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Effects of different preparation methods on the physical, chemical and functional properties of protein powders from Skipjack tuna (Katsuwonus pelamis) liver
Abstract
Tuna livers (TL), which are often discarded as waste, are a valuable source of protein for human consumption. However, the preparation method used affects the nutritional and functional characteristics of protein powders. This work aimed to investigate the effects of different preparation methods on the physical, chemical, and functional properties of tuna liver protein powders (TLPPs) following heat (H) treatment, heat and ultrasound-assisted (HU) extraction, alkaline pH shift (APS) process, and supercritical carbon dioxide fluid (SC-CO2 ) extraction. H at 85°C (H85), HU at 80 kHz and 100 W (HU-80-100), APS at pH 11.5 (APS 11.5), and SC-CO2 at 350 bars (SC-CO2 -350) resulted in the remarkably highest total protein content among the different preparation conditions. All TLPPs, except for APS 11.5, showed lighter color characteristics. The most abundant amino acids in all TLPPs were glutamic acid, aspartic acid and alanine. The protein solubility and foaming capacity were efficiently improved by SC-CO2-350. Nevertheless, the emulsion properties and oil holding capacity were greatly enhanced by H85 and HU-80-100, and a significant foaming stability and water holding capacity were found in APS 11.5. Therefore, the TLPPs obtained following different preparation methods are unique and could be potentially utilized as a source of protein ingredients in several food systems.
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This study evaluated the effects of different levels of ultrasonic power (200, 400, 600 W) and treatment time (0, 10, 15 and 30 min) on the structure, emulsification characteristics, and in vitro digestibility of chickpea protein isolate (CPI). The changes in surface hydrophobicity of CPI indicated that ultrasound treatment exposed more hydrophobic amino acid residues. The analysis of sulfhydryl content and zeta potential showed that ultrasound caused the disulfide bond of CPI to be opened, releasing more negatively charged groups, and the solution was more stable. In addition, Fourier Transform Infrared Spectroscopy (FT-IR) and intrinsic fluorescence spectroscopy showed that ultrasound changes the secondary and tertiary structure of CPI, which is due to molecular expansion and stretching, exposing internal hydrophobic groups. The emulsification and foaming stability of CPI were significantly improved after ultrasonic treatment. Ultrasonic treatment had a minor effect on the solubility, foaming capacity and in vitro digestibility of CPI. All the results revealed that the ultrasound was a promising way to improve the functional properties of CPI.
To enhance the extraction yield of pecan protein and modify its functional properties, this study investigated whether both ultrasound and enzyme have a synergistic impact on the extraction of pecan (Carya illinoinensis (Wangenh.) K. Koch) protein. The highest protein extraction rate (25.51%) was obtained under the conditions of 1415.43 W.cm⁻², 15 min, pH 10.0, 50°C, and 1% (w/w) alkaline proteinase. Owing to its high shear, mechanical energy and cavitation, the ultrasound process increased the solubility of the substrate making it readily accessible to the enzyme, thereby accelerating the chemical reaction and improving the yield of the protein. The optimized ultrasound-assisted enzymatic method (400W, 20kHz, 5s/3s) effectively changed the secondary and tertiary structure of the pecan protein. The results of surface hydrophobicity, intrinsic fluorescence spectra, sulfhydryl content and scanning electron microscopy all indicated the unfolding of protein and exposure of hydrophobic groups and sulfhydryl groups. Moreover, the protein obtained by this method showed higher solubility (70.77%), higher emulsifying activity (120.56 m²/g), smaller particle size (326.7 nm), and better dispersion (0.305) than single ultrasound and non-ultrasound methods (p < 0.05). To conclude, ultrasound-assisted enzymatic method could be an appropriate technique to improve the yield and quality of the pecan protein. The study also provides a theoretical basis for the application of pecan protein in food processing.
The purpose of this study was to examine the impact of various types of heat processing used by consumers (water bath cooking WBC, oven convection roasting OCR, grilling G, pan frying PF) on the energy and the nutritional value of goose breast meat (with and without skin). The material used in the study comprised 72 breast muscles cut from carcasses of 17-week-old White Koluda® geese. The energy value (MJ), the chemical composition (water, fat, protein, ash) and mineral composition (phosphorus P, sodium Na, calcium Ca, potassium K, magnesium Mg, iron Fe, zinc Zn, cooper Cu, manganese Mn) were determined in both raw and thermally processed muscles. It has been concluded that various methods of heat processing have a significant impact on the energy and nutritional values of meat. From a dietary point of view, the most beneficial was OCR meat without skin, and WBC, OCR, PF meat with skin as well, since it had the lowest energy value as well as content and retention of fat, phosphorus, and sodium. However, as for the content of the other minerals and their retention, WBC seems to be the optimal form of heat treatment of skinless muscles. 100 g of such meat provides 3.1; 33.7; 145; 180 and 9% Nutrient Reference Values-Requirements (NRVs-R) for Ca, Mg, Fe, Cu, and Mn respectively in a diet of an adult person. As for meat with skin, the optimal method of heat processing to retain minerals is grilling. 100 g of meat processed in this way provides 3.9; 39.7; 125.7; 175; 6 and 12.7% NRVs-R of Ca, Mg, Fe, Cu, and Mn. It follows from the above information that goose breast meat, as analyzed here, cannot be considered as a source of calcium since it provides less than 4% of NRVs-R. The results of the study will be useful for the consumers’ nutritional choices. The geese breast meat, depending on the heat processing used and the content of skin, may be a valuable component of a varied diet, providing nutrients and minerals.
