purification and identification of corn peptides that facilitate alcohol metabolism by semi-preparative high-performance liquid chromatography and nano liquid chromatography with electrospray ionization tandem mass spectrometry.

In this study, peptides that facilitate alcohol metabolism were purified and identified from corn protein hydrolysates. The ultra-filtered fraction with a molecular weight < 3 kDa (F3) potential activity was separated into six fractions (F3-H1-F3-H6) by semi-preparative high-performance liquid chromatography. Among the resultant six fractions, F3-H4 and F3-H5 exhibited the highest ability to eliminate alcohol in vivo. A total of 16 peptides with strong signal values were identified from F3-H4 and F3-H5 fractions by nano liquid chromatography coupled with electrospray ionization tandem mass spectrometry. Several identified peptides were then selected and synthesized to determine their potential to facilitate alcohol metabolism. We found that Leu-Leu and Pro-Phe were the key structure units in Gln-Leu-Leu-Pro-Phe responsible for this peptide's ability to facilitate alcohol metabolism. However, the role of Leu-Leu and Pro-Phe may be affected by peptide chain length and hydrophobic properties. Our results have thus provided some insight into the study of the structure-activity relationships of corn peptides.

Walleye Sander vitreus performance, water quality, and waste production in replicated recirculation aquaculture systems when feeding a low phosphorus diet without fishmeal versus a traditional fishmeal-based diet

Walleye Sander vitreus is a popular sport- and food-fish in areas surrounding the Great Lakes. Walleye are mainly provided as food-fish by limited capture fisheries, but have potential for profitable production to market-size in recirculation aquaculture systems (RAS). Walleye are piscivorous with a supposed requirement for fishmeal in artificial diets, thus little information is available regarding the effects of feeding fishmeal-free diets to walleye. During this study, the health and growth performance of juvenile walleye cultured in RAS were compared between groups fed either a traditional fishmeal-based diet (FM) or a low phosphorous, fishmeal-free (FMF) diet. Water quality and waste production rates resulting from feeding each diet were evaluated. The FM diet contained fishmeal, poultry meal, soybean meal, wheat flour, and blood meal proteins; and the FMF diet used poultry meal, wheat flour, soy protein concentrate, and corn protein concentrate proteins. The only lipid source used in the FM diet was fish oil from menhaden, whereas the FMF diet used menhaden oil and poultry oil. Each diet was formulated with a protein: fat ratio of approximately 42/18. Fish (initial weight 85g fish−1) were cultured in 6 replicated RAS for 9 months, each operated with 99.9% water recycle on a flow basis, a mean system hydraulic retention time of 135days, and a mean feed loading rate of 3.5kg feed/m3 of daily makeup water. At study’s end, mean weights±standard error of fish fed the FM and FMF diets were 571±26 and 589±15g, respectively (P>0.05). Cumulative survival for both diet treatments was ≥98.5%. Average thermal growth coefficient (TGC), condition factor (CF), and feed conversion ratio (FCR) were similar (P>0.05) for the FM and FMF diets, respectively: TGC was 0.82±0.01 and 0.83±0.02; CF was 1.05±0.02 and 1.03±0.02; and FCR was 1.32±0.02 and 1.27±0.03. Water color index and UV transmittance values (P<0.05) indicated slightly clearer water in RAS where the FMF diet was fed. Total nitrogen (TN) was greater (P<0.05) in the culture water of RAS associated with the FM diet; however, TN production per unit feed was similar between treatments; 0.031±0.010kg TN/kg feed for the FM diet and 0.030±0.009kg TN/kg feed for the FMF diet. Total phosphorous (TP) concentration in the culture water of RAS associated with the FMF diet was 48% of that measured for the FM diet; TP produced per unit feed reflected this trend, 0.107±0.003 vs. 0.0049±0.006kg TP/kg feed for the FM and FMF diets, respectively. Average fillet yield (skin and scales on) of fish harvested at the end of the trial was 47–49% (P>0.05). Whole-body and fillet proximate composition was similar between treatments; however, gonadosomatic index and the ratio of omega 6: 3 fatty acids was greater (P<0.05) for walleye fed the FMF diet. This was the first study of its kind to report comparable walleye growth when feeding a specially formulated diet devoid of fishmeal and while culturing this species in RAS. Reduced phosphorous discharge resulting from feeding this fishmeal-free diet formulation increases the feasibility of meeting stringent effluent requirements and possibly reduces the capital investment required for waste treatment.

