Effects of activated earth, activated alumina, and chitosan adsorption processes on thermal and rheological and chemical characteristics of menhaden oil.

The objective of this study was the effectiveness of using activated earth, activated alumina, and/or chitosan, either separately or in combination, as adsorbents to remove free fatty acids (FFA) and peroxides from unpurified menhaden oil (MO). Thermal and rheological properties of MO were also evaluated. Five different combinations of absorbents were used to purify MO: Processes 1-3 involved purifications of MO by 5% chitosan (wt/wt of oil), 5% activated earth, and 5% activated alumina, respectively, process 4 involved MO purification with a combination of 6.5% chitosan, 3.5% activated earth, and 5% activated alumina, and process 5 involved MO purification process with a combination of adsorbents of 9% chitosan, 1% activated earth, and 5% activated alumina. All the adsorption processes were conducted at 25°C. Purified MO and MO were evaluated for their fatty acid profile, FFA, peroxide value (PV), moisture content (MC), minerals, and color. Triplicate experiments were conducted, and data were statistically analyzed using α = 0.05. Processes 4 and 5 were effective in reducing PV, FFA, and MC in MO. Thermal properties indicated processes 4 and 5 produced purer MO than processes 1-3. All the oil samples became less viscous, and the flow behavior index of MO was close to 1 after the adsorption processes. This study demonstrated that adsorption processes that include chitosan, activated earth, and activated alumina could effectively improve MO quality.

Development of pelleted feed containing probiotic Lactobacillus rhamnosus GG and Jerusalem artichoke for Nile Tilapia and its biocompatibility studies.

Growth performance and immune systems of tilapias could be improved by Lactobacillus rhamnosus GG (LGG) and Jerusalem artichoke. This research aimed to determine the effects of Jerusalem artichoke on LGG viability after drying and pelleting and their subsequent exposure to simulated gastrointestinal conditions. Fresh LGG cells were added into wall material solutions, including alginate (AL), alginate + milk powder (AM), and alginate + milk powder + Jerusalem artichoke at different concentrations (AMJ). The solutions were then spray dried to obtain LGG powders. The powder with the highest cell number was then selected to mix with tilapia feed mash and pelleted using a nonthermal feed extruder to obtain pelleted feed containing LGG and Jerusalem artichoke. The LGG viability spray dried powders and pelleted feed were analyzed for their cell counts after drying and after exposure to simulated gastrointestinal conditions. The result showed that the number of viable cells in AMJ was significantly higher than AM and AL after drying. The number of viable cells under both simulated gastric and bile salt fluids was improved with the increasing of Jerusalem artichoke concentrations. The number of viable cells after pelleting process could be maintained. LGG in the pelleted feed could also survive under the simulated gastric and bile salt conditions. The study indicates that JA enhanced LGG viability after drying and exposure to simulated gastrointestinal conditions. The pelleted feed containing LGG and Jerusalem artichoke could be applied in tilapia farming, providing convenience to the farmers, and valuable effects to the fish.

A pectin-gelatin gel containing oral rehydration solution and the release of sodium chloride under simulated gastric conditions.

Both gelatin and pectin have the ability to trap salt and facilitate its release under simulated gastric conditions. The objective of this study was to develop a pectin-gelatin gel fortified with oral rehydration solution/s (ORS) that can maintain a more rigid structure to limit salt mobility (potentially less salty taste), yet allow rapid release in simulated gastric conditions. Two gels containing both pectin and gelatin were developed: (1) low salt (LS) containing 2.6 g/L salt and 13.5 g/L sugar and (2) high salt (HS) containing 5.2 g/L salt and 27.0 g/L sugar. The ORS-fortified gels were compared with commercially available gelatin gels and a control pectin-gelatin gel without added salt or sugar. A stronger gel network (higher G') and higher viscosity was noted for HS compared to other samples. HS had slower salt release (80.70 ±â€¯1.92%) than LS (95.95 ±â€¯3.82%) at 1 min in simulated gastric conditions. After 120 min, HS showed up to 99.38 ±â€¯1.08% release of salt, while LS had 95.95 ±â€¯3.82% release. HS had a favorable textural profile, having values more similar to the ready-to-eat commercial cup gel than did the LS formulation. The HS formulation resulted in a stable structure for ORS delivery and beneficial release properties.

Delivery of alpha-tocopherol through soluble dietary fibre-based nanofibres for improving the life span of Caenorhabditis elegans.