An increase in the consumption of poultry meat has been observed due to its availability, nutritional value, and delicate flavor. These characteristics make it possible to prepare, with the use of spices and other additives, many different dishes and products for increasingly demanding consumers. The sous-vide technique is increasingly being used to give new sensory attributes to dishes in gastronomy. The study aimed to assess the impact of the heat treatment method, i.e., the sous-vide method, as compared to traditional cooking, on the sensory quality of poultry meat, as well as the efficiency of the process with regard to technological quality. The cooking yield with the sous-vide method of processing poultry meat was higher than with the traditional method of cooking in water (88.5% vs. 71.0%, respectively). The meat was also found to be redder (a* = 254 vs. 074) and less yellow (b* = 1512 vs. 1649), as well as more tender. The sensory quality of chicken breast meat obtained by the sous-vide method was higher in terms of attributes such as color tone, tenderness, juiciness, and overall quality. At the same time, it was lower in terms of the odor of cooked meat and the flavor of cooked meat as compared to meat subjected to traditional cooking.
For the high-value utilization of tuna liver, the effects of acid-aided (Acid-pH) and alkali-aided pH-shifting (Alkali-pH) on the physicochemical and functional properties of the protein powder prepared by pH-shifting and freeze-drying were studied. As expected, the protein powder with high purity could be obtained through Acid-pH or Alkali-pH followed by freeze drying, while the Alkali-pH led to a higher protein yield, higher protein ratio, lower lipid ratio and lower heavy metal content than Acid-pH. The amino acid profile of the protein powder prepared by Alkali-pH (Alkali-PP) was similar with that prepared by Acid-pH (Acid-PP). In addition, compared with Acid-PP, the Alkali-PP possessed the greater capacities in emulsion activity, foaming capacity and fat absorption capacity. Furthermore, the foaming capacity, foam stability and fat absorption capacity of Alkali-PP was better than soy protein powder. Therefore, Alkali-pH followed by freeze-drying would be a better alternative to prepare high-quality protein powder from tuna liver in the food industry.
In recent years, the demand for nutritive, functional and healthy foods has increased. This trend has induced the food industry to investigate novel technologies able to produce ingredients with enhanced functional and physicochemical properties. Among these technologies, one of the most promising is the encapsulation based on supercritical fluids. Thanks to the inherent absence of organic solvent, the low temperature of the process to reach a supercritical state and the capacity to dissolve lipid soluble bioactives, the encapsulation with supercritical carbon dioxide represents a green technology to produce several functional ingredients, with enhanced stability, high load and tailored protection from environmental factors. Furthermore, from the fine-tuning of the process parameters like temperature, pressure and flow rate, the resulting functional ingredient can be easily designed to tailor the controlled release of the bioactive, or to reach specific levels of taste, odor and color. Accordingly, the aim of the present review is to summarize the state of the art of the techniques based on supercritical carbon dioxide for the encapsulation of bioactive compounds of food interest. Pros and cons of such techniques will be highlighted, giving emphasis to their innovative aspects that could be of interest to the food industry.
This study evaluated the effects of ultrasound treatment on walnut meal protein (WMP) extraction and techno‐functional properties. The Box‐Behnken Design (BBD) was adopted for the optimization of the traditional and ultrasound‐assisted extraction (UAE) processes. Standard protocols were used to assay the techno‐functional characteristics. The extraction models’ statistical results exhibited adequacy with the least desirability index of 95.8%. The UAE enhanced the WMP extraction yield, purity, and chemical score by 30.15%, 16.27%, and 9.74%, respectively, while reducing the extraction time by 25% over the control. The emulsion and foam stabilities and bulk density increased by 34.5%, 39.8%, and 6.1%, respectively, over the control. The α‐helix decreased while β‐sheet, β‐turns and random coil secondary structure components increased significantly (p < .05) by 95.76%, 101.3%, 105.1%, and 85.7% correspondingly. The dual‐frequency combination (20/40 kHz/kHz) was the best frequency mode. WMP could serve as a functional additive in manufactured foods as texture and flavor enhancer.