The mTORC1-Signaling Pathway and Hepatic Polyribosome Profile Are Enhanced after the Recovery of a Protein Restricted Diet by a Combination of Soy or Black Bean with Corn Protein.

Between 6% and 11% of the world’s population suffers from malnutrition or undernutrition associated with poverty, aging or long-term hospitalization. The present work examined the effect of different types of proteins on the mechanistic target of rapamycin (mTORC1)-signaling pathway in: (1) healthy; and (2) protein restricted rats. (1) In total, 200 rats were divided into eight groups and fed one of the following diets: 20% casein (C), soy (S), black bean (B), B + Corn (BCr), Pea (P), spirulina (Sp), sesame (Se) or Corn (Cr). Rats fed C or BCr had the highest body weight gain; rats fed BCr had the highest pS6K1/S6K1 ratio; rats fed B, BCr or P had the highest eIF4G expression; (2) In total, 84 rats were fed 0.5% C for 21 day and protein rehabilitated with different proteins. The S, soy + Corn (SCr) and BCr groups had the highest body weight gain. Rats fed SCr and BCr had the highest eIF4G expression and liver polysome formation. These findings suggest that the quality of the dietary proteins modulate the mTORC1-signaling pathway. In conclusion, the combination of BCr or SCr are the best proteins for dietary protein rehabilitation due to the significant increase in body weight, activation of the mTORC1-signaling pathway in liver and muscle, and liver polysome formation.

Use of dry hydrolysate from squid and scallop product supplement in plant based practical diets for Pacific white shrimp Litopenaeus vannamei

A series of trials were designed to evaluate hydrolysates from waste streams of squid and scallop processing centers for the use in practical shrimp feeds. Towards this goal, three growth trials and a consumption trial were conducted to evaluate the use of dry hydrolysate from squid and scallop waste as specialty ingredients in commercial type feed formulations for Pacific white shrimp Litopenaeus vannamei. In the three six-week growth trials, the basal diet (35% crude protein, 8% lipid) consisted primarily of soybean meal (SBM), corn protein concentrate, corn starch, and whole wheat. In Trial 1, the basal diet was supplemented with 3%, 6%, and 9% from squid hydrolysate (Squ) or scallop hydrolysate (Sca) as well as two treatments using SBM which was impregnated with the hydrolysate prior to use. In Trial 2, the basal diet was supplemented with 3% Squ or Sca, shrimp but the shrimp were offered diets in slight excess to allow for possible increases in consumption of feeds. In Trial 3, Squ and Squid meal were compared at 6%. At the end of the three growth trials, no significant differences were found in final biomass, final mean weight, percent weight gain, feed conversion ratio, and survival. Additionally, a group of shrimp (3g initial mean weight) were used to estimate consumption of the feeds over three 1-hour feedings over three days. Interestingly, the estimated feed intake of the basal diet was significantly higher than that of diets supplemented with 3% Squ or Sca. Results of the present study indicate that Squ and Sca as well as the SBM impregnated with Squ or Sca are good marine ingredients and can be used as feed ingredients. However, no evidence of improved feed intake or enhancement of growth were observed even though the diets were plant based. Statement of relevanceIn this study, a series of trials were used to assess the efficacy of dry hydrolysate from squid and scallop as well as traditional squid meal use in plant based practical diets designed for the Pacific white shrimp. These findings will be useful because the feed producers are interested in how specific produce may improve performance either as a nutrient source or attractant, particularly in diets that do not contain fishmeal. The conclusion provide valuable information that indicates feed manufacturer and researchers can use these hydrolysate products as feed ingredients in diets of shrimp, but no evidence for use of these products to improve the shrimp growth performance was observed.

Impact of Dietary Carbohydrate and Protein Source and Content on Swine Manure Foaming Properties