The effect of alpha-tocopherol (α-TOC) delivered by soluble dietary fibre-based nanofibres (α-TOC-SDNF) on the life span of nematode Caenorhabditis elegans N2 (wild type) and TK22 (mev-1 mutants) with and without heat shock was investigated. Without heat shock, the wild-type and mev-1 mutants maintained in the 100 µg/mL of α-TOC-SDNF had longer life spans than their respective blank control groups. With heat shock, the wild-type N2 in the 200 µg/mL of α-TOC-SDNF had a survival rate of 5% at day 49, while no nematodes survived in the blank control group. An increased pharyngeal pumping rate was observed in the α-TOC-SDNF treated mev-1 mutants worms compared to the blank control group. Encapsulating α-TOC in SDNF yielded protective effects and the life span and pumping rate of C. elegans was increased with α-TOC delivered by SDNF.

Effect of bambara groundnut supplementation on the physicochemical properties of rice flour and crackers.

This study evaluated the effect of bambara groundnut supplementation on the physicochemical properties of local rice flour and baked crackers. Bulk and true density, porosity, water absorption index, oil absorption capacity, pasting properties by RVA, morphological appearance by SEM, color by calorimetry, and textural properties by TA.XT2 analysis of wheat and two formulations of rice-legume flours and crackers were studied. Moisture (10.94%) and carbohydrate (77.42%) levels were significantly greater in wheat flour than the rice-legume flours, while the reverse was true for fat and ash. Also rice-legume flours had significantly greater water and oil absorption capacity and lower water solubility compared to wheat flour. Compared to wheat crackers, rice-legume crackers had greater fat and ash, 20.51 and 3.57%, respectively, while moisture was significantly lower in the rice-legume crackers by 41 to 58%. Rice legume crackers were significantly harder and had significantly increased spread ratio. The results obtained from the development of locally grown rice and underutilized legume bambara groundnut showed great promise in physicochemical and functional properties and may be a good replacement for wheat flour to serve as a gluten-free product.

Releasing characteristics of anthocyanins extract in pectin-whey protein complex microcapsules coated with zein.

This study investigated pectin-based capsules as delivery systems for purple rice bran anthocyanin extract (AE) during exposure to simulated gastrointestinal conditions. Four different capsules loaded with AE were prepared by ionotropic gelation/extrusion, including (1) pectin capsules (PE), (2) pectin capsules coated with zein (PE/ZE), (3) pectin-whey protein isolate complex capsules (PE + WP), and (4) pectin-whey protein isolate complex capsules coated with zein (PE + WP/ZE). CaCl2 in an ethanol solution with or without zein was used as a crosslinking solution. Swelling and release characteristics of all capsules under simulated gastric fluid at pH 1.2 (SGF) and simulated intestinal fluid at pH 6.8 (SIF) for 120 and 180 min, respectively, were examined. PE + WP, PE + WP/ZE, and PE/ZE capsules had higher encapsulation efficiency than PE capsules. After incubation, PE + WP/ZE and PE capsules had the lowest swelling ratio in SGF and SIF, respectively. PE + WP/ZE capsules had the lowest AE release in SGF, while PE capsules had the highest. Both PE + WP and PE + WP/ZE capsules had significantly lower AE release in SIF than PE and PE/ZE capsules. The study demonstrated that PE + WP and PE + WP/ZE capsules have potential to function as a slow release delivery system for AE.

Application of Edible Films Containing Oregano (Origanum vulgare) Essential Oil on Queso Blanco Cheese Prepared with Flaxseed (Linum usitatissimum) Oil.

Fortification of queso blanco (QB) with flaxseed oil (FO) containing omega-3 polyunsaturated fatty acids may provide a functional food with health benefits such as improved cell, brain, and retina functionality, and protection against cardiovascular and immune-inflammatory diseases. However, QB experiences a short shelf life because of the early development of yeasts and molds and addition of FO may increase susceptibility to lipid oxidation. Oregano essential oil (OEO) is known for its antimicrobial and antioxidant properties, but due to its intense flavor compounds it may not be suitable for direct incorporation into QB. Thus, incorporation of OEO into an edible film prepared with whey protein isolate (WPI) may improve the shelf life of QB. Scanning electron microscopy (SEM) micrographs revealed that FO was successfully retained by the cheese after homogenization. The thiobarbituric-acid-reactive-substances (TBARS) and yeast and mold counts (YMC) of the wrapped cheeses were analyzed during 60 d of refrigerated storage. The oxidation rate increased significantly for nonwrapped QB containing FO (QBFO) during storage, however wrapping with WPI edible films containing OEO (WOF) significantly limited lipid oxidation and prevented growth of yeasts and molds. This study demonstrated the antioxidant and antimicrobial properties of WOF for preservation of QBFO during refrigerated storage.