Practical applications
Walnut meal protein (WMP) has a well‐balanced amino acid profile and its economic use could be practically increased as a food ingredient by ultrasound‐assisted extraction. By this technique, WMP could be employed for the development of enhanced food ingredients rather than being discarded as animal feed. This study showed a positive effect of ultrasonic‐assisted alkaline pretreatment on WMP extraction, functionality and structure characteristics. In addition to process improvement, ultrasound is energy efficient and environmentally friendly. Therefore, the applicability of this technique to improve the functionality of plant proteins from industrial by‐products to be included in food products is promising.
Four roe protein isolates (RPIs) from skipjack tuna were prepared using isoelectric solubilization (pH 11 and 12) and precipitation (pH 4.5 and 5.5) (ISP) at different pH points to evaluate their physicochemical and functional properties and in vitro bioactivities. Moisture (<6.3%) and protein (71%–77%) content were maintained. Sulfur, sodium, phosphorus, and potassium were the major elements, and glutamic acid and
leucine were the prevalent amino acids (12.2–12.8 and 9.6–9.8 g/100 g protein, respectively) in RPIs. RPI-1 showed the highest buffering capacity at pH 7–12. RPIs and casein showed similar water-holding capacities. At pH 12, RPI-1(pH 11/4.5) showed the highest solubility, followed by RPI-3(pH 12/4.5), RPI-2(pH 11/5.5), and RPI-4(pH 12/5.5) (p < .05). Oil-in-water emulsifying activity indices of RPI-1 and RPI-3 significantly differed. At pH 2 and 7–12, pH-shift treatment improved the food functionality of RPIs, which was superior to positive controls (casein and hemoglobin). RPI-1 showed ABTS+ radical scavenging (102.7 μg/ml) and angiotensin-converting enzyme inhibitory activities (44.0%).
Production of catfish protein isolates can be an alternative to provide added value to this commodity, which is expected to be a potential source of quality protein and promote human health. This study was aimed to characterize the chemical and functional properties of large-size catfish protein isolates and its functional properties. The stages of this study were to produce catfish protein isolates by using alkaline (pH 11) and isoelectric point (pH 5.5) methods and characterize the chemical and functional properties of catfish protein isolates produced. The result showed that catfish protein isolates contained 9 essential amino acids, protein content of 86.74% (wb) or 90.46% in dry basis(dB) and fat content of 0.54% (wb) or 0.56% (dB). Functionally, the catfish protein isolates produced have the ability in gelling forming a concentration of 5%, 4.08 g/mL oil absorption, 3.38 g/mL water absorption, emulsion capacity and stability of 1.52 mL/mL and stable over 90 minutes, 0.89 mL/mL foam capacity, and 0.64 g/mL density of bulky.
If the principle of "enhanced function" and "reduced risk of disease" claim is valid regarding the definition of functional foods, then fish must be chosen as one of the most important functional foods. Functional foods are foods that have potentially positive effects on health beyond basic nutrition. Fish contains components that can improve physical and mental health, and even can reduce the risk of diseases such as heart disease, cancer, diabetics, dementia, osteoporosis, psoriasis, lupus, arthritis, retinopathy, and other chronic and inflammatory diseases. Fish and fish products are a rich source of important components such as proteins, lipids, vitamins, minerals, and antioxidants, which are of significant nutritional values. Example of functional food components are important n-3 fatty acids EPA and DHA which have anti-inflammatory property and many health related roles. So, fish in human nutrition is required for growth, development, maintenance, and optimum health. As consumers of the age become more health conscious, the demand and market values for health promoting functional foods are expected to grow. The present study is to review the efficiency of functional food components of fish and fish products including safety for promotion of quality of human life.
Protein isolates were recovered from scallop (Patinopecten yessoensis) gonads to develop a novel functional matrix by investigating their physiochemical and functional properties. Scallop gonad protein isolates (SGPIs) were prepared from degreased scallop gonads (DSGs) by an alkali extraction and isoelectric solubilization/precipitation (ISP) process. The protein compositions of the SGPIs were mainly vitellogenin and beta‐actin with molecular weights of 266 and 42 kDa, respectively, as determined using Nano‐liquid chromatography‐mass/mass (Nano‐LC‐MS/MS). After the ISP process, the protein solubility of the SGPIs was significantly improved, and the surface hydrophobicity of SGPIs intensely increased by 1.1‐fold, which were attributed to the exposure of aromatic residues such as phenylalanine, tyrosine, and tryptophan. However, the content of total/reactive sulfhydryl in SGPIs was decreased compared with that of DSGs. Meanwhile, the ISP process caused partial protein unfolding, as indicated by circular dichroism analysis, which exhibited a remarkable rise in the β‐sheet content with a parallel decline in the α‐helix and random coil contents (P < 0.05). SGPIs exhibited a better oil absorption capacity and foaming property than both DSGs and soybean protein isolates (SPIs). Moreover, the emulsifying capacity of SGPIs was greatly enhanced by the ISP process, which was superior to the effect of commercial SPIs and was ascribed to its favorable solubility as well as surface characteristics.