Abstract. Diet ingredients are thought to contribute to foaming problems associated with swine manure stored in deep-pit systems. Two experiments explored the impact of protein and carbohydrate sources and levels in swine diets on the physicochemical properties, methane production potential, and foaming potential of swine manure. The first experiment was specific to protein and evaluated the impact of dietary protein level and source on manure properties, while the second experiment focused on evaluating the impact of different dietary carbohydrate sources on manure foaming properties. Manure from the animals was tested for total and volatile solids, methane production rate and biochemical methane potential, surface tension, foaming capacity and stability, and microbial community structure. No single diet yielded manure with all of the anticipated qualities associated with foaming manure. However, manure collected from pigs fed diets containing soy hulls and distillers dried grains with solubles (DDGS) exhibited higher methane production rates (0.95 ±0.20 and 0.96 ±0.20 L CH 4 kg -1 VS, respectively) and biochemical methane potential (322 ±25 and 269 ±22 mL CH 4 g -1 VS, respectively) when compared to manure obtained from pigs fed the other diets. Additionally, the results showed that both protein level and source exhibited greater influence over the microbial community than carbohydrate source, with manipulations in the protein diet leading to positive correlations with specific microbial community and higher methane production rates, foaming capacity, and foam stability. In this study, these parameters appeared to be tied to higher levels of corn, or corn protein, in the diet. Although some of the microbial community was explained by diet, this study also demonstrated that factors other than diet have significant influence on microbial community.

Iron-loaded zein beads as a biocompatible adsorbent for arsenic(V) removal

This work aims to modify zein, a corn protein, to be a biocompatible adsorbent for the removal of As(V) from water. This adsorbent was prepared by the incorporation of iron(III) chloride into 50% (w/v) of zein in ethanol and water (70:30 (v/v)) and dropping into cold water (5°C) to form adsorbent beads. In the batch operation, various parameters, i.e., pH of solution, iron loading concentration, competing ions and adsorption time, were studied. Under the optimum conditions, the As(V) adsorption appeared to follow the Langmuir isotherm model with the maximum adsorption capacity of 1.95mg/g.

Potential use of corn co-products in fishmeal-free diets for juvenile Nile tilapia Oreochromis niloticus

We conducted a 12-week feeding trial to evaluate the effects of total fishmeal replacement with different corn co-products on growth performance, feed utilization efficiency, and body composition in juvenile Nile tilapia Oreochromis niloticus. Five isonitrogenous diets were prepared. Fifty percent of the dietary protein was obtained from fishmeal (control diet) or from one of four corn co-products (experimental diets), namely corn protein concentrate, corn gluten meal, high-protein distillers’ dried grains (HPDDG), or distillers’ dried grains with solubles (DDGS). Fish with an initial mean weight of 4.5 g were fed one of the five diets twice a day to near satiety. Significantly higher (P < 0.05) specific growth rates and survival occurred in the fish fed the control diet or DDGS, followed by those fed the HPDDG; mean feed intakes by fish in these three groups were significantly greater than those in the others. Food conversion ratio, protein efficiency ratio, and total amino acid content of the whole body were not affected by changes in dietary ingredients. Whole-body and fillet protein contents were highest in the HPDDG group, whereas the lipid content was highest in those fed DDGS. DDGS can be used to fully replace the fishmeal components of Nile tilapia diets.

Allergic reaction from fingerprint kit attributable to unlabeled gluten, probable wheat flour

Allergic reaction from fingerprint kit attributable to unlabeled gluten, probable wheat flour

Comparison of crystalline lysine and intact lysine used as a supplement in practical diets of channel catfish (Ictalurus punctatus) and Nile tilapia (Oreochromis niloticus)

The study was conducted using channel catfish and tilapia to evaluate the production performance of these fish to increasing levels of lysine from crystalline and intact lysine supplemented in practical diets. A practical lysine deficient basal diet was developed using corn protein concentrate (Empyreal® 75) as a primary protein source. To this diet either graded levels of crystalline lysine or similar levels from a high lysine corn protein concentrate (Lysto™) were added. In the channel catfish trial, the first five diets were designed to contain increasing levels of crystalline lysine (1.21%, 1.34%, 1.45%, 1.56%, and 1.72%) with an additional four diets using intact protein from a high lysine corn protein concentrate (1.40%, 1.57%, 1.77%, and 1.91% lysine). In the tilapia trial, lysine from two sources was added to 11 diets to produce analyzed lysine levels of 0.92%, 1.11%, 1.23%, 1.34%, 1.54% 1.65% in the first six diets using crystalline lysine and 1.13%, 1.38%, 1.61%, 1.81%, 2.02% in the last five diets using intact lysine. Results indicated that channel catfish and tilapia have positive performance with increasing lysine supplementation up to the requirement. Fish fed with the higher levels of lysine had the highest weight gain and lowest feed conversion ratio. The regression analysis on the increased level of inclusion of crystalline lysine and intact lysine showed no significant difference in slope. Based on the growth, feed conversion ratio and apparent net protein retention data obtained from this study, it can be concluded that the effectiveness of using intact lysine via high lysine corn protein concentrate as a lysine supplement is not significantly different from crystalline lysine. Thus, the high lysine corn protein concentrate is a feasible ingredient for aquaculture feeds, which can be used to balance the amino acid composition of the diet without addition of crystalline lysine. Statement of relevancePresent study shows that high lysine corn protein concentrate is a feasible ingredient for aquaculture feeds, which can be used to balance the amino acid composition of the diet without addition of crystalline lysine.