Physicochemical Properties of Microencapsulated ω-3 Salmon Oil with Egg White Powder.

The objective of this study was to produce microencapsulated omega(ω)-3 fatty acids (PUFAs) fortified egg white (EW) powders and to characterize their nutritional and physical properties. Stable emulsions (E-SO-EW) containing 3.43 (g/100 g) salmon oil (SO), 56.21 (g/100 g) EW, and 40.36 (g/100 g) water and a control (E-EW) containing EW and water were prepared. E-SO-EW and E-EW were separately spray dried at 130, 140, and 150 °C inlet air temperatures. This resulted in 3 microencapsulated SO fortified EW powders (SO-EW), and 3 dried EW powders (DEW). The powders were analyzed for microencapsulation efficiency (ME), color, fatty acids methyl esters, protein, fat, moisture, ash, amino acids, minerals, microstructure, and particle size. The EPA and DHA content of SO and the ME of the powders were not affected by the inlet air temperature. The crude protein content of SO-EW powders was approximately 24 (g/100 g) lower than dried EW powders. Leucine was the most abundant essential amino acid found in all the powders. Most of the powders' median particle size ranged from 15 to 30 µm. The study demonstrated that microencapsulated ω-3 salmon oil with high quality EW protein can be produced by spray drying.

Functional properties of protein fractions of channel catfish (Ictalurus punctatus) and their effects in an emulsion system.

This study demonstrated the feasibility of producing soluble protein (CFSP) and insoluble protein (CFISP) fractions from catfish muscle protein. CFSP and CFISP contained 60.6% and 73.8% protein and 8.6% and 20.3% fat, respectively. Both CFSP and CFISP contained essential amino acids. Differences were observed between physicochemical properties of the 2 protein fractions, including nitrogen solubility, emulsion stability, and fat adsorption capacity. The flow and viscoelastic properties of the emulsions prepared with CFSP and CFISP were investigated using a rheometer. The power law model and the Casson model were used to determine the flow behavior index (n), consistency index (K), and yield stress. Emulsion containing CFSP (ECFSP) had a higher K value than emulsion containing CFISP (ECFISP). Both ECFSP and ECFISP emulsions exhibited pseudoplastic behavior and viscoelastic characteristics. The G' (an elastic or storage modulus) and G″ (a viscous or loss modulus) values for ECFSP were higher than ECFISP. Catfish muscle tissue can be easily separated into soluble and insoluble protein powders that have desirable functional properties.

Microencapsulation of menhaden fish oil containing soluble rice bran fiber using spray drying technology.

Emulsion (EFMO) containing purified menhaden oil (PMO) and soluble rice bran fiber (SRBF) was dried in a pilot scale spray dryer and produced microencapsulated PMO with SRBF (MFMO). EFMO had well isolated spherical droplets with the size of 1 to 10 µm and showed pseudoplastic fluid and viscoelastic characteristics. EFMO had lower lipid oxidation than the emulsion containing PMO without SRBF when both emulsions were stored at 20 and 40 °C for 88 h, which indicated that the SRBF reduced the lipid oxidation in the EFMO. The estimated MFMO production rate (3.45 × 10(-5) kg dry solids/s) was higher than the actual production rate (2.31 × 10(-5) kg dry solids/s). The energy required to spray dry the EFMO was 12232 kJ/kg of emulsion. EPA and DHA contents of MFMO were 11.52% and 4.51%, respectively. The particle size of 90% MFMO ranged from 8 to 62 µm, and the volume-length diameter of MFMO was 28.5 µm.

Evaluation of green tea extract as a glazing material for shrimp frozen by cryogenic freezing.