Practical Application
During the processing of scallop (Patinopecten yessoensis) adductors, scallop gonad, a high‐protein part, is usually discarded as processing by‐products despite its edibility. In recent years, scallop gonads are regarded as good sources to develop protein matrices due to their high protein content and numerous nutrients. In this study, scallop gonad protein isolates (SGPIs) were isolated by isoelectric solubilization/precipitation (ISP) process. The preferable solubility, foaming property coupled with high emulsifying property of SGPIs indicated that the SGPIs could be potentially utilized as a good protein emulsifier and additives in production of kamaboko gels, hamburger patties, sausages, and pet foods.
Late embryogenesis abundant (LEA) proteins comprise a diverse family whose members play a key role in abiotic stress tolerance. As intrinsically disordered proteins, LEA proteins are highly hydrophilic and inherently stress tolerant. They have been shown to stabilise multiple client proteins under a variety of stresses, but current hypotheses do not fully explain how such broad range stabilisation is achieved. Here, using neutron reflection and surface tension experiments, we examine in detail the mechanism by which model LEA proteins, AavLEA1 and ERD10, protect the enzyme citrate synthase (CS) from aggregation during freeze–thaw. We find that a major contributing factor to CS aggregation is the formation of air bubbles during the freeze–thaw process. This greatly increases the air–water interfacial area, which is known to be detrimental to folded protein stability. Both model LEA proteins preferentially adsorb to this interface and compete with CS, thereby reducing surface-induced aggregation. This novel surface activity provides a general mechanism by which diverse members of the LEA protein family might function to provide aggregation protection that is not specific to the client protein.
The impacts of variation in fish filleting by-products origin including white muscle (cod), dark muscle (herring) and farmed fish (salmon) on physicochemical and gel-forming properties of protein recovered using the pH-shift method were studied. The effects of different solubilization pHs (acid or alkaline) on protein yield/composition, and its properties were also studied. Alkaline version (pH 11.5–12.5) resulted in maximum protein yield for the three resources which ranked them as: salmon > herring > cod. Increasing solubilization pH from 11.5 to 12.5 increased protein yield in salmon and herring, while maximum protein yield of cod was obtained at pH 12. However, increasing solubilization pH from 11.5 to 12.5 required a two-fold higher amount of alkali compared to the adjustment to 11.5. All recovered proteins had gel-forming capacity; however, cod gels showed higher WHC and breaking force compared with salmon and herring protein gels. Increasing solubilization pH from 11.5 to 12.5 negatively affected the breaking force and color of the salmon and cod protein gels, but improved heme pigment removal, breaking force and whiteness of herring protein gels. The pH-shift process thus showed good potential for recovering high quality protein from the by-products, but protein solubilization pH should be carefully selected based on the target species.
Nutritional, structural, functional, and sensorial properties of protein isolate developed from salmon (Salmo salar), cod (Gadus morhua), and herring (Clupea harengus) by-products using the pH-shift method was studied. Function of the proteins in an emulsion system in terms of viscoelastic properties was also evaluated. Regardless of origin, the proteins showed satisfying nutritional value as reflected in their high essential amino acid content. The proteins contained significantly (p < 0.05) higher proportion of active sulfhydryl groups and surface hydrophobicity compared to whey and egg white protein reflecting conformational changes caused by the pH-shift process. Solubility, emulsion, and foaming capacity of the proteins showed a trend similar to soy protein and dependent on their origin. Cod protein had better emulsion and foaming capacity than salmon and herring proteins which was in line with its high surface hydrophobicity and myosin heavy chain content. Emulsions developed from cod and salmon proteins showed substantially better viscoelastic properties, with higher stability and viscosity compared to herring protein emulsions. Cod protein scored low for sensorial attributes related to lipid oxidation while herring protein showed high levels of fishy and rancid flavor and odor. Altogether, results showed that the proteins from fish filleting by-products have potential to be used as food ingredients, but their application would be governed by their origin and sensorial properties.
The purpose of this paper is to explore the possibilities of subcritical dimethyl ether extraction (SDME) of oil from tuna liver with high-moisture content. The results showed that the oil and water were successfully co-extracted from the liver, and could be easily separated by centrifugation. In addition, the response surface method was employed to optimize the process parameters of SDME, including temperature/pressure, time and stirring speed. It was predicted that a temperature/pressure of 42/0.80 °C/MPa, time of 50 min and stirring speed of 925 rpm were the optimum within the experimental ranges, with an oil yield of 17.46 ± 0.23%. Furthermore, supercritical carbon dioxide extraction (SC-CO2) was studied comparatively. Only minor differences were observed between the oils extracted by SDME and SC-CO2, which indicated the high-quality of the SDME-oil. With no freeze-drying procedure and the relatively low pressure used in SDME, SDME could be a promising technique for extraction of marine fish liver oil.