Comparison of the colloidal stability, bioaccessibility and antioxidant activity of corn protein hydrolysate and sodium caseinate stabilized curcumin nanoparticles.

The aims of this work were to construct corn protein hydrolysate (CPH)-based curcumin nanoparticles (Cur NPs) and to compare the colloidal stability, bioaccessibility and antioxidant activity of the Cur NPs stabilized CPH and sodium caseinate (NaCas) respectively. The results indicated that Cur solubility could be considerably improved after the Cur NPs fabrication. The spectroscopy results demonstrated that the solubilization of Cur should be attributed to its complexation with CPH or NaCas. The Cur NPs exhibited good colloidal stability after 1week's storage but showed smaller (40nm) size in CPH than in NaCas (100nm). After lyophilization, the Cur NPs powders showed good rehydration properties and chemical stability, and compared with NaCas, the size of Cur NPs stabilized by CPH was still smaller. Additionally, the Cur NPs exhibited higher chemical stability against the temperature compared with free Cur, and the CPH could protect Cur from degradation more efficiently. Comparing with NaCas, the Cur NPs stabilized by CPH exhibited better bioaccessibility and antioxidant activity. This study demonstrated that CPH may be better than NaCas in Cur NPs fabrication and it opens up the possibility of using hydrophobic protein hydrolysate to construct the NPs delivery system.

Effects of long-term feeding of corn co-product-based diets on growth, fillet color, and fatty acid and amino acid composition of Nile tilapia, Oreochromis niloticus

We conducted a 24-week feeding trial with Nile tilapia Oreochromis niloticus to evaluate the effects of long-term feeding of corn co-product-based diets on growth, fillet color, and fillet fatty acid and amino acid composition. Five iso-nitrogenous diets were prepared (34% protein). The control diet included 10% fishmeal. Fishmeal was eliminated from the other four diets, and 50% of the dietary protein was supplied by one of four corn co-products, namely high-protein distillers' dried grains (HPDDG), distillers' dried grains with solubles (DDGS), corn gluten meal (CGM), and corn protein concentrate (CPC). Fish with an initial mean weight of 21g were fed one of the five diets twice a day to near satiety. Fish fed the control, HPDDG, or DDGS diet had significantly higher (P<0.05) mean weight gain, specific growth rates, mean feed intake, protein efficiency ratio, and survival than those fed the other diets. Fish in these three treatments also had the lowest food conversion ratio. The dietary treatments did not affect the lightness, redness, yellowness, or crude protein and total amino acid content of fish fillets. Fillet lipid and ash content were highest in the CGM group. Fillet fatty acid composition was greatly affected by the dietary treatments. The CGM and CPC groups had significantly highest palmitic acid (16:0) and total saturated fatty acid levels, whereas linoleic acid (18:2n−6) and total polyunsaturated fatty acid levels were highest in the DDGS group. Similarly, the total n−6 level was highest in the DDGS group, followed by HPDDG. The total n−3 levels and n−3:n−6 ratios in the fillets of the control group were almost double those of the corn-based dietary groups. Our results suggest that dietary inclusion of HPDDG or DDGS in non-fishmeal diets at up to 50% of dietary protein does not negatively affect growth performance, feed utilization efficiency, or fillet color and amino acid composition, but further improvement of n−3 fatty acid composition is necessary to ensure human health benefits. Statement of relevanceFishmeal free diets ensure the sustainability of aquaculture.