Solutions of green tea (Camellia sinensis) extract (GTE) in distilled water were evaluated as a glazing material for shrimp frozen by cryogenic freezing. Total of 2%, 3%, and/or 5% GTE solutions (2GTE, 3GTE, 5GTE) were used for glazing. Distilled water glazed (GDW) and nonglazed shrimp (NG) served as controls. The GTE was characterized by measuring color, pH, (o) Brix, total phenols, and % antiradical activity. Individual catechins were identified by HPLC. The freezing time, freezing rate, and energy removal rate for freezing shrimp by cryogenic freezing process were estimated. The frozen shrimp samples were stored in a freezer at -21 °C for 180 d. Samples were analyzed for pH, moisture content, glazing yield, thaw yield, color, cutting force, and thiobarbituric acid reactive substances (TBARS) after 1, 30, 90, and 180 d. The HPLC analysis of GTE revealed the presence of catechins and their isomers and the total polyphenol content was 148.10 ± 2.49 g/L. The freezing time (min) and energy removal rate (J/s) were 48.67 ± 2.3 and 836.67 ± 78.95, respectively. Glazed samples had higher moisture content compared to NG shrimp after 180 d storage. GTE was effective in controlling the lipid oxidation in shrimp. Glazing with GTE affected a* and b* color values, but had no significant effect on the L* values of shrimp.

Rheological and functional properties of catfish skin protein hydrolysates.

Catfish skin is an abundant and underutilized resource that can be used as a unique protein source to make fish skin protein hydrolysates. The objectives of this study were to isolate soluble and insoluble proteins from hydrolyzed catfish skin, study the rheological and functional properties of the protein hydrolysates, and evaluate the properties of emulsions made from the protein powders. Freeze-dried catfish skin soluble (CSSH) and insoluble hydrolysate (CSISH) powders were analyzed for proximate analysis, emulsion stability, fat absorption, amino acids, color, and rheological properties. CSSH had significantly (P < 0.05) higher protein, ash, and moisture content but lower fat content than that of CSISH. The yield of CSSH (21.5%+/- 2.2%) was higher than that of CSISH (3%+/- 0.3%). CSISH had higher emulsion stability than CSSH. CSSH was light yellow in color and CSISH was darker. The mean flow index values for emulsion containing CSSH (ECSSH) and CSISH (ECSISH) were both less than 1, indicating that they were both pseudoplastic fluid. The G' and G'' values for the ECSISH were higher than that of ECSSH, indicating that the viscoelastic characteristic of the emulsion containing CSISH was greater than that of the emulsion containing CSSH. The study demonstrated the CSSH and CSISH had good functional and rheological properties. They have potential uses as functional food ingredients.

Physical properties and oxidation rates of unrefined menhaden oil (Brevoortia patronus).

Unrefined menhaden oil was evaluated for thermal and rheological properties and its temperature-dependent viscosity and lipid oxidation rate were determined. Peroxide value, free fatty acids, density, specific gravity, water activity, moisture content, and enthalpy of the unrefined menhaden oil were 5.70 meq/kg, 3.80%, 0.93 g/mL, 0.93%, 0.52%, 0.15%, and 20.2 kJ/kg, respectively. The melting point range of unrefined menhaden oil was found to be -69.5 to 27.21 degrees C. The menhaden oil exhibited non-Newtonian fluid behavior at lower temperatures (5 to 25 degrees C), while it behaved like a Newtonian fluid at 30 degrees C. The oil apparent viscosity at 5 degrees C (0.22 Pa.s) was significantly higher (P < 0.05) than that at 30 degrees C (0.033 Pa.s). The average magnitude of activation energy for viscosity of the unrefined menhaden oil was 50.37 kJ/mol. The predicted apparent viscosity agreed (R(2)= 0.9837) satisfactorily with the experimental apparent viscosity. The minimal lipid oxidation rate of the oil was found at 25 and 35 degrees C for 6 h, higher lipid oxidation rates were observed when the oil was heated for 6 h at 45 to 85 degrees C. The rate of lipid oxidation for unrefined menhaden oil was temperature dependent (R(2)= 0.9425). This study showed that the magnitude of the apparent viscosity and oxidation rate of the unrefined menhaden oil was greatly influenced by temperature.

Properties of protein powders from arrowtooth flounder (Atheresthes stomias) and herring (Clupea harengus) byproducts.

Functional, nutritional, and thermal properties of freeze-dried protein powders (FPP) from whole herring (WHP), herring body (HBP), herring head (HHP), herring gonad (HGP), and arrowtooth flounder fillets (AFP) were evaluated. The FPP samples have desirable nutritional and functional properties and contained 63-81.4% protein. All FPP samples had desirable essential amino acid profiles and mineral contents. The emulsifying and fat adsorption capacities of all FPP samples were higher than those of soy protein concentrate. The emulsifying stability of WHP was lower than that of egg albumin but greater than that of soy protein concentrate. Thermal stability of the FPP samples is in the following order: HGP > HBP > WHP > HHP > AFP.