Defatted bovine liver (DBL) is a potential source of protein and minerals. Supercritical carbon dioxide (SC-CO2) and a traditional organic solvent method were used to remove lipid from bovine liver, and the quality characteristics of a control bovine liver (CBL), bovine liver defatted by SC-CO2 (DBLSC-CO2) at different pressures, and bovine liver defatted by organic solvent (DBL-OS) were compared. The DBLSC-CO2 samples had significantly higher (p<0.05) protein, amino acid, carbohydrate, and fiber contents than CBL and DBL-OS. There was a higher yield of lipid from CBL when using SC-CO2 than the organic solvent method. SDS-PAGE analysis demonstrated that the CBL and DBLSC-CO2 had protein bands of a similar intensity and area, whereas DBL-OS appeared extremely poor bands or no bands due to the degradation of proteins, particularly in the 50 to 75 kDa and 20 to 25 kDa molecular weight ranges. In addition, DBLSC-CO2 was shown to have superior functional properties in terms of total soluble content, water and oil absorption, and foaming and emulsification properties. Therefore, SC-CO2 treatment offers a nutritionally and environmentally friendly approach for the removal of lipid from high protein food sources. In addition, SC-CO2 may be a better substitute of traditional organic solvent extraction for producing more stable and high quality foods with high-protein, fat-free, and low calorie contents.
Livers of skipjack tuna (Katsuwonus pelamis) and yellowfrn tuna (Thunnus albacares) were investigated on the food compositional characteristics and also compared to that of Alaska pollack (Theragra chalcogramma). The proximate compositions of skipjack tuna and yellowfrn tuna livers were high in crude protein, carbohydrate, and crude ash, while were low in crude lipid when compared to that of Alaska pollack liver. The results of heavy metal suggested that tuna livers appeared safe as a food resource. The total amino acid contents of skipjack tuna and yellowfrn tuna livers were 17.7 and 17.1 g/100 g, respectively, and the major amino acids in both livers were aspartic acid, glutamic acid, alanine, valine, leucine, and lysine. Tuna livers were good sources of iron and zinc, while have low lipid content. The extractive nitrogen contents of skipjack tuna and yellowfrn tuna livers were 526.5 and 468.2 mg/100 g, respectively, and their major free amino acids were taurine, glutamic acid, and alanine. From the results of taste value, the major taste active compounds among free amino acids were glutamic acid and aspartic acid.
The subject of this study was the validation of a high-performance liquid chromatography method for the analysis of amino acids in fodder. The contents of amino acids were determined in maize, soybean, soybean meal, as well as in their mixtures enriched with different amounts of methionine, threonine and lysine. The method involved the acid hydrolysis of the sample (6 h at 150 °C), automated derivatisation of the amino acids with the aid of o-phthaldialdehyde and 9-fluorenylmethyl chloroformate reagents, separation on a ZORBAX Eclipse-AAA column and detection using a diode-array detec-tor. The method is characterized by high specificity (the difference between the retention times of the fodder samples and standard mixtures were below 1.7 %), wide linear range (from 10 to 1000 nmol cm -3 , r 2 = 0.9999), high accuracy (recovery 93.3–109.4 %), and the precision of the results (RSD below 4.14 % in the case of repeatability and below 4.57 % in the case of intermediate precision). The limit of detection and the limit of quantification were in the ranges 0.004–1.258 µg cm -3 and 0.011–5.272 µg cm -3 , respectively. The results demonstrated that the procedure could be used as a method for the deter-mination of the composition of primary amino acids of fodder proteins.
a b s t r a c t Cape hake protein powder (HPP) was prepared by alkaline extraction, isoelectric precipitation and freeze drying. It contained 90% protein, 0.53% fat, and 1.44% ash. HPP showed high levels of Na, K, Ca and Mg but lower than in hake mince. The protein profile of HPP was similar to the raw material. The surface hydrophobicity and sulfhydryl group content of HPP were identical to those of the proteins before freeze-drying. The HPP had higher fat absorption capacity, lower emulsifying and foaming capac-ity than soy protein concentrate, pea protein isolate and egg white powder. The gel strength of HPP was medium (44.8 Nxmm) and was increased by addition of transglutaminase. Gels with different HPP concentrations showed a typical pattern of myofibrillar protein networks with a thermo-reversible behavior. The structure of emulsions prepared with HPP showed increasing complex-ity as the protein level increased. An increase in the magnitude of the viscoelastic functions and an incre-ment in the magnitude of the zero shear rate limiting viscosity with increasing HPP content were observed.