Effects of feeding a fishmeal-free versus a fishmeal-based diet on post-smolt Atlantic salmon Salmo salar performance, water quality, and waste production in recirculation aquaculture systems

The Atlantic salmon farming industry has progressively decreased the proportion of fishmeal used in commercial diets due to rising costs and sustainability concerns. A variety of alternate proteins have been identified to partially replace fishmeal; however, very little research has described the effect of feeding alternate protein, fishmeal-free diets to Atlantic salmon, particularly post-smolts cultured in recirculation aquaculture systems (RAS). Therefore, a 6-month study was conducted to compare the effects of feeding a fishmeal-free diet (FMF) versus a fishmeal-based diet (FM) on post-smolt Atlantic salmon performance, water quality, and waste production rates in six replicated RAS. Experimental diets were fed to Atlantic salmon (281±5g to begin) in triplicate RAS. Protein ingredients used in the FMF diet included mixed nut meal, poultry meal, wheat flour, and corn protein concentrate; while the FM diet contained menhaden meal, poultry meal, soy protein concentrate, and blood meal proteins. Fish oil derived from whiting fish trimmings was used in the FMF diet to establish a wild fisheries input to farmed fish output ratio of 0:1; while menhaden oil was the primary lipid source for the FM diet. Both diets were formulated with approximately 42% crude protein and 27% crude fat. Each RAS was operated with flushing rates that created an average system hydraulic retention time of 20 days (5% system volume flushed daily) and a mean feed loading rate of 3.2kg feed/m3 of daily make-up water volume. Atlantic salmon growth, survival, and feed conversion ratios (FCR) were unaffected (P>0.05) by diet. At the conclusion of the study, Atlantic salmon fed the FMF and FM diets were 1.716±0.076 and 1.720±0.065kg; cumulative survival was >99% for both; and average FCR was 0.89±0.03 and 0.90±0.02, respectively. The FMF diet resulted in greater total phosphorous (TP), carbonaceous biochemical oxygen (cBOD), and total suspended solids (TSS) mass per kg feed in the effluent (P<0.05). The FMF and FM diets produced 0.009±0.001 v. 0.006±0.001kg TP/kg feed; 0.079±0.005 v. 0.056±0.005kg cBOD/kg feed; and 0.297±0.028 v. 0.221±0.032kg TSS/kg feed, respectively. A significantly higher percentage of TSS was captured by radial flow settlers of RAS receiving the FMF diet compared to capture by settlers associated with the FM diet. Mass balance data, radial settler removal efficiency, and observations of flushed solids suggested that the FMF diet produced fecal matter with better settling characteristics. Lower TSS and true color values (P<0.05), indicative of clearer water, were measured in RAS receiving the FMF diet. Total phosphorous (most of which was dissolved) was 4 times greater in the culture water of RAS that received the FMF diet, e.g., 4.3±0.1mg/L v. 0.9±0.0mg/L for the FM Diet. This was the first research attempt to formulate a fishmeal-free diet for Atlantic salmon with this ingredient profile and one of few studies to demonstrate uncompromised Atlantic salmon performance when feeding a diet without fishmeal.

Cell spreading and viability on zein films may be facilitated by transglutaminase

Zein is a biocompatible corn protein potentially useful in the development of biomaterials. In this study, the deposition of zein on oxygen plasma treated glass cover slips significantly enhanced cell spreading and viability. The mechanism for cellular response to zein coated surfaces was thought to involve the polyglutamine peptides on the zein structure. We hypothesized that zein was a substrate for tissue transglutaminase (tTG), an extracellular enzyme involved in cell-surface interactions. SDS-PAGE results suggested an interaction between zein and tTG, where zein was the glutamine donor. Cross-linking between zein and tTG may be the first step in successful cell adhesion and spreading.

Corn protein hydrolysate as a novel nano-vehicle: Enhanced physicochemical stability and in vitro bioaccessibility of vitamin D3

The application of colloidal delivery systems for the encapsulation, protection and increased bioavailability of bioactive ingredients has recently gained increasing interest. The aim of this work was to prepare corn protein hydrolysate-based vitamin D3 (CPH-VD3) nanocomplexes. UV and FT-IR spectra indicated the existence of non-covalent interactions (i.e. hydrogen bonding) between CPH and VD3. The result from X-ray diffraction further suggested the formation of amorphous structure of VD3 after its complexation with CPH. Additionally, dynamic light scattering and transmission electron microscope showed that the CPH-VD3 complexes exhibited a spherical structure with a size scale from 102 to 121 nm. The encapsulation and loading efficiency of VD3 could reach 97% and 9%, respectively. Furthermore, the complexation obviously avoided spontaneous particle aggregation of VD3 against ionic strength ([NaCl] ≤ 200 mmol/L). The remaining ratio of the encapsulated VD3 after exposure to high levels of UV light was as high as 72%. More importantly, in vitro bioaccessibility of VD3 could be up to 95% for the complexes. This study demonstrated that CPH could serve as a novel nano-vehicle for VD3 and it opens up the possibility of using CPH to construct the colloidal delivery system.