In this paper, the effects of limited hydrolysis on functional properties, as well as on protein composition of laboratory-prepared pea protein isolates, were investigated. Pea protein isolates were hydrolyzed for either 15, 30 and 60 min with recombined chymosin (Maxiren). The effect of enzymatic action on solubility, emulsifying and foaming properties at different pH values (3.0; 5.0; 7.0 and 8.0) was monitored. Chymosin can be a very useful agent for improvement of functional properties of isolates. Action of this enzyme caused a low degree of hydrolysis (3.9-4.7%), but improved significantly functional properties of pea protein isolates (PPI), especially at lower pH values (3.0-5.0). At these pH values all hydrolysates had better solubility, emulsifying activity and foaming stability, while longer-treated samples (60 min) formed more stable emulsions at higher pH values (7.0, 8.0) than initial isolates. Also, regardless of pH value, all hydrolysates showed improved foaming ability. A moderate positive correlation between solubility and emulsifying activity index (EAI) (0.74) and negative correlation between solubility and foam stability (-0.60) as well as between foam stability (FS) and EAI (-0.77) were observed. Detected enhancement in functional properties was a result of partial hydrolysis of insoluble protein complexes.
The process-related physicochemical, digestive and rheological properties of protein prepared by subcritical dimethyl ether extraction (SDEE) were comprehensively investigated and compared with those obtained by pH-shift, to study the industrial potential of SDEE. Two different materials from tuna (meat and liver) were studied in parallel, and SDEE had similar effects on the proteins in them.
The protein component was almost unchanged before and after SDEE, while the content of water-soluble protein and alkali-soluble protein was substantially reduced and increased after pH-shift, respectively. We also found that SDEE had superior ability to pH-shift to conserve light metals, remove lipids and heavy metals, and maintain protein structure. Furthermore, SDEE-produced protein powders were easier for humans to digest, and their gelation and emulsification were also superior to those prepared by pH-shift. The aforementioned results suggest that SDEE can remove more impurities, and the obtained protein has outstanding potential in industrial applications.
The subcritical dimethyl ether extraction (SDEE) was applied in the preparation of liver protein powder (LPD) in this paper. As expected, the lipids and water in tuna liver were co-removed by SDEE, and LPD with a high protein content could be obtained. Besides that, the maximal protein content (88.51%) of LPD was obtained by optimized extraction conditions (liquid-solid ratio 34 mL/g, time 70 min and stirring speed 945 rpm).
Furthermore, the traditional preparation technique, pH-shift, was used for comparisons. Compared with pH-shift, the higher quality LPD could by obtain by SDEE with slight fishy and excellent yield, because of SDEE could prevent the loss of nutrition constituents and remove more flavor-active components. Moreover, the functional properties of prepared LPDs were compared with soybean protein powder (SPD) and egg white powder (EWP). The results showed that the LPD prepared by SDEE possessed the greater capacities in foaming, foam stability and fat absorption. Therefore, SDEE, with the advantages of no freeze-drying procedure and relatively low pressure, would be a better alternative to prepare high-quality protein powder in the food industry.
The aim of this study was to assess the effects of power ultrasound-assisted (0, 400, 600, 800 and 1000 W, frequency of 20 kHz) cooking (80, 100, 120 min) on spiced beef. The results showed that power ultrasound could significantly increase the salt content (P < 0.05). For water holding capacity, the ultrasonic treatment could significantly reduce the pressure loss and free water content while improving the immobilised water content (P < 0.05). And ultrasonic treatment improved hardness compared with control (P < 0.05). However, the effects on the springiness, the chewiness and the resilience of the spiced beef were not significant (P > 0.05). As for microstructure, the myofibrils of beef were ruptured by ultrasonic treatment along with the Z-lines leading to the muscle swelling. The results indicated that the application of ultrasound during cooking could effectively promote the penetration of salt, improve the water holding capacity and ameliorate the tenderness of spiced beef.
In this study, the effect of high power ultrasound (US) probe in varying intensities and times (18.4, 29.58, and 73.95 W/cm² for 5, 12.5 and 20 min respectively) on functional properties of millet protein concentrate (MPC) was investigated, and also the structural properties of best modified treatment were evaluated by FTIR, DSC, Zeta potential and SDS-PAGE techniques. The results showed the solubility in all US treated MPC was significantly (p < .05) higher than those of the native MPC. Foaming capacity of native MPC (271.03 ± 4.51 ml) was reduced after US treatments at low intensities (82.37 ± 5.51 ml), but increased upon US treatments at high intensities (749.7 ± 2 ml). In addition, EAI and ES increased after US treatments. One of the best US treatments that can improve the functional properties of MPC was 73.95 W/cm² for 12.5 min that resulted in reduction of molecular weight and increase nearly 36% in the negative surface charge that was confirmed by SDS-page and Zeta potential results, respectively.
The functional properties of pH-shifted protein isolates from bigeye snapper head were evaluated. Alkaline isolate showed a superior salt-solubility and gel forming ability to acid counterpart as indicated by a regular gel structure (i.e. imaged by scanning electron microscope) with higher gel strength and lower expressible drip (p<0.05). Acid isolate exhibited higher surface hydrophobicity (p<0.05) and thereby improved interfacial properties. Emulsifying activity index of acid isolate was lower than commercial whey protein and egg white (p<0.05) but its emulsion stability was better (p<0.05). Both protein isolates had lower foamability than commercial proteins but their foam stability was not different (p>0.05).
The increasing awareness that dried fish protein can be applied for food fortification and production of value added/functional foods has encouraged the food industry to examine different methods for developing fish protein ingredient from different raw materials. Fish protein powder (FPP) is a dried and stable fish product, intended for human consumption, in which the protein is more concentrated than in the original fish flesh. Quality and acceptability of FPP depend on several factors. The fat content of the FPP is a critical issue because when it is oxidized a strong and often rancid flavour is produced. Protein content of FPP depends on the raw materials, amount of additives and moisture content, but it contains at least 65 % proteins. FPP is used in the food industry for developing re-structured and ready-to-eat food products. The FPP maintains its properties for 6 months at 5 °C but loses them rapidly at 30 °C. Deterioration of the FPP during storage is prevented by lowering the moisture content of the product and eliminating of oxygen from the package. The FPP can be applied as a functional ingredient for developing formulated ready-to-eat products. This article reviews methods for extracting fish proteins, drying methods, characteristics and applications of FPP and factors affecting FPP quality.
Minced beef meat was packaged under vacuum, air or oxygen, and pressurized at 10°C for 10 min. L* colour values increased significantly in the range 200–350 MPa, the meat becoming pink, while a* values decreased at 400–500 MPa, the meat becoming grey-brown. Simultaneously, total extractible myoglobin decreased in the range 200–500 MPa, while the proportion of metmyoglobin increased at the expense of oxymyoglobin at 400–500 MPa. Pressurization did not significantly increase the extractibility of heme iron by an acid solution. Packaging of meat under vacuum with an oxygen scavenger partly protected meat colour, since samples processed at 400 MPa became pink, without any change in a* value or metmyoglobin content. Blending chilled minced meat with NaNo2(and NaCl) 18 h before processing at 350–500 MPa afforded a similar protection. Cysteine, ascorbic acid, nicotinamide or nicotinic acid had no protective effects. Meat discoloration through pressure processing may result from (1) a whitening effect in the range 200–350 MPa, due to globin denaturation and/or to heme displacement or release, and (2) oxidation of ferrous myoglobin to ferric metmyoglobin, at or above 400 MPa. Only the latter phenomenon is prevented by total oxygen removal or prior formation of nitrosomyoglobin.
Extraction of rice bran lipids was performed using supercritical carbon dioxide (SC−CO2) and liquid propane. To provide a basis for extraction efficiency, accelerated solvent extraction with hexane was performed
at 100°C and 10.34 MPa. Extraction pressure was varied for propane and SC−CO2 extractions. Also, the role of temperature in SC−CO2 extraction efficiency was investigated at 45,65, and 85°C. For the SC−CO2 experiments, extraction efficiencies were proportional to pressure and inversely proportional to temperature, and the maximal
yield of oil achieved using SC−CO2 was 0.222±0.013 kg of oil extracted per kg of rice bran for conditions of 45°C and 35 MPa. The maximal yield achieved with
propane was 0.224±0.016 kg of oil per kg of rice bran at 0.76 MPa and ambient temperature. The maximum extraction efficiencies
of both SC−CO2 and propane were found to be significantly different from the hexane extraction baseline yield, which was 0.261±0.005 kg
oil extracted per kg of rice bran. A simulated economic analysis was performed on the possibility of using SC−CO2 and propane extraction technologies to remove oil from rice bran generated in Mississippi. Although the economic analysis
was based on the maximal extraction efficiency for each technology, neither process resulted in a positive rate of return
on investment.
The study was undertaken to determine the physico-chemical properties of proteins isolated from mechanically separated turkey meat (MSTM) by a pH-shifting technique. The effect of four pH values (2.5, 3.5, 10.5 and 11.5) was investigated. Protein yield did not show any statistical difference between the extractions carried out at pH 2.5, 10.5 and 11.5. However, yield was considerably lower when pH of extraction was 3.5 (P = 0.0097). Total protein extractability and myofibrillar protein hydrophobicity showed the same pattern, with the highest values at pH 10.5 and the lowest at pH 2.5. No significant (P > 0.05) differences were found between the various pH of extractions on total, neutral and polar lipids, which on average were equal to 92.3%, 93.0% and 90.7%, respectively. TBARs analysis showed no difference between acid and alkaline treatments; however, the values were significantly lower compared to raw MSTM (P < 0.0001). SDS-PAGE analysis showed a greater concentration of myosin heavy chain and actin in protein isolates compared to raw MSTM. Amino acid analysis of isolates showed higher concentration of glutamic acid and reduced levels of histidine and methionine compared to raw MSTM. Uronic acid and hydroxyproline analysis revealed that most of the proteoglycans and collagen were deposited in the sediment fraction obtained during the centrifugation step following protein solubilization.
An experimental design was used to study the effect of various pressure values (50–600 MPa) and holding times (20–300 s) on color and microbiological quality of bovine muscle (Biceps femoris). The experiments were conducted at 10°C. The pressure intensity is more significant than holding time for redness, total color difference and metmyoglobin content. Pressure higher than 300 MPa induces modifications of meat color parameters such a decrease of the total color difference (ΔE), a decrease in the total flora and a 1 week delay before microbial growth (520 MPa, 260 s). During the first 3 days of storage (4°C), the increase in redness is maintained for the 130 MPa samples while the redness of the 520 MPa samples decreases gradually, in relation to the increase of metmyoglobin. The cooking (1 h at 65°C) done after pressurization led to the disappearance of color differences observed between the nontreated and pressurized samples.
Proximate composition and physicochemical properties of a protein concentrate prepared from fenugreek seed were determined. The effects of pH and/or NaCl concentration on these properties were investigated. The protein content of fenugreek was found to be 28.4%. The crude fibre content was 9.3% and crude fat was 7.1%. The minimum protein solubility was observed at pH 4.5, which was 18.5%, while maximum protein solubility was observed at pH 11, which was 91.3%.Measurement of emulsion and foaming properties of fenugreek protein concentrate showed that they were greatly affected by pH levels and salt (NaCl) concentration. The minimum values of both emulsion and foam properties were attained at pH 4.5 which was the isoelectric point of the protein; maximum values were obtained at pH 2 and pH 12. Results showed that fenugreek protein concentrate had high oil absorption capacity (1.56 ml oil/g protein), water absorption capacity (1.68 ml H2O/g protein) and bulk density (0.66 g/ml).
Considerable amounts of fish processing byproducts are discarded each year. By developing enzyme technologies for protein recovery and modification, production of a broad spectrum of food ingredients and industrial products may be possible. Hydrolyzed vegetable and milk proteins are widely used food ingredients. There are few hydrolyzed fish protein foods with the exception of East Asian condiments and sauces. This review describes various manufacturing techniques for fish protein hydrolysates using acid, base, endogenous enzymes, and added bacterial or digestive proteases. The chemical and biochemical characteristics of hydrolyzed fish proteins are discussed. In addition, functional properties of fish protein hydrolysates are described, including solubility, water-holding capacity, emulsification, and foam-forming ability. Possible applications of fish protein hydrolysates in food systems are provided, and comparison with other food protein hydrolysates where pertinent.
Impact of processing technology on macro-and micronutrient profile of protein
- M Abdollahi
- H Wu
- I Undeland
Abdollahi, M., Wu, H. and Undeland, I. (2021). Impact of
processing technology on macro-and micronutrient
profile of protein-enriched products from fish
https://doi.org/10.26656/fr.2017.8(2).465
© 2024 The Authors. Published by Rynnye Lyan Resources
RESEARCH
PAPER
backbones. Foods, 10(5), 950. https://doi.org/10.3390/
foods10050950
Interlaboratory Study Workbook for Blind (Unpaired) Replicates. Ver. 2.1
Association of Official Analytical Chemists (AOAC).
(2013). Interlaboratory Study Workbook for Blind
(Unpaired) Replicates. Ver. 2.1. Rockville, USA:
AOAC.
Separation and quality of fish oil from precooked and non-precooked tuna heads
- S Chantachum
- S Benjakul
- N Sriwirat
Chantachum, S., Benjakul, S. and Sriwirat, N. (2000).
Separation and quality of fish oil from precooked and
non-precooked tuna heads. Food Chemistry, 69(3), 289
-294. https://doi.org/10.1016/S0308-8146(99)00266-6
Physico-chemical characteristics and in vitro gastro-small
- L Kaur
- H Lamsar
- I F López
- M Filippi
- D O S Min
- K Ah-Sing
- J Singh
Kaur, L., Lamsar, H., López, I.F., Filippi, M., Min, D.O.S.,
Ah-Sing, K. and Singh, J. (2021). Physico-chemical
characteristics and in vitro gastro-small. Foods, 10(2),
331. https://doi.org/10.3390/foods10020331
The effect of low-intensity ultrasound treatment on shear properties, color stability and shelf-life of vacuumpackaged beef semitendinosus and biceps femoris muscles
- F W Pohlman
- M E Dikeman
- J F Zayas
Pohlman, F.W., Dikeman, M.E. and Zayas, J.F. (1997). The
effect of low-intensity ultrasound treatment on shear
properties, color stability and shelf-life of vacuumpackaged beef semitendinosus and biceps femoris
muscles. Meat Science, 45(3), 329-337. https://
doi.org/10.1016/S0309-1740(96)00106